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1
Halirova, Marcela, Radek Janousek, Hana Sevcikova, Radek Fabian e Eva Machovcakova. "Economic Comparison of Fire Fighting Measures of Gypsum-Based Materials". Applied Mechanics and Materials 835 (maggio 2016): 467–71. http://dx.doi.org/10.4028/www.scientific.net/amm.835.467.
Testo completoAbstract (sommario):
Fire resistance of building structures is important not only in terms of prevention of hazards to human health, but also from the economic point of view. The choice of method of fire protection of steel structures depends on the responsible choice of finish or cladding material and suitable technology implementation. Although the assessment of fire risk is a priority, when selecting the decisive criteria we must not also forget the cost of fire protection measures. This article aims at economic comparison of the two fire protection measures for the steel column of rolled profiles.
2
Garanikov, V. V., e E. O. Kornilev. "RESEARCH OF THE PATTERNS OF DEFORMATION ALONG CURVILINEAR TRAJECTORIES OF CONSTANT CURVATURE WITH A CHANGING PROCESS DIRECTION". Bulletin of the Tver State Technical University. Series «Building. Electrical engineering and chemical technology», n. 3 (2020): 17–24. http://dx.doi.org/10.46573/2658-7459-2020-3-17-24.
Testo completoAbstract (sommario):
Abstract. An experimental study of the vector and scalar properties was carried out when changing the direction of deformation on samples made of 9X2 steel. It is shown that after the exhaustion of a certain interval of the trajectory lengths, scalar and vector properties seem to forget the change in the direction of deformation and correspond to the trajectories without changing the direction.
3
Kozák, Vladislav, e Libor Vlček. "Parameters Identification for GTN Model and Their Verification on 42CrMo4 Steel". Materials Science Forum 482 (aprile 2005): 335–38. http://dx.doi.org/10.4028/www.scientific.net/msf.482.335.
Testo completoAbstract (sommario):
The base of this paper is exact measurement of deformation and fracture material characteristics in laboratory, evaluation of these parameters and their application in models of finite element analysis modelling the fracture behaviour of components with defects. The base of the work is dealing with ductile fracture of forget steel 42CrMo4. R-curve is modelled by 3D FEM using WARP3D and Abaqus. Crack extension is simulated in sense of element extinction algorithms. Determination of micro-mechanical parameters is based on combination of tensile tests and microscopic observation. Input parameters for the next computation and simulation were received on the base of image analysis, namely fN and fo. The possibility of transferring these parameters to another specimen is discussed.
4
Béres, Gábor, e József Danyi. "Experimental Investigation on Forming of Tailor Welded Blanks". Materials Science Forum 885 (febbraio 2017): 147–52. http://dx.doi.org/10.4028/www.scientific.net/msf.885.147.
Testo completoAbstract (sommario):
One of the main aims of automotive developers is vehicle weight reduction. There are many well known ways related to weight reduction, for example using thinner and higher strength sheet materials, or using of formed tubes as load-bearing elements in car body structures. In the field of modern automotive industry we must not forget that the heavy loaded, and in passenger-safety aspect relevant elements frequently consist of tailor welded blanks (TWBs). The components could have different strength or thickness or coatings too. Therefore, certain segments of the welded elements could behave differently during forming. Generally the higher strength coupled with less formability, but in the case of welded blanks, the interaction of each parts are unknown in many aspects.This paper presents the results of the experimental work, carried out to evaluate the drawability of tailor welded blanks. The welded blanks were prepared by laser beam welding technology. The blanks consisted of a well drawing component, marked DC04, and a high strength steel component. The applied high strength steels are DP600, DP800 and DP1000 types. Our current object was to determine some basic parameters of deep-drawability as a typical sheet metal forming operation. It can be stated that as the strength ratio (SR) is increasing between the segments, the limiting drawing ratio is decreasing.
5
Koval, Petro, e Vladimir Zelenovskiy. "INFLUENCE OF CONCRETE COMPOSITION ON THE CORROSIVE STATE OF THE STEEL ARMATURES AND DURABILITY OF REINFORCED CONCRETE STRUCTURES". Avtoshliakhovyk Ukrayiny, n. 1 (257)’ 2019 (29 marzo 2019): 33–39. http://dx.doi.org/10.33868/0365-8392-2019-1-257-33-39.
Testo completoAbstract (sommario):
The influence of the composition of the concrete mixture on the state of reinforcing steel as the main problem of corrosion of reinforced concrete structures is considered. The main attention is paid to the need for individual and mandatory consideration of the influence of the properties of additives to concrete on the passivation of reinforcing steel. The purpose of conducting studies to determine the effect of concrete composition on the state of reinforcing steel is to analyze the causes of corrosion of reinforcement, determine the influence of the environment, apply appropriate prevention of this phenomenon and use methods to determine the corrosion state at the design stage of building structures for which reinforced concrete is used. The composition of concrete, in addition to the standard set in various quantitative combinations (cement, gravel, sand, water) today it is advisable to use special additives. Due to their correct and proportional application, you can create a mixture with significantly improved characteristics: with increased frost resistance, strength, durability, with accelerated or delayed setting of the mixture, etc. Nevertheless, you should not forget that the individuality of the composition of additives could affect the ability of concrete to passivate reinforcing steel. It is possible to eliminate the possibility of reducing the passivation of concrete by testing reinforced concrete samples for its protective properties in relation to the reinforcement. The test method is based on the passivation of reinforcing steel in an alkaline environment and consists in evaluating the protective effect of a sample of concrete in relation to a sample of steel reinforcement by comparing data obtained with a change in potential depending on changes in the density of electric current passing through the sample. The issue of quality and durability of reinforced concrete structures, both technically and economically, is attracting increasing attention of builders. It is obvious that in most cases an increase in the initial cost of manufacturing the structure and its reliable protection is economically justified, if this allows reducing the number and cost of repairs during operation. Keywords: reinforcement, corrosion, concrete, reinforced concrete, concrete additive, concrete composition, corrosion state of reinforcement, durability of reinforced concrete structures.
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Masoud, M. I., M. Tashkandi, J. Al-Jarrah e A. I. Z. Farahat. "Behavior of triplex steel containing different aluminum content". Advances in Materials Science 17, n. 1 (1 marzo 2017): 34–43. http://dx.doi.org/10.1515/adms-2017-0003.
Testo completoAbstract (sommario):
Abstract Medium-carbon alloy steels containing different aluminum contents were hot forged by 95% reduction at 1200°C followed by air cooling. Optical and scanning electron microscopes were used to investigate the morphologies of the different phases present. An austentizing process followed by water quenching (after hot forging) was carried out to obtain different hardness values. The intensity of the different planes was investigated using X-ray diffraction. The mechanical properties were characterized using tensile and hardness tests. Optical and scanning electron micrographs revealed a great effect of aluminum content on the steel properties. A matrix of bainite and pearlite and traces of ferrite was revealed for hot forged steel type 1 containing 1% Al. Steel type 2 containing 2% Al showed a matrix of pearlite and ferrite with the absence of bainite. The hardness increased with increasing the temperature to a maximum value then decreased for steel containing 1 and 2% aluminum. After austentizing at 925°C, the maximum hardness of 649Hv was recorded for hot forged steel type 2 of 2% aluminum, while steel type 1 of 1% aluminum showed a maximum hardness of 531Hv after austentizing at 1000°C. Thus, the maximum hardness of hot forged steels decreased with increasing aluminum content. In addition, the maximum tensile and yield strength were decreased by increasing the aluminum content in the steel. The changes in microstructure and mechanical properties of these steels could be explained by the effect of aluminum as a ferrite forming element.
7
Egashira, Makoto, Shigefumi Nishitani, M. Yuya e N. Sano. "Effect of Prior Heat Treatment on Hardness Profile after Nitrocarburization in Medium Carbon Steel". Materials Science Forum 638-642 (gennaio 2010): 3200–3205. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3200.
Testo completoAbstract (sommario):
Gaseous ferritic nitrocarburization is one of the major surface hardening methods to improve the fatigue strength of machinery parts made of medium carbon steels. The fatigue strength of nitrocarburized steel parts depends on the hardness profile below the surface; however, the mechanism of its evolution during nitrocarburization has not been fully understood. Recently, as-forged steels, in which thermal refining process like normalizing is omitted from the viewpoints of environmental considerations, energy savings and manufacturing cost reductions, have been widely used in the machinery parts industry. Therefore, it is important to understand the mechanism of hardness increase below the surface of the nitrocarburized steels with respect to the effect of prior refining heat treatment. In the present study, the hardness increase at the subsurface region of nitrocarburized steels containing 0.4mass%C was characterized, and the influence of prior normalizing treatment was investigated. Microstructure of both the as-forged and the normalized specimens was the ferrite/perlite mixture, while the ferrite volume fraction in the as-forged steel was smaller than the latter. These as-forged and normalized steels were gaseous nitrocarburized at 853K for 2 hours under the atmosphere of RX gas and NH3 gas mixture, and then they were oil-quenched to 373K. Overall hardness below the surface after nitrocarburization was higher for the specimen without prior normalizing treatment, although both specimens had the similar nitrogen concentration profiles and precipitation behaviors of the nitrides. However, it was found that the individual ferrite grains in the as-forged steel were more hardened than those in the normalized steel. These indicate that the most likely cause of the hardness increase near the surface after nitrocarburization is the solid solution hardening by dissolved nitrogen and that the ferrite grains of the as-forged steel were likely to soak up more nitrogen and were hardened to the higher degree since the similar amount of nitrogen were incorporated mainly within ferrite grains. Thus, the prior heat treatment strongly affects the amount of hardening through the ferrite fraction.
8
Olives, Régis, Enrique Ribeiro e Xavier Py. "Materials for the energy transition: Importance of recycling". MATEC Web of Conferences 379 (2023): 07002. http://dx.doi.org/10.1051/matecconf/202337907002.
Testo completoAbstract (sommario):
The energy transition aims, among other things, to reduce the impacts on climate change, and in particular the CO2 emissions linked to the very high consumption of fossil fuels (coal, oil, gas). The solution lies firstly in energy sobriety, secondly in improving efficiency and finally, in the development of carbon-free energies with, in particular, renewable energies (EnR). On this last point, the deployment of renewable energy processes requires the mobilization of materials in relatively large quantities due to the low concentration of the energy resource (Vidal, 2018). We highlight here the quantities of materials necessary for the implementation of the various energy production systems by focusing on the main materials which are concrete, steel, copper, aluminum, glass and polymers. We will only discuss these materials here. However, we must not forget the so-called critical materials which are also used, albeit in smaller quantities, but which can pose a problem in terms of resources due to their scarcity (IEA 2021). Attention is paid to the recycling of materials which significantly changes the point of view. It is shown the interest of, of course, maximizing this recycling.
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Herbirowo, Satrio, Luqmanul Hakim e Bintang Adjiantoro. "Microstructure and mechanical characteristics of hot forged lateritic steels". MATEC Web of Conferences 204 (2018): 05007. http://dx.doi.org/10.1051/matecconf/201820405007.
Testo completoAbstract (sommario):
The current development of steel industry has constraints on the availability of raw materials, so we have developed local raw materials that are lateritic steels as a high potential for alternative manufacturing of steel. This research was conducted to understand the characteristics of lateritic steel through hot forging process by the mechanical and microstructure behaviour. The research methodology was chained by variety of preheating temperature of 800; 1000; 1200 °C and forging force from 0 until 1000 kilonewton. In case of hot forging values was obtained the impact and hardness properties also microstructure that compared with as-cast steels. The results of impact strength increased by 81.83% at the temperature of 1200 °C and the hardness increased by 4.99% at 1000 °C, for the microstructure analysis was produced the ferrite and pearlite phases with the fine grains. The chemical composition of steel is classified in low carbon steel included in lateritic steel it contains low alloy 1.78 Ni and 0.553 Cr %wt.
10
Ahmed, A., S. N. Ghali, M. Eissa e S. A. El Badry. "Influence of Partial Replacement of Nickel by Nitrogen on Microstructure and Mechanical Properties of Austenitic Stainless Steel". Journal of Metallurgy 2011 (16 novembre 2011): 1–6. http://dx.doi.org/10.1155/2011/639283.
Testo completoAbstract (sommario):
A new modified austenitic stainless steel has been developed through partial replacement of nickel by nitrogen. Nitrogen stainless steel was produced in 10 kg induction furnace under nitrogen pressure, while reference one, AISI 316 steel grade, was produced in open-induction furnace. Both were cast and hot forged, and the total nitrogen was determined. Furthermore, the produced forged steels were subjected to solution treatment at different temperatures. The microstructure of produced stainless steels was observed. The X-ray diffractmeter and Mossbauer effect spectroscopy were used to follow the phase change in reference and modified steels after different heat treatment temperatures. The influence of grain-size, soluble, and insoluble nitrogen on tensile strength and hardness was investigated. The major phase in the modified steel has a fcc structure similar to the reference one, but with finer grains and more expanded lattice. The yield strength and hardness of the nitrogen-modified stainless steel are higher than the reference steel. On the other hand, the increase of nitrogen content deteriorates the steel ductility.
11
Plumtree, Alan, e M. M. Mirzazadeh. "Fully Reversed Uniaxial Tension-Compression High Cycle Fatigue Behaviour of Shot-Peened Steels". Key Engineering Materials 488-489 (settembre 2011): 21–24. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.21.
Testo completoAbstract (sommario):
The effect of shot-peening on the uniaxial fatigue behaviour of four engineering steels, heat treated to a similar final hardness was investigated. Forged 0.39%C and 0.72%C steels, a quenched and tempered 0.51%C steel and a 0.50%C powder forged (PF) steel were fatigue tested under fully reversed (R=-1) push-pull loading conditions. Following long life (107) cycling, shot-peening had little effect on the fatigue limit of the 0.39%C and 0.72%C steels whereas the fatigue limit of the PF steel increased 10.4%. Conversely, the fatigue limit of the quenched and tempered steel decreased 12.0% after shot-peening. The results showed that the beneficial effects of shot-peening, such as compressive residual stresses and work hardening, balanced the effects of surface roughness since crack initiation tended to occur below the surface. Microhardness profiles showed that the greatest amount of cyclic softening in the shot-peened regions occurred in the hot rolled steels. Softening was accompanied by a decrease in the depth of surface hardness.
12
Sydorchuk, O. M., L. A. Myroniuk, D. V. Myroniuk, K. O. Gogaev e O. K. Radchenko. "Increased stability die forged steel 4H4N5M4". Metaloznavstvo ta obrobka metalìv 96, n. 4 (1 dicembre 2020): 30–38. http://dx.doi.org/10.15407/mom2020.04.030.
Testo completoAbstract (sommario):
The results of researches on steel 4H4N5M4F2 modes thermo-deformation processing optimization are given. It is established that incomplete annealing (750 °С ± 20 °С in comparison with full annealing 860 °С) in cast and forged condition promotes to improve the machining of blanks for the manufacture of matrices. It is shown that the use of incomplete annealing, namely partial recrystallization promotes the formation of spheroidized rather than lamellar carbide phase, which leads to a decrease in the characteristics: strength threshold, yield strength, hardness 900 MPa, 800 MPa, 32 33 HRC in the cast state and 1200 MPa, 1050 MPa, 38 39 HRC in forged condition, respectively. This increases the fracture toughness: 180 J/cm2 in the cast state and 130 J/cm2 in the forged state. The optimized mode of forging at the temperature of 1170 ± 20 °С and heat treatment (hardening at 1100 ± 5 °С and tempering at 595 ± 5 °С) of steel 4H4N5M4F2 allowed to increase impact strength five times in comparison with cast experimental steel, and also to increase strength threshold of 100 MPa. Forged steel 4H4N5M4F2 has slightly lower heat resistance compared to cast, which hardens at temperatures above 630 °C during operation of the die steel tool. After operation of the extruder wheels made of investigated forged steel and forged steel 4H5MF1S, which was used at the enterprise in copper processing, the properties of both steels were determined. The investigated forged steel 4H4N5M4F2 is characterized by an increase in the strength threshold by 200 MPa and hardness by 6 HRC. After operation (production of 60 tons of copper products of M1 grade) the tool (wheel extruder) from H13 steel (analog 4H5MF1S) had micro and macrocracks on the side and inner parts, and in the investigated steel 4H4N5M4F2 such defects were absent. Thus, the studied steel is characterized by increased stability. Keywords: steel, heat treatment, forging, structure, physical and mechanical properties.
13
Mengaroni, Sabrina, Paolo Emilio di Nunzio, Stefano Neri, Massimo Calderini, Claudio Braccesi, Filippo Cianetti e Andrea di Schino. "Boron Effect on Hardenability of High Thickness Forged Steel Materials". Materials Science Forum 879 (novembre 2016): 1282–87. http://dx.doi.org/10.4028/www.scientific.net/msf.879.1282.
Testo completoAbstract (sommario):
To fulfill the industrial demand of forged steels with high mechanical and microstructural requirements coupled with reduced cost, the possibility to decrease the content of Mo and other elements has been evaluated. In order to do that, the effect of boron addition (up to 30 ppm) on the steel hardenability has been investigated on two steels with different chemical composition at laboratory scale. In particular, the steel chemical composition has been designed in order to make effective the B addition in terms of hardenability. Two 80 kg ingots cast by a vacuum induction melting plant have been hot rolled by a pilot mill. The effect of B addition on hardenability has been evaluated and compared to that of steel for same application but without B. Results show an improvement of hardenability if 30 ppm B are added even if a Mo reduction is performed.
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Yang, L., e A. Fatemi. "Impact Resistance and Fracture Toughness of Vanadium-Based Microalloyed Forging Steel in the As-Forged and Q&T Conditions". Journal of Engineering Materials and Technology 118, n. 1 (1 gennaio 1996): 71–79. http://dx.doi.org/10.1115/1.2805936.
Testo completoAbstract (sommario):
Microalloyed (MA) steels are a family of steels which are becoming an increasingly important economic alternative to the traditional quenched and tempered (Q&T) steels. Impact resistance and fracture toughness of vanadium-based MA forging steel, which is the most commonly produced MA steel, are investigated in this study. To compare the behavior with the Q&T steel, both the as-forged and the Q&T conditions are evaluated. Experimental results from Charpy V-notch impact and fracture toughness (KR-curve and JIC) tests are presented and discussed. Correlations between fracture resistance properties based on several proposed equations in the literature are also examined.
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Sydorchuk, O. M. "Steel with control austenitic transformation during operation". Metaloznavstvo ta obrobka metalìv 98, n. 2 (7 giugno 2021): 47–53. http://dx.doi.org/10.15407/mom2021.02.047.
Testo completoAbstract (sommario):
The intermediate class of steels, which at room temperature belong to the ferritic state, and at operating temperature pass into the austenitic region, are called steels with control of austenitic transformation during operation. The possibility of increasing the service life of such intermediate steels at high temperatures (above the critical point A3) is shown. For the first time, the cast structure and phase-structural state of steel (grade 4Kh3N5М3F) obtained by electroslag remelting were studied. An improved composition of steel (4Kh4N5М3F) for the production of stamping tools for hot pressing of copper, copper and aluminum alloys is proposed. When setting the critical points (A1 and A3) of the investigated steel, which was confirmed by the results of high-temperature X-ray phase analysis, it was possible to optimize the heat treatment (annealing) of steel 4Kh3N5M3F and 4Kh4N5M4F2 in cast and forged condition, which facilitated processing tool. The results of researches on optimization of modes of heat treatment (hardening, tempering) of steel are given. The mechanical properties (strength, toughness, heat resistance) of steel in cast and forged state depending on the tempering and tempering temperature are determined. The tempering brittleness of the experimental steel is determined. An experimental-industrial test of a stamping tool (die dies, extruder parts) made of the investigated steel was carried out. The possibility of using stamped steel with adjustable austenitic transformation for a wide range of operating temperatures of hot deformation of aluminum alloy AK7h (450-500 ºC), copper M1 (600-630 ºC) and copper-nickel alloy MNZh 5-1 (900-950 ºC) with increased service life in comparison with steels of ferrite class 4Kh5МF1S and 3Kh3М3F. Keywords: die steel, composition, thermal treatment, structure, mechanical properties.
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Černý, Michal, Josef Filípek, Pavel Mazal e Petr Dostál. "Basic mechanical properties of layered steels". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, n. 1 (2013): 25–38. http://dx.doi.org/10.11118/actaun201361010025.
Testo completoAbstract (sommario):
This article deals with identifying attributes of layered steel materials (damask steel) with the help of mechanical tests. Experimentally verify basic mechanical properties of layered steel and subsequently assessed it in comparison with the values obtained for the classic steel materials. In conclusion, there are listed the possibilities of using multilayer steel materials in technical practice, depending on the economics of production.The damask steel was prepared by forge welding from a packet consisting of 17 layers (9 layers of tool steel 19 133 (ČSN) with the thickness of 6 mm and 8 layers 80NiCr11 steel in the form of saw bands with the thickness of 1.2 mm. The packet was cut into 8 parts, folded 3 times and forged together, which provided damask steel with 136 layers. The resulting steel bars were used to make semi-finished products with the approximate dimensions of the test specimens. For evaluation of mechanical properties were applied the following tests: tensile test, Charpy impact test, hardness and microhardness measurementsThe results of tests proved that the properties of damask steel are dependent not only on the direction led impact quality forge weld layers and content iof nhomogeneities in the place of discord, but also on the quenching and tempering temperature, resp. on the choice of quenching bath, which determine the final structure of steel and the resulting hardness, respectively microhardness.
17
Gramlich, Alexander, Robert Lange, Udo Zitz e Klaus Büßenschütt. "Air-Hardening Die-Forged Con-Rods—Achievable Mechanical Properties of Bainitic and Martensitic Concepts". Metals 12, n. 1 (4 gennaio 2022): 97. http://dx.doi.org/10.3390/met12010097.
Testo completoAbstract (sommario):
Three air-hardening forging steels are presented, concerning their microstructure and their mechanical properties. The materials have been produced industrially and achieve either bainitic or martensitic microstructures by air-cooling directly from the forging heat. The bainitic steels are rather conservative steel concepts with an overall alloy concentration of approximately 3 wt.%, while the martensitic concept is alloyed with 4 wt.% manganese (and additional elements), and therefore belongs to the recently developed steel class of medium manganese steels. The presented materials achieve high strengths (YS: 720 MPa to 850 MPa, UTS: 1055 MPa to 1350 MPa), good elongations (Au: 4.0% to 5.9%, At: 12.3% to 14.9%), and impact toughnesses (up to 37 J) in the air-hardened condition. It is shown that air-hardened steels achieve properties close to standard Q + T steels, while being produced with a significantly reduced heat treatment.
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Strobl, Susanne, Roland Haubner e Wolfgang Scheiblechner. "New Steel Combinations Produced by the Damascus Technique". Advanced Engineering Forum 27 (aprile 2018): 14–21. http://dx.doi.org/10.4028/www.scientific.net/aef.27.14.
Testo completoAbstract (sommario):
Multilayered forged steel plates, which combine the properties of diverse steel qualities, are referred to as Damascus steels. Since the 3rd century AD blades and weapons have been produced by the Damascus technique in Europe. In this work four different steel combinations were investigated. Combining Fe with carbon steel C60 resulted in a ferritic-pearlitic microstructure. By forging two heat-treatable steels C40 and C60 martensite with an inhomogeneous carbon distribution was formed. Combining Fe with an austenitic stainless steel showed ferrite and austenite with grain boundary carbides and segregation bands. The last combination of two cold working steels K110 and K600 led to a complex microstructure with martensite, retained austenite and two special types of carbides. After metallographic preparation and using of different etchants the various microstructures were characterized by light optical microscopy and confirmed by Vicker ́s microhardness measurements. Of high interest are the interfaces and the quality of the weld between the individual steel layers. In some regions oxidation and carbon diffusion were observed.
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Chen, Xuewen, Lele Guo, Bo Zhang e Rongren Bai. "An Enhanced Lemaitre Model and Fracture Map for Cr5 Alloy Steel during High-Temperature Forming Process". Materials 15, n. 11 (31 maggio 2022): 3935. http://dx.doi.org/10.3390/ma15113935.
Testo completoAbstract (sommario):
To effectively control and predict crack defects in the high-temperature forming process of Cr5 alloy steel, based on the traditional Lemaitre damage model, a new high-temperature damage model of Cr5 alloy steel was proposed which considered the change of material elastic modulus with temperature, the influence of material hydrostatic pressure as well as temperature and strain rate on material damage. Because Cr5 alloy steels are usually forged at high temperatures, tensile testing is an important method to study the damage behaviour of materials. Through the high-temperature tensile test and elastic modulus measurement test of the Cr5 alloy steel, the stress–strain curves and the relationship curves of the elastic modulus value with the temperature of Cr5 alloy steel under different temperatures and strain rates were obtained. A new high-temperature damage model of Cr5 alloy steel was built by introducing the Zener–Hollomon coefficient considering the influence of temperature and strain rate. The established high-temperature damage model was embedded in Forge® finite element software through the program’s secondary development method to numerically simulate the experimental process of Cr5 alloy steel. Comparing the difference between the displacement–load curves of the numerical simulation and the actual test of the tensile process of the experimental samples, the correlation coefficient R2 is 0.987 and the difference between the experimental value and the simulated value of the tensile sample elongation at break is 1.28%. The accuracy of the high-temperature damage model of Cr5 alloy steel established in this paper was verified. Finally, the high-temperature damage map of Cr5 alloy steel was constructed to analyse the variation law of various damage parameters with the temperature and strain rate of the high-temperature damage model of Cr5 alloy steel.
20
Ryabov, A. V., Aleksandr A. Dyakonov e M. G. Vakhitov. "A New Free-Machining Steel Containing Bismuth and Calcium". Materials Science Forum 857 (maggio 2016): 251–55. http://dx.doi.org/10.4028/www.scientific.net/msf.857.251.
Testo completoAbstract (sommario):
The paper presents a new environmentally friendly lead-free free-machining structural steel AVTs19KhGN containing bismuth and calcium. The following quality characteristics of the new steel (in as-cast and forged condition) are determined: mechanical properties; austenite grain size; amount of non-metallic inclusions; surface quality. In forged rods (square 20 mm) a tendency towards an increase of bismuth content is observed from bottom to top of the ingot. Calcium distribution along the billet is uniform. Surface quality of billets in heats following the test heats is comparable to that of analog steels. Austenite grain size does not exceed ASTM number 6. Austenite grain is refined with increasing bismuth content. Mechanical properties are at the same level as for the steel without bismuth and calcium.
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Strobl, Susanne, e Roland Haubner. "Characterisation of a San Mai Steel Composite for the Manufacture of Knives". Materials Science Forum 1082 (31 marzo 2023): 183–88. http://dx.doi.org/10.4028/p-5jp4r1.
Testo completoAbstract (sommario):
The term San Mai is used for the manufacture of knife blades consisting of three layered steel composites. The middle layer, which forms the cutting edge, consists of hard steel and on the outside a soft stainless steel is forged. Mr. Benjamin Kamon, an Austrian blacksmith, provided the examined sample. Three different steels and a thin Ni layer are symmetrically connected (1.4301/1.3520/Ni/1.2519/Ni/1.3520/1.4301). The middle layer is a cold work steel (1.2519) and the Ni layer is to prevent diffusion processes. 1.3520 is a heat treatable steel for rolling bearings, followed by an austenitic stainless steel (1.4301). Metallography and SEM-EDX were used to study the microstructure, the interfaces between the different steels as well as diffusion zones. It can be stated that all layers are well connected and no defects are evident.
22
Raj, A., B. Goswami, S. B. Kumar e A. K. Ray. "Forge and Heat-treatments in Microalloyed Steels – A Review". High Temperature Materials and Processes 32, n. 6 (1 dicembre 2013): 517–31. http://dx.doi.org/10.1515/htmp-2012-0178.
Testo completoAbstract (sommario):
AbstractImproved designs, mostly for lightweight component manufacturer, have been made for improvement of forging and heat-treatment techniques. Low temperature precipitation strengthening and resistance to austenite grain size coarsening at reheat temperature for forging have been property improvement technique in these microalloyed steels. Studies of peak strain and flow stress at 1123–1423 K have shown increase in peak strain, peak stress and increment in mean flow stress in austenite phases in presence of vanadium. Partial vanadium alloying (1 part V substitute for 2 parts Mo) by substituting molybdenum has improved hardenability properties of conventional steels. Ultrafine grained steels have shown strain hardening effects from severe deformation by equal channel angular pressing (ECAP) followed by annealing. The strain induced precipitation of nano-metric sizes have pinned dislocations for strain hardening. Estimation of remaining life for reactor components have been done by simulated experiments under similar conditions as the service exposure. Vanadium in ferritic stainless steel has shown competitive performance, e.g. chloride environment. This has shown equivalent effects like nickel. In welding of microalloyed steel inter-critical grain coarsened heat affected zone (IC GC HAZ) has martensite austenite (M-A) blisters to yield poorest toughness.
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Kulkarni, Vinay R., Jagannath Nayak e Vikram V. Dabhade. "Effect of chromium addition on properties of sinter-forged Fe–Cu–C alloy steel". International Journal of Modern Physics B 32, n. 19 (18 luglio 2018): 1840040. http://dx.doi.org/10.1142/s0217979218400404.
Testo completoAbstract (sommario):
The present work deals with sinter-forged powder metallurgical (P/M) steels alloyed with chromium by addition of ferrochrome powder, which allows a close control over the chromium contents of alloy steels. Chromium contents can be varied by adjusting appropriately weighed ferrochrome powder in the P/M mixtures. Fe–Cu (2%) and C (0.7%) is the base composition for this P/M alloy steel. Study with the addition of 0.5% and 3% chromium by weight in the form of ferrochrome powder is carried out. The P/M alloy steel of base composition with no chromium content is also prepared for comparative study. The paper deals with these three alloy steels formed by the sinter-forging technique of powder metallurgy. The results of hardness and wear in hardened and tempered condition are reported in the present work.
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Kaltzakorta, Idurre, Teresa Gutierrez, Roberto Elvira, Teresa Guraya e Pello Jimbert. "Low Density Steels for Forging". Materials Science Forum 941 (dicembre 2018): 287–91. http://dx.doi.org/10.4028/www.scientific.net/msf.941.287.
Testo completoAbstract (sommario):
In the last years numerous works have been done to try to reduce car weight in order to decrease CO2 emissions. In this line, Low Density Steels can be considered as one alternative in the lightweight approximation strategy [1-2] for the automotive industry. Generally, in low density steels, a considerable amount of Aluminum is added in order to reduce the overall steel density, but high Aluminum contents lead to processing drawback, that make it difficult to bring these new/lighter steel grades into the market. In the literature, different low density steel grades can be found but most of them are aimed at structural parts of the car, whereas almost none of them is aimed at forged components. In this research, different compositions of the three families of low density steels (ferritic, duplex and austenitic) were fabricated at low scale in order to try to understand the phenomena taking place in these steels, and try to find the best candidate for getting a low density steel suitable for forging in the upcoming research.
25
BEHRENS, BERND-ARNO, MARCUS BISTRON, ARMIN KUEPER e KAI MOEHWALD. "INVESTIGATION OF LOAD ADAPTED GEARS AND SHAFTS MANUFACTURED BY COMPOUND-FORGING". Journal of Advanced Manufacturing Systems 07, n. 01 (giugno 2008): 175–82. http://dx.doi.org/10.1142/s0219686708001292.
Testo completoAbstract (sommario):
The demand for economic processes concerning manufacturing technology, cycle time and material properties has led to the development of near net-shape techniques. Precision forging is a well-known manufacturing technology to achieve high output rates. An approach of optimization concerning the part material to produce load-adapted material properties is the so-called compound-forging. Therefore, two different alloys are forge-welded together. Non-tempering and tempering steels are used to compound-forge gears with a hard and wear-resistant surface layer as well as a ductile bulk material. Compound-forging was developed to forge spur gears and shall now be introduced to manufacture helical gears and shafts. For the production of gears and shafts billets made from non-tempering steels are forge-welded together with billets consisting of tempering steels by precision forging as well as indirect impact extrusion. In this paper, the comparison of the material properties of compound-forged gear wheels and shafts with a hard and wear resistant surface layer and a ductile bulk material is given. Mechanical properties as well as the micro-structure of the parts were investigated. The results of the investigations show a load-adapted material distribution of forge-welded materials for the production of gears and shafts.
26
Sugimoto, Koh-ichi, Sho-hei Sato, Junya Kobayashi e Ashok Kumar Srivastava. "Effects of Cr and Mo on Mechanical Properties of Hot-Forged Medium Carbon TRIP-Aided Bainitic Ferrite Steels". Metals 9, n. 10 (30 settembre 2019): 1066. http://dx.doi.org/10.3390/met9101066.
Testo completoAbstract (sommario):
In this study, the effects of Cr and Mo additions on mechanical properties of hot-forged medium carbon TRIP-aided bainitic ferrite (TBF) steel were investigated. If 0.5%Cr was added to the base steel with a chemical composition of 0.4%C, 1.5%Si, 1.5%Mn, 0.5%Al, and 0.05%Nb in mass%, the developed steel achieved the best combination of strength and total elongation. The best combination of strength and impact toughness was attained by multiple additions of 0.5%Cr and 0.2%Mo to the base steel. The excellent combination of strength and impact toughness substantially exceeded those of quenched and tempered JIS-SCM420 and 440 steels, although it was as high as those of 0.2%C TBF steels with 1.0%Cr and 0.2%Mo. The good impact toughness was mainly caused by uniform fine bainitic ferrite matrix structure and a large amount of metastable retained austenite.
27
Saidi, M. Tadayon, N. Baghersaie e N. Varahram. "Effect of Heat Treatment on the Thermal Expansion Coefficient of Austempered Ductile Iron". Materials Science Forum 475-479 (gennaio 2005): 203–12. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.203.
Testo completoAbstract (sommario):
Austempered ductile iron provide a unique combination of strength and toughness coupled with excellent design flexibility for automotive application as compared to forged or cast steels. Some material properties such as thermal expansion coefficient and its influence in final machining tolerance is a matter of discussion in the automotive industry. In this study the effect of heat treatment cycle on the microstructure & thermal expansion of ADI was investigated. Samples were austempered at 275 º C and 375 º C for one hour and then dilatometric test carried out in the temperature range of 50 °C to 350 °C, then the result was compared with the thermal expansion coefficient of forged steel. Microstructure and mechanical investigations were used to the assurance of these results. The results indicate that replacing of forged steel with ADI due to lower cost production and reduction in weight is possible if the correct tolerance were selected.
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Larson, Ellen. "“Blast Off!”: The Afterlives of Nostalgia in Su Yu Hsin’s Blast Furnace No. 2". Arts 12, n. 5 (6 settembre 2023): 191. http://dx.doi.org/10.3390/arts12050191.
Testo completoAbstract (sommario):
In her 2022 video installation, Blast Furnace No. 2, artist Su Yu Hsin explores the history of the German factory, Henrichshütte Ironworks. Namely, the artist focuses on Henrichshütte’s former blast furnace, which was bought by a Chinese steel mill in September 1989 and moved to China, where it operated until 2015. Now a state-owned museum, this former factory, located in Hattingen, Germany, is a snapshot of the past—a memorial of sorts for the region’s bygone industrial prosperity. The history and intercontinental movement of this blast furnace inspires Su’s affinities towards spaces located in-between shifting temporalities, identities, and changing environmental conditions within Hattingen and beyond. Su weaves archival materials, documentary film, and interview excerpts into a speculative narrative that connects the years 1989, 2022, and 2050. Blurring reality and imagination, the video follows the fictionalized trail of Lin, a Chinese translator who accompanied the dismantling of the blast furnace over thirty years ago. According to the narrative, Lin left behind an unfinished science fiction novel, which takes place in 2022. In Lin’s novel, the protagonist develops a utopian machine in the form of a blast furnace. With this apparatus, she sends herself into space with the goal of finding an alternative energy source to replace coal. Blast Furnace No. 2 constellates temporal spaces of socio-political and environmental nostalgia, predicated upon both remembered and imagined understandings of the past, present, and future. The work emphasizes contradictory gaps in between socially driven ideological systems and their afterlives, determined to memorialize what most would just as soon forget.
29
Kurka, Vladislav, Zdeněk Kuboň, Ladislav Kander, Petr Jonšta e Ondřej Kotásek. "The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability". Metals 12, n. 2 (9 febbraio 2022): 301. http://dx.doi.org/10.3390/met12020301.
Testo completoAbstract (sommario):
The aim of this work is to compare the technological and material properties of CMnCr steels without bismuth, with 0.08 wt. % Bi and 0.12 wt. % Bi. Experimental heats showed that the most advantageous alloying of Bi into the heat was in the ladle, with an efficiency of about 20%. The optimal temperature range for forming steel was found to be 1160–1050 °C. With increasing Bi content, the formability of steels and plastic properties decreased, while the yield stress and tensile strength increased. Manganese sulfides, aluminum oxides, or oxysulfides, which were segregated both individually and in clusters, were found in the matrix of all tested steels. In steels with Bi, the Bi particles segregate the separately in the form of globules, either as envelopes of elongated MnS or Al2O3 particles segregated in rows. Sulfur dot-shaped segregations in the steel with 0.12 wt. % of Bi and the steel without Bi were essentially uniform over the whole area. For the steel with 0.08 wt. % of Bi, both dot-like and ray-ordered sulfur segregations were observed. The microstructure of all tested steels was ferritic–pearlitic with islands of bainite. Towards the center of the forged bars, variable shape and size of bainite blocks were observed. Machinability tests evaluated by the extend of tool wear showed that the most advantageous was CMnCr steel alloyed with 0.08 wt. % Bi.
30
Burja, Jaka, Barbara Šetina Batič e Tilen Balaško. "Kappa Carbide Precipitation in Duplex Fe-Al-Mn-Ni-C Low-Density Steel". Crystals 11, n. 10 (18 ottobre 2021): 1261. http://dx.doi.org/10.3390/cryst11101261.
Testo completoAbstract (sommario):
The microstructural evolution of a Fe-Mn-Al-Ni-C low-density steel was studied. The lightweight low-density steels are a promising material for the transportation industry, due to their good mechanical properties and low density. The base microstructure of the investigated steel consists of ferrite and austenite. Thermo-Calc calculations showed the formation of an ordered BCC (body-centred cubic) B2 phase below 1181 °C and kappa carbides below 864 °C. The steel was produced in a vacuum induction furnace, cast into ingots and hot forged into bars. The forged bars were solution annealed and then isothermally annealed at 350, 450, 550, 650, 750, and 850 °C. The microstructure of the as-cast state, the hot forged state, solution annealed, and isothermally annealed were investigated by optical microscopy and scanning electron microscopy. The results showed the formation of kappa carbides and the ordered B2 phase. The kappa carbides appeared in the as-cast sample and at the grain boundaries of the isothermally annealed samples. At 550 °C, the kappa carbides began to form in the austenite phase and coarsened with increasing temperature.
31
Ryabov, A. V. "Mastering of production of lead-free ecologically clean free-machining steels". Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 75, n. 3 (27 giugno 2019): 337–43. http://dx.doi.org/10.32339/0135-5910-2019-3-337-343.
Testo completoAbstract (sommario):
Both in the domestic and world steel industry alternative ecologically clean free-cutting steels, having cutting machinability characteristics and mechanicalproperties, comparable with lead-containing steels, but voided of their drawbacks,are actively searched. First ofall the alternative steels should not be not so ecologically harmful. Scientific and technological aspects of lead-free free-machining steels production, alloyed by bismuth, calcium, tin, boron and nitrogen presented. Solubility of bismuth in iron and iron alloys with chromium, manganese, nickel, tungsten, vanadium, cobalt,phosphor, sulphur, aluminum, carbon and other elements at the temperature of 1550–1650 ºСdetermined. Parameters of interaction of the first and second order calculated. Study of bismuth behavior and tin spherical samples in 40X steel melt accomplished. The study done at the high temperature facility with controlled atmosphere and X-ray TV observation system. Simulation of phase compositions multicomponent alloys of steel АВЦ40ХГНМaccomplished by application of a program package FactSage. Within the study,a production technology of lead-free, ecologically clean free-machining, steels elaborated and masteredat OJSC “Zlatoust electro-metallurgical works”. Free-machining corrosion-resistant steels (АВЦ19ХГН, АВЦ40Х, АВЦ40ХГНМ, АВЦ12Х18Н10, АВЦ40Х13, АВЦ14Х17Н2) alloyed by bismuth and calcium, steels (АО40Х, АО30ХМ) alloyed by tin, and steels (А38ХГМАРand А30ХМАР) containing BN were the objects of the study. The steels samples were in the form of forged billet of 10, 20 and 80 mm diameter and ingots of 18 and 500 kg (round 345 mm). Steel quality characteristics determined such as mechanicalproperties in longitudinal and cross directions of ingots, uniformity of distribution of fusible elements, carbon and Sulphur along the axis zone and in billet transverse sections. Pictures of ingots macrostructure by height and section obtained. Estimation of hardenability and steel contamination by non-metallic inclusions, austenitic grain size, steel machinability by cutting, surfacequality of re-worked billet and steel macrostructure accomplished. Comparable ecological studies of atmosphere contamination during the steel alloying also accomplished.
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Opiela, M. "Effect of boron microaddition on hardenability of new-developed HSLA-type steels". Archives of Materials Science and Engineering 1-2, n. 99 (1 settembre 2019): 13–23. http://dx.doi.org/10.5604/01.3001.0013.5878.
Testo completoAbstract (sommario):
Purpose: The paper presents the results of investigations on the effect of 0.003% boron microaddition on the hardenability of new-developed HSLA-type steels. In order to prevent the binding of the boron microaddition with nitrogen in BN nitrides, Ti microaddition at concentrations of 0.033% and 0.028% was also added into the tested steels. Design/methodology/approach: Evaluation of hardenability of the investigated steels was carried out on the basis of the Jominy test and the analytical method, according to the ASTM 255-89 standard, taking into account the effect of the boron microaddition. Additionally, developed of the CCT-diagram of investigated steel. A DIL 805A/D dilatometer with a LVDT-type measuring head was used to carry out the dilatometric test. Findings: Microaddition of boron, introduced into steel in a concentration of 0.003% along with Ti microaddition shielding (in concentration of 0.033% in steel A and 0.028% in steel B), advantageously improves hardenability. This is reflected in calculated ideal critical diameter DIB, which is equal 163 mm for steel A and 155 mm for steel B. The form of curves of phase transformations of supercooled austenite is typical for steels with microaddition of boron, with similar chemical composition. Research limitations/implications: Due to similar chemical composition of investigated steels, the kinetics of phase transformations of austenite, supercooled under continuous cooling, was determined for steel B containing 0.28% C, 1.4% Mn, 0.3% Si, 0.26% Cr, 0.22% Mo and Nb, Ti, V and B microadditions at 0.027%, 0.028%, 0.019% and 0.003% respectively. Practical implications: Tested steels have high hardenability and show the full usability for production of forged parts with the method of thermomechanical treatment, i.e., hot- deformed in the temperature range adjusted to the type of microadditions added to steel, with direct quenching of forgings from finishing forging temperature. The results of the tests may be useful for developing the parameters of heat treatment and thermomechanical treatment of investigated steels. Originality/value: The hardenability of new-developed HSLA-type steels was determined.
33
Zhang, J., Anja Kutzsche, K. Rosenberg, Christoph Leyens e Bernd Viehweger. "A Novel Canning Technology for Forging of Gamma-TiAl Alloys". Materials Science Forum 546-549 (maggio 2007): 1421–26. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1421.
Testo completoAbstract (sommario):
A novel canning technology to forge gamma-TiAl alloys was developed at the BTU Cottbus. A TiAl specimen was encapsulated with multilayer stainless steel foil and glass. The steel foil layers prevented the heat loss through radiation and the glass layer reduced the temperature decrease through conduction. First, the effect of steel foil on the cooling rate was investigated. Cooling curves were recorded for TiAl specimens without steel foil layer, with 1, 2, 3 and 4 layers of steel foil, as well as with 3 coated steel foil layers, respectively. While the unprotected specimen cooled from 1200 °C to 1100 °C within 12 s, the specimen with 3 coated steel foil layers needed 52 s for the same temperature decrease. The efficiency of the glass layer was examined with forging of steel specimens. The cooling rate during forging of the specimen with a glass layer was only half of that without a glass layer. Based on the results, Ti-45Al-0.5Mo-0.5Cu-0.2Si specimens, canned with steel foil and glass, were successfully forged at strain rates of 0.1 s-1 and 0.04 s-1 with warm dies which were heated to 500 °C. Visual and metallographic examinations revealed no cracks, pores or micropores. The microstructures are fine-equiaxed grains.
34
Agherkakli, B., A. Najafi e S. H. Sadeghi. "Ground based operation effects on soil disturbance by steel tracked skidder in a steep slope of forest". Journal of Forest Science 56, No. 6 (24 giugno 2010): 278–84. http://dx.doi.org/10.17221/93/2009-jfs.
Testo completoAbstract (sommario):
In this study, the effects of slope and traffic intensity on soil compaction, rutting and forest floor removal was evaluated on a skid trail in the natural forest of north of Iran. Combination of two levels of slope < 20% (SC1) and > 20% (SC2) and three levels of traffic (one, five and nine traffics) were studied. Treatment plots, with three replications, were established on the skid trail prior to skidding. The results of this study showed that all bulk densities were considerably higher in SC2 than in SC1 and average soil bulk densities were measured from 1.07 (g∙cm<sup>–3</sup>) to 1.23 (g∙cm<sup>–3</sup>) on skid trail and 0.91 (g∙cm<sup>–3</sup>) in undisturbed areas. With the increment of traffic, soil compaction increased but there was no significant difference among the three levels of traffic frequency in SC1 whereas it was significant between one and five cycles in SC2. Greatest rut depth was measured as 12 cm at nine traffics in SC2, although increase of traffic density caused deeper rut depth at all slope treatments, but it was higher at the SC2 in comparison to SC1. Litter mass decreased considerably on the skid trail with the increasing in slope and traffic. No important difference has been detected between SC1 and SC2 in terms of Litter mass removal. These results provide clear evidence that soil disturbance on steep trail is intensified.
35
Martinez, M. A., J. Abenojar, J. M. Mota e R. Calabrés. "Ultra High Carbon Steels Obtained by Powder Metallurgy". Materials Science Forum 530-531 (novembre 2006): 328–33. http://dx.doi.org/10.4028/www.scientific.net/msf.530-531.328.
Testo completoAbstract (sommario):
The objective of the present work is to study the manufacturing process of steels with high carbon content (1.5–2.1wt%) obtained by powder metallurgy. The reference material was the Damascus steel, which was employed to manufacture swords named after it and has been widely known due to its very good mechanical properties. The main reasons of the success of this product are: the high carbon content of the initial steel and the thermomechanical treatment (forge and quenching) that ancient iron forgers kept secretly during centuries. Different carbon contents (2 to3 wt%) were added to the same Fe powder matrix (ASC 300), and compacted and sintered steels are heat laminated (750°C) with a reduction of 20%. For 2% carbon content, the result is a steel with yield strength of 450 MPa, Young’s Modulus of 14.3 GPa and hardness of 109 HV(30).
36
Sydorchuk, О. "DIE STEEL 4Х4Н5М4Ф2 (WITHOUT FORGING TREATMENT) FOR HOT DEFORMATION OF ALUMINUM ALLOY". Innovative Materials and Technologies in Metallurgy and Mechanical Engineering, n. 2 (9 gennaio 2023): 46–49. http://dx.doi.org/10.15588/1607-6885-2022-2-8.
Testo completoAbstract (sommario):
Purpose. Production of steel with controlled austenitic transformation during operation of the 4Х4Н5М4Ф2 grade (without forging treatment) using the technology of electroslag remelting and establishing optimal modes of heat treatment (annealing, quenching and tempering). Production of tools (matrices) from 4Х4Н5М4Ф2 steel (without forging treatment) for hot deformation of aluminum alloy at operating temperatures below the critical point A1.
Research methods. Metallographic analysis of experimental die steels 4Х4Н5М4Ф2 (without forging treatment) and forged 4Х5МФ1С: study of metal structure; determination of specific resistance; determination of tensile strength; determination of hardness and impact strength.
Results. The results of research on the optimization of heat treatment modes (quenching and tempering) of 4Х4Н5М4Ф2 steel (without forging treatment) are given. Adjusted chemical composition (4Х4Н5М4Ф2) and optimized mode of heat treatment of steel, which allowed to increase heat resistance up to a temperature of 650 °С. The tempering temperature of steel (475±25 °С) at which irreversible temper brittleness occurs is established. Experimental and industrial tests of steel 4Х4Н5М4Ф2 (without forging treatment) for hot deformation of AK7ч aluminum alloy are presented. It is shown that compared to forged steel H13 (an analogue of 4Х5МФ1С), which is used at one of the Chinese enterprises, the experimental steel has practically the same resistance .
Scientific novelty. In the process of partial recrystallization (incomplete annealing at a temperature of 750±20 °C) of 4Х4Н5М4Ф2 steel (without forging treatment), a spheroidized carbide component is formed, which leads to an improvement in the mechanical processing of the workpiece for the manufacture of matrices.
Practical value. The possibility of using steel with an adjustable austenitic transformation during operation of the 4Х4Н5М4Ф2 grade (without forging treatment) is shown for a wide range of operating temperatures of hot deformation: copper-nickel (at an operating temperature above the critical point A3) and aluminum alloy (at an operating temperature below the critical point A1) with increased service life compared to forged steel 4Х5МФ1С.
37
Mengaroni, Sabrina, Massimo Calderini, Giuseppe Napoli, Chiara Zitelli e Andrea di Schino. "Micro-Alloyed Steel for Forgings". Materials Science Forum 941 (dicembre 2018): 1603–6. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1603.
Testo completoAbstract (sommario):
To fulfill the industrial demand of forged steels with high tensile properties and microstructural requirements coupled with reduced cost, the possibility to increase the properties of C-Mn steels by means of precipitation strengthening as achieved by micro-alloying (and without the addition of expensive elements such as Mo and Cr) has been evaluated. In order to do that, the effect of V addition has been exploited by means of metallurgical modelling followed by a laboratory ingot manufacturing. Heat treatment has been designed aimed to achieve the desired target tensile properties. Results show that ASTM A694 F70 grade requirements can bel fulfilled by 0.15% V addition and a proper heat treatment in a ferrite-pearlite microstructure, representative of a forged component. Results are discussed in comparison to those of a similar steel without V addition.
38
Wiewiórowska, Sylwia. "The Influence of Strain Rate and Strain Intensity on Retained Austenite Content in Structure of Steel with TRIP Effect". Solid State Phenomena 165 (giugno 2010): 216–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.216.
Testo completoAbstract (sommario):
TRIP (transformation induced plasticity) steels are low and medium-carbon steels containing soft ferritic groundmass responsible for low yield point and phases of hard particles such as martensite and/or bainite, which ensure high values of tensile strength. The most important content in structure of TRIP steel is occupied by a non-transformation retained austenite. The advantageous properties of these steels are obtained as a result of martensite transformation generated by plastic deformation process. The retained austenite induces increase of steel plasticity till the moment when by the impact of plastic deformation will undergo deformation in martensite, which results in the increase of steel mechanical properties. The speed of transformation of retained austenite in martensite is highly dependent on strain magnitude and strain rate magnitude. The paper presents the research of strain rate and intensity on retained austenite content ensuring TRIP effect in structure of low carbon steel (0.29%C). Finite element analysis for different strain rate and strain degree values in upsetting test was performed by means of software FORGE 3D. The practical analysis obtained from simulation results was realized by using metallurgical processes simulator Gleeble 3800.
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Eggbauer, Gernot, e Bruno Buchmayr. "Optimized Cooling Strategies for Bainitic Forging Steels". Key Engineering Materials 716 (ottobre 2016): 472–80. http://dx.doi.org/10.4028/www.scientific.net/kem.716.472.
Testo completoAbstract (sommario):
New steel grades for forged components are designed to meet the requirements of the automotive industry in order to obtain excellent strength and toughness behavior as well as a high endurance limit. Beside precipitation hardened ferritic-pearlitic steels, bainitic steels have gained more and more importance. Basic considerations on the alloy design (C-, Si-, Cr-; B-content) are done using JMatPro-Calculations and by some experimental trials. Using the thermomechanical testing system Gleeble 3800, various cooling strategies have been applied and the kinetics of the bainite formation has been measured at different holding temperatures and times. A detailed microstructural characterization has been done with relation to the mechanical properties. The isothermal tests are compared to continuous cooling situations. Finally, forging trials are performed to find out the most suitable and robust production schedule to be used in practice. The actual findings support the increasing use of bainitic steels for forged parts, especially regarding material saving, independence of cross section and good fatigue performance.
40
Sydorchuk, Oleg, Gennadii Bagliuk, Denys Myroniuk, Oleksandr Myslyvchenko e Ye Hongguang. "Die steel for hot deformation of copper and copper alloys". MATEC Web of Conferences 366 (2022): 04003. http://dx.doi.org/10.1051/matecconf/202236604003.
Testo completoAbstract (sommario):
The possibility of using die steels (4Kh3N5М3F and 4Kh4N5М4F2) with adjustable austenitic transformation during operation for a wide range of operating temperatures (below the critical point A1 and above the critical point A3) is shown for hot deformation of M1 copper (up to 630 °С) and МNZh5-1 copper-nickel alloy (900-950 °C) with increased service life. During hot deformation of copper-nickel alloy МNZh5-1, the service life of matrices made of steel with adjustable austenitic transformation 4Kh3N5М3F was increased, compared to steel 3Kh3М3F. The studied forged steel 4Kh4N5М4F2 is characterized by an increase in hardness and strength threshold compared to H13 steel, after the use of extruder wheels (production of more than 60 tons of copper products). In order to facilitate mechanical processing by cutting the work piece during the manufacture of matrices from experimental steels, it was proposed to carry out partial recrystallization, namely, incomplete annealing at a temperature of 750±20 ºС, which made it possible to improve mechanical processing (cutting) for the manufacture of dies and large-sized parts such as wheels extruders.
41
Ghali, Saeed, Mamdouh Eissa, Hoda El-Faramawy, Azza Ahmed, Fathy Baiomy e Michael Lamie. "Influence of Nitrogen on Oxidation Resistance of Automotive Steel Grades". Key Engineering Materials 835 (marzo 2020): 83–92. http://dx.doi.org/10.4028/www.scientific.net/kem.835.83.
Testo completoAbstract (sommario):
With the objective of partial and total replacement of nickel by nitrogen in austenitic exhausted valve steel X45CrNiW18-9, a program of work with series of experimental heats was designed. Experimental heats were carried out in 10 Kg. induction furnace under nitrogen pressure. The chemical composition of produced stainless steels was determined. The produced automotive steel grades were forged. The nitrogen contents were determined. The produced forged stainless steels were subjected to solution treatment at 1050 °C for 1 hour, followed by water cooling. Isothermal oxidation test is used to detect the behavior of new grades at different temperatures in air for solution treated stainless steels. The mass gain was measured for samples exposed to air at temperatures (500 °C, 600 °C, 700 °C, 800°C) for different time intervals, up to 1000 hrs. The oxide layer thickness for two selected steels was investigated by using optical microscope. XRD was used to detect types of oxides which are formed during oxidation process at 800 °C for 1000 hrs for represented investigated exhausted valve steels. Scanning Electron Microscope was used to make scan steels surface, after heating at 500 °C and 800 °C for l000hr. The mechanism of the oxidation of developed steels was investigated. It was found controlled by diffusion mechanism and the kinetic of oxidation process is parabolic. Oxidation rate of the investigated stainless steels for times, up to 8 h and between 200 andl000 h, at all investigated temperatures (500 °C - 800 °C), is parabolic and the oxidation is diffusion controlled. While in the time region 10 to 200 h, it obeys combined mechanisms. Partial replacement of nickel, by nitrogen, improves the oxidation resistance in air at temperature range 500°C - 800°C.
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A. Souf, A. Souf, K. Talea K. Talea, A. Bakali A. Bakali, M. Talea M. Talea e B. Boubeker B. Boubeker. "Powder metal forged and C-70 Steel forged. Fatigue analysis of connecting rod". Indian Journal of Applied Research 3, n. 1 (1 ottobre 2011): 152–60. http://dx.doi.org/10.15373/2249555x/jan2013/58.
Testo completo
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Le, Hoang, Cao-Son Nguyen e Anh-Hoa Bui. "EXPERIMENTAL PROCESSING OF ULTRA-LOW CARBON STEEL USING VACUUM TREATMENT". Acta Metallurgica Slovaca 24, n. 1 (22 marzo 2018): 4. http://dx.doi.org/10.12776/ams.v24i1.1070.
Testo completoAbstract (sommario):
This paper presents experimental process of ultra-low carbon (ULC) steel using vacuum heat treatment. After adjusting the chemical compositions as desired, the ULC steel was casted into plate, hot-forged and cold-rolled to sheet of 1 mm thickness, finally annealed at 800<sup>o</sup>C. Microstructure, crystalline phase, non-metallic inclusions and mechanical properties of the ULC steels were characterized by optical microscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and tensile test. Under argon vacuum atmosphere, decarburization occurred and C contents of the treated steels were reduced to 36 and 40 ppm corresponding to the decarburizing rate of 84.2 and 82.4%, respectively. The vacuum induction melting is thought to accelerate the rate of carbon removal from liquid steel. Electromagnetic force was attributed to promote the decarburization due to increasing the mass transfer coefficient during vacuum treatment. The annealed steels obtained a good combination of the strength and ductility; the total elongations were 45.2 and 42.9 %, while the yield strengths were 199 and 285 MPa, respectively. The results indicated that the ULC steels have only ferrite phase, of which grains size were 30 µm in average. The relative volume of non-metallic inclusions in the ULC steels was calculated as 0.23 vol. %, resulting positive contribution in the mechanical properties.
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Palanisamy, Vinothkumar, Jan Ketil Solberg e Per Thomas Moe. "Shielded Active Gas Forge Welding of an L80 Steel in a Small Scale Shielded Active Gas Forge Welding Machine". Journal of Manufacturing and Materials Processing 5, n. 1 (8 febbraio 2021): 16. http://dx.doi.org/10.3390/jmmp5010016.
Testo completoAbstract (sommario):
The Shielded Active Gas Forge Welding (SAG-FW) method is a solid-state welding technique in which the mating surfaces are heated by induction heating or direct electrical heating before being forged together to form a weld. In this article, an API 5CT L80 grade carbon steel alloy has been welded using the SAG-FW method. A small-scale forge welding machine has been used to join miniature pipes extracted from a large pipe wall. The welding was performed at three different forging temperatures, i.e., 1300 °C, 1150 °C and 950 °C, in some cases followed by one or two post weld heat treatment cycles. In order to qualify the welds, mechanical and corrosion testing was performed on miniature samples extracted from the welded pipes. In addition, the microstructure of the welds was analysed, and electron probe microanalysis was carried out to control that no oxide film had formed along the weld line. Based on the complete set of experimental results, promising parameters for SAG-FW welding of the API 5CT L80 grade steel are suggested. The most promising procedure includes forging at relative high temperature (1150 °C) followed by rapid cooling and a short temper. This procedure was found to give a weld zone microstructure dominated by tempered martensite with promising mechanical and corrosion properties. The investigation confirmed that small scale forge welding testing is a useful tool in the development of welding parameters for full size SAG-FW welding.
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Strobl, Susanne, e Roland Haubner. "Characterisation of Steel Composites Produced by the Damascus Technique". Materials Science Forum 825-826 (luglio 2015): 852–59. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.852.
Testo completoAbstract (sommario):
The Damascus technique is a manufacturing process where steels with different compositions, in particular the carbon content, are forge welded. Materials with contrary properties are generated by different carbon additions: e.g., substantial toughness and elongation are combined with high tensile strength and hardness. Since the 3rd century AD blades and weapons have been produced by this technique in Europe.In this work various Damascus steels with different compositions were investigated by means of metallographic methods. The focus is set on the interface between individual steel layers. While the majority of interfaces look uniform and are influenced only by carbon diffusion, some areas show the enclosement of oxides and slag stringers as a result of faulty workmanship during the forge welding process.After metallographic preparation the various microstructures were characterised by light optical microscopy and confirmed by Vicker´s microhardness measurements.
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Dogan, B., e T. J. Davies. "Thermomechanical processing of microalloyed powder forged steels and a cast vanadium steel". Metallurgical Transactions A 16, n. 9 (settembre 1985): 1599–608. http://dx.doi.org/10.1007/bf02663015.
Testo completo
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Bhowmik, Ayan, Somjeet Biswas, Satyaveer Singh Dhinwal, Apu Sarkar, Ranjit Kumar Ray, Debashish Bhattacharjee e Satyam Suwas. "Microstructure and Texture Evolution in Interstitial-Free (IF) Steel Processed by Multi-Axial Forging". Materials Science Forum 702-703 (dicembre 2011): 774–77. http://dx.doi.org/10.4028/www.scientific.net/msf.702-703.774.
Testo completoAbstract (sommario):
In this study, severe plastic deformation (SPD) of Ti-bearing interstitial-free steel was carried out by multi-axial forging (MAF) technique. The grain refinement achieved was comparable to that by other SPD techniques. A considerable heterogeneity was observed in the microstructure and texture. Texture of multi-axially forged steels has been evaluated and reported for the first time. The material exhibited a six-fold increase in the yield strength after four cycles of MAF.
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Skubisz, P., J. Sinczak, M. Packo, K. Mordalska e L. Lisiecki. "Effect of thermomechanical processing schedule on microstructure and mechanical properties of ultra high strength steel forgings". Izvestiya MGTU MAMI 7, n. 2-2 (20 marzo 2013): 101–5. http://dx.doi.org/10.17816/2074-0530-68079.
Testo completoAbstract (sommario):
The paper presents results of determination and industrial verification of cooling cycles in thermomechanical processing (TMP) of steel AISI 4130, designed to produce good combination of strength and ductility directly after forging and quenching. The results indicate possibility of replacement costly high alloy steels with common grades offering higher strength in combination with good plasticity after cost-effective TMP cycles utilizing blast-air cooling from controlled forge end temperature.
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Sourmail, Thomas, Véronique Smanio, Francisca García Caballero, J. Cornide, C. Capdevilla e Carlos García-Mateo. "Evolution of Microstructure and Mechanical Properties during Tempering of Continuously Cooled Bainitic Steels". Materials Science Forum 706-709 (gennaio 2012): 2308–13. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.2308.
Testo completoAbstract (sommario):
With the increasing demand for high performance engine or suspension components, bainitic steels are receiving interest as potential replacement of their quench and tempered counterparts. Indeed, for a number of mechanical components, ferrite pearlite microstructures are no longer sufficient in terms of mechanical properties. Bainitic steel grades allow production of hot-rolled bars or forged components exhibiting a homogeneous bainitic microstructure and achieving UTS up to 1200 MPa without the need for additional heat-treatments [1]. During tempering, these V-microalloyed bainitic steels exhibit unusual yield strength variations, with a very pronounced increase around 250-300 °C followed by the better known secondary hardening peak for temperatures around 600-650 °C. Indeed, after tempering at 250-300 °C, some of these steels exhibit an increase in yield strength of up to 200 MPa, concurrent with an increase in impact toughness of up to 25%. This, however, goes unnoticed if hardness measurements are used to characterize tempering. In the following, results are presented for three different bainitic steel grades, and the origins of the changes in mechanical properties are discussed.
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Giskaas, Shane, Preston Wolfram, Kip O. Findley, Bernard S. Levy e Chester J. Van Tyne. "Yield Strength of Hot Forging Die Steels at Working Temperatures". Materials Science Forum 773-774 (novembre 2013): 56–62. http://dx.doi.org/10.4028/www.scientific.net/msf.773-774.56.
Testo completoAbstract (sommario):
One mode that limits the usefulness of hot forging die steels is localized plastic deformation in regions of high pressure. To understand this behavior the yield strength of the steel needs to be measured at working temperatures in order to determine the likelihood of localized plasticity. One of the issues in using die steels for hot forging applications is that they are initially tempered to a hardness value when put into service. As the die is used to produce forged components, the contact with the hot forging causes the die to continue to temper and hence soften with continued used. To explore these issues three different die steels were obtained and tested experimentally. Experimental compressive yield strengths were determined for the three die steels (FX, 2714 and WF). The die steels were tempered to various hardness values prior to compression testing. The five room-temperature hardness values after tempering ranged from 20 to 38 HRC. The five temperatures for compression testing ranged from 593 to 704 °C (1100 to 1300 oF). From these tests a good characterization of the high temperature plastic behavior of each steel was obtained. It was found that the WF steel which had the highest alloy content was the strongest of the three steels under all test conditions. The FX and 2714, which had similar alloy contents (with FX having slightly less carbon, nickel and vanadium), had yield strengths that were close to each other at the intermediate temperatures, but at the high and low end of the testing range for temperature the FX was stronger than the 2714. Hence, to obtain the greatest resistance to localized plastic deformation during operations the choice of die steel should be WF, followed by FX and then 2714.