Journal articles: 'Nitrogen pearlite'

1

Xiong, X. C., A. Redjaïmia, and M. Gouné. "Pearlite in hypoeutectoid iron–nitrogen binary alloys." Journal of Materials Science 44, no. 2 (2009): 632–38. http://dx.doi.org/10.1007/s10853-008-3054-7.

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Radović, Nenad, Ankica Koprivica, Dragomir Glišić, Abdunnaser Fadel, and Djordje Drobnjak. "Influence of V and N on Transformation Behavior and Mechanical Properties of Medium Carbon Forging Steels." Materials Science Forum 638-642 (January 2010): 3459–64. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3459.

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The influence of vanadium and nitrogen on microstructure and mechanical properties of medium-carbon steels has been studied by means of metallography and mechanical testing. Vanadium addition to the low nitrogen steel suppresses the formation of ferrite-pearlite following the low reheating temperatures and microstructure consists of bainitic sheaves. Increasing nitrogen at the same vanadium level promotes the acicular ferrite formation. For high reheating temperatures, dominantly acicular ferrite structure in both the low nitrogen and the high nitrogen vanadium steels is obtained. The results suggest that vanadium in solid solution promotes the formation of bainite, whereas the effect of nitrogen is related to the precipitation of VN particles in austenite with high potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C,N) particles in ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen considerably increases the strength level, while CVN20 impact energy increases on changing the microstructure from bainitic ferrite to the fine ferrite-pearlite and acicular ferrite.

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Tong, Lifeng, Shichao Liu, Jinchuan Jie, and Tingju Li. "Preparation of High-Nitrogen Ductile Iron by Injecting Nitrogen Gas in Molten Iron." Materials 13, no. 11 (2020): 2508. http://dx.doi.org/10.3390/ma13112508.

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High-nitrogen ductile iron (DI) was prepared by a new method of injecting nitrogen gas into molten iron and nodularizing treatment. The microstructure and mechanical properties of the as-prepared DI for different nitrogen gas injection periods were characterized. The graphite morphology gradually deteriorated with the increase in the nitrogen gas injection time. The maximum nitrogen and pearlite contents were obtained after 20 min of nitrogen gas injection, and the corresponding tensile strength and elongation of the DI were calculated as 492 MPa and 9.5%, respectively, which were 9.3% and 22% higher than those of the DI prepared without the nitrogen gas injection treatment, respectively.

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Glisic, Dragomir, Abdunnaser Fadel, Nenad Radovic, Djordje Drobnjak, and Milorad Zrilic. "Deformation behavior of two continuously cooled vanadium microalloyed steels at liquid nitrogen temperature." Chemical Industry 67, no. 6 (2013): 981–88. http://dx.doi.org/10.2298/hemind121214015g.

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The aim of this work was to establish deformation behaviour of two vanadium microalloyed medium carbon steels with different contents of carbon and titanium by tensile testing at 77 K. Samples were reheated at 1250?C/30 min and continuously cooled at still air. Beside acicular ferrite as dominant morphology in both microstructures, the steel with lower content of carbon and negligible amount of titanium contains considerable fraction of grain boundary ferrite and pearlite. It was found that Ti-free steel exhibits higher strain hardening rate and significantly lower elongation at 77 K than the fully acicular ferrite steel. The difference in tensile behavior at 77 K of the two steels has been associated with the influence of the pearlite, together with higher dislocation density of acicular ferrite.

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Popova, N. A., E. L. Nikonenko, A. V. Nikonenko, V. E. Gromov, and O. A. Peregudov. "INFLUENCE OF ELECTROLYTIC PLASMA CARBONITRIDING ON STRUCTURAL PHASE STATE OF FERRITIC-PEARLITIC STEELS." Izvestiya. Ferrous Metallurgy 62, no. 10 (2019): 782–89. http://dx.doi.org/10.17073/0368-0797-2019-10-782-789.

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The change in phase composition and fine texture occurring in the ferritic-pearlitic 0.18C – 1Cr – 3Ni – 1Mo – Fe, 0.3C – 1Cr – 1Mn – 1Si – Fe and 0.34C – 1Cr – 1Ni – 1Mo – Fe steels under electrolytic plasma carbonitriding was investigated by transmission electron microscopy (TEM) method conducted on thin foils. Carbonitriding was implemented by surface saturation with nitrogen and carbon in aqueous solution under the temperature of 800 – 860 °C during 5 minutes. All steels were investigated before and after carbonitriding. It was ascertained that in the original state steel is given as a mixture of grains of pearlite and ferrite. Carbonitriding has led to creation of modified layers: the bigger was the amount of pearlite before the beginning of carbonitriding, the thicker was modified layer. Carbonitriding resulted in significant qualitative changes in phase state and structure of steel. It was revealed that in the surface area of modified layer along the matrix, there were also particles of other phases: carbides, nitrides and carbonitrides. In the course of removing from the surface of carbonitrided sample, their complete set and volume fractions decrease and at the end of modified layer only one carbide phase is present in all steels, i.e. cementite. It was found that matrix of all steels after carbonitriding is tempered packet (lath) and lamellar martensite. In the surface area of carbonitrided layer the volume fractions of lath and lamellar martensite depend on the original state of steel – the bigger was the amount of pearlite in steel the less lath martensite and the more lamellar martensite was formed. Such a dependency cannot be observed in the central area, and at the end of carbonitrided layer volume fractions of martensite packets and plates are commensurate.

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Chen, Wei, Zhe Shi, Yu Zhao, Jian Chun Cao, and Yu Mei Yu. "500MPa Seismic Rebars Developed by Nitrogen-Rich and Vanadium-Microalloyed, Controlled Cooling Technology." Advanced Materials Research 189-193 (February 2011): 752–61. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.752.

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500MPa high-strength seismic rebars was developed by nitrogen-rich & vanadium -microalloyed, controlled cooling technology in domestic steel plant of china, microalloy precipitates, microstructure, mechanical properties, welding performance and aging properties of rebars were researched by using metallographic microscopy, scaning electron microcopy, transmission electron microscopy, x-ray diffraction apparatus, flash-butt welding and mechanical properties testing. The results show that a large number of the dispersed V (C, N) precipitates are precipitated in the grain boundary, dislocation line and the ferrite matrix, precipitation size in the ferrite matrix is 10~ 20nm, V(C,N) precipitates amount accounts for 67.54% of the total amount of vanadium in steel, effect of precipitation strengthening is remarkable; when termination temperature after controlled cooling for rebars is controlled at 710°C ～750°C , the core microstructure is polygonal ferrite and pearlite, ferrite grain grade is 11.0, outer layer microstructure is acicular ferrite, pearlite and a small amount of bainite, good effects on fine-grain strengthening and seismic performance are obtained; rebars have low strain aging and good welding performance; production cost is reduced by RMB 100 Yuan per ton steel compared with VN micro-alloyed and hot-rolling process, benefit is obvious.

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Elagin, V. P., V. N. Lipodaev, and G. N. Gordan. "Peculiarities of development of structural heterogeneity in the fusion zone of pearlite steel with austenitic nitrogen-containing weld metal." Paton Welding Journal 2016, no. 8 (2016): 23–28. http://dx.doi.org/10.15407/tpwj2016.08.05.

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Shi, Xiao Fang, Li Zhong Chang, Chun Feng Jiang, and Lin Bao Liang. "Effect of Vanadium-Nitrogen Concentration and Cooling Rate on Grain Refinement in V-N Steel." Advanced Materials Research 538-541 (June 2012): 1138–44. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1138.

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Effect of vanadium and nitrogen concentration in V-N steel and cooling rate after deformation on grain refinement has studied in this paper. The results show that with the increase of vanadium and nitrogen concentration, ferrite grain size is smaller compared with carbon steel; with the increase of cooling rate after deformation, ferrite grain size is finer and pearlite content of microstructure significantly is reduced too. Compared with the Nb-bearing steel, as long as selecting reasonable the process parameters and adding the appropriate vanadium, nitrogen to the steel, V-N steel can also get a good strength and toughness, and the cost is lower than Nb-bearing steel. This method of producing the steel with good Strength and toughness is very suitable to China who possesses the abundant vanadium resource, but is lack of niobium.

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9

Zhang, Jing, Fu-ming Wang, Chang-rong Li, and Zhan-bing Yang. "Effect of Nitrogen Content and Cooling Rate on Transformation Characteristics and Mechanical Properties for 600 MPa High Strength Rebar." High Temperature Materials and Processes 35, no. 9 (2016): 905–12. http://dx.doi.org/10.1515/htmp-2015-0080.

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AbstractTo obtain appropriate chemical composition and thermo-mechanical schedules for processing the V-N microalloyed 600 MPa grade high strength rebar, the microstructure analysis during dynamic continuous cooling and tensile tests of three experimental steels with different nitrogen contents were conducted. The results show that increasing nitrogen content promotes ferrite transformation and broadens the bainite transformation interval, when the nitrogen content is in the range of 0.019–0.034 mass%. Meanwhile, the martensite start temperatures decrease and the minimal cooling rate to form martensite increases. To achieve a good combination of strength and ductility, the cooling rates should be controlled in the range of 0.5–3°C/s, leading to the microstructure of ferrite, pearlite and less than 10% bainite (volume fraction). Furthermore, all the experimental steels satisfy the performance requirement of 600 MPa grade rebar and the rebar with nitrogen content of 0.034 mass% shows the highest strength through systematically comparative investigation.

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10

Cao, Jian Chun, Dong Wei Zhao, Wei Chen, Zhe Shi, and Wei Dong Zhao. "Strengthening Mechanisms and Microstructure of Vanadium and Nitrogen Microalloyed High Strength Seismic Rebar." Advanced Materials Research 450-451 (January 2012): 600–604. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.600.

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Using metallographic test, physicochemical phase analysis, X-ray diffraction and transmission electron microscope, the microstructure of seismic rebars with yield strength of 500MPa, which were fabricated by vanadium and nitrogen microalloying and controlled rolling and controlled cooling, were investigated. The results of metallographic test show that the microstructure in centre and interlayer of tested rebar samples are made up of ferrite, pearlite and a small amount of bainite, but tempered sorbite with thickness of 0.9mm on the edge of the rebars. Physicochemical phase analysis indicates that vanadium in the rebars had precipitated by VN mainly, and the precipitation rates of V and N are 60% and 70%, respectively. The result of strengthening mechanisms analysis shows that fine grain strengthening and transformation strengthening are the dominated contributions to strength and strengthening increments of them are 184.4 MPa and 111.6 MPa, respectively.

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11

Cias, A., and M. Stoytchev. "Nickel and Copper-Free Sintered Structural Steels Containing Mn, Cr, Si, and Mo Developed for High Performance Applications." Archives of Metallurgy and Materials 62, no. 1 (2017): 11–17. http://dx.doi.org/10.1515/amm-2017-0002.

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AbstractIn an attempt to study the sinterability of potential high-strength nickel-free sintered structural steels containing Mn, Cr, Si and Mo compacts were prepared based on sponge and water atomised iron powders and on Astaloy prealloyed powders. To these were admixed ferromanganese, ferroslicon, and graphite. The samples were sintered at temperatures 1120 and 1250°C in laboratory tube furnaces in hydrogen, hydrogen-nitrogen atmospheres with dew points better than -60°C or in nitrogen in a semiclosed container in a local microatmosphere. After sintering the samples were slowly cooled or sinterhardened. Generally resultant microstructures were inhomogeneous, consisted of pearlite/ bainite/martensite, but were characterised by an absence of oxide networks. Sintering studies performed over a range of compositions have shown that superior strength, ranging beyond 900 MPa, along with reasonable tensile elongation, can be achieved with these new steels.

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12

Popova, Natalya, Lyudmila Erygina, Elena Nikonenko, and Mazhin Skakov. "Influence of electrolytic plasma nitriding mode on structural phase state of pearlitic steel." MATEC Web of Conferences 143 (2018): 03004. http://dx.doi.org/10.1051/matecconf/201814303004.

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The paper describes results of studies of phase transitions in structural phase state occurring in the type 0.34C-1Cr-1Ni-1Mo-Fe steel under electrolytic plasma nitriding in nitrogen-containing water solution. The nitriding voltages considered in the given study were 550 and 600 V. The research was conducted by means of X-ray diffraction electron microscopy. The specimens were studied in two states : 1) before modification (original state) and 2) after nitriding in the surface layer of the specimen. The study was conducted on thin foils. It was found that nitriding lead to significant changes in the structure of steel, namely in its phase composition and in the number of existing phases. In the original state the structure of steel was given as lamellar pearlite, ferritic carbide mix and fragmented ferrite. After 550 V nitriding it was lath martensite, plates of α-phase, with colonies of thin parallel plates of γ-phase and coarse grains of α-phase, containing γ-phase grains which were different in size and shape and were various-directional. Increase in nitriding voltage up to 600 V lead to change in the structure given as a lamellar non-fragmented pearlite and fragmented ferrite. The original state was marked by presence of particles of M3C cementite, after nitriding irrespective of the voltage it had the particles of M3C alloyed cementite, Fe3Mo3N nitride and Cr2C0.61N0.39 carbonitride. The sizes, volume fractions and locations of particles were dependent on nitriding voltage.

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13

Elagin, V. P., V. N. Lipodaev, and G. N. Gordan. "Peculiarities of development of structural heterogeneity in the fusion zone of pearlite steel with austenitic nitrogen-containing weld metal." Автоматическая сварка 2016, no. 8 (2016): 29–34. http://dx.doi.org/10.15407/as2016.08.05.

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14

Yuan, Wu Hua, Qiang Fu, and Heng Zhou. "The Effect of Controlled Rolling and Cooling on the Microstructure Evolution of Boron Microalloyed Medium-Carbon Steel." Advanced Materials Research 146-147 (October 2010): 1305–9. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1305.

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The processes of controlled rolling and cooling were simulated using hot compression tests on a Gleeble 1500 simulator with boron microalloyed medium-carbon steel. Effects of finish rolling temperature ranging from 760oC to 840oC and loop-laying temperature ranging from 660oC to 700oC on the microstructure evolution were studied. Experimental observations show that the average grain size of ferrite decreases while the volume fractions of ferrite and spheroidized pearlite increase when lowering rolling temperature. The maximum volume fraction of ferrite (62%) reached in our tests was obtained in the specimen whose rolling temperature and loop-laying temperature was 760oC and 700oC respectively. Excessive precipitation of the ferrite resulted in the carbon enrichment on some grain boundaries. Boron addition is effective to improve hot plastic deformation ability by removing nitrogen from AlN to form coarse BN particles on the grain boundaries.

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15

Aftandiliants, Ye G. "Modelling of structure forming in structural steels." Naukovij žurnal «Tehnìka ta energetika» 11, no. 4 (2020): 13–22. http://dx.doi.org/10.31548/machenergy2020.04.013.

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The study showed that the influence of alloying elements on the secondary structure formation of the steels containing from 0.19 to 0.37 wt. % carbon; 0.82-1.82 silicon; 0.63-3.03 manganese; 1.01-3.09 chromium; 0.005-0.031 nitrogen; up to 0.25 wt.% vanadium and austenite grain size is determined by their change in the content of vanadium nitride phase in austenite, its alloying and overheating above tac3, and the dispersion of ferrite-pearlite, martensitic and bainitic structures is determined by austenite grain size and thermal kinetic parameters of phase transformations. Analytical dependencies are defined that describe the experimental data with a probability of 95% and an error of 10% to 18%. An analysis results of studying the structure formation of structural steel during tempering after quenching show that the dispersion and uniformity of the distribution of carbide and nitride phases in ferrite is controlled at complete austenite homogenization by diffusion mobility and the solubility limit of carbon and nitrogen in ferrite, and secondary phase quantity in case of the secondary phase presence in austenite more than 0.04 wt. %. Equations was obtained which, with a probability of 95% and an error of 0.7 to 2.6%, describe the real process.

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Bidulský, Róbert, Marco Actis Grande, Zbigniew Brytan, and Mario Rosso. "Effect of Different Vacuum Heat Treatments on the Microstructure of a Low Alloyed Sintered Steel." Materials Science Forum 672 (January 2011): 293–96. http://dx.doi.org/10.4028/www.scientific.net/msf.672.293.

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The main aim of the present contribution is to show how different heat treatment conditions influence the microstructure of a Fe - [1.5Cr - 0.2Mo] - 0.6C powder system. In vacuum furnaces, the cooling rate is generally determined by the pressure of the gas (basically N2) introduced into the chamber. Different gas pressures have been applied, from 0 to 6 bars. The average cooling rates were calculated in the range of 1180 °C to 400 °C and were varying from 0.1 to 6 °C/s, according to the gas pressure. Considering the cooling rates, increasing the nitrogen pressure resulted in an increased amount of bainite/martensite microstructure. The microstructure constituents ranged from 97% pearlite + 3% ferrite in the system treated at 0 bar to 82 % martensite + 18 % bainite (with small amount of tempered martensite) in the system cooled applying N2 at 6 bars. Mechanical properties have been evaluated in terms of toughness, TRS and hardness for all processing conditions; the analysis of the properties allowed to plot graphs correlating the different properties as function of the characteristic microstructures.

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Nesterenko, Anatoliy, Alexander Sychkov, Valeriy Plyuta та Mikhail Blokhin. "Strain Aging in Boron Alloyed Multi-Phase С- Mn – Si – Steel Wire Rod". Journal of Materials Science Research 7, № 3 (2018): 78. http://dx.doi.org/10.5539/jmsr.v7n3p78.

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The specimens of C – Mn – Si - steel wire rod 5.5 mm in diameter with 0.005% B and without B additions from Moldova Steel Works had been studied. It was been established by crystallographic-geometrical analysis, that the boron atoms could be allocate in B – alloyed a – Fe only in the positions of a sub-interstitial solid solution. By study a static strain aging (SSA) and a dynamic strain aging (DSA) specimens of wire rod by C – Mn – Si - steel with B and without B (both with multi-phase (ferrite- martensite (bainite)-pearlite) microstructures) more expressed decreasing of strengthening properties and higher characteristics of ductility had been determined for C – Mn – Si - steel specimens with B. These results could be explained by “de - nitrogenous” and “de - carbonaceous” mechanisms, when boron atoms from a – Fe sub-interstitial solid solution by producing wire rod and by its strain aging thermal treatment with temperatures 150 - 450 °С generate boron- nitrogenous and boron - carbonaceous – nitrogenous precipitations. By realizing these mechanisms nitrogen and carbon atoms are partly excluded from the dislocation pinning’s process. This, in fact, explains to inhibit the development of strain aging (SSA and DSA) in boron- micro-alloyed C – Mn – Si - steel.

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18

Rashev, Ts V., A. V. Eliseev, L. Ts Zhekova, and P. V. Bogev. "High nitrogen steels." Izvestiya. Ferrous Metallurgy 62, no. 7 (2019): 503–10. http://dx.doi.org/10.17073/0368-0797-2019-7-503-510.

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The article provides a brief overview of the properties and production technology of high-nitrogen steels (HNS), which have several advantages over traditional ones. The main advantages are: up to four times higher yield strength with unique preservation of the remaining characteristics; reduction in consumption or a 100 % elimination of the use of some expensive alloying elements, such as Ni, Mo, Co, W, and others; effective alloying with unconventional elements (Ca, Zn, Pb, etc.). The basics of HNS technology, dependence of the properties on nitrogen content in steels, producing technologies for ferritic-pearlitic, martensitic and austenitic steel, their properties and applicability are discussed. Alloying with nitrogen for ferritic-pearlitic steel requires more precise adherence to the chemical composition in order to prevent the formation of insoluble nitrides during heat treatment (due to its greater solubility compared to carbon). Features of martensitic steels are associated with the possibility of formation of nitrides and carbonitrides during tempering. The possible effect of nitrogen in these steels may be as a decrease in the size of nitride particles as compared with carbide ones. Increased stability temperature of nitrides and carbonitrides provides increased mechanical and physical properties. In austenitic steels, nitrogen, due to the strong γ-forming equivalence to nickel, replaces it in a ratio of 1 kg of nitrogen ≈ 6 – 39 kg Ni. In austenitic-martensitic steels, the main role is played by thermal martensite. Stable austenite is obtained in the process of its aging at operating temperatures. Examples of effective use of HNS in important details are described.

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19

Wan, Yi, Zhan Qiang Liu, and Xing Ai. "Experimental Research on High-Speed Machining Pearlitic Gray Cast Iron." Key Engineering Materials 315-316 (July 2006): 459–63. http://dx.doi.org/10.4028/www.scientific.net/kem.315-316.459.

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High-speed machining (HSM) has received great interest because it leads to an increase of productivity and a better workpiece surface quality. However, tool wear increases dramatically due to the high temperature at the tool/workpiece interface. Proper selection of cutting tool and cutting parameters is the key process in high-speed machining. In this paper, experiments have been conducted to high speed milling pearlitic cast iron with different tool materials, including polycrystalline cubic boron nitrogen, ceramics and coated cemented carbides. Wear curves and tool life curves have been achieved at various cutting speeds with different cutting tools. If efficiency is considered, Polycrystalline Cubic Boron Nitrogen cutting tool materials are preferred in finish and semi-finish machining. According to the different hardness of cast iron, the appropriate range of cutting speed is from 850 m/min to 1200m/min.

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20

Zhou, Can Dong, Jun Fei Fan, Hai Rong Le, Guo Chang Jiang, and Jing Guo Zhang. "An Investigation of a Nitrogen Enhanced Steel Processed by Explosive Powder Compaction." Materials Science Forum 475-479 (January 2005): 265–68. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.265.

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A structural steel, 35CrMoV steel, has been attempted firstly by explosive powder compaction followed by sintering (EPC-sintering). The nitrogen content of the steel was 0.15wt%, which was accordant with the definition of high nitrogen steel (HNS). The final density of the EPC-sintering steel was only about 6.9g/cm3, which indicated that the processing parameters must be modulated further. In the sample of this steel, some radial cracks were found around the center of the cross-section of the steel, resulting in no mechanical tests carrying out. Observing the majority of the rim region of the sample of this steel, the microstructures were very tight, suggesting that it was possible and successful to manufacture HNS through EPC-sintering. The characteristics of the EPC-sintering high nitrogen 35CrMoV steel were that the cementites in the pearlites were found to be extremely fine. There were many (Cr,Mo)23(C,N)6 carbonitrides precipitates in the matrix. Some precipitates were round and others were needle-like. Some were distributing orderly in matrix and crossing over the dislocations. The dislocation density in the EPC-sintering steel remained high.

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Mardoukhi, Ahmad, Jari Rämö, Taina Vuoristo, Amandine Roth, Mikko Hokka, and Veli-Tapani Kuokkala. "Effects of microstructure on the dynamic strain aging of ferriticpearlitic steels at high strain rates." EPJ Web of Conferences 183 (2018): 03009. http://dx.doi.org/10.1051/epjconf/201818303009.

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This paper presents an experimental study of the effects of dynamic strain aging on the mechanical behavior of selected high carbon and chromium-manganese steels in dynamic loading condition. In ferritic-pearlitic steels, the dynamic strain aging is typically caused by carbon, nitrogen, and possibly some other small solute atoms. Therefore, the thermomechanical treatments affect strongly how strong the dynamic strain aging effect is and at what temperature and strain rate regions the maximum effect is observed. In this work, we present results of the high temperature dynamic compression tests carried out for two different ferritic-pearlitic steels, 16MnCr5 and C60, that were heat treated to produce different microstructure variants of these standard alloys. The microstructures were analyzed using electron microscopy, and the materials were tested with the Split Hopkinson Pressure Bar device at three different strain rates at temperatures ranging from room temperature up to 680 °C to study the effect of the heat treatments and the resulting microstructures on the dynamic behavior of the steels and the dynamic strain aging effect. The results indicate that for both steels, a coarse grain structure has the strongest dynamic strain aging sensitivity at small plastic strains. However, at higher strains, all microstructures show similar strain aging sensitivities.

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Kolchin, G. G., N. V. Korolev, and B. S. Ermakov. "Effect of nitrogen on the phase composition and physical and mechanical properties of stainless austenitic-pearlitic steels." Metal Science and Heat Treatment 28, no. 4 (1986): 272–76. http://dx.doi.org/10.1007/bf00707655.

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Kodzhaspirov, Georgii, and Andrey Rudskoy. "The Effect of Thermomechanical Processing Temperature-Strain-Time Parameters on the Mesostructure Formation." Materials Science Forum 879 (November 2016): 2407–12. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2407.

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The effects of Temperature-Strain-Time parameters at the Thermomechanical Processing (TMP) of austenitic, duplex and pearlitic structural steels on the mesostructure formation has been studied based on the laboratory, industrial experiments and TEM analysis. The fragmented dislocation substructure observed in steels with a different carbon, nitrogen, titanium, niobium content as well as recrystallization gave evidence that TMP effects the work-hardening and softening behaviour. The problem of mesostructure appearing in various steels and alloys due to various modes of TMP used hot and hot-warm deformation is discussed. The role of plastic strain in the formation of mesostructure and the relation between the changes in the crystal structure due to TMP and the mechanical properties of the steels are considered.

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24

Xue, Yan-Fang, Tristan Eagling, Jibin He, et al. "Effects of Nitrogen on the Distribution and Chemical Speciation of Iron and Zinc in Pearling Fractions of Wheat Grain." Journal of Agricultural and Food Chemistry 62, no. 20 (2014): 4738–46. http://dx.doi.org/10.1021/jf500273x.

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Sicoe, Gina Mihaela. "Researches on the Diffusion Phenomena in the Thermo-Chemical Treatment of Oxy-nitrocarburizing of Some Grey Cast Irons." Revista de Chimie 69, no. 12 (2019): 3367–71. http://dx.doi.org/10.37358/rc.18.12.6751.

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The thermo-chemical treatment of oxy-nitrocarburizing consists in the enrichment of materials in C, N and O in order to improve the physico-mechanical properties and the use of the materials. This leads to the increase in exploitation life, the increase of wear resistance, galling, corrosion, and slight erosion. The research presented in this article followed the study of the application of this treatment and the results obtained on pearlitic grey cast iron with different chemical compositions, domain in which there are few experimental results published. The results obtained on a number of 10 samples, presented in the article, highlighted the good compatibility of these materials with the thermo-chemical treatment of oxy-nitrocarburizing, obtaining on the surface some white layers which give good anti-corrosive properties, similar to those obtained on steel. There was no correlation between the depth of the white layer and the chemical composition of the studied cast iron. It was also emphasized that the depth of nitrogen diffusion is influenced by the chemical composition of the studied materials which is directly proportional to carbon equivalent (Ceq) of cast iron.

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Zhong, Yingxin, Mengtian Yang, Jian Cai, et al. "Nitrogen topdressing timing influences the spatial distribution patterns of protein components and quality traits of flours from different pearling fractions of wheat (Triticum aestivum L.) grains." Field Crops Research 216 (February 2018): 120–28. http://dx.doi.org/10.1016/j.fcr.2017.11.016.

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Miller, M. C., J. A. Froseth, C. L. Wyatt та S. E. Ullrich. "Effect of starch type, total β-glucans and acid detergent fiber levels on the energy content of barley (Hordeum vulgare L.) for poultry and swine". Canadian Journal of Animal Science 74, № 4 (1994): 679–86. http://dx.doi.org/10.4141/cjas94-098.

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Effects of starch type, total β-glucans and ADF levels on DMD, nitrogen-corrected TME for poultry and DE for swine were evaluated in four experiments utilizing synthetic barley mixtures produced by differential pearling and milling. Forty-seven mature roosters were used in exp. 1 and 45 were used in exp. 3 to determine DMD and TME for poultry and 3 duodenally cannulated pigs were used in exps. 2 and 4 to determine DMD and DE for swine utilizing the MNBT. In exps. 1 and 2, synthetic barley (normal starch) with 11.0% ADF contained lower TME (2733 kcal kg−1) and DE (3278 kcal kg−1) compared to barley with 3.5% ADF (3371 and 3943 kcal kg−1, respectively). Increasing total β-glucans from 3.4 to 6.8% decreased TME from 3248 to 2855 kcal kg−1 and DE from 3679 to 3542 kcal kg−1. In exps. 3 and 4, there was an interaction between ADF and starch type. With normal starch, increasing ADF from 2.1 to 12.0% reduced TME from 3301 to 2630 kcal kg−1 and DE from 4018 to 3247 kcal kg−1 but with waxy starch, increasing ADF had no effect on either TME (2996 vs. 3086 kcal kg−1) or DE (3918 vs. 3712 kcal kg−1). These data suggest that the energy content of barley for poultry and swine is decreased greatly by high ADF and less by high total β-glucans, that β-glucans have a larger negative effect on energy for poultry than for swine, but that high ADF has a minimal effect on energy when barley starch is waxy regardless of the level of β-glucans. The negative effects of high β-glucans from waxy barley in exps. 3 and 4 were more apparent when the diets were low in ADF. Key words: Barley, fiber, energy, digestibility, β-glucans

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Kuksenova, L. I., M. S. Alekseeva, M. A. Gress, and D. A. Kozlov. "Elaboration of methodological base of quality evaluation of nitrogenization of steels of tribotechnical application." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 77, no. 1 (2021): 34–45. http://dx.doi.org/10.32339/0135-5910-2021-1-34-45.

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Nitrogenization is one of most spread methods of surface hardening of critical parts of machines. To elaborate methodological base of structural evaluation of quality parameters of nitrogenized surface layers of sliding friction couple by methods of X-ray structural analysis and tribotechnical tests, structure and performance properties of nitrogenized structural steels and alloys were studied. Namely pearlitic and martensitic steels (40Х, 38Х2МЮА, ВКС-7), model iron-based alloys with a BCC lattice, steels alloyed by Cr, Mo, Al in amount of up to 4 % (at.), iron-based alloys with FCC lattice, alloyed by Ni (29 % (at.)), Cr, Al, Ti in the amount of up to 4 % (at.), as well as austenitic high-chromium steels 12Х18Н10Т, 08Х16Г15Н5МАФ, steel 16Х3НВФМБ-Ш and high manganese steel 40Г14Н8Х3Б1. The surface saturation of the samples was made by gas, ion, gas-baric nitrogenizing and by ion implantation of nitrogen. The sum of macroscopic (tribotechnical) and microscopic (structural) indicators was evaluated, which characterize the physics and mechanics of friction process at various hierarchical levels. This sum of indicators also provides information on properties of antifriction coatings, modified layers and performance ability of the friction couple under conditions of contact deformation. It was established, that increasing of the nitrogenizing temperature from 540 up to 700 °C for alloys with a ferrite matrix results in a decrease of the hardness of the surface layer and physical broadening of X-ray lines. In this case, the relative wear resistance reaches maximum at 620 °C. For alloys with an austenitic matrix, an increase of hardness, broadening of X-ray lines and relative wear resistance occurs with increasing of temperature. These parameters grow in the sequence Fe−Ni, Fe−Ni−Al, Fe−Ni−Cr, Fe−Ni−Ti. Gas-baric nitrogenizing enables to obtain higher performance characteristics of parts (wear resistance and contact strength). Based on the generalization of the results of experimental studies of nitrogenized steels and alloys with various compositions and various crystal lattices, the most significant characteristics of the structural state and properties of near-surface microvolumes were established, that affect the level of surface destruction during friction, as follows: the size of the alloying element nitrides particles, the distance between them, the micro-deformation of the crystal lattice of the solid solution, the values of the physical broadening of the X-ray lines of the solid solution, its hardness and the change in hardness during friction, the plasticity reserve. Generalized criteria for the properties of the surface layer, taking into account the characteristics of the structure and properties of the nitrogenized layer and the zone of surface contact plastic deformation elaborated. Also methodological foundations for the structural assessment of the quality parameters of the surface layers of sliding friction couples elaborated. Bench tests have confirmed the effectiveness of the application of the generalized structure parameter and properties of surface layers for the selection of materials for the friction unit. The formulated conditions are recommended for optimizing the nitrogenizing technological process from the standpoint of tribology and choice of materials for friction couple.

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Journal articles on the topic 'Nitrogen pearlite'

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