Journal articles: 'Steel casting defects'

1

Li, Xin Cheng, Yong Chun Tang, Wei Xing Zhu, Jie Liu, and Xiao Li Wang. "Research on Criterion and Prediction of Surface Defects in Alloy Steel Casting Slab." Advanced Materials Research 1049-1050 (October 2014): 23–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1049-1050.23.

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To effectively control all types of surface defects in alloy steel casting slab, quantitative characterization must be taken. Thus, corresponding quantitative characterization criterion of various casting slab surface defects was established firstly in this paper. Mapping relationships between casting process parameters (like carbon content, slab thickness, casting speed, depth of submerged nozzle, water ratio of secondary cooling, and so on) and surface defects, and simplified surface defect prediction model of alloy steel casting slab were established by using Partial Least Squares Regression. Application results indicated that the prediction results of surface defects highly coincided with casting production situation, which fully verified the applicability of the prediction model.

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Lee, Jun Youn, Soon Bok Lee, and Jae Kyung Yi. "Ultrasonic Transmission Characteristics of Continuous Casting Slab for Medium Carbon Steel." Key Engineering Materials 297-300 (November 2005): 2201–6. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2201.

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Until now, surface defects of continuous casting slab have been removed by the enforced surface scarfing to produce high quality steel materials. An evaluation technique for surface and internal defects of slab is required to enhance the production of medium carbon steels and acquire defect-map. Accordingly as a preliminary step, longitudinal wave testing and Rayleigh wave testing were carried out on slab specimens of medium carbon steel to get basic transmission characteristics of ultrasonic waves. This research provides as basic data for on-line defect estimation using a laser ultrasonic or EMAT in non-contact ultrasonic detecting techniques in future.

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Yan, Huadong, Hui Jin, and Ruigen Yao. "Prediction of the damage and fracture of cast steel containing pores." International Journal of Damage Mechanics 29, no. 1 (2019): 166–83. http://dx.doi.org/10.1177/1056789519872000.

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For spatial design freedom, steel castings are widely used in bridges, airport terminals, and offshore platforms. However, different from hot-rolling technology, casting process variables, such as the casting temperature and those related to graphite spheroidization and post-heat treatment, may cause casting defects. To improve the safety and effectiveness of steel castings, a study consisting of experiments and numerical calculations is performed to investigate the effect of pores on the damage and fracture of cast steel. The chemical composition, metallography, and tomographic imaging of cast and hot-rolled steels were compared, providing a clear understanding of cast steel at the microstructure level. In addition, a complete Gurson–Tvergaard–Needleman damage model is used to predict the ductile fracture of cast steel containing pores. Good agreement is obtained between the measured and predicted tensile curves as well as between the measured and predicted void volume fraction evolution.

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Khan, Muhammad Azhar Ali. "Simulation Based Mold Design Optimization of a Spring Flap Casting." Solid State Phenomena 305 (June 2020): 178–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.305.178.

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The complex nature of metal casting process brings about a need to simulate it before undertaken in a foundry. Casting simulations provide insights on flow of molten metal within the mold, solidification sequence, nature and location of defects etc. Moreover, mold design can be optimized to minimize defects without undergoing physical trials-and-errors as previously practiced in traditional metal casting. This study is based on casting an ASTM A216 WCB steel spring flap for automotive suspension system using a simulation based optimized mold design. The initial and optimized mold designs are simulated in MAGMASoft for mold filling, solidification, stress distribution and defects prediction. The results of simulations and actual castings are found to be in good agreement. It is concluded that simulations are accurate in modeling casting process and in predicting defects followed by their minimization through mold design optimization. The use of auxiliary components in a carefully designed mold can lead to a nearly defect-free and high quality cast product.

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KIM, JONG-YUP, JOON-HYUN LEE, and SEUNG-HOON NAHM. "EFFECT OF CASTING DEFECT ON MECHANICAL PROPERTIES OF 17-4PH STAINLESS STEEL." International Journal of Modern Physics B 20, no. 25n27 (2006): 4463–68. http://dx.doi.org/10.1142/s0217979206041525.

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Damage and integrity evaluation techniques should be developed steadily in order to ensure the reliability and the economic efficiency of gas turbine engines. Casting defects may exist in most casting components of gas turbine engines, and the defects could give serious effect on mechanical properties and fracture toughness. Therefore, it is very important to understand the effect of casting defects on the above properties in order to predict the safety and life of components. In this study, specimens with internal casting defects, made from 17-4PH stainless steel, were prepared and evaluated and characterized based on the volume fraction of defects. The relation between mechanical properties such as tensile, low cycle fatigue and fracture toughness and volume fraction of defect has been investigated. As a result of the analysis, the mechanical properties of 17-4PH decreased as the defect volume fraction increased with very good linearity. The mechanical properties also showed an inversely proportional relationship to electrical resistivity.

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Скрябин, М. Л. "Effect of the chemical composition of 35HGSL steel on shrinkage, casting defects and microstructure." Informacionno-technologicheskij vestnik, no. 1(23) (March 11, 2020): 171–79. http://dx.doi.org/10.21499/2409-1650-2020-23-1-171-179.

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Стальные отливки на сегодняшний день стали неотъемлемой частью современного литейного производства. В процессе получения отливок неизбежно появляются какие-либо дефекты. В данной работе рассмотрены причины образования дефектов при изготовлении отливок из стали 35ХГСЛ при литье по выплавляемым моделям. Также рассмотрены особенности отвода теплоты от отливки при первичной и вторичной кристаллизации. Приведена классификация зон отливок по ориентации кристаллов в отливках. Выявлена закономерность влияния интенсивности охлаждения на характер усадки. Today, steel castings have become an integral part of modern foundry production. In the process of obtaining castings, any defects inevitably appear. In this paper, we consider the production reasons for the formation of defects in the manufacture of castings made of 35XGSL steel when casting on investment models. The features of heat removal from the casting during primary and secondary crystallization are also considered. The classification of casting zones by the orientation of crystals in castings is given. The regularity of the influence of the cooling intensity on the shrinkage character is revealed.

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Huang, Pei Hsing, Wei Ju Huang, and Chuen Shii Chou. "Preventing Casting Defects of Stainless Steel Flanges Using a Water-Soaking Method." Materials Science Forum 962 (July 2019): 189–93. http://dx.doi.org/10.4028/www.scientific.net/msf.962.189.

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High-precision flanges are used in conjunction with O-rings, bolts, and nuts in a variety of pipe connections to prevent the leakage of harmful fluids. Flanges require good hermeticity; i.e., without pores, cavities, blow holes, or other shrinkage defects. This study employed mold flow analysis to predict where and how defects are likely to occur during the casting process. In this study, we soaked the bottom of the casting system in cold water to direct the direction of solidification from the bottom upward. Simulation results indicate that this method significantly reduces the probability of shrinkage defects in castings.

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Xiong, Jia Ji, Fan Lin Meng, Qing Jin Liang, and Chong Cao. "Casting Process Design and Simulation of Large Cast Steel Bracket." Key Engineering Materials 815 (August 2019): 125–30. http://dx.doi.org/10.4028/www.scientific.net/kem.815.125.

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The casting process design of large cast steel supports is carried out, and the special integrated sand core and forged steel cast lugs are used to simplify the cavity manufacturing process. The ProCAST software was used to simulate the casting process of the stent, simulating the filling and solidification of the casting, and predicting the occurrence of defects such as shrinkage and shrinkage of the casting. According to the simulation results, the cause of the defects is analyzed, and the casting process of the stent is optimized. The simulation results show that the optimization scheme effectively reduces the casting defects and the surface of the stent is free from defects.

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9

He, Bin Feng. "Simulation and Optimization of Steel Casting by Sand Casting." Advanced Materials Research 706-708 (June 2013): 258–61. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.258.

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Casting defects will always occurred in the cast-steel castings. In order to eliminate the shrinkages more and more risers had been used which increased the final cost sharply. The traditional method was used to the designing process; besides that, the foundry simulation software was introduced to prove the rationality of the technique. The software helps to predict the proper position of the shrinkages. The cooling system was optimized after the analyzed and the final simulation results show the rationality of foundry technique.

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10

Kim, Jong Yup, Joon Hyun Lee, and Seung Hoon Nahm. "Statistical Analysis of Casting Defects in Microstructure for Understanding the Effect on Fatigue Property of 17-4PH Stainless Steel." Key Engineering Materials 321-323 (October 2006): 1503–6. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1503.

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High strength materials have been used for critical components in order to ensure the reliability of aircraft gas turbine engine. But it usually costs high to maintain their premium quality. Therefore, the optimum quality level of materials should be defined under operating condition by material property estimation technique in order to meet the requirement of reliability and economical efficiency. Most cast rotating parts of gas turbine engine have casting defects caused during the casting process. The casting defects less than certain acceptable limit can be permissible for usage. So, it is very important to understand material defect shape and distribution, and its effect on mechanical properties exactly. In this study, 17-4PH stainless steel specimens with variable internal casting defects were prepared to investigate the fatigue property characteristics. The defect fraction and condition were estimated in microstructure by statistical analysis. The correlation between estimated defect condition and fatigue property was discussed.

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11

Stolyarov, A. M., A. M. Retunskaya, M. G. Potapov, and M. V. Potapova. "Effect of steel casting speed mode on quality of continuously casted billet." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 75, no. 4 (2019): 460–64. http://dx.doi.org/10.32339/0135-5910-2019-4-460-464.

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The speed of billet withdrawal from a continuous caster (CC) mold has a decisive effect on the CC productivity. However, increase of the speed results in an increase of pollution of the CC metal by non-metallic inclusion and increase of surface defects of CC billet. Estimation of steel casting speed mode impact on the degree of different defects formation presented for long products CC billets, casted at a five-strand CC of radial type. Defects of CC billet from Ст3сп steel grade studied for a billet having section of 150×150 mm. The purpose of the study was to determine the degree of influence of withdrawal speed, metal chemical composition and billets cross section dimensions on billets quality. Array of industrial data of more than 550 billets studied, 80.4% of which were casted by an open stream and the balance – by a closed stream. As a result of the CC billets quality study it was confirmed, that during metal casting by an open stream the degree of evolution of form defect, like rhombic defects, internal and surface defects is higher comparing with those when casting by a closed stream. General tendency of increase of the CC metal pollution by non-metallic inclusions at the increase of billet withdrawal speed. The tendency is similar for both casting by an open and by a closed stream. However, during casting by an open stream the increase takes place rather evenly. During casting by a closed stream a sharp increase of billets with defects were observed at the billets withdrawal speed exceeding 2.4 m/min. Linear dependencies of billets withdrawal speed while casting by a closed stream on the degree of liquation cracks evolution and general strips, edge point pollutions and peripheral fine structure metal zone thickness determined. To improve the long products billets surface, casted by a closed stream, it was recommended to restrict the withdrawal speed of the billet from a carbon steel of general quality by the value of 2.4 m/min.

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12

Stoian, Elena Valentina, Vasile Bratu, Cristiana Maria Enescu, and Carmen Otilia Rusanescu. "Analysis of Internal Defects Appeared in the Continuous Casting." Scientific Bulletin of Valahia University - Materials and Mechanics 16, no. 14 (2018): 23–27. http://dx.doi.org/10.1515/bsmm-2018-0005.

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Abstract The paper presents the study of internal defects resulting from the continuous casting of steels. The 50 samples were taken from a total of 20 continuously cast bits of different steel grades. The investigation of the causes of internal defects, shown on the analyzed samples, started from the assumption that the secondary metallurgy was performed correctly. The following internal defects have been evident: internal cracks (axial cracks, section cracks), central porosity and marginal punctuation impurities.

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13

Selivyorstov, Vadim, Tatjana Selivyorstova, and Anton Guda. "SYSTEM ANALYSIS OF POROSITY FORMATION PROCESSES IN STEEL CASTINGS AND THEIR MATHEMATICAL MODELS." System technologies 6, no. 125 (2019): 89–104. http://dx.doi.org/10.34185/1562-9945-6-125-2019-09.

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The analysis of scientific and technical information about the hardening features of steel castings, which lead to the formation of shrinkage defects is presented. The mechanisms of the relationship of the casting properties of alloys are shown. The analysis of factors that determine fluidity is carried out. The technological parameters of casting are determined, which lead to the formation of pores in steel castings. The mechanisms of porosity formation of endogenous and exogenous nature are considered. Siverts law is given, that describes the dependence of gas concentration on pressure. Graphs of changes in the concentration of nitrogen and hydrogen in the pressure range 1 - 4 atm are given for medium alloyed steel, open-hearth steel, cast iron. The mechanism of the influence of temperature and gas pressure on the process of gas evolution in the melt is analyzed. Technological methods for influencing the solubility of gases during the solidification of the casting are described. The microporosity model of Advanced Porosity Module, the Niyama criterion are analyzed. The need for further studies to develop a general model for the formation of shrinkage defects, which will take into account, inter alia, the dependence of the concentration of gases dissolved in the metal on pressure temperature, is noted.

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Yao, Cheng Gong, Shou Qian Yuan, Lie Chen, Zhi Jun Wang, Hai Long Wang, and Lin Lin Jing. "Research of Transverse Corner Crack and Optimization of Concasting Process for Bloom of Peritectic Steel Q235D." Advanced Materials Research 284-286 (July 2011): 1115–19. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.1115.

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Q235D is one kind of peritectic steel, so the casting production inevitably encounter the universality defects of peritectic steel casting. The bloom(250mm×280mm) of Q235D is produced by 60t consteel EBT—LF(VD)—CC process at Xining Special Steel. The main problem in the production is the transverse corner crack, finally lead to occur the cracks and “triangular gaps” at surface of round bar（Φ130mm）after rolled. In order to eliminate the defects caused by transverse corner crack of bloom, the morphology and microstructure and principle of crack formation is researched. The results showed that the crack is caused by stress along the intergranular, and no obvious segregation and particles founded around the defects. The following parameters on the continuous casting process are optimized: steel composition, superheat, the choice of a various slag, the cooling water of different section, casting speed and the electromagnetic stirring parameters. Finally the cracking defects of the bloom is eliminated, and the quality of the bar is optimized.

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15

Dineshraj, S., Mayukh Acharya, Alok Agarwal, et al. "Development of Hot Isostatic Pressing Technology for Investment Cast Products." Materials Science Forum 830-831 (September 2015): 19–22. http://dx.doi.org/10.4028/www.scientific.net/msf.830-831.19.

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Hot isostatic pressing (HIPping) technology is used for healing the casting defects for aerospace applications. Castings used for aerospace applications like turbo-pumps need to meet very stringent quality requirements. Complexity of the castings used in these applications, makes it difficult to meet the quality requirements in all the areas. Defects like gas holes, shrinkages, cavities etc. may occur in few locations and need to be repaired by welding or healed by HIPping. In the present study, we attempted to simulate the defect healing capability of HIP in a systematic manner. Artificial defects were created in Austenite-Martensite grade stainless steel cast rod. These rods were then subjected to HIP prcoss cycle at 1150 °C and at a pressure of 1620 bar. Healing of the defects was ensured through X-ray radiography. Detailed microstructural analysis using optical metallography and scanning electron microscopy (SEM) with EDX was carried out before and after HIPping, to understand the defect healing mechanisms. These results are discussed in detail here.

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Skryabin, M. L., and V. A. Likhanov. "The study of casting defects in steel 35HGSL." Journal of Physics: Conference Series 1399 (December 2019): 044063. http://dx.doi.org/10.1088/1742-6596/1399/4/044063.

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Huang, Pei-Hsing, Jenn-Kun Kuo, Te-Hua Fang, and Wei-ren Wu. "Numerical simulation and design of casting system for stainless steel exhaust manifold." MATEC Web of Conferences 185 (2018): 00008. http://dx.doi.org/10.1051/matecconf/201818500008.

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During operation, exhaust manifolds must bear the corrosion of high temperatures and repeated stress, which can easily lead to cavitation, corrosion, and creeping damage in the casting structure and affect product safety. To improve the structure of exhaust manifolds and increase their service life, we employed AnyCasting mold flow analysis to SUS304 stainless steel exhaust manifolds. We examined the influence of casting system design and process parameters such as ceramic shell temperature, casting temperature, and pouring speed on the filling and solidification processes of the liquid metal. Finally, we used the Niyama criterion to predict the probability and distribution of shrinkage porosity defects in the exhaust manifold and made improvements to enhance the quality of exhaust manifold castings. Keywords: exhaust manifold, mold flow analysis, casting system.

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18

Stopyra, Michał, Robert Jarosz, and Andrzej Kiełbus. "The Quality of Produced Sand-Cast Engine Block Made from Elektron 21 Magnesium Alloy." Solid State Phenomena 211 (November 2013): 71–76. http://dx.doi.org/10.4028/www.scientific.net/ssp.211.71.

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The casting defects, microstructure and hardness of Elektron 21 Mg sand casting alloy was investigated. Visual and radiographic examination showed the presence of non-metallic inclusions and porosity. Quantitative analysis of microstructure was performed, no correlation between section thickness, grain size, volume fraction of eutectic areas and hardness was observed. Casting defects were responsible for cracking at magnesium casting/steel tube interface.

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Lee, Bo Young, Dae Hwan An, Jae Sung Kim, Hyung Kook Jin, and Duck Hee Ryu. "Study on Development of a Surface Build-Up Welding Using CH-90 Electrode to Replace Mn-Containing Rail Steel." Advanced Materials Research 15-17 (February 2006): 989–94. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.989.

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Rail steel at crossing areas bears much higher loads over any other section of a regular railway. Mn-containing casting steel is normally used for its high load-carrying capability and reduced wear rate. However, since Mn-containing casting steel tends to have casting defects, the cost of manufacturing defect-free Mn-containing casting steel becomes quite expensive. Therefore, through the use of welding, this study investigates the possibility of resurfacing Mn-containing rail steel using a CH-90 electrode as an alternative to completely replacing it. In this study, a series of experimental build up weldings was made and their microstructures, chemical compositions, work-hardening index and friction coefficients were investigated. The results showed that both microstructures and chemical compositions from the build up weld section were similar to that of Mn-containing casting steel, showing an austenitic microstructure with approximately 13% Mn. The friction coefficients measured closely to one another as well (mu of Mn-containing steel = 0.847 and mu of the resurfaced weld metal = 0.831). The work-hardening index of the build up weld metal was 30% higher than that of Mn-containing casting steel. This difference could be attributed to the residual stresses in the build up weld metal which indicates that the hardening speed of the build up weld metal is faster than that of Mn-containing casting steel by impact. Therefore, build up welding, using a Mn-alloyed steel electrode on rail steel, could be a safe and economic alternative to the high cost of Mn-containing casting rail steel replacement.

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20

Odarchenko, I. B., A. A. Sinitskij, and I. N. Prusenko. "The stability of the internal cavities of steel casting." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 1 (April 10, 2019): 24–27. http://dx.doi.org/10.21122/1683-6065-2019-1-24-27.

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The mechanism and causes of the formation of casting defects, manifested in the deviation of the geometry of the internal cavities from the «cylindrical», are investigated. It is shown that the causes of distortion of the geometric shape are associated with deformation of the casting rod during thermal and mechanical interaction with the melt. Using the possibilities of computer simulation in the MAGMASOFT package, the temperature distributions of the metal in the casting body during the casting and solidification were analyzed. Areas of distortion of the geometric shape of the inner part of the casting correspond to the area of the rod subjected to the highest and longest thermal loads. The characteristics of the temperature fields in the respective zones indicate overheating of individual areas of the rod to temperatures causing phase stresses in the structure of the core mixture, sufficient for the occurrence of deformations in it. To eliminate the defect under consideration, two approaches were used to reduce the magnitude of phase stresses in the casting rod and to adjust the design of the rod tooling.

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21

Yang, Da Chun. "Foundry Technology of the Pressure Board Steel Casting Based on Proportional Solidification Theory." Advanced Materials Research 314-316 (August 2011): 691–94. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.691.

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For plate steel castings, the foundry technology was designed according to the dynamic directional solidification of proportional solidification theory. Adopting chilling process for the thick and large plane, it may cause the casting basically even cooling. Using self-feeding shrinkage in solidification achieved the dynamic directional feeding of molten steel, and the casting was poured and congealing at the same time. The shrinkage of finally congealing part was fed by small riser. Adopting this foundry technology, the large plane downwards avoided appearing the defects such as sand buckle, slag, pinhole porosity, and pore, etc.; the process yield was greatly increased with this foundry technology, too.

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Cho, Seong-Mook, and Brian G. Thomas. "Electromagnetic Forces in Continuous Casting of Steel Slabs." Metals 9, no. 4 (2019): 471. http://dx.doi.org/10.3390/met9040471.

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This paper reviews the current state of the art in the application of electromagnetic forces to control fluid flow to improve quality in continuous casting of steel slabs. Many product defects are controlled by flow-related phenomena in the mold region, such as slag entrapment due to excessive surface velocity and level fluctuations, meniscus hook defects due to insufficient transport of flow and superheat to the meniscus region, and particle entrapment into the solidification front, which depends on transverse flow across the dendritic interface. Fluid flow also affects heat transfer, solidification, and solute transport, which greatly affect grain structure and internal quality of final steel products. Various electromagnetic systems can affect flow, including static magnetic fields and traveling fields which actively accelerate, slow down, or stir the flow in the mold or strand regions. Optimal electromagnetic effects to control flow depends greatly on the caster geometry and other operating conditions. Previous works on how to operate electromagnetic systems to reduce defects are discussed based on results from plant experiments, validated computational models, and lab scale model experiments.

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Han, Zhan Guang, and Jia Quan Zhang. "An Advanced Dynamic Secondary Cooling Control Model for Bloom Castings." Advanced Materials Research 154-155 (October 2010): 171–78. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.171.

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For bloom casting, typical quality defects such as midway crack usually occur upon improper cooling control during non-steady casting conditions specially for the production specialty steels,. A key measure to eliminate the defects formation has been presented by the adoption of more sophisticated secondary cooling strategies to balance the surface reheating due to casting speed fluctuation. With the consideration of the complex casting conditions and the characteristics of bloom casters, a dynamic control model for the secondary cooling has been developed in the paper to obtain a reasonable temperature profile and solidification progress for the bloom casting process, which is based on a slice residence time method combined with a multi-level control strategy. The feedback system, based on the difference between the calculated surface temperatures and the predetermined or measured surface temperatures, has been integrated into two-dimensional thermal model. The interlocking protection system between level-1 and level-2 is included in the model together with the data diagnosis and processing. Furthermore, the control model also offers technological interface for the introduction of new steel grades in production and the related modification to the secondary cooling parameters. It is shown from online application that the dynamic control system of secondary cooling for bloom casting is robust during operation and adaptable to any change of real casting conditions. Sound quality bloom castings according to acid etched tests have been obtained from the caster accordingly.

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Haušild, Petr, Clotilde Berdin, Philippe Bompard, and Nicolas Verdière. "Ductile fracture of duplex stainless steel with casting defects." International Journal of Pressure Vessels and Piping 78, no. 9 (2001): 607–16. http://dx.doi.org/10.1016/s0308-0161(01)00069-2.

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Roy, Snehangshu, R. K. Singh, Kiran Kumar Keshari, et al. "Reduction in Surface Defect in Continuous Cast Slab through Intervention in Process Parameters." Materials Science Forum 978 (February 2020): 91–96. http://dx.doi.org/10.4028/www.scientific.net/msf.978.91.

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Occurrence of defects like crack on the surface of the cast products has long been recognized as a critical challenge for steelmakers in the continuous casting. Cracks on the surface can severely reduce yield and required further operations like salvage and scarfing. Depending on the severity of defect slabs can be diverted or in worst cases a slab can be rejected altogether if the defect cannot be removed by surface conditioning. Rourkela Steel Plant (RSP) of Steel Authority of India Limited (SAIL) produces continuously cast slabs as feed material for plate mills and hot strip mill. Sometimes the slabs produced through continuous casting are faced issues intermittently due to presence surface defects like midface longitudinal cracks (LC) and transverse edge crack (EC) etc. A systematic investigation of the operating parameters of these casters e.g. monitoring of oscillation parameters, slabs and mould flux, simulation and analysis of fluid flow inside mould, steel chemistry and role of dissolve gases in steel. Based on the investigation critical parameters responsible for crack formation have been identified and key areas identified where modification need to be done. Modifications has been done in terms of mould flux addition practice, optimization of the grade chemistry, optimization of process route, optimization of casting speed, checking of strand thermal profile, mould & machine allignment etc. It was observed that the crack incidences are significantly lower after the modifications were done.

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Ray, Amitava. "Electron-Probe Microanalysis: Some Revelations in the Investigation of Defects in Steel Products." Materials Science Forum 492-493 (August 2005): 627–34. http://dx.doi.org/10.4028/www.scientific.net/msf.492-493.627.

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The unique imaging and microanalytical capability of the electron-probe microanalyser (EPMA) has been exploited in conjunction with light microscopy for exploring the genesis of some defects, which are detrimental to steel product quality. Investigations of surface and internal defects have revealed that defects in the finished steel product are often inherited at upstream stages and accentuated in the later stages of steel processing. While the occurrence of surface defects such as “slivers” in hot-rolled sheets and “linear cracks” in hot-rolled rounds has been largely attributed to subsurface non-metallic inclusions and slag/casting powder entrapment, microprobe analysis of internal defects such as “centre-line cracking” of thick plates have revealed the deleterious role of C and Mn macrosegration inherited during the continuous casting of steel slabs. The paper elucidates some of these findings, as unravelled by both qualitative and quantitative microprobe analysis.

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Li, Chang Rong, Zhen Yao, and Zhao Hua Liang. "Continuous Casting Process Parameters on Central Defect of SWRH82B Billet." Advanced Materials Research 317-319 (August 2011): 361–65. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.361.

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Continuous casting process parameters such as casting speed, superheat, secondary cooling water flow rate have greatly affections to central defects in SWRH82B billet. These parameters were investigated by the methods of chemical content analysis and etch test for macrostructure in some steel plant of china. The results shows that the central defect of SWRH82B billet can be improved when the superheat is controlled at the range of 15~25°C, casting speed is 1.80m•min-1 and secondary cooling water flow rate is 0.72 L•kg-1.

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Kovaleva, I. A., and N. A. Khodosovskaya. "Defect “steel-melting captivity and swelling” on the inner surface of seamless hot-rolled pipes. Characteristic genetic features, the causes of formation and measures of prevention." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 4 (January 20, 2020): 58–62. http://dx.doi.org/10.21122/1683-6065-2019-4-58-62.

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In a market economy, increasing the competitiveness of steel products is an urgent trend in science and practice. Development of production of new pipe steels in terms of pipe-rolling plant open joint-stock company «BSW – management company of holding «Belarusian metallurgical company» casted on continuous casting machine, was complicated by the emergence of low-alloy pipe steel grades of internal defects, which negatively affects the quality of the pipes. Visual evaluation of samples on the inner surface revealed rolled defects significant clusters, close to each other, having a longitudinal orientation. The edges of the defects are tortuous, torn. Defects found on the inner surface of the pipes are characterized as steel melting captivity and swelling. The reason for the formation of internal defects of hot rolled pipes «steel-melting captivity and swelling» was the rolling of defects in the macrostructure of the central zone (central porosity and axial liquation) of a continuously cast workpiece with a diameter of 200 mm.

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Choudhari, C. M., K. J. Padalkar, K. K. Dhumal, B. E. Narkhede, and S. K. Mahajan. "Defect Free Casting by Using Simulation Software." Applied Mechanics and Materials 313-314 (March 2013): 1130–34. http://dx.doi.org/10.4028/www.scientific.net/amm.313-314.1130.

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The use of Aluminum castings parts in the automotive industry has increased dramatically over the past few decades. The driving force for this increased use is vehicle weight reduction for improved performance. In many cases the mechanical properties of the cast aluminum parts are superior to those of the cast iron or wrought steel parts being used.This paper proposes the computer simulation of the sand casting of Aluminum Plate. It aims to study the behavior of fluid flow during mould filling and solidification and to optimize the process parameters, which help to predict and control casting defects such as gas porosity and shrinkage porosity. Here an attempt is being made to model and simulate the casting process using the AutoCAST software. The technological as well as practical aspects of using casting software are illustrated with an industrial case study.

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Mi, Guo Fa, Li Lin Chen, and Hong Yan Nan. "Application of Numerical Simulation on Cast-Steel Axle’s V-Method Foundry." Advanced Materials Research 139-141 (October 2010): 576–79. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.576.

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The V-method foundry is an advanced casting technology compared with traditional sand casting. The Pro/E software was used to generate three-dimensional model of cast parts. The solidification process of the automotive axle casting with V-method foundry was simulated by the numerical simulation software, ViewCast. The location and scale of the shrinkage defects caused by the original process were predicted. According to the simulation results, the position of the flange round cooled too fast, which blocked the feeding passage of the round near sprue. The reason was that solidifying sequence was unperfected. The casting process was optimized by means of adding runner and chill. Progressive solidification can be obtained and the shrinkage defects can be eliminated or transferred by the improved technology. The reasonable casting process was obtained and the process has been proofed by the productive practice.

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Wang, Shuo Ming, Yan Wang, and Ruo Si Wang. "Analysis of Large Inclusions in Q195 Steel." Advanced Materials Research 997 (August 2014): 522–25. http://dx.doi.org/10.4028/www.scientific.net/amr.997.522.

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Aimed at the Q195 steel strip inclusion defects in a steel mill, using tracer analysis make system analysis to casting of large inclusions content. Large inclusions in casting containing ladle slag accounted for about 39% of the total number of test, containing tundish covering agent accounts for about 42.2%, while containing protection slag accounted for 45%. Shows that large inclusions in the billet is mainly comes from the crystallizer mold powder entrapment, secondly is the tundish slag and the ladle slag powder entrapment. When transient casting large inclusions content is steady casting several times, increasing the stability of operation on transient casting, controlling the stability of cast-on and ladle changing, stabilizing the liquid level of tundish and mould can improve the quality of the steel.

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Maryani, Edna, Humiras Hardi Purba, and Sunadi. "Analysis of Aluminium Alloy Wheels Product Quality Improvement Through DMAIC Method in Casting Process: A Case Study of the Wheel Manufacturing Industry in Indonesia." Journal Européen des Systèmes Automatisés 54, no. 1 (2021): 55–62. http://dx.doi.org/10.18280/jesa.540107.

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The global market demand for automotive wheels with alloy materials is 55%, which is quite high compared to other materials such as steel, magnesium, chromed, and carbon fiber. The high competition of the global alloy wheels market demands to be able to offer quality alloy wheels. The purpose of this research is to reduce the number of defects in the casting process step by using the Define Measure Analyze Improve Control (DMAIC) method. This study shows the systematic approach to find the root cause of major defects in aluminum castings using the defect diagnostic approach as well as cause and effect diagram. Quality improvement using quality tools, namely the Pareto diagram, fishbone diagram. The major defects for the rejections during production were identified as leak defects, porosity motive holes, and oval defects. In determining the proposed quality improvements using the FMEA tool. The results of data processing on the calculation of process capabilities and product performance show improvements after quality improvements in the casting process. Product performance from DPMO = 15.462, sigma level = 3.6 to DPMO = 8.186 and sigma level = 3.9. The effect of decreasing the percentage of defects could save production costs by IDR 413.350.000. Therefore, the application of the DMAIC method can provide a significant improvement in product quality and impact on production cost savings.

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Chen, Yong, Jian Hua Zeng, and Guo Rong Wu. "Control for Surface Faint-Sliver Defects in Cold-Rolled IF Steel Sheet." Advanced Materials Research 396-398 (November 2011): 1145–50. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1145.

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The samples of cold-rolled sheets, hot-rolled plates and continuously cast slabs have been analyzed with the condition of faint-sliver defects appeared in IF steel of Pangang, and it was shown that faint-sliver defects in cold-rolled steel sheet were mainly caused by micro-cracks in the surface of strands, slag entrapment in mold during casting and inclusions in sub-surface of strand. Faint-sliver defects were controlled effectively with the technical measures, which were decreasing oxidation of ladle slag, controlling the ratio of CaO/Al2O3 in slag, extending circulation time of deoxidization and alloying in RH process, controlling the casting speed and increasing the viscosity of mold fluxes. Therefore, the ratio of downgrade induced by faint-sliver defects reduced from 10.97% to 1.0%.

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Pan, Hong, Guo Rong Wu, and Zhi Qiang Li. "Quality Control of Casting Slab for 510L Steel." Applied Mechanics and Materials 117-119 (October 2011): 756–59. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.756.

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Slab quality affects the quality of hot rolled sheet significantly. There were serious transverse corner cracks on continuous casting slab of 510L steel plate in Panzhihua Steel before. Based on this, some effective countermeasures are put forward, such as the optimization of ratio of heat flux on narrow side and broad side of casting slab and mold powder, as well as the stabilization of casting speed and working condition of caster. With these countermeasures, transverse corner cracks on continuous casting slab have been significantly reduced, and the lines and peeling defects on hot rolled sheet reduce from 30% to 0.

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Zappulla, Matthew L. S., and Brian G. Thomas. "Surface Defect Formation in Steel Continuous Casting." Materials Science Forum 941 (December 2018): 112–17. http://dx.doi.org/10.4028/www.scientific.net/msf.941.112.

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Serious defects in the continuous casting of steel, including surface cracks and depressions, are often related to thermal mechanical behavior during solidification in the mold. A finite-element model has been developed to simulate the temperature, shape, and stress of the steel shell, as it moves down the mold in a state of generalized plane strain at the casting speed. The thermal model simulates transient heat transfer in the solidifying steel and between the shell and mold wall. The thermal model is coupled with a stress model that features temperature-, composition-, and phase dependent elastic-visco-plastic constitutive behavior of the steel, accounting for liquid, δ-ferrite, and γ-austenite behavior. Depressions are predicted to form when the shell is subjected to either excessive compression or tension, but the shapes, severity, and appearance differ with conditions. Cracks appearing without depressions are suggested to form in the lower ductility trough when the shell is colder but more brittle. The local thickness of the shell and austenite layer appears to have major effects as well. The model reveals new insights into the formation mechanisms and behavior of surface depressions and longitudinal cracks in the continuous casting process.

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Ayvazyan, Lilya A., Nadezhda K. Nikoli, and Aleksey N. Shapovalov. "Improvement the Round Bloom Continuous Casting Technology at JSC “Ural Steel”." Defect and Diffusion Forum 410 (August 17, 2021): 275–80. http://dx.doi.org/10.4028/www.scientific.net/ddf.410.275.

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The results of assessment of macrostructure and surface quality of round blooms 455 mm in diameter, cast on 4-strand continuous casting machine (CCM) at JSC “Ural Steel” are presented. The analysis of technological casting parameters of round blooms 455 mm in diameter (from steel grade “2”) at bloom caster of JSC “Ural Steel” are completed. Violations in casting temperature and rate parameters, which deteriorate thermal conditions of solidification and quality of continuous casting blooms, have been revealed. The main causes of unsatisfactory bloom quality have been determined, which are the increased overheating of cast metal and irrational secondary cooling mode. The results of the experiment to evaluate the surface temperature dynamics of a round bloom in the secondary cooling zone are presented, which confirmed the inefficiency of the secondary cooling mode for the defect-free bloom formation. As a result of thermal calculations of round blooms solidification of 455 mm in diameter, rational coolant flow rates by secondary cooling sections for bloom caster of JSC “Ural Steel” have been proposed. Optimized secondary cooling parameters provide a softer secondary cooling of the round bloom, which reduces the probability of the surface and internal defects development.

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Shuai, Ge Wang, You Li, and Zheng Hua Guo. "Fabrication and Microstructure of Zn-Sn Target Material Alloy." Advanced Materials Research 785-786 (September 2013): 924–27. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.924.

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In this paper, Zn-Sn target material alloys were prepared in an electric resistance furnace. The effects of cooling condition on casting macro-defect, microstructure and segregation of ingots during solidification have been investigated by SEM and EDX analyses. The results show that the alloys casted in air-cooled and water-cooled steel moulds have not apparent casting macro-defects. The measured Sn concentration of alloys is very close to the nominal composition. The microstructures of Zn-Sn alloys are consisting of Zn-rich primary dendrite phase and divorced eutectic Sn-rich phase. The ingots solidified in water-cooled steel moulds have smaller grains than in air-cooled moulds.

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Xie, Jing Pei, Ai Qin Wang, Wen Yan Wang, Ji Wen Li, Hui Min Zhang, and Jin Ling Hou. "The Computer Solidification Simulation of Oceangoing Freighter Rudder Horn." Materials Science Forum 575-578 (April 2008): 22–26. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.22.

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The numerical solidification simulation for oceangoing freighter rudder horn steel casting has been made and the location and reasons forming casting defects have been predicted by HUAZHU CAE software. Simulating result shows that the casting perfects can be realized by means of the technological optimization and rationally assembling gating system, risers and iron chill. After magnetic particle detection and ultrasonic inspection, the properties and microstructure of the oceangoing freighter rudder horn steel casting are in accord with the standard of USA, Germany and Japan.

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Kunakbaeva, A. T., A. M. Stolyarov, and M. V. Potapova. "Influence of technology parameters of free-cutting steel continuous casting on the billet internal structure." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 76, no. 2 (2020): 139–42. http://dx.doi.org/10.32339/0135-5910-2020-2-139-142.

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Free-cutting steel gains specific working properties thanks to the high content of sulfur and phosphorus. These elements, especially sulfur, have a rather high tendency to segregation. Therefore, segregation defects in free-cutting steel continuously cast billets can be significantly developed. The aim of the work was to study the influence of the chemical composition of freecutting steel and casting technological parameters on the quality of the macrostructure of continuously cast billets. A metallographic assessment of the internal structure of cast metal made of free-cutting steel and data processing by application of correlation and regression analysis were the research methods. The array of production data of 43 heats of free-cutting steel of grade A12 was studied. Steel casting on a five-strand radial type continuous casting machine was carried out by various methods of metal pouring from tundish into the molds. Metal of 19 heats was poured with an open stream, and 24 heats – by a closed stream through submerged nozzles with a vertical hole. High-quality billets had a cross-sectional size of 150×150 mm. The macrostructure of high-quality square billets made of free-cutting steel of A12 grade is characterized by the presence of central porosity, axial segregation and peripheral point contamination, the degree of development of which was in the range from 1.5 to 2.0 points, segregation cracks and strips – about 1.0 points. In the course of casting with an open stream, almost all of these defects are more developed comparing with the casting by a closed stream. As a result of correlation and regression analysis, linear dependences of the development degree of segregation cracks and strips both axial and angular on the sulfur content in steel and on the ratio of manganese content to sulfur content were established. The degree of these defects development increases with growing of sulfur content in steel of A12 grade. These defects had especially strong development when sulfur content in steel was of more than 0.10%. To improve the quality of cast metal, it is necessary to have the ratio of the manganese content to the sulfur content in the metal more than eight.

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Kong, Yiwen, Dengfu Chen, Qiang Liu, and Mujun Long. "A Prediction Model for Internal Cracks during Slab Continuous Casting." Metals 9, no. 5 (2019): 587. http://dx.doi.org/10.3390/met9050587.

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Slab continuous casting internal cracking is a common quality defect in the production process. The ability to predict the quality of each continuous casting product and assess whether it is suitable for hot delivery or needs to be cleaned down will greatly increase the rolled product rate and reduce the scrap rate and production management cost. According to the quality defects of internal cracks during slab continuous casting and based on the solidification and heat transfer simulations, stress and strain calculations and theoretical analysis of metallurgical processes related to continuous casting combined with an abnormal casting event expert system, the internal crack generation index of the slice unit is used to predict the crack occurrence rating of each sized slab. Moreover, the internal crack prediction model for the slab is successfully developed and applied in a domestic steel mill. The accuracy of the model prediction reached 86.85%. This method achieved the organic combination of theoretical analysis and an expert system and provides an important theoretical tool for the prediction of crack quality defects in slab continuous casting; the method can be applied in slab continuous casting production.

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Wang, Ai Qin, Jing Pei Xie, Wen Yan Wang, and Ji Wen Li. "The Computer Solidification Simulation and Process Optimization of Gear Ring." Materials Science Forum 704-705 (December 2011): 88–91. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.88.

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The numerical solidification simulation for gear ring steel casting has been made, and the location and reasons forming casting defects have been predicted by HUAZHU CAE software. Simulating result shows that the directional solidification and efficient feeding were maintained and the casting perfects can be realized by means of the computer simulation optimizing technological and rationally design of gating system, insulated risers, iron chill and compensating efficiently. After magnetic particle detection and ultrasonic inspection, the properties and microstructure of the Gear ring steel casting are in accord with the international standard.

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42

Perzyk, M., and A. Kochański. "Detection of causes of casting defects assisted by artificial neural networks." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 217, no. 9 (2003): 1279–84. http://dx.doi.org/10.1243/095440503322420205.

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Defects in castings often appear unexpectedly and it is difficult to identify their source as they can be brought about by a large number of randomly changing production parameters. Artificial neural networks were used for detection of the causes of gas porosity defects in steel castings. The applied procedure included systematic storing of two types of information: about the process parameters, materials used and even employees involved in the production (as the network inputs) and about the appearance of a given defect (as the network output). The trained network was able to detect interdependences among various factors influencing water vapour pressure in the mould and thus to indicate the most probable cause of porosity.

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Jayet-Gendrot, S., P. Gilles, and C. Migné. "Behavior of duplex stainless steel casting defects under mechanical loadings." Nuclear Engineering and Design 197, no. 1-2 (2000): 141–53. http://dx.doi.org/10.1016/s0029-5493(99)00262-9.

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Zhao, Yuzhuo, and Shusheng Yao. "The shape and evaluation of defects in formed steel-casting." Engineering Fracture Mechanics 43, no. 5 (1992): 847–54. http://dx.doi.org/10.1016/0013-7944(92)90014-6.

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Duška, Jaroslav, Gabriel Grimplini, Marek Molnár, Lucia Hrabčáková, and Atila Drotár. "Star Cracks in Continuously Cast Deep-Drawing Tin Steel Slab." Materials Science Forum 782 (April 2014): 235–38. http://dx.doi.org/10.4028/www.scientific.net/msf.782.235.

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The final quality of flat products is directly related to surface and internal quality of continuously cast slabs. This aspect is very important especially in case of IF and deep-drawing tin grades, in which even the smallest defects can cause problem in the final processing of the material, especially during forming by stamping, when the material fails. This work is devoted to the analysis of the surface defect of star crack type. The presence of defect was visually detected after scarfing process during removal of surface layer on the small radius side of the slab. This type of defect occurs particularly in cases, when steel is contaminated by copper in the process of continuous slab casting. In view of the copper melting point (1083°C) and the surface temperature of the cast slab shell at the mold exit (about 1200°C) in the process of steel cooling at continuous casting, Cu penetrates along the boundaries of primary austenitic grain, or separate particles are precipitated at the grain boundaries. Initial cracks are formed in the area of primary cooling in the mold. Thermal and mechanical stresses acting in the surface area of slab shell when the slab passes thorough the rollers of secondary cooling cause gradual expansion of crack defects along boundaries of grains contaminated by copper.

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46

Stolyarov, A. M., Ye A. Buneyeva, and M. V. Potapova. "Interrelation of CCM (Steel Billet Continuous Casting Machine) Tube Steel Casting Parameters and Hot-Rolled Plate Quality." Solid State Phenomena 316 (April 2021): 479–83. http://dx.doi.org/10.4028/www.scientific.net/ssp.316.479.

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The quality of the hot-rolled plate up to 36 mm thick was estimated by the percentage of rolled products, sorted due to the presence of a surface defect "Non-metallic inclusions", and internal defects, detected by ultrasonic plate control. The analysis of the data on the total sorting of hot-rolled plates demonstrated that the amount of sorting differs significantly on the melting from which each series of tubular metal casting commenced, compared to all the other melting in the series. The sorting of the sheets rolled from the metal of the first in a series of melting proved to be 1.9 times higher than that of the metal of all other melts. The main reason (in 68% of cases) of sorting is the presence of non-metallic inclusions on the surface of the plates. The effect of sorting of hot-rolled plates on non-metallic inclusions of various parameters has been studied: the duration of the intermediate ladle-heating; the length of time from the end of the heating of the intermediate ladle, prior to the beginning of the casting; lining temperatures of the intermediate ladle before the beginning of casting; duration of filling the intermediate ladle; the filling rate of the intermediate ladle with metal; mass of metal in the intermediate ladle before the beginning of casting into the crystallizer; chemical composition of metal; overheating of the metal over the liquidus point at the beginning, middle and end of the casting. On the sorting of flat products for non-metallic inclusions, of all the parameters considered, a statistically significant effect is due only to the overheating of the metal above the liquidus point, which varies in the range from 19 to 35 ° C. In order to obtain an acceptable quality of both the surface of slabs and the surface of hot-rolled plates for non-metallic inclusions, the first in a series of melts recommends overheating of the metal in the intermediate ladle above the liquidus temperature of 30-35 ° C.

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47

Opryshko, L. V., and T. V. Golovnyak. "Study of surface defects in tubes made from nondeformed continuously cast billets." Metaloznavstvo ta obrobka metalìv 98, no. 2 (2021): 54–62. http://dx.doi.org/10.15407/mom2021.02.054.

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Defects of outer and inner surfaces of hot-rolled tubes of various steel grades and sizes manufactured on tube-rolling unit with a continuous mill (TPA 30-102) at Interpipe Nikotube LLC from a nondeformed continuously cast billets produced by MZ Dniprostal LLC have been studied. Characteristic genetic and morphological signs of defects were revealed which makes it possible to reliably classify them, identify cause of defect formation and recommend measures to eliminate them. Defects on the outer and inner surfaces of tubes are of metallurgical origin and associated with quality of initial continuously cast billets (a consequence of violation of the smelting and continuous casting technology). Defects on the inner surface of tubes were caused on defects in the axial zone of original billets (unacceptable porosity, looseness, chemical inhomogeneity, liquation stripes and cracks, etc.) and are classified as steel-smelting films and bulges. It was found that displacement of the thermal center of crystallization (a feature of the machines for continuous steel casting of curvilinear type) had an additional negative effect on quality of the inner surface of the studied tubes. Defects on the outer surface of tubes are tears of burning in places of accumulation of low-melting inclusions and their eutectics, as well as steel-smelting scabs on rolled dirt and gas bubbles. Likelihood of formation of scabs on outer surface of the studied tubes over rolled crust introversions is not excluded. The study results will allow manufacturers to reliably classify defects, promptly reject tubes with unacceptable defects of metallurgical origin and minimize supply of low-quality products to consumers. These results will later be included in the classifier of defects in tubes manufactured on the TPA 30-102 unit from nondeformed continuously cast billets. The results of the study of natural signs of defects of metallurgical origin in the tube surface will be useful for elaboration of measures aimed at improvement of the technology of manufacturing initial tube billets. Keywords: tube surface defects, continuously cast billets, microstructure, rolled contamination, low-melting inclusions, eutectic, gas bubbles, decarburization, liquation.

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Berezovskiy, Alexander V., Michael P. Shalimov, and Ekaterina B. Votinova. "The Repair of Defects in High-Manganese Steel Castings by Welding Technology." Defect and Diffusion Forum 410 (August 17, 2021): 209–14. http://dx.doi.org/10.4028/www.scientific.net/ddf.410.209.

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Welding technologies are used to repair defects in cast parts of high - manganese austenitic steel (Hadfield steel). These include repair welding for newly manufactured castings, welding the formed defects in the old operating cast parts and, finally, for cladding layer of wear-resistant metal on the surface of the cast parts. Manual metal arc welding (MMAW) are used as often as gas metal arc welding (GMAW) and of flux-core wire welding (FCAW-S). These welding processes make possible to obtain a weld metal with the expected quality of the restored surface and a slight distortion of the base metal structure. The article presents methods of the casting repair by welding and surfacing. The parameters of welding and surfacing procedures are given, welding materials are recommended, and the methods for nondestructive testing of welds are prescribed.

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Vamsi, M. Madhu, V. Pradeep Kumar, and S. H. Shariff. "A Feasibility Report on the Comparsion of the Characteristics of Manufacturing a Bearing Cover by the Processes of Sand Casting and Shell Moulding." Advanced Materials Research 1148 (June 2018): 204–10. http://dx.doi.org/10.4028/www.scientific.net/amr.1148.204.

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The use of aluminum castings in the automotive industry has increased dramatically over the past two decades. The Al-Si system forms the basis of many important casting alloys, LM 0, LM 2, LM 4, LM 5, LM 6, LM 12, LM 13, LM 24 and LM 26 are the major cast alloys used in aerospace casting (e.g., fuel pump connectors) and premium automotive castings (e.g., suspension arms). The driving force for this increased use is vehicle weight reduction for improved performance, particularly fuel efficiency. In many cases the mechanical properties of the cast aluminum parts are superior to those of the cast iron or wrought steel parts being replaced; however, in some applications, defects in the cast microstructure undermine performance characteristics.

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Liao, Dun Ming, Li Liang Chen, Jian Xin Zhou, and Rui Xiang Liu. "Numerical Simulation of Thermal Stress Fields of Steel Casting." Advanced Materials Research 179-180 (January 2011): 1118–23. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.1118.

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Many defects relative to stress occur during the complicate casting process, such as hot tearing, residual stress concentration and distortion. Modeling of casting thermal stress during casting solidification process is of great significance to predict and analyze casting stress defects. Involving too many complex influencing factors, the stress simulation is very difficult and retains a hot spot of macro simulation in foundry engineering. Currently most researchers adopt integrated FDM/FEM method, i.e. using finite difference method (FDM) to calculate solidification and heat transferring, while finite element method (FEM) to simulate stress. Some universal commercial FEA packages are usually adopted. This study has tried two kinds of approaches to simulate casting thermal stress. One is based on ANSYS, a well-known powerful FEA analysis software. Another is to develop an independent own copyrighted casting stress simulation system based on FDM. The routes of these two methods were given respectively. To calibrate the simulation system, a stress frame sample and a real practical casting were simulated and pouring experiment was also carried on. The results of simulation were in agreement with the experiment results and practical cases. It indicates that these two approaches can all meet demands. When adopting FDM method, thermal analysis and stress analysis can use the same FD model, which can avoid the nodes matching between different models and reduce the errors of thermal load transferring. It makes the simulation of fluid-flow field, temperature field and stress field unify into one model. This system takes full advantages of mature FDM technology and can be used to simulate the forming of residual stress and predict the occurrence of hot tearing.

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Journal articles on the topic 'Steel casting defects'

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