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Austenite Grain Size Evolution in Railway Wheel During Multi-Stage Forging Processes

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Journal of Iron and steel Research International 2013年第3期20卷 57-65页

作者： SHEN Xiao-hui YAN Jun ZHANG Lei GAO Lin ZHANG Jing co.lege of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics School of Materials Science and Engineering Anhui University of Technology Tyre and Wheel co.pany Ma'anshan Iron and Steel Co.Ltd.

The knowledge of microstructure evolution of railway wheel during hot forming process is the prerequisite of improving mechanical properties of the final *** order to investigate the austenite grain size evolution of railway wheel during multi-stage forging process,mathematical models of recrystallization and austenite grain growth were derived firstly by hot co.pression tests for railway wheel steel CL50D,which then were integrated with a thermal-mechanical finite element model by the developed *** information about kinetics of recrystallization and grain size distribution during the forging process was obtained by *** predicted results were validated by experiments in an industrial scale,and the average error between the predicted grain sizes and the measured ones is about 5%.The result shows that,under the current railway wheel forging process,the grain size distribution after final forging is inhomogeneous *** is a narrow co.rse grain zone between the external part and center of the hub caused by static recrystallization after final *** co.ling of 60 s after final forging,the grain size is about 85 μm for the areas near the web surface and 175 μm for center areas of the hub and rim.

关键词： austenite grain size railway wheel forging

Stress-strain partitioning analysis of co.stituent phases in dual phase steel based on the modified law of mixture

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International Journal of Minerals,Metallurgy and Materials 2009年第4期16卷 393-398页

作者： Shuang Kuang Yong-lin Kang Hao Yu Ren-dong Liu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Technology Center Anshan Iron ＆ Steel Group Corporation Anshan 114001 China

A more accurate estimation of stress-strain relationships for martensite and ferrite was developed, and the modified law of mixture was used to investigate the stress-strain partitioning of co.stituent phases in dual phase （DP） steels with two different martensite volume fractions. The results show that there exist great differences in the stress-strain co.tribution of martensite and ferrite to DP steel. The stress-strain partitioning co.fficient is not co.stant in the whole strain range, but decreases with increasing the true strain of DP steel. The softening effect caused by the dilution of carbon co.centration in martensite with the increase of martensite volume fraction has great influence on the strain co.tribution of martensite. The strain ratio of ferrite to martensite almost linearly increases with increasing the true strain of DP steel when the martensite volume fraction is 22%, because martensite always keeps elastic. But the strain ratio of ferrite to martensite varies indistinctively with the further increase in true strain of DP steel above 0.034 when the martensite volume fraction is 50%, because plastic deformation happens in martensite. The stress ratio ofmartensite to ferrite decreases monotonously with increasing the true strain of DP steel whether the martensite volume fraction is 22% or 50%.

关键词： stress and strain partitioning dual phase steel ferrite martensite

Distinct element method simulation of mechanical properties of material layer of pellet belt roasting machine

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Journal of Iron and steel Research International 2024年第11期31卷 2633-2644页

作者： Yin-hua Tang Xing-wang Li Xu Gao Tao Yang Hong-ming Long Jie Lei School of Metallurgical Engineering Anhui University of TechnologyMa’anshan243032AnhuiChina Xinyu Iron and steel Group co. Ltd.Xinyu338000JiangxiChina Key Laboratory of Metallurgy Engineering&Resources Recycling(Anhui University of Technology) Ministry of EducationMa’anshan243002AnhuiChina

The thick layer and graded feeding technology of a belt roasting machine is an effective method for improving the production efficiency and quality index of pellet production,and a reasonable design of the mechanical structure of the layer is the basis for optimizing the heat and mass transfer performance of the *** effect and von Mises yield criterion were used to establish a simplified mathematical model describing the elastic and plastic deformation of the green pellet under the action of an external *** mechanical characteristics of extrusion,co.tact,and elastic-plastic deformation between green pellet particles in the material layer of the belt roasting machine were modeled using EDEM *** a green pellet size of 12 mm,as the layer height increases from 300 to 1000 mm,the maximum vertical pressure on the pellets increases from 11.64 to 24.01 N,and the porosity decreases from 27.04%to 22.01%.As the layer height increases,the co.tact between the green pellets beco.es more intense,and the force chain structure of the layer beco.es more stable;the Janssen effect is observed when the layer reaches 700 *** co.pressive strength of the green pellets is linearly related to the particle size,and the co.pressive strength increases with an increase in particle *** a layer height of 600 mm,as the particle size of the green pellets increases from 8 to 20 mm,the maximum vertical pressure increases from 7.54 to 44.16 N,and the porosity increases from 23.20%to 31.47%,while the yield per unit of the layer decreased by 12.1%.Small particles have a more stable force chain structure,larger co.parative area,and higher production efficiency;however,their co.pressive strength is *** particles have higher co.pressive strength and good permeability in the layer,but the production efficiency is relatively *** actual production,a variety of factors should be integrated to optimize the feeding,and a multi-granularity graded feeding is the most ideal

关键词： Belt roasting machine Distinct element method Green pellet Thick material layer Mechanical property

co.trolling oxygen co.tent in electro-slag remelting steel by optimizing slag-steel reaction process

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China Foundry 2023年第6期20卷 503-510页

作者： Dian-dong Sun Yong Wang Lei Jin Zong-xu Pang Jian Huang Jian-ping Zhang Iron&steel Research Institutes of Ansteel Group co.poration Anshan 114009LiaoningChina State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009LiaoningChina Shenyang Research Institute of Foundry co. Ltd.CAMNational Key Laboratory of Advanced Casting TechnologiesShenyang 110022China

The thermodynamic equilibrium of deoxidation reactions between molten slag and steel was calculated using a slag-steel co.pling thermodynamic model and the mass co.servation model based on the ion-molecular co.xistence *** study focused on the effects of slag co.position and deoxidizer type on the oxygen co.tent of low alloy steel during the electroslag remelting(ESR)*** measured and predicted values of the oxygen co.tent in remelted ingots,and the co.tents of FeO and MnO in slags were co.pared and *** show that the measured co.tent of total oxygen has a certain co.relation with the trend of dissolved oxygen predicted by the model when using Ca-Si alloys as deoxidizer,but it is not co.related with the trend of dissolved oxygen predicted by the model when using Al as *** deoxidation mechanisms of Ca-Si and Al are ***-Si alloy directly reacts with FeO and MnO in slag to reduce the oxygen potential of slag,hence it can inhibit the transfer of oxygen from the slag to molten ***,when Al deoxidizer is used,the oxygen co.tent in steel is mainly reduced through floating up the alumina *** to Al,utilizing Ca-Si alloy as a deoxidizer is more effective in reducing the oxygen co.tent and the amount of inclusions in ESR ingot.

关键词： ion-molecular co.xistence theory slag-steel reaction deoxidation electro-slag remelting

Effect of co.tinuous annealing parameters on the mechanical properties and microstructures of a co.d rolled dual phase steel

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International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 159-164页

A co.d rolled dual phase （DP） steel with the C-Si-Mn alloy system was trial-produced in the laboratory, utilizing a Gleeble-3800 thermal simulator. The effects of co.tinuous annealing parameters on the mechanical properties and microstructures of the DP steel were investigated by mechanical testing and microstructure observation. The results show that soaking between 760 and 820℃ for more than 80 s, rapid co.ling at the rate of more than 30℃/s from the quenching temperature between 620 and 680℃, and overaging lower than 300℃ are beneficial for the mechanical properties of DP steels. An appropriate proportion of the two phases is one of the key factors for the favorable properties of DP steels. If the volume fraction of martensite and, thereby, free dislocations are deficient, the tensile strength and n value of DP steels will decrease, whereas, the yield strength will increase. But if the volume fraction of martensite is excessive to make it beco.e a dominant phase, the yield and tensile strength will increase, whereas, the elongation will decrease obviously. When rapid co.ling rate is not fast enough, pearlite or cementite will appear, which will degrade the mechanical properties. Even though martensite is sufficient, if it is deco.posed in high temperature tempering, the properties will he unsatisfied.

关键词： austenization intercritical annealing dual phase steel co.d rolling diffusion

Effects of Austenizing Temperature on Reprecipitation of BN

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Journal of Iron and steel Research International 2013年第9期20卷 99-104页

作者： YIN Shi-ke A Rong Mitsuru Tanino China Iron and steel Research Institute Group Fundamental Research Laboratory Nippon Steel Co.

Most of BN was precipitated around the spherical MnS and formed the co.pound of MnS and BN during the isothermal treatment at 850 ℃ after austenizing at 950-1050 ℃. Most of MnS was transformed into polygon when austenized at 1 150 ℃ or above, which co.ld not be the nuclei of BN anymore. During the insulation process at 850 ℃, MnS kept the state of monomer. The co.pound of MnS and BN at earlier time was of fine polycrystalline in spherality and BN was formed as a plate-like monocrystal on a certain part of the polycrystalline when its dimension reached 0.6 μm.

关键词： austenizing temperature BN repreeipitation isothermal treatment

An innovative process of clad teeming for preparing slab ingot

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Journal of Iron and steel Research International 2022年第12期29卷 2006-2015页

作者： Wen-bin Ma Yao-hui Jin Yu-an Jing Wen-bin Li Wei-da Yu Guang-long Li Wan-ming Li School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Iron and steel Research Institutes of Ansteel Group co.poration Anshan 114001LiaoningChina

An innovative process of clad teeming was proposed to prepare slab ingot,which featured a built-in co.d co.e to inhibit solidification defects.A 20-kg clad ingot was prepared in the experiment,using a volume ratio of solid co.e to molten steel of 1:13 and a preheating temperature of co.d co.e of 573 *** microstructures of the clad ingot were analyzed by co.paring with a reference ingot without co.d *** morphologies and mechanical properties of the clad ingot were studied before and after hot *** effect of co.d co.e on heat transfer and nucleation during the solidification in clad ingot was *** show that the solidification microstructures in the clad ingot are refined and homogenized *** grain size in the center of the reference ingot is 2–3 times greater than that of clad ingot,and there is almost no co.umnar grain in the clad *** interfacial shear strength reaches 318 MPa,which shows excellent metallurgical bonding at the interface of co.d co.e and molten *** defects at the interface are eliminated,and interfacial shear strength reaches 426 MPa after hot rolling with a 68.4%total reduction *** experiment and analysis of this process are expected to provide a new idea to prepare large ingots with refinement and homogeneity at a low co.t.

关键词： Clad teeming steel ingot Grain refinement Interface co.d co.e Interfacial mechanical property

Effect of inclusions on the formation of acicular ferrite in Ti-bearing non quenched-and-tempered steel

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Journal of University of Science and Technology Beijing 2007年第6期14卷 501-506页

作者： Ying Yang Chaobin Lai Fuming Wang Zhanbing Yang Bo Song Metallurgical and Eco.ogical Engineering School University of Science and Technology Beijing Beijing 100083 China Technology Centre Anshan Iron and Steel Group Corporation Anshan 114009 China Technology Centre Xinyu Iron and Steel Group Xinyu 336501 China

Nucleation of acicular ferrite and its influence factors in non quenched-and-tempered steel was studied by using TEM and thermodynamic calculation. The results show that the co.plex particles with a center made of Ti oxide, Al2O3, and silicate and an outside made of a small quantity of mixture of TiN and MnS are able to act as ferrite nucleation nuclei. The acicular ferrite percentage changes little with Ti. When the oxygen co.tent was 80 ppm, the volume percentage of acicular ferrite decreased due to an increase in allotriomorphic ferrite. The larger the co.ling rate and the shorter the incubation time, the finer the titanium oxide and the higher the nucleation ratio of acicular ferrite.

关键词： acicular ferrite titanium inclusions non quenched-and-tempered steel

A New Route for Identification of Precipitates on Austenite Grain Boundary in an Nb-V-Ti Microalloyed steel

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Journal of Iron and steel Research International 2011年第8期18卷 53-57页

作者： SHA Qing-yun HUANG Guo-jian GUAN Ju MA Xiao-jun LI Da-hang Technology Center Angang Steel Company Limited Anshan 114009 Liaoning China

The precipitates on austenite grain boundaries in an Nb-V-Ti microalloyed steel have been investigated by transmission electron microsco.e （TEM） examination of carbon extraction replica. The replica was prepared from specimen etched with saturated picric solution rather than Nital which is co.ventionally used. Then particles on both grain boundaries and triple point of grain [aoundaries were clearly observed and identified as （Nb,Ti）（C, N） parti- cles. In case of co.ventional way, it is difficult to determine the location of particles with respect to austenite grain boundaries. The number of particles observed in new way developed was greatly reduced co.pared with that found in replica prepared by the co.ventional way, which may be caused by the dissolution of partial precipitates during the etching with longer time and at higher temperature involved in new way. Despite this, the new way developed pro- vides an effective way to determine the precipitate particles on austenite urain boundaries_

关键词： precipitate austenite grain boundary replica etch