检索结果-南通市图书馆

Precipitation behavior of titanium nitride on a primary inclusion particle during solidification of bearing steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2017年第7期24卷 685-690页

作者： Liang Yang Bryan A. Webler guo-guang cheng State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Center for Iron and Steelmaking Research Department of Materials Science and EngineeringCarnegie Mellon University

Titanium nitride precipitation on a primary inclusion particle during solidification of bearing steel has been tracked by varying temperature in a confocal scanning violet laser *** precipitation,an obvious growth of titanium nitride on a primary inclusion particle was observed due to the rapid solute diffusion in liquid *** onset of titanium nitride precipitation did not change with primary inclusion particle size,but the time of growth was greater for a smaller primary inclusion ***,the particle size displayed little influence on the total precipitated amount of titanium nitride on it under the same *** the later period of solidification,almost no change occurred in inclusion size,but the inclusion shape varied from circle to almost square in two-dimension,or cubic in three-dimension,to attain the equilibrium with steel.

关键词： Real time observation Titanium nitride growth Bearing steel Precipitation Solidification Inclusion

Detection and analysis of magnetic particle testing defects on heavy truck crankshaft manufactured by microalloyed medium-carbon forging steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第5期27卷 608-616页

作者： Jin-long Lu guo-guang cheng Meng Wu guo Yang Ju-long Che State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Research and Development Department Xining Special Steel Co.Ltd.Xining 810005QinghaiChina

An unqualifed six-cylinder heavy truck crankshaft has been studied to investigate the cause of magnetic particle testing defects on the rod ***-sized long-striped MnS inclusions are regarded as the major cause for the magnetic particle testing failure because they have been detected in situ under the magnetic particle *** the observation of macroscopic structures of the rod journals and corresponding counterweight blocks,it is found that for the 1#and 3#rod journals,the center metal of the original hot-rolled bar has been extruded to the inboard edge of the rod journals and large-sized long-striped MnS inclusions are exposed on the surface after fash removal,leading to the failure of magnetic particle *** for the 2#rod journal,the center metal of the original bar has not been extruded to the surface and MnS inclusions on the rod journal surface are small in size,few in number,resulting in passing the magnetic particle *** the quality of the hot-rolled bars fuctuates,it is more recommended to apply magnetic particle testing on samples at the center of bars before forging to evaluate the severity of defects caused by the long-striped MnS inclusions for fear of the scrap of the fnal crankshafts.

关键词： Crankshaft Magnetic particle testing MnS inclusion Microalloyed medium-carbon forging steel Defect

Design of a submerged entry nozzle for optimizing continuous casting of stainless steel slab

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2023年第11期30卷 2229-2241页

作者： Jia-chen Pang guo-yu Qian Sheng Pang Wen-hui Ma guo-guang cheng School of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming650093YunnanChina CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

To solve slag entrapment and casting slab defects in the process of stainless steel continuous casting,submerged entry nozzle(SEN)for slab casters operating at casting speed of 1 m/min was developed based on 3D numerical simulation and water modeling experiments by controlling the outlet shape and angle of original SEN with oval and 15°angle outlet under current industrial *** simulations of fluid velocity at outlets with different shapes and angles of SENs have been carried *** results showed that oval outlet with 5°and 15°angle led to asymmetric rotating flow pattern at outlet,as well as square outlet with 15°angle,but symmetric flow pattern formed at square outlet with 5°*** effect of these SENs on meniscus stability,flow field and slag entrapment behavior of stainless steel slab casting mold was further studied by water modeling *** results showed that difficult floating fine droplets formed when the angle of outlet was 15°under the dual effect of vortex convection and shear force due to the strong swirling flow from outlet and rotating flow of ***,outlet with 5°angle could lead to the formation of larger slag droplets,while the oval outlet with 5°angle could result in the scour to the mold ***,the square outlet with 5°angle was a relatively ideal solution for the submerged entry nozzle from the aspects of the stability of the mold and the slag entrapment *** the design of a new SEN according to the experimental result,the solidification structure of continuous casting slab was obviously improved by industrial test.

关键词： Stainless steel Continuous casting Submerged entry nozzle Water modeling Slag entrapment

Mechanism of generation of large(Ti,Nb,V)(C,N)-type precipitates in H13 + Nb tool steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第11期23卷 1264-1274页

作者： You Xie guo-guang cheng Lie Chen Yan-dong Zhang Qing-zhong Yan State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Xining Special Steel Co. Ltd.

The characteristics and generation mechanism of（Ti,Nb,V）（C,N） precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of（Ti,Nb,V）（C,N） phases exist—a Ti-V-rich one and an Nb-rich one—in the form of single or complex precipitates. The sizes of the single Ti-V-rich（Ti,Nb,V）（C,N） precipitates are mostly within 5 to 10 μm, whereas the sizes of the single Nb-rich precipitates are mostly 2–5 μm. The complex precipitates are larger and contain an inner Ti-V-rich layer and an outer Nb-rich layer. The compositional distribution of（Ti,Nb,V）（C,N） is concentrated. The average composition of the single Ti-V-rich phase is（Ti_（0.511）V_（0.356）Nb_（0.133））（CxNy）, whereas that for the single Nb-rich phase is（Ti_（0.061）V_（0.263）Nb_（0.676））（C_xN_y）. The calculation results based on the Scheil–Gulliver model in the Thermo-Calc software combining with the thermal stability experiments show that the large phases precipitate during the solidification process. With the development of solidification, the Ti-V-rich phase precipitates first and becomes homogeneous during the subsequent temperature reduction and heat treatment processes. The Nb-rich phase appears later.

关键词： precipitates carbonitrides generating mechanism tool steel niobium

Roles of titanium-rich precipitates as inoculants during solidification in low carbon steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第3期17卷 276-281页

作者： Ming-lin Wang guo-guang cheng Sheng-tao Qiu Pei Zhao Yong Gan The State Key Laboratory for Advanced Steel Process and Products Central Iron and Steel Research Institute Beijing 100081 China National Engineering and Research Center for Continuous Casting Technology Central Iron and Steel Research Institute Beijing 100081 China Metallurgical and Ecological Engineering School University of Science and Technology Beijing Beijing 100083 China

The effect of titanium on the as-cast structure and the growth form of titanium precipitates, and the effect of cooling rate on the size and distribution of titanium precipitates were studied. It is shown that Ti-rich precipitates acting as heterogeneous nucleation sites play an important role in refining the grain size and increasing the equiaxed grain ratio. Cooling rate has a great effect on the size and distribution of precipitates. The number of precipitates increases and the size decreases with the increase of cooling rate. Ti-rich particles acting as het- erogeneous nucleation sites at the onset of solidification are observed in the experiment. This result suggests that TiN nucleated on Ti2O3 is an effective inoculant for δ-ferrite during solidification in low carbon steel.

关键词： precipitate titanium oxide titanium nitride cooling rate solidification

A process model for BOF process based on bath mixing degree

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 715-722页

作者： guang-hui Li Bao Wang Qing Liu Xin-zhong Tian Rong Zhu Li-ning Hu guo-guang cheng School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Research and Development Center Xingtai Steel Co. Ltd. Xingtai 054027 China

The process model for BOF process can be applied to predict the liquid steel composition and bath temperature during the whole steelmaking process. On the basis of the traditional three-stage decarburization theory, the concept of mixing degree was put forward, which was used to indicate the effect of oxygen jet on decarburization. Furthermore, a more practical process model for BOF steelmaking was developed by analyzing the effect of silicon, manganese, oxygen injection rate, oxygen lance height, and bath temperature on decarburization. Process verification and end-point verification for the process model have been carried out, and the verification results show that the predic- tion accuracy of carbon content reaches 82.6% （the range of carbon content at the end-point is less than 0. 1wt%） and 85.7% （the range of carbon content at end-point is 0. 1wt% -0.7wt%） when the absolute error is less than 0.02wt% and 0.05wt%, respectively.

关键词： steelmaking basic oxygen furnace (BOF) decarburization modelling prediction

Mathematical model for design of optimized multi component slag for electroslag remelting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第4期27卷 380-391页

作者： Shi-jian Li guo-guang cheng Yu Huang Wei-xing Dai Zhi-qi Miao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

Slag is the heart of electroslag remelting(ESR)process.A new mathematical model to design the optimized slag for ESR was developed based on slag–metal equilibrium theory,ion and molecule coexistence theory and modified Butler’s *** was assumed that an overall thermodynamic equilibrium did exist at electrode tip–slag *** this model,the equilibrium slag and its surface tension could be obtained quantitatively when the initial compositions of consumable electrode were *** industrial experiment with four types of slags was carried out in a special steel plant in *** variation of Al,Si and Mn corresponded well with the deviation of corresponding oxide from equilibrium,reflecting the reasonability of the *** that,the effects of Al in electrode as well as CaO,CaF2 and MgO in slag on the equilibrium slag,dissolved oxygen and surface tension were discussed in detail.

关键词： Electroslag remelting Model Slag design Ion and molecule coexistence theory Equilibrium slag

Influence of refining process and utilization of different slags on inclusions, titanium yield and total oxygen content of Ti-stabilized 321 stainless steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第8期27卷 913-921页

作者： Xing-run Chen guo-guang cheng Yu-yang Hou Jing-yu Li Ji-xiang Pan State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Hongxing Iron and Steel Co. Ltd.Jiuquan Iron and Steel Group CorporationJiayuguan 735100GansuChina

Ti-stabilized 321 stainless steel was prepared using an electric arc furnace, argon oxygen decarburization (AOD) furnace, ladle furnace (LF), and continuous casting processes. In addition, the effect of refining process and utilization of different slags on the evolution of inclusions, titanium yield, and oxygen content was systematically investigated by experimental and thermodynamic analysis. The results reveal that the total oxygen content (TO) and inclusion density decreased during the refining process. The spherical CaO–SiO2–Al2O3–MgO inclusions existed in the 321 stainless steel after the AOD process. Moreover, prior to the Ti addition, the spherical CaO–Al2O3–MgO–SiO2 inclusions were observed during LF refining pro-cess. However, Ti addition resulted in multilayer CaO–Al2O3–MgO–TiOx inclusions. Two different samples were prepared by conventional CaO–Al2O3-based slag (Heat-1) and -TiO2-rich CaO–Al2O3-based slag (Heat-2). The statistical analysis revealed that the density of inclusions and the -TiOx content in CaO–Al2O3–MgO–TiOx inclusions found in Heat-2 sample are much lower than those in the Heat-1 sample. Furthermore, the TO content and Ti yield during the LF refining process were controlled by using -TiO2-rich calcium aluminate synthetic slag. These results were consistent with the ion–molecule coexist-ence theory and FactSage?7.2 software calculations. When -TiO2-rich CaO–Al2O3-based slag was used, the -TiO2 activity of the slag increased, and the equilibrium oxygen content significantly decreased from the AOD to LF processes. Therefore, the higher -TiO2 activity of slag and lower equilibrium oxygen content suppressed the undesirable reactions between Ti and O.

关键词： 321 Austenitic stainless steel Oxygen content Inclusion TiO2-rich CaO–Al2O3-based slag Ladle furnace(LF)refining process Ion–molecule coexistence theory

Effect of slag on oxide inclusions in carburized bearing steel during industrial electroslag remelting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第3期26卷 291-300页

作者： Shi-jian Li guo-guang cheng Zhi-qi Miao Lie Chen Xin-yan Jiang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Xining Special Steel Group Co. Ltd.

Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable electrode and remelted using a 2400-kg industrial furnace. The results showed that most inclusions in the electrode were low-melting-point CaO-MgO-Al_2O_3. After ESR, all the inclusions in ingots were located outside the liquid region. When the slag consisted of 65.70 wt% CaF_2, 28.58 wt% Al_2O_3, and 4.42 wt% CaO was used, pure Al_2O_3 were the dominant inclusions in ingot, some of which presented a clear trend of agglomeration. When the ingot was remelted by a multi-component slag with 16.83 wt% CaO, a certain amount of sphere CaAl_4O_7 inclusions larger than 5 μm were generated in ingot. The slag with 8.18 wt% CaO exhibited greater capacity to control the inclusion characteristics. Thermodynamic calculations indicated that the total Ca and Mg in ingots were attributed from the relics in electrode and strongly influenced by the slag composition. The formation of ingot inclusions was calculated by FactSage^(TM) 7.0, and the results were basically in accordance with the observed inclusions, indicating that a quasi-thermodynamic equilibrium could be obtained in the metal pool.

关键词： bearing steel electroslag remelting slag inclusions thermodynamics