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Progress in Natural Science:Materials International 2023年第5期33卷 718-732页

作者： Junyang Wang Jinwen Mu Shanhong Wan Gewen Yi Jun Jiang Xianglong Yu Xinlong Yang State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences jiugang hongxing iron & steel co.ltd. State Key Laboratory of Tribology Department of Mechanical Engineering Tsinghua University

Surface quality and tensile strength are required for the deep processing yield of high-carbon steel wires,particularly those with a cumulative reduction rate above 60 %. A systematic investigation was conducted to discern the influence mechanism of cooling rate on microstructure and crystallographic characteristics for the matrix from 650°C. The results show that the microstructure of the sample cooled at 1.5°C/s consists of a single pearlite, and the grain orientation is mainly the easy sliding crystal plane {101}. The retained austenite/martensite microstructure appears and grows with the cooling rate increasing to 4.5 and 7.5°C/s. The grain orientation shifts from an easy slip {101} plane orientation to hard slip {001} and {111} plane orientations. The number of high-angle grain boundaries that inhibit crack expansion decreased. In addition, the number of twin boundaries in the austenite/martensite grains increased. An increase in the cooling rate increased the material hardness and decreased the plastic toughness. Therefore, the cooling rate of 1.5°C/s from 650°C might concurrently yield the optimal surface quality and the microstructure of the matrix during steel production.

关键词： High carbon steel wire 3500 gleeble thermal simulator cooling rate Fe_3O_4 seam layer Matrix microstructure EBSD

Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： Ji-peng Li De-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu steel Group hongxing iron and steel co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

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

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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

Inclusion composition control During LF Refining for SPCC Using FactSage combined With Industrial Trials

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Journal of iron and steel Research International 2013年第2期20卷 14-20页

作者： CHENG Zi-jian GUO Jing CHENG Shu-sen State Key Laboratory of Advanced Metallurgy School of Metallurgy and Ecology Engineering University of Science and Technology Beijing hongxing iron and steel co ltd

steel plate cold common （SPCC） is a Al-killed steel with Ca-treatment. The control of Al2O3 inclusion into low melting point liquid region is beneficial for inclusion removal, cast-ability promotion and defects reduction during rolling. Thus it is essential to understand steel-inclusion equilibrium since inclusion composition is determined by composition of liquid steel directly through steel-inclusion reaction. Thermodynamic calculation software FactSage is performed to understand how to control inclusion composition during ladle furnace （LF） refining, and industrial trials are carried out to verify calculated results. Firstly, target region for controlling CaO-Al2O3-MgO ternary inclusion is analyzed on the basis of the ternary phase diagram and the relationship between activities related to pure solid and activities related to pure liquid was fixed by thermodynamic analysis in order to obtain reliable activities for components of inclusions in the target region by FactSage. In addition, inclusions in steel samples are detected by scanning electron microscopy （SEM） combined with energy dispersive spectroscopy （EDS）. It is found that most of Al2O3 inclusions are modified into lower melting point region but a number of them are still located in high melting point region at the end of LF refining after Ca-treatment. Moreover, the composition of liquid steel equilibrating with liquid CaO-Al2O3-MgO inclusion is obtained by steel-inclusion equilibrium calculation when w[Al]s is approximating 0.03% as： a[O] is 1.0×10-6 to 4.0×10-6, w[Ca] is 20×10-6 to 50×10-6 and w[Mg] is 0.1×10-6 to 3.0×10-6. At last, stability diagrams of various calcium aluminates and CaS are established and they show that liquid calcium aluminate inclusions form when w[Ca] is more than 20×10-6, but CaS precipitation is difficult to prevent because sufficiently low w[S] （〈0.003%） is required.

关键词： LF refining inclusion control steel-inclusion equilibrium FactSage

corrosion mechanism of Zn-Al-Mg-coated steel in simulated polluted marine atmosphere

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Journal of iron and steel Research International 2024年第9期31卷 2294-2307页

作者： Pei-dong Ning Li-yuan Xiao Jin Wang Qian-qian Liu Kui Xiao Research Institute JISCO Hongxing Iron and Steel Co.Ltd.Jiayuguan735100GansuChina Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing100083China

The corrosion behaviour of zinc–aluminium–magnesium-coated steel in a simulated polluted marine atmospheric environment was ***,an indoor ageing acceleration test was carefully designed by simulating a polluted marine *** objective was to in-depth investigate the corrosion mechanism of Zn–Al–Mg-coated steel exposed to a simulated polluted marine *** experiments were carried out by scanning electron microscopy for micro-morphological characterization,X-ray diffraction,electrochemical impedance spectroscopy and electrodynamic polarization curves for the aged *** analysis of the results obtained after an indoor accelerated ageing test shows that Zn–Al–Mg coatings generate insoluble Zn_(5)Cl_(2)(OH)_(8)·H_(2)O and Zn_(4)SO_(4)(OH)_(6)during the corrosion process,which hinders the diffusion of corrosive substances into the substrate,and the insoluble substances are structurally dense and thus inhibit further ***,this effectively inhibits the occurrence of further corrosion,and thus,Zn–Al–Mg coating can significantly extend the service life of Zn–Al–Mg-coated steel.

关键词： Zn-Al-Mg-coated steel Electrochemical impedance spectroscopy Polarization curve Atmospheric corrosion Marine atmosphere

Thermodynamic Analysis of Desulfurization and Its connection With Deoxidation and Temperature for SPHC in JISC During LF Refining Process

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Journal of iron and steel Research International 2011年第S2期18卷 135-140页

作者： GUO Jing1, CHENG Zi-jian1,2, CHENG Shu-sen1, CHENG Ze-wei1, ZOU Ming2, MA Ming-sheng2 (1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology of Beijing, Beijing 100083, China 2. China’s hongxing Stock company of jiugang,jiugang 735000,Gansu,China) Univ Sci & Technol Beijing State Key Lab Adv Met Beijing 100083 Peoples R China Chinas hongxing Stock co jiugang Jiugang 735000 Gansu Peoples R China

The thermodynamic characteristics of desulfurization reaction (CaO)+[S]=(CaS)+[O] is analyzed based on the detailed composition of liquid steel and slag of steel Plate Hot commercial (SPHC) in Jiuquan iron & steel corporation(JISC), where the activities of CaO, CaS and Al2O3 in molten slag are calculated by thermodynamic software FactSage for a more accurate result. The critical values of [O%]/[S%] for desulfurization at different temperature is are obtained, typically 0.09 at 1873K, which shows directly that it should deoxidize adequately for obtaining a favorable desulfurization condition. In addition, the thermodynamic analysis indicates that the actual dissolved O is much higher than that of equilibrium calculation which shows Al-O reaction in LF is far away from equilibrium, but it is perfect agreement with the computing results when taking the activity of Al2O3 as 1 that due to the inclusion component in LF is mainly Al2O3. Besides, with the temperature rise, the sulfur partition ratio increases softly meanwhile the reaction between Al and O is limited to a great degree resulting in the increase a dissolved oxygen in liquid steel that decreases the sulfur partition ratio seriously. As a result, the sulfur partition ratio appears to decrease with temperature increase in Al killed steel.

关键词： LF refining desulfurization deoxidation sulfur partition ratio

Effect of microstructure evolution on Luders strain and tensile properties in an intercritical annealing medium-Mn steel

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Journal of iron and steel Research International 2021年第6期28卷 762-772页

作者： Shuai Wang Wei-jian Chen Zheng-zhi Zhao Xiao-long Zhao Xiao-yang Luo Qiang Wang collaborative Innovation Center of steel Technology University of Science and Technology BeijingBeijing 100083China Beijing Laboratory for Modern Transportation Advanced Metal Materials and Processing Technology University of Science and Technology BeijingBeijing 100083China Carbon steel and Thin Slab Factory of hongxing iron and steel co. Ltd.Jiuquan Iron and Steel GroupJiayuguan 735100GansuChina

The influence of microstructural characteristics on Lu¨ders strain and mechanical properties was explored by means of altering thermo-mechanical circumstances in an intercritical annealing(IA)medium-Mn Fe-11Mn-0.09C-0.25Si(wt.%)*** IA of cold-rolled samples with severe plastic deformation,exclusively equiaxed dual phases were obtained because of active recovery and *** equiaxed austenite(gamma E)with a larger size and inadequate chemical concentration was more readily transformed into martensite,and subsequent transformation-induced plasticity(TRIP)effect was triggered actively at relatively higher IA temperature,lessening localized *** addition,grown-in dislocations were prone to multiply and migrate around a broad mean free path for coarser equiaxed ferrite(alpha E)due to weakening dynamic recovery;therefore,it was the ensuing increased mobility of dislocations instead of reserving plentiful initial dislocation density that facilitated the propagation velocity of Luders bands and the accumulation of work *** contrast,the bimodal-grained microstructure with lath-like and equiaxed austenite(gamma L+gamma E)satisfactorily contributed to a smaller yield point elongation(YPE)without compromise of comprehensive mechanical properties on the grounds that austenitic gradient stability gave rise to discontinuous but sustainable TRIP effect and incremental work ***,Luders strain is closely related to the absence of work hardening in the region which yields *** follows that the decreased stability of retained austenite,favorable mobility of dislocations and the bimodal-grained structure all prominently make up for the insufficiency of work hardening,thereof resulting in a limited YPE.

关键词： Luders strain Medium-Mn steel Work hardening Dislocation Mechanical property

Dependence of microstructure and mechanical properties on solidification condition of directionally solidified Zn-55Al-1.6Si alloys

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China Foundry 2024年第6期21卷 685-692页

作者： Ji-peng Li De-gao Qiao Jian Li Peng Peng Kai-di Hu Xian-tao Yan Shu-sen Cheng Yuan-li Xu School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Gansu Jiu steel Group hongxing iron and steel co. Ltd.Jiayuguan 735100GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

In this study,directional solidification was utilized to explore the relationship between microstructure,mechanical properties,and withdrawal speeds of Zn-55Al-1.6Si *** order to assess the characteristics of Zn-55Al-1.6Si alloys,both the microstructure and mechanical properties were thoroughly *** involved conducting room temperature tensile tests on samples with different withdrawal speeds(5,10,100,200,and 400μm·s^(-1)).The results reveal that both the as-cast alloy and samples after directional solidification are composed of zinc,aluminum,and silicon *** the withdrawal speed increases,an evident decrease in the size of the primary dendrites is *** results of tensile experiments show that Zn-55Al-1.6Si alloys after directional solidification exhibit brittle fracture characteristics,both the tensile strength and elongation of the alloys increase with withdrawal speed.

关键词： Zn-55Al-1.6Si alloy directional solidification microstructure mechanical properties

Analysis on phase selection and microstructure evolution in directionally solidified Zn-Al-Mg-Ce alloy

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China Foundry 2023年第4期20卷 347-355页

作者： Ji-peng Li De-gao Qiao Shi-wen Dong Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu steel Group hongxing iron and steel co. Ltd.Jiayuguan 735199GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China School of Physics and Electronic Information Engineering Qinghai Normal UniversityXining 810016QinghaiChina

In the process of hot-dip Zn-Al-Mg alloy coating,the plating solution dissipates heat in the direction perpendicular to the steel plate,which is considered to be a process of directional *** understand the relationship between microstructure and cooling rate of Zn-Al-Mg alloys,both the phase constitution and microstructure characteristic length scales of Zn-9.5Al-3Mg-0.01Ce(wt.%)alloy were investigated by the directional solidification experiments at different growth velocities(V=40,80,160,250μm·s^(-1)).The experimental results show that the microstructure of directionally solidified Zn-9.5Al-3Mg-0.01Ce alloy is composed of primary Al dendrites and(Zn-Al-Mg2Zn11)ternary eutectics at the growth velocities ranging from 40 to 250μm·s^(-1).The primary Al dendrites are aligned regularly along the growth direction,accompanied with obvious secondary *** relationship between the microstructure length scale and the thermal parameters of solidification is obtained:λ1=374.66V-0.383,andλ2=167.5V-0.563(λ1is the primary dendrite arm spacing,andλ2 is the secondary dendrit arm spacing).In addition,through the interface response function(IRF)and the nucleation and constitutional undercooling(NCU),the phase selection of Zn-9.5Al-3Mg-0.01Ce is obtained:(Zn+Al+Mg2Zn11)ternary eutectics in the Zn-9.5Al-3Mg-0.01Ce alloy will be replaced by ternary eutectics(Zn+Al+MgZn2)when the growth rate is lower than 7.53μm·s^(-1).

关键词： Zn-Al-Mg alloy directional solidification microstructure length scale phase selection

Phase precipitation and corrosion properties of copper-bearing ferritic stainless steels by annealing process

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Journal of iron and steel Research International 2023年第11期30卷 2280-2292页

作者： Fan Wang De-ning Zou Xing-yu Yan Ying-bo Zhang Ji-xiang Pan Yun-xia Cheng Ran Xu Yi-cheng Jiang School of Metallurgy and Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina Shaanxi Special Equipment Inspection and Testing Institute Xi’an710048ShaanxiChina Jilin Railway Technology college Jilin132200JilinChina Stainless steel Branch of Gansu Jiu steel Group hongxing iron and steel co. Ltd.Jiayuguan735100GansuChina

The effects of different annealing processes on the phase precipitation behavior and corrosion properties of copper-bearing 430 ferritic stainless steel were systematically *** shape,quantity and distribution of copper-rich precipitates by different annealing processes were characterized by scanning electron microscopy,transmission electron microscopy,backscatter electron and backscatter *** pitting resistance behavior in simulated physiological saline envi-ronments(0.9 wt.%NaCl)was investigated using electrochemical workstation and X-ray photoelectron *** results showed that the copper-rich phase prepared by repeated rolling and annealing gradually changed from long needle-like to short thick rod-like and granular,whose distribution tended to be uniform and diffusive,and the number of copper-rich phases *** solution/antibacterial annealing process,the size and density of the copper-rich phase increase,resulting in a discontinuity of the passivation film on the stainless steel,which reduces the pitting resistance to some *** refinement mechanism revealed that pre-deformation brings about a modification in both precipitation mechanism and growth kinetics of epsilon copper.

关键词： 430 stainless steel Annealing Cu-rich phase Pitting corrosion Passivation film