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Linghu K.-Z.,Shougang Institute of Technology | Wen D.,Beijing Shougang Cold Rolling Co. | Cai A.-Y.,Beijing Shougang Cold Rolling Co.
Journal of Iron and Steel Research | Year: 2010

After the critical stress for tensile cross buckling of four-edge simply supported steel strips was studied, the critical tensile cross buckling stress calculation for various-supported steel strips was obtained by changing the coefficient K in critical cross buckling stress formula. Consequently, the tensile cross post-buckling behavior of the strips were studied, and then the effective width was introduced to calculate the limit load for steel strips before strip yielding.


Linghu K.-Z.,Shougang Institute of Technology | Song H.-Y.,Beijing Shougang Cold Rolling Co. | Wang Y.-Q.,Shougang Institute of Technology | Li F.,Shougang Institute of Technology
Kang T'ieh/Iron and Steel | Year: 2014

By means of 3D Finite Element Method (FEM), a new 6-high CVC cold rolling mill model, which couples CVC profile, rolling force distribution between rolls, elastic deformation of rollers, and elastic-plastic deformation of strip, was built. The rolling force distribution between rolls and elastic-plastic deformation of roll and workpiece were obtained by the iteration calculation method. The model was verified in comparison with the actual rolling schedule data. The absolute error between the simulated results and the actual values is obtained to be less than 10 μm, and relative error is less than 1%. Thus, the simulated results are in good agreement with the measured data. Consequently, the effect of flatness actuators such as intermediate roll bending, intermediate roll shifting and work roll bending on secondary crown and quartic crown was studied and actual center-edge buckles of the industrial products of wide and thin strips in the cold rolling process were successfully eliminated according to the research results. ©, 2014, Chinese Society for Metals. All right reserved.


Linghu K.-Z.,Shougang Institute of Technology | Qiao J.-J.,Beijing Shougang Cold Rolling Co. | Wang Y.,Beijing Shougang Cold Rolling Co. | Zhu G.-S.,Shougang Institute of Technology | Liu G.-M.,Shougang Institute of Technology
Kang T'ieh/Iron and Steel | Year: 2012

The heat-buckling in CAL had bad effect on the processing, which caused economic loss to production lines. The hot buckling of thin-and-wide strips in the furnace was investigated in both mechanical theories and FEM simulation. The results show that the critical stresses for different initial flatness are quite different. After optimization and modification of the flatness target curves in TCM, the probability of hot buckling is reduced more than 50%.


Yin H.,University of Science and Technology Beijing | Zhao A.,University of Science and Technology Beijing | Zhao Z.,University of Science and Technology Beijing | Yu W.,Shougang Institute of Technology | And 2 more authors.
Cailiao Kexue yu Gongyi/Material Science and Technology | Year: 2014

To study the feasibility of the production of automobile steel of medium-manganese TRIP steel with the continuous annealing process, the effect of different manganese content on microstructure and mechanical properties of medium-manganese TRIP steel was investigated on heat treatment system for thin steel sheet CCT-AY-II type. The microstructure of the steel with different Mn content was observed by means of SEM, TEM and EBSD. The amount of retained austenite in the steel was determined by X-ray diffraction analysis and its mechanical properties were measured in the laboratory. When the steel is at 650℃ for 3 min, and with the increase of manganese content, the yield strength first increases and then decreases, the tensile strength continuously rises, while the elongation almost maintains at about 20%. Research on the microstructure shows that the retained austenite increases with the increasing of Mn content. When Mn content is more than 6% (including 6%), the real stress-strain curves appears jagged due to the dynamic strain aging, and the work hardening exponent is far greater than that of the 5Mn steel. TRIP effect of metastable austenite and ultrafine ferrite and martensite together provide high plasticity.


Zhu G.-M.,University of Science and Technology Beijing | Kuang S.,University of Science and Technology Beijing | Chen G.-J.,University of Science and Technology Beijing | Chen B.,Beijing Shougang Cold Rolling Co. | Ren J.-R.,Beijing Shougang Cold Rolling Co.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2011

Based on the annealing and tempering in lab, the effect of martensite volume fraction (MVF) and tempering temperature on yield characteristics of trial dual phase (DP) steel were investigated by mechanical test and microstructure analysis. The results show that the MVF increases from 0% to about 15%, the yield stress of DP steels decreases significantly, the decrease values are between 80MPa and 100MPa; When MVF is in 15%-35%, the yield stress of DP steels maintains at a lower level, whereas, when MVF is more than 35%, the yield stress increases rapidly. When MVF exceeds 10%, the DP steels represent continuous yield. With the increasing of tempering temperature from 200°C to 400°C, the yield stress of DP steels increases monotonously, and the yield platform reappears when tempering temperature is more than 300°C. Based on the observation and analysis to the fine microstructures of DP steels, the high density phase transformation induced dislocation and residual stress are considered as the potential reasons for the low stress and continuous yield of DP steels.


Dong R.,University of Science and Technology Beijing | Dong R.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Zhao A.,University of Science and Technology Beijing | Zhao A.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | And 7 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2014

Microstructure and mechanical properties of continuous cold rolling strip steel welded joint from weld seam to heat affected zone were analyzed by SEM, vickers microhardness tester and forming experiment machine. The results show that, the microstructure of the continuous cold roll strip steel welded joint is composed of granular bainite, lath bainite and minor martensite-austenitic unit, and amount of polygonal ferrite appears in the critical coarse grained region. The microhardness value achieves peak in the weld metal, which fluctuates in the heat affected zone, and decreases sharply in the critical coarse grained region, then approaching the hardness value of the base mental gradually. Forming experiment shows that the crack startes from the critical coarse grained region, and the metal ductile fractures after a slight plastic deformation.


Li Z.,Beijing Shougang Cold Rolling Co Ltd | Cheng X.-J.,Beijing Shougang Cold Rolling Co Ltd | Cai A.-Y.,Beijing Shougang Cold Rolling Co Ltd | Wen D.,Beijing Shougang Cold Rolling Co Ltd | And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

The effects of annealing process on mechanical properties and the stability of retained austenite of third generation of AHSS of cold-rolled low-carbon medium-manganese TRIP steels were investigated. The results show that the mechanical properties are significantly influenced by intercritical annealing temperature and soaking time. When the samples of 6.72%Mn-TRIP steel are annealed at approximately 590 ℃ for 18 h, the tensile strength is 815 MPa and the elongation is 38%, the UTS×TE values in excess of 30 GPa·% can be obtained. During the intercritical soaking time, C and Mn atoms in the martensite have partitioned into retained austenite, thereby, the retained austenite can be stabilized at room temperature. Due to the combination of the retained austenite, martensitic and recrystallization ferrite, that the remarkable combinations of strength and ductility are obtained.


Cheng X.-J.,Beijing Shougang Cold Rolling Co Ltd | Li Z.,Beijing Shougang Cold Rolling Co Ltd | Cai A.-Y.,Beijing Shougang Cold Rolling Co Ltd | Qiao J.-J.,Beijing Shougang Cold Rolling Co Ltd | And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

Effect of cold rolling reduction ratio on microstructure, mechanical properties and texture of 390 MPa IF steel during continuous annealing was studied by observing microstructure, testing performance and analyzing texture. The results show that as the cold rolling reduction ratio increasing, stored energy and strength of the steel increase, recrystallized grain size becomes small and even, and increase cold rolling reduction ratio can eliminate the deformation texture {112}<110>. {111}<110>texture increases and {001}<110>texture decreases with the increasing of cold rolling reduction ratio. When the cold rolling reduction ratio is 80%, rm value and elongation reache the peak, while Δr value is relatively small, and the deep drawability of the steel sheets is the best.


Yuan X.H.,Control Iron and Steel Research Institute, China | Qi C.Y.,Beijing Shougang Cold Rolling Co | Zhang Q.F.,Control Iron and Steel Research Institute, China
Advanced Materials Research | Year: 2014

The surface morphology and microstructure of galvannealed steel sheet (GA) coatings prepared at different galvannealing parameters were analyzed by X-ray diffraction and SEM, and powdering amount of GA coating was investigated by the double-Olsen powdering tester. The results show that when the Al contents below 0.16 wt%, the Ra of GA coating surface was measured namely below 1.0 μm, and powdering amount of GA coating was below 30 mg/m2, it is within a reasonable value required by automotive makers. After that with the Al contents increased in zinc liquid the amount of powdering increased, this means that the powdering resistance performance of GA coating not only depended on the iron content in the coating, but depended on the roughness profiles of the surface coating. When the galvanizing coating with 0.22 wt% Al content and galvannealing at 500 °C, with the inhibition effect of Fe2Al5Znx inhibit layer, the thickness of δ1k-phase was different in the GA coating, which deteriorated the powdering resistance performance of GA coating. © (2014) Trans Tech Publications, Switzerland.


Wang Q.,Northeastern University China | Yan H.,Beijing Shougang Cold Rolling Co. | Ren N.,Northeastern University China | Li B.,Northeastern University China
JOM | Year: 2015

The influence of the slag thickness on macrosegregation and transition zone (TZ) width of electroslag remelting (ESR) dual alloy ingot was investigated. To produce a dual alloy ingot, an electrode, constituted by a CrMoV bar and a NiCrMoV alloy bar, was remelted by using the ESR process. The slag thickness ranged from 50 mm to 70 mm. The results indicate that the slag temperature and melt rate first increase and then decrease with the increasing of the slag thickness. The metal sump depth, however, monotonically decreases. The most pronounced macrosegregation is found when the slag thickness is 50 mm and is alleviated with a thicker slag. The minimal TZ width appears when the slag thickness is 60 mm. Processing the ESR dual alloy ingot with a 60-mm slag layer is the best choice for reducing the TZ width and macrosegregation in the present work. © 2015 The Minerals, Metals & Materials Society

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