Laiwu Iron and Steel Co

Laiwu, China

Laiwu Iron and Steel Co

Laiwu, China

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Wu S.-L.,University of Science and Technology Beijing | Wu S.-L.,Control Iron and Steel Research Institute, China | Han H.-L.,University of Science and Technology Beijing | Li H.-X.,University of Science and Technology Beijing | And 4 more authors.
International Journal of Minerals, Metallurgy and Materials | Year: 2010

The basic sintering characteristics of Yandi ore from Australia, including assimilation ability, liquid phase fluidity, self-strength of bonding phase, forming ability of silico ferrite of calcium and aluminum (SFCA), and so on, were investigated in detail. Besides, the high temperature behavior and function of sintering were obtained. As a result, the techniques for ore-proportioning in sintering were obtained. The results show that Yandi ore possessing higher assimilation ability, better liquid phase fluidity, lower self-strength of bonding phase, and better forming ability of SFCA, should be mixed with iron ores whose properties are opposite to those of Yandi ore. In the optimization of sintering ore-proportioning, Yandi ore, whose price is relatively low, can be mixed as high as 40wt%. © University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2010.

Wang B.,University of Science and Technology Beijing | Liu Q.,University of Science and Technology Beijing | Yang Z.,University of Science and Technology Beijing | Yang Z.,Laiwu Iron and Steel Co.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2013

The criticality evaluation criteria system of equipment, which consists of reliability, maintainability, economy and monitoring factors, fuzzy analytic hierarchy process (FAHP) was established and employed to determine the relative initial weights of various criticality factors considering the fuzziness of these factors, and the consistency adjustment method for fuzzy judgment matrix was proposed. Then the criticality index (CI) for 12 subsystems of electric arc furnace (EAF) steelmaking process was calculated by adopting Monte Carlo simulation. Moreover, the criticality area index was used to represent the importance level of equipment, and the equipment system was divided into four categories according to this indicator, including critical equipment, main equipment, general equipment and minor equipment. Maintenance strategy was presented based on the classification of equipment in steel plants. The results show that the methodology of equipment criticality calculation based on FAHP and Monte Carlo simulation can alleviate the impact of subjective factors, and is easy to implement, therefore, it is highly significant to improve system reliability and availability, and to ensure the steel production process running continuously, stably and efficiently by applying this method to maintenance decision-making for complex equipment systems in steel plants.

Guan B.,University of Science and Technology Beijing | Zang Y.,University of Science and Technology Beijing | Qu W.,Laiwu Iron and Steel Co. | Lu Z.,Laiwu Iron and Steel Co. | Feng W.,Laiwu Iron and Steel Co.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2012

Through studying the coupling between stress evolvement and reversely bending behaviour during roller leveling process, it is demonstrated that the bending history of the section needs to be taken into account during the analysis of continuous recurvate process. With the application of elastic-plastic theory, a numerical solution has been established to describe the continuous recurvate process precisely considering the section deformation history. With this solution, the stress evolvement and its affect to the M-C curve are studied detailedly during the straightening process under small deformation procedure. It is found that the deformation history has a non-negligible effect on the bending characteristics of the section in reversely bending, and the difference of bending characteristics will make the M-C curve of the different section under the same process conditions not converged. In the roller leveling process, although the beam goes through the same device, the sections with different initial curvatures will possess different deformation history and different bending characteristics, which eventually results in that the range of the residual curvature of beam can not gradually reduce with the increase of the number of reverse bending as expected. This theoretically explains why the small deformation procedure shows poor performance at the production site. ©2012 Journal of Mechanical Engineering.

Zhao J.-Y.,University of Science and Technology Beijing | Zang Y.,University of Science and Technology Beijing | Yin D.-Q.,Laiwu Iron and Steel Co.
Suxing Gongcheng Xuebao/Journal of Plasticity Engineering | Year: 2013

Reversing break-down rolling processes of different sizes of H-beam were simulated by ABAQUS software using explicit method in this paper. The technology of mesh adaptation (ALE) was used to solve the problem of mesh distortion in multi-pass rolling. The simulation model was more accurate by introducing the measurement data of temperature. The results indicated that the groove obviously affected the final cross-section of break-down rolling. When broadening groove was used to roll large size H-beam, the cross-section of rolled pieces in last pass didn't match the groove, which caused the incomplete flange. When box groove was used to roll small size H-beam, the cross-section of rolled pieces in last pass almost matched the groove. The cross-section dimension of H700×300 was verified by the measurement data. According to the above phenomena, the groove of large size H-beam has been optimized to improve the incompleteness of flange. Results of this study could provide guidance for designing rolling schedule of BD.

Zhang Z.,Northeastern University China | Zhou H.,Central South University | Liu X.,Northeastern University China | Li S.,Laiwu Iron and Steel Co | And 4 more authors.
Materials Science and Engineering A | Year: 2013

Hot compression test of coiled tubing steel is performed on Gleeble3500 at 850-1100°C and strain rate from 0.001s-1 to 5s-1. It is found that the flow stress behavior is described by the hyperbolic sine constitutive equation in which the average activation energy of 390kJ/mol is calculated. And the hot deformation behavior of coiled tubing steel is characterized by using processing maps developed on the basis of the dynamic materials model. The processing map shows the flow instable region and the flow stable region. The dynamic recovery (DRV) and dynamic recrystallization (DRX) occur in the stable region. In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. According to the processing map, the coiled tubing steel is rolled by the Thermo-Mechanical-Control-Process (TMCP), and finally it is obtained that the yield strength and tensile strength of coiled tubing steel are 565MPa and 685MPa respectively, and the elongation percentage is 32.1%. © 2012 Elsevier B.V.

Li Z.-F.,Laiwu Iron and Steel Co. | Dong S.-S.,Shandong University | Lin Q.-N.,Laiwu Iron and Steel Co. | Guan S.-J.,Laiwu Iron and Steel Co.
Corrosion and Protection | Year: 2011

The corrosion of gas pipeline inwall due to dried blast furnace gas after dedusting in Laiwu Steel analyzed. A protection program using vapor corrosion inhibitor was proposed. The industrial tests proved feasibility of the program.

Huang S.-W.,Laiwu Iron and Steel Co Ltd | Ma G.-T.,Laiwu Iron and Steel Co Ltd | Huo X.-X.,Laiwu Iron and Steel Co Ltd | Wang T.-F.,Laiwu Iron and Steel Co Ltd
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2015

Effects of quenching and tempering heat treatment on microstructure and properties of X100 pipeline steel were investigated by means of SEM, TEM, tensile test and instrumented impact test. The results show that thermo mechanical control process (TMCP) plate after tempering at 450℃, the yield strength (Rt0.5) reduces from 785 MPa to 731 MPa, tensile strength (Rm) increases from 845 MPa to 931 MPa, the material's strength, plasticity and toughness improve. The lath bainite (LB)'s lath structure of the steel is weakened, volume fraction of granular baintie (GB) decreases and martensite/austenite (M/A) constituents are refined to sub micrometer grade. The tempering resistance of acicular ferrite (AF) is higher than that of LB and GB. After quenching at 940℃ and then tempering at 450℃, the Rt0.5 and Rm of the test steel are 819 MPa and 893 MPa, respectively, Rt0.5/Rm is 0.92, A50 is 33.5%, the strength and toughness improve. The improvement effect of the quenching and tempering heat treatment on the test steel's brittle crack propagation energy (E3) and brittle crack arrest energy (E4) is better than tempering at 450℃, and with the test temperature decreasing, the improvement effect of crack arrest property becomes worse. The coarsening grains are refined by the division of LB, GB and the parallel arrangement of M/A constituents. Due to the sub micrometer grade M/A constituents' distribution difference, the different areas in ferrite grain presents LB and GB microstructure characteristic. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.

Wang X.,Shandong University | Wang Z.-C.,Shandong University | Wang X.-B.,Shandong University | Wang Y.-R.,Shandong University | And 2 more authors.
Journal of Iron and Steel Research International | Year: 2012

Microstructures and critical phase-transformation temperature of boron-nickel added Nb-treated high strength low alloy (HSLA) H-beams cooled at different cooling rate, with different deformation were investigated. Continuous cooling transformation (CCT) diagram of this new type of steel was obtained by using Gleeble 1500 ther-momechanical simulator. Microstructures and hardness, especially micro-hardness of the experimental steel were investigated by optical microscopy (OM), scanning electron microscope (SEM), Rockwell and Vickers hardness tests. Phase analysis was also studied by X-ray diffraction (XRD). The results indicated that with increase of cooling rate, microstructures of continuous cooled specimens gradually transformed from polygonal ferrite and pearlite, grain boundary ferrite and bainite, bainite and martensite to single martensite. The CCT diagram revealed that slow cooling was needed to avoid austenite-bainite transformation to ensure toughness of this steel. By plastic deformation of 40%, austenite-ferrite transformation temperature increased by 46 °C, due to deformation induced ferrite transformation during continuous cooling, but Rockwell hardness has little change. © 2012 Central Iron and Steel Research Institute.

Wang X.,Shandong University | Wang Z.-C.,Shandong University | Wang X.-B.,Shandong University | Li X.-D.,Shandong University | And 2 more authors.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2012

Microstructures and mechanical properties of subcritical/complete quenched and quenched & tempered boron-nickel added Nb-treated high strength low alloy (HSLA) H-beams were investigated. The results indicate that the subcritical quenched and tempered steel exhibits good combination of strength, plasticity and toughness. Yield strength, tensile strength and elongation of the subcritical quenched and tempered steel is 512 MPa, 595 MPa and 27%, respectively. Its ductile-brittle transition temperature is -88°C. The quasi-polygonal ferrite and dispersed small carbides make sure high plasticity without dramatic decrease of strength after tempering. The carbides promote grain refinement by pinning effect and have little influence on toughness.

Li H.,Shandong University | Wang Z.-C.,Shandong University | Xue C.-S.,Shandong University | Zhuang D.-D.,Shandong University | And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2013

To study the effect of alloying elements, Nb, B and Ni, on lamination crack resistant property (Z-direction property) of high strength low alloy H-beam steels, contrast experiment was designed. Microstructure, composition and mechanical properties, especially the Z-direction property of the experimental steels were investigated by means of SEM, XRD, TEM, EDS analysis and tensile test. The results indicate that the microalloy elements of Nb, B and small amount of Ni do harm to the lamination crack resistant property, and the experiment steel of Q345E, which contains Nb, B, Ni and lower inclusions, exhibits lower Z-direction property after ladle refining than the steel of Q345B, which does not contain Nb, B, Ni and does not experience the refining process. Mechanism of this phenomenon is mainly ascribed to the effect of Nb, B and Ni on obstruction of dislocations at grain boundaries and inside grains.

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