Hunan Valin Xiangtan Iron and Steel Co.

Hunan, China

Hunan Valin Xiangtan Iron and Steel Co.

Hunan, China
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Xiao H.,Hunan International Engineering Consulting Center Co. | Zhang H.,Hunan Valin Xiangtan Iron and Steel Co.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2017

By measuring the dilatometric curves of SCM435 steel under different cooling rates on MMS-200 thermo-mechanical simulator, and combining with metallographic analysis, continuous cooling transformation behavior of undercooled austenite of SCM435 steel was studied, and the static CCT curve of the tested steel was measured. And high temperature phase transformation of SCM435 steel from 750℃ to 550℃ was studied based on CCT curve. The results show that during continuous cooling, bainite transformation occur mainly in SCM435 steel, and martensite phase transformation occur easily too. While the independent phase transformation range of ferrite and pearlite is not obtained. During cooled from 750℃ to 550℃, when the cooling rate is decreased to 0.15℃/s, the complete high temperature phase transformation microstructure ferrite+pearlite that is favorable for subsequent processing can be obtained. © 2017, Editorial Office of "Jinshu Rechuli". All right reserved.


Miao Z.,Wuhan University of Technology | Miao T.,Wuhan University of Technology | Qiu F.,Hunan Valin Xiangtan Iron and Steel Co. | Leng S.,Wuhan University of Technology | Niu L.,Wuhan University of Technology
Applied Mechanics and Materials | Year: 2012

The design and fabrication of offshore structure depend on material science and solid mechanics, such as steel processing technology and welding and materials testing and evaluation and so on. In this paper, CTOD (Crack Tip Opening Displacement) toughness test for weld joint of heavy thickness S355G10+N steel has been carried out to evaluate the fracture resistance of this weld joint under Submerged Arc Welding(SAW). The results show that (1) the weld joint of heavy thickness S355G10+N steel tested possesses excellent toughness. That is to say the materials in the weld joint possess enough capacity resisting the crack and propagation. Therefore the welding procedure specification evaluated can be applied to fabricate offshore structure. What is more, being at the case of as-weld condition for the weld joint the CTOD test was carried out herein, hence the offshore structure fabricated with the welding procedure specification evaluated can avoid the post welding heat treatment. (2) Different positions in weld joint have their special toughness. The position which is 2mm away from the fusion line (located in base metal) (FL+2) possesses best toughness (average value is 0.825mm). The fusion line position (FL) possesses slightly worse toughness (average value is 0.672mm). The weld metal position possesses worst toughness (average value is 0.553mm). This distribution character is different from other references reported and comparision has been made in this study. (3) Being a lower fracture toughness in weld metal, as a design suggestion high stresses should be avoided in this position. © (2012) Trans Tech Publications.


Yang S.,Xiangtan University | Wen Z.,Xiangtan University | Li L.,Hunan Valin Xiangtan Iron and Steel Co. | Tan Y.,Xiangtan University | Chen X.,Xiangtan University
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014

Based on the meshing theory, the meshing equations of a globoidal cam mechanism with error were deduced. By using the differential method, the motion accuracy influence coefficient expressions of the globoid cam mechanism were obtained. Firstly a simple tolerance allocation method was proposed. Then the improved optimal limit deviation tolerance allocation method was proposed by comprehensively considering the processing cost, size and the assembly performance of practical engineering. On the basis of that, the globoidal cam mechanism tolerance allocation problems were discussed. Targeted to a specific globoidal cam mechanism transmission system example, the tolerance distribution problems were solved by using two methods. The results show that the improved optimal limit deviation method is reasonable. A tolerance allocation method is provided for the globoidal cam mechanism, and provides reference for other spatial conjugate transmission mechanism tolerance allocation.


Yang J.,Hunan Valin Xiangtan Iron and Steel Company Ltd | Du J.,Hunan Valin Xiangtan Iron and Steel Company Ltd | Chen B.-T.,Hunan Valin Xiangtan Iron and Steel Company Ltd | Wu J.-X.,Hunan Valin Xiangtan Iron and Steel Company Ltd
Kang T'ieh/Iron and Steel | Year: 2015

The influence of calcium treatment was studied on non-metallic inclusions when control technology of refining top slag in ladle furnace was used in ultra-low oxygen refining process. Sufficient aluminium was added to test heats for final deoxygenation during BOF tapping, and the refining top slag with high basicity and strong reducibility in ladle furnace was used to produce ultra-low oxygen steel, and the transformation of non-metallic inclusions in molten steel was compared by calcium treatment and not calcium treatment. The results show that aluminium deoxidation products have finished the transformation of Al2O3→MgO·Al2O3 spinel→CaO-MgO-Al2O3 complex inclusions with lower melting point and need not calcium treatment to molten steel when using the control technology of ladle furnace refining top slag to produce ultra-low oxygen steel, and the complex inclusions with lower melting point are liquid at the temperature of steelmaking and easy removed to obtain very high cleanliness steel by collision and coalescence and flotation. Furthermore, the problems of nozzle clogging in casting operations are not happen because the remaining oxide inclusions in steel are lower melting point complex inclusions. ©, 2014, Chinese Society for Metals. All right reserved.


Zhang H.,Hunan Valin Xiangtan Iron and Steel Co. | Xiao H.,Hunan International Engineering Consulting Center Co. | Bao Y.,Control Iron and Steel Research Institute, China
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

Through thermal expansion experiment on Formastor-FII thermal dilatometer, combined with observation of microstructure and hardness measurement, effect of Mo content on undeformed austenite continuous cooling transformation of 1000 MPa grade low carbon bainitic steel was investigated, and CCT curves of the steels with different Mo contents were measured. The results show that the higher Mo content reduces the temperature of phase transformation point of bainite, narrows the bainite transformation temperature range, and makes the CCT curves move to right. © 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


Jun Y.,Hunan Valin Xiangtan Iron and Steel Company Ltd | Bo-Tao C.,Hunan Valin Xiangtan Iron and Steel Company Ltd | Wei T.,Hunan Valin Xiangtan Iron and Steel Company Ltd | Fan-Zheng Z.,Hunan Valin Xiangtan Iron and Steel Company Ltd | And 2 more authors.
Steel Research International | Year: 2013

Experimental study on the LF refining of aluminum killed cold heading steel shows that calcium content in the molten steel increased to about 0.0010% at the end of refining, and the aluminum deoxized products were transformed from Al2O3 to the complex inclusions CaO-MgO-Al 2O3 with lower melting point by the high basicity, high Al2O3, and strong deoxidizing slag. The inclusions are in liquid state and can be easily floated up during LF refining and continuous casting. The total oxygen content of the steel falls to about 0.0020%. The experimental technology uses only 50 m calcium wire to the 80-t heat or even without calcium treatment. As compared to the traditional technology with higher amount of calcium for treatment, which forms CaS and CaO-MgO-Al 2O3 inclusions with high melting point, the experimental technology improves the castability and reduces the manufacturing cost. The aluminum deoxized products were transformed from Al2O3 to the complex inclusions CaO-MgO-Al2O3 with lower melting point by adjusting the compositions of LF refining top slag. The inclusions are in liquid state and can be easily floated up during LF refining and continuous casting. This method needs a little or no calcium treatment to obtain favorable castability of molten steel. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Ma C.,University of Science and Technology Beijing | Zhang J.-L.,University of Science and Technology Beijing | Qi C.-L.,University of Science and Technology Beijing | Yin J.,Hunan Valin Xiangtan Iron and Steel Co. | And 2 more authors.
Guocheng Gongcheng Xuebao/The Chinese Journal of Process Engineering | Year: 2012

Based on the physical and process properties of 9 kinds of pulverized coal in Xiangsteel, including ash fusion point, grindability index, ignition point, explosibility, fluidity, combustibility and reactivity, all the properties of bituminite and anthracite coals are evaluated, and reasonable options recommended. It is concluded that (1) Hengda is the best kind of bituminite to be used in Xiangsteel blast furnaces, Weihua bituminite the next choice. Their combustion rates are both above 85%. Because of low sulphur content, combustion rate over 70%, high grindability, good fluidity and high ash fusion temperature, Yangyang, Xiangyindu and Xingxing anthracite are suitable to blast furnace injection. (2) In accordance with the principle of coal blending, two options are recommended: mixture of Hengda, Xiangyindu and Baisha, and mixture of Weihua, Xingxing and Yangyang.


Wang S.-C.,Central South University | Li Z.-C.,Central South University | Yi D.-Q.,Central South University | Cao Z.-Q.,Hunan Valin Xiangtan Iron and Steel Co. | Zhang H.,Central South University
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2011

Microhardness tester, optical microscope and electron back scattered diffraction technique were used to examine the property and microstructure of a low temperature tempered 20MnCr5 carburized gear. {110}α polar figure of Martensite was calculated according to the K-S and N-W orientation relationship. Orientation distribution of Martensite at the center of the gear was examined by electron back scattered diffraction technique. {110}α polar figure of Martensite in a selected prior austenite grain was plotted. The orientation distributes randomly in the whole scanned area, but distributes regularly in local area. The misorientation of the scanned area distributes mainly below 5° and above 45°. In order to characterize the orientation distribution law in local areas, stereographic projection of Martensite {110}α in a selected prior austenite area was plotted. The orientation relationship in the selected prior austenite is determined to be mainly N-W orientation by fitting the polar figure. Discrepancy between practical and theoretical orientation distribution is interpreted by cooperative strain mechanism.


Qi C.-L.,University of Science and Technology Beijing | Zhang J.-L.,University of Science and Technology Beijing | Lin C.-C.,University of Science and Technology Beijing | Yin J.,Hunan Valin Xiangtan Iron and Steel Co. | And 2 more authors.
Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing | Year: 2011

Seven samples of a blast furnace at representative positions were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and atomic absorption spectrometry to study the erosion of carbon bricks at the BF hearth sidewall by harmful elements and the mechanism of pulverizing fracture. The results show that the erosion mechanism of carbon bricks at different parts of the hearth is different. In the first layer the erosion is mainly caused by the catalytic effects of harmful elements in the carbon loss reaction and the generation of leucite; in the upper area, penetration of K into brick work joints leading to a quality change of carbon bricks plays the leading role; in the tuyere, Zn is the main cause of erosion; but in the taphole the content of K is larger, with enrichment of Pb. It is also found that a harmful element has different effects at different parts of the hearth. In the upper area, the erosion mechanism is mainly the catalytic effect of K in the erosion reaction, but in lower part is the penetration of K into carbon bricks leading to a quality change of carbon bricks; Zn significantly crystallizes on carbon bricks in the tuyere, however in the hearth bottom Zn attaches to carbon bricks without obvious crystallization.


Wang D.-M.,Institute of Materials and Metallurgy | Zhang P.-Y.,Institute of Materials and Metallurgy | Zhu F.-X.,Institute of Materials and Metallurgy | Yang Y.-Q.,Hunan Valin Xiangtan Iron and Steel Co Ltd
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2013

Effects of tempering process on microstructure and mechanical properties of Q550E steel with different thickness manufactured by ultra fast cooling(UFC) process were investigated. Microstructure of the experimental steel was analyzed by means of optical microscope and transmission electron microscopy. Mechanical properties of the experimental steel were tested by tensile and impact tests. The results indicate that mechanical properties of the tested steel plate with different thickness show a non-monotonic changing feature with increasing tempering temperature. The general trend is that the strength gradually increases and then decreases while the elongation firstly decreases then increases as the tempering temperature increases, and impact energy is of no fluctuation. The tested steel plate with 16-30 mm thickness can satisfy the GB/T 15 91-2008 specifications when the tempering temperature is in the range of 520 to 640°C.

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