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Hao Y.,Wuhan University of Technology | Hua L.,Wuhan University of Technology | Zhao D.,North China University of Water Conservancy and Electric Power | Chen G.,Zhengzhou Coal Mining Machinery Group Co.
2nd International Conference on Computer Research and Development, ICCRD 2010 | Year: 2010

Guide-roll has significant effect to ring roundness and ring rolling stability. An initiative control mode for guideroll movement is proposed to adapt the continuous change of the radial ring rolling state, in which the guide-roll placed to rolling entry side, moving with constant position angle. A modified method for the guide-roll initiative movement is introduced. The constituents of modifying factor include slips, wall thickness change, roundness error, fluctuant of neutral angle, and deflection of ring; their effects are analyzed. In addition, the modified formulae of ring expansion and guideroll movement velocity are educed. With dynamic simulation FE software of ABAQUS/Explicit, ring rolling process experiments are performed. Ring rolling stability and ring roundness are analyzed. Shown that, with the position angle 60° of the mode, the ring rolling stability is better and the ring roundness smaller when the modifying factor is about 0.7. © 2010 IEEE.

Liu J.,Chongqing University | Peng X.,Chongqing University | Peng X.,National Engineering Research Center for Magnesium Alloys | Wang B.,Chongqing University | And 5 more authors.
Journal of Rare Earths | Year: 2016

Double change channel angular extrusion (DCCAE) was performed in dual-phase Mg-9.5Li-3Al-1.6Y (wt.%) alloy to develop fine-grained microstructures. The microstructure evolution during DCCAE and conventional extrusion (CE) was investigated. The microstructure of the extruded dual-phase Mg-Li alloy consisted of recrystallized β-Li grains, banded α-Mg phases, and Al2Y phases distributed in β-Li phases and phase-interface uniformly. Compared with CE, the specimens after DCCAE had smaller β-Li grain size (3-5 μm by the DCCAE and 6-10 μm by the CE) and the α-Mg phases were refined during the DCCAE. The distribution of the Al2Y phases was improved a lot by DCCAE. Furthermore, the specimens after DCCAE had better tensile strength than conventional extrusion ones. © 2016 The Chinese Society of Rare Earths.

Zhao X.,Jilin University | Zhao X.,Zhengzhou Coal Mining Machinery Group Co. | Liu Y.,Jilin University | Gao Y.,Jilin University
Materials and Design | Year: 2014

Fatigue fracture behavior of the 30. mm thick Q460C-Z steel cruciform welded joint with groove was investigated. The fatigue test results indicated that fatigue strength of 30. mm thick Q460C-Z steel cruciform welded joint with groove can reach fatigue level of 80. MPa (FAT80). Fatigue crack source of the failure specimen initiated from weld toe. Meanwhile, the microcrack was also found in the fusion zones of the fatigue failure specimen, which was caused by weld quality and weld metal integrity resulting from the multi-pass welds. Two-dimensional map of the longitudinal residual stress of 30. mm thick Q460C-Z steel cruciform welded joint with groove was obtained by using the contour method. The stress nephogram of Two-dimensional map indicated that longitudinal residual stress in the welding center is the largest. © 2014 Elsevier Ltd.

Wang Z.,Zhengzhou Coal Mining Machinery Group Co. | Wang Z.,Zhengzhou University | Ni H.P.,Zhengzhou Coal Mining Machinery Group Co.
Applied Mechanics and Materials | Year: 2013

According to the plastic floor assumptions, the floor pressure distribution law was obtained based on plane force analysis of hydraulic support. In order to compare the floor pressure on the elastic floor and plastic floor, Elastic foundation beam theory was introduced to the calculation of the floor pressure. The results show that the pressure distribution is changed with the changing of the subgrade coefficient. The pressure is trapezoidal distributed when the floor is relatively soft and the plastic floor assumptions is reasonable. In a relatively hard rock floor, the maximum pressure appear near the column nest which is very different from the calculation results based on the plastic base plate assumptions. It is suggested that the soft and the hard rock floor should be treated differently during the design and selection of hydraulic support. © (2013) Trans Tech Publications, Switzerland.

Zhao K.,Zhengzhou Coal Mining Machinery Group Co. | Du N.,Zhengzhou Linda Compressor Co. | Yan Y.,Henan University of Science and Technology | Li C.,Zhengzhou Coal Mining Machinery Group Co.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2013

The resistivity and solder abilities of Zn4Al3CuxSn solder alloy were investigated by adding Sn(0-15%) into Zn4Al3Cu alloy through alloying principle. Results show that the resistivity of the Zn4Al3CuxSn solders is reduced with the increasing of the addition of Sn. The resistivity of the Zn4Al3Cu15Sn solder is 7.9×10-7 Ω·m which is approximately 47.0% lower than that of the matrix solder. When the content of Sn is lower than 10%, the spreading area of the Zn4Al3CuxSn solder alloy is increased linearly. The spreading area of Zn4Al3Cu10Sn reaches to the maximum value of 98.3 mm2, which is about 59.1% larger than that of the matrix solder. It is mainly related to the formation of the new SnZn eutectic phase and the metal intermetallic compounds between the solder and the substrate. Therefore, for the consideration of resistivity and spreading property of the novel solders, the proper addition of Sn is about 10%.

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