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Qu J.,Control Iron and Steel Research Institute, China | Wang M.,Control Iron and Steel Research Institute, China | Dong J.,University of Science and Technology Beijing | Wu G.,Northeast Special Steel Group Co. | Zhang J.,Control Iron and Steel Research Institute, China
7th International Symposium on Superalloy 718 and Derivatives 2010 | Year: 2010

In this paper, a compound jacketed rolling technique for superalloy GH4720Li is experimentally investigated. The results show that microstructure of GH4720Li is susceptible to hot working parameters. When rolling temperature is about 1130°C, a fine-grained microstructure, excellent mechanical properties and high yield strength can be obtained. In addition, the rolling temperature can be controlled effectively, friction force between ingot and roller can be reduced, surface cracking induced by rolling can be avoided, -and uniform microstructure can be obtained using compound jacketing. When accumulative strain of rolling is greater than 65%, the coarse columnar dendritic microstructure can be refined completely and grain size of ASTM 8 obtained. After heat treatment, GH4720Li bars exhibit excellent mechanical properties.

Li K.-M.,Control Iron and Steel Research Institute, China | Yang Y.-J.,Northeast Special Steel Group Co Ltd. | Wang Z.-G.,Northeast Special Steel Group Co Ltd. | Han G.-W.,Control Iron and Steel Research Institute, China
Journal of Iron and Steel Research | Year: 2012

The as casting microstructure and homogenization of the GH350 alloy ingot was investigated by means of optical microscopy, scanning electron microscopy (SEM) and EDX analysis. The precipitation of as-cast GH350 alloy is complicated and the dendritic segregation is severe. Nb, Ti and Ta are segregated to the interdendritic region and enriched in the precipitates such as Laves phase, while Cr and Mo are segregated to the dendrites. It is found that the dendritic segregation between the dendrites within the casting grains of the GH350 alloy ingot can be basically eliminated by annealing at 1180 °C × 40h.

Ju Q.,Control Iron and Steel Research Institute, China | Ma H.,Control Iron and Steel Research Institute, China | Fu X.,Control Iron and Steel Research Institute, China | Wang M.,Northeast Special Steel Group Co.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2012

The hot deformation behavior of the cast Ni-35Cr based GH4648 superalloy was studied though hot compressing testing on a Gleeble-1500 simulator. The results show that the onset temperature of the dynamic recrystallization (DRX) in the cast GH4648 alloy is 1050°C. The DRX process is going more sufficient with higher temperature. Below 1050°C, there is no DRX grain. The effect of homogenization heat treatment on the hot working ability of cast GH4648 alloy was studied. After homogeneous heat treatment at 1180°C for 45 h, the DRX process is restrained and resistance of deformation is increased. © 2012, Northwest Institute for Nonferrous Metal Research.

Wang L.,Northeastern University China | Yu T.,Northeast Special Steel Group Co. | Zhao Y.-Q.,Northwest Institute for Nonferrous Metal Research | Liu Y.,Northeastern University China
Ti 2011 - Proceedings of the 12th World Conference on Titanium | Year: 2012

The deformation and fracture behavior of Ti alloys with LM and BM microstructures under both monotonic and cyclic loading were investigated. The results indicate that the ductile rupture occurs with coarse LM microstructure under monotonic loading,since the crystal orientation of part lamellar is often changed by the annealing twins. While,for the BM microstructure,the deformation easy occurs with the dislocation multiplication and movement in both αp phase and lathlike second a phase, it leads the early yielding and larger plastic deformation before fracture. Under the cyclic loading, because the crack propagation direction can be hindered by the αp phase in BM microstructure, the fracture will be delayed by the present of αp phase, and also the resistance of crack propagation of αp phase in BM can be increased by the precipitation of α2 phase. It is found that after thermal exposure the fracture of the specimen become hardly with the α2 phase precipitated in αp phase.

Zhao M.,Northeast Special Steel Group Co. | Dong J.,Northeast Special Steel Group Co.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

Effect of heat treatment process, especially solution temperature on the microstructure and mechanical properties of the TC11 alloy rolled bars as well as the content of each phase in the alloy were studied. The results show that TC11 alloy could not gain excellent mechanical property when solution temperature is lower than the recrystallization temperature at 900 ℃ or higher than phase-transformation temperature at 1010 ℃, while TC11 alloy could get fine and uniform equiaxled microstructure of α+β, when the alloy is annealed at (950±10) ℃ for 1 h, and cooled in air plus subsequent annealed at 530 ℃ for 6 h and cooled in air, which is the optimum annealing procedure. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.

Loading Northeast Special Steel Group Co Ltd. collaborators
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