Behavior of precipitation in bainitic steel during relaxation processing of RPC technique

Shanwu Yang;Shaoqiang Yuan;Xuemin Wang;Huibin Wu;Xinlai He Materials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China Tangshan College, Tangshan 063000, China

摘 要：<正> Thermal simulation test, TEM （Transmission Electron Microscope） and nanobeam EDS （Energy Dispersed x-ray Spec-trum） techniques were used to investigate the precipitation behavior of Nb, Ti, Mo etc. in HSLA （High Strength Low Alloy） steel.The strain induced precipitation occurred during the isothermal relaxation stage after deformed in the non-recrystallization tempera-ture region. After 30% predeformation at 850 and 900℃, there are two kinds of particles, （Ti,Nb）（C,N） and a few Nb（C,N）, to pre-cipitate during holding. The content of Nb in particles rises with the relaxation time increasing. During the final holding stage, someNb and Ti atoms in the lattice sites of the precipitates would be replaced by Mo atoms, and the Mo content in the precipitates in-creases with the relaxation time. The results were compared with the refinement effect of microstructures caused by relaxation-precipitation controlling transformation （RPC） processing.

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