Effect of Quenching and Partitioning Process on MA Constituent in Nb-Bearing HSLA Steel  

作　　者：YU Wei CHEN Tao JIAO Duotian WU Huibin 余伟;CHEN Tao;JIAO Duotian;WU Huibin(Engineering Research Institute,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]Engineering Research Institute,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2012年第1期21-26,共6页武汉理工大学学报（材料科学英文版）

基　　金：Key Projects in the National Science & Technology Support Program during the Eleventh Five-Year Plan (No.2006BAE03A06)

摘　　要：The effect of quenching-partitioning （Q-P） process on martensite-anstenite （MA） constituent is investigated by the thermo-analysis simulator for a niobium-bearing HSLA steel. The process includes quenching from 950 ℃ to the intermediate temperature of 350-550 ℃ at the rate of 30 ℃/s and subsequent reheating at the rate of 20-50 ℃/s and partitioning at 660-800 ℃. The microstructure is characterized by nano probe, EBSD, colored metallograph, optical microscope and graphic analytic method. The results show that the improvement of distribution homogeneity of MA in microstructure, the diminishment of the MA average grain size and increment of the MA volume fraction is caused by the intermediate temperature decrease, the reheating rate increase and a proper partitioning temperature. The volume fraction of MA is up to 7.9% while the sample is quenched to 450 ℃, reheated at 50 ℃/s and partitioned at 750 ℃ The grain is granular or equiaxed in shape and the average grain size of MA is about 0.77-1.48 grn after treated by Q＆P process. The grains tend to be coarse and with sharpy-angle as the intermediate temperature is up and the reheating rate and the partitioning temperature rises. The MA volume fraction depends on the untransformed austenite volume fraction after quenching and carbon diffusion time and temperature during partitioning process.The effect of quenching-partitioning （Q-P） process on martensite-anstenite （MA） constituent is investigated by the thermo-analysis simulator for a niobium-bearing HSLA steel. The process includes quenching from 950 ℃ to the intermediate temperature of 350-550 ℃ at the rate of 30 ℃/s and subsequent reheating at the rate of 20-50 ℃/s and partitioning at 660-800 ℃. The microstructure is characterized by nano probe, EBSD, colored metallograph, optical microscope and graphic analytic method. The results show that the improvement of distribution homogeneity of MA in microstructure, the diminishment of the MA average grain size and increment of the MA volume fraction is caused by the intermediate temperature decrease, the reheating rate increase and a proper partitioning temperature. The volume fraction of MA is up to 7.9% while the sample is quenched to 450 ℃, reheated at 50 ℃/s and partitioned at 750 ℃ The grain is granular or equiaxed in shape and the average grain size of MA is about 0.77-1.48 grn after treated by Q＆P process. The grains tend to be coarse and with sharpy-angle as the intermediate temperature is up and the reheating rate and the partitioning temperature rises. The MA volume fraction depends on the untransformed austenite volume fraction after quenching and carbon diffusion time and temperature during partitioning process.

关 键 词：QUENCHING partitioning TRANSFORMATION martensite-austenite HSLA 

分 类 号：TG156.3[金属学及工艺—热处理]