Effect of TiN precipitation on hardenability in 20CrMnTi gear steel
LI Yao1, CHENG Guo-guang1, LU Jin-long1,2, SUN Jun3, HUANG Yu1
1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing,Beijing 100083, China; 2. Technology Center, Baowu Group Guangdong Shaoguang Iron and Steel Co., Ltd., Shaoguan 512123, Guangdong, China; 3. Technology Center, Xinning SpecialSteel Co., Ltd., Xining 810005, Qinghai, China
Abstract：In order to study the effect of TiN precipitation on the hardenability in 20CrMnTi gear steel,based on the two kinds of end quenching specimens of 20CrMnTi steel with different hardenability characteristics come from the actual production,the peripheral hardness of the samples was tested,the microstructure and the austenite grain structure were observed by metallography microscope,the characteristics of TiN particles in steel were observed and analyzed by scanning electron microscopy,and the precipitation process of TiN was analyzed by Thermo-Calc software. The results show that the austenite grain size has a significant effect on the hardenability. The larger the grain size,the higher the martensite ratio,and the higher the hardness. The uniform and finer of the grain size reduces the maximum peripheral hardness difference of end-quenched samples from 9.1HRC to 3.3HRC. The precipitation of as much TiN as possible in the solid phase plays an important role in obtaining finer and uniform austenite grains. TiN precipitates out actually less during the solidification process and more in solid phase in the sample with better hardenability,which promotes grain refinement and more uniform peripheral hardness. In actual production,under the condition with specific mass percent of Ti,how to effectively inhibit the precipitation of TiN during solidification is the key to control narrow hardenability bandwidth for 20CrMnTi gear steel.
李尧, 成国光, 鲁金龙, 孙军, 黄宇. 20CrMnTi齿轮钢中TiN析出相对淬透性的影响[J]. 钢铁, 2021, 56(1): 75-84.
LI Yao, CHENG Guo-guang, LU Jin-long, SUN Jun, HUANG Yu. Effect of TiN precipitation on hardenability in 20CrMnTi gear steel[J]. Iron and Steel, 2021, 56(1): 75-84.
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2021, Vol. 56 
