Abstract：Effect of austenizing temperature on hardenability, microstructure of 40CrNiMo steel after quenching at a cooling rate of 0.7 ℃/s and microstructure and mechanical properties of 40CrNiMo steel after tempering was studied. Results showed that with increasing temperature from 800 to 1 000 ℃, the hardenability was increased gradually, especially when the temperature exceeded 950 ℃. When the austenitizing temperature was 800 ℃, there was some ferrite in the microstructure, resulting in lower hardness but higher toughness. When the austenitizing temperature was 900 ℃, the specimen possessed the highest strength but the ductility was lower. The fracture mechanism was also changed with increasing temperature, especially for impact specimens. All tensile specimens exhibited ductile fracture with dimples in the fracture surface. However, impact specimens changed from dimple fracture to cleavage or quasi-cleavage fracture, with more typical river pattern in the fracture surface when the austenitizing temperature exceeded 900 ℃.
熊国源, 刘利华, 朱文涛. 奥氏体化温度对40CrNiMo钢组织和性能的影响[J]. 中国冶金, 2021, 31(7): 30-37.
XIONG Guo-yuan, LIU Li-hua, ZHU Wen-tao. Effect of austenizing temperature on microstructure and mechanical properties of 40CrNiMo steel[J]. China Metallurgy, 2021, 31(7): 30-37.
2021, Vol. 31 
