关键词: A100钢, 回火, 逆转变奥氏体, 抗拉强度, 断裂韧度

Abstract: Effect of tempering time on microstructure, tensile strength, and fracture toughness of A100 steel was investigated by using metallographic microscope, universal testing machine and other equipment. The results show that with the extension of tempering time, reversed austenite appears in the matrix, leading to a decrease in tensile strength and an increase in fracture toughness. When the tempering time is extended from 380 min to 440 min, the tensile strength of the A100 steel decreases gradually from 2025 MPa to 1918 MPa, while the fracture toughness increases continuously from 93.3 MPa·m^1/2 to 125 MPa·m^1/2. When the position of the A100 steel in the pit furnace is changed during tempering, there are differences in the properties of the steel parts, but the differences are small. It can be seen that the A100 steel is relatively sensitive to the holding time during the tempering process. For the A100 steel requiring a strength range of 1930-1980 MPa and a fracture toughness range of 105-115 MPa·m^1/2, when tempered at 482 ℃, the recommended tempering time is 370-380 min, at which the optimal comprehensive mechanical properties are obtained.

Key words: A100 steel, tempering, reversed austenite, tensile strength, fracture toughness