Effect of Austenitizing Temperature on the Quenching Microstructure and Properties of 51CrV4

Abstract

The effect of austenitizing temperature on the quenching microstructure and properties of 51CrV4 steel was studied. The results show that with the increase of austenitizing temperature, the austenite grains grow gradually. After quenching, the hardness increased first and then decreased, and the strength increased first and then decreased after tempering at 460°C. When the austenitizing temperature was 880°C, the austenite grains were fine and uniform, about 16μm, the martensite structure was dense, the strength and hardness reached maximum. When the austenitizing temperature was 910°C, the decarburization phenomenon was obvious, and the strength, hardness and plasticity of the test steel decreased obviously. When the austenitizing temperature exceeded 910°C, the austenite grains grow sharply and some grains were abnormally coarse. The austenite grain size reached 20μm and the microstructure was coarser at austenitizing temperature of 950°C. Therefore, in order to ensure uniform grain size and no decarburization under the premise of complete austenitization, the best austenitizing temperature of 51CrV4 steel for good properties is 880°C.