Effects of Heat Treatment on Microstructure and Mechanical Properties of High Quality 65Si2MnWA Spring Steel for Aviation

65Si2MnWA spring steel was heat treated at different temperatures. The effects of different temperature heat treatment on microstructure and mechanical properties of 65 Si2MnWA spring steel were studied by microstructure observation and tensile test. The results show that, the microstructure of the steel quenched at 850 ℃-950 ℃is mainly martensite and uniformly distributed granular carbides.The quenched samples at 850 ℃-950 ℃are tempered at 435 ℃, with the increase of quenching temperature, the tensile strength does not change greatly, the yield strength increases gradually and the brittleness increases.Subsequently, the tempering test at 435 ℃-515 ℃of 65Si2MnWA spring steel quenched at 850 ℃was carried out. As the tempering temperature increases, the strength of 65 Si2MnWA spring steel decreases gradually, and the yield ratio decreases first and then increases, the section shrinkage of spring steel first increases and then decreases.When tempered at 455 ℃, 65Si2MnWA spring steel achieves the best mechanical properties.