Effect of Heat Treatment Preservation Time on the Mechanical Properties and Microstructure of 25Mn2 Steel

25Mn2 steel was heat treated by different processes and the effect of quenching preservation time and temper preservation time on the mechanical properties and microstructure of the steel was analyzed. The results show that the influence on the mechanical properties of temper preservation time was significant. However,the influence of quenching preservation time was insignificant. When the quenching temperature was 900 ℃ and temper temperature was 615 ℃,20 min temper preservation was necessary and enough. Mechanical properties of the steel heat treated with the optimal process can meet the requirements of API 5CT standard very well.