淬火及回火工艺对中锰钢组织和性能的影响

Effect of quenching and tempering process on microstructure and mechanical properties of medium manganese steel

通过热处理工艺实验及SEM与TEM组织观察,研究了不同淬火及回火工艺对碳锰钢与中锰钢组织和性能的影响。结果表明,提高锰含量显著降低了实验钢的Ac1和Ac3温度,缩小了两相区范围;随着淬火温度的升高,实验钢的屈服强度、抗拉强度有所降低;随着回火时间的增加,实验钢的冲击功升高;碳锰钢与中锰钢最优淬火温度分别为800~900℃和750~800℃,其屈服强度、抗拉强度分别为818、847和820、878 MPa,-40℃的冲击功在200 J左右,均具有良好的综合性能,中锰钢具有低成本、高强度及高韧性的综合优势。两种实验钢均可获得细小均匀的马氏体组织,马氏体板条束交错分布,随着回火时间的增加,实验钢中大尺寸碳化物的数量有所降低。

Influence of quenching and tempering processes on microstructure and mechanical properties of carbon manganese steel and medium manganese steel were investigated by means of heat treatment test,SEM and TEM. The results show that the Ac1 and Ac3temperatures of the steels are reduced by increasing the content of manganese,and the two phase region is narrowed. The yield and tensile strength of the tested steels decrease with the increasing of quenching temperature,and impact energy of the steels increases with the increasing of tempering time. When the quenching temperatures are between 800-900 ℃ and 750-800 ℃,and the yield strength and tensile strength are 818 MPa,847 MPa and 820 MPa,878 MPa for carbon manganese steel and medium manganese steel,respectively,and the impact energy of the steels at- 40 ℃ are about 200 J,and good properties of both steels are obtained,and the medium manganese steel has better performance with low cost,high strength and high toughness; fine and uniform martensite with martensite laths staggered distribution is obtained for both steels,and the large size carbides in the steel decreases with the increasing of tempering time.