低温回火工艺对1100MPa级高强钢组织和力学性能的影响

Effect of Low Temperature Tempering Process on Microstructure and Mechanical Property of 1100 MPa Grade High Strength Steel

研究了无镍低合金1100 MPa、E级高强钢的热处理工艺,并对其显微组织和力学性能进行了分析。结果表明,原奥氏体晶粒度为9.5级,夹杂物主要为球状钙铝酸盐。经890℃淬火和不同工艺回火后钢的组织均为均匀的回火马氏体。随着回火温度的升高,马氏体中碳化物数量增加,其形态逐渐由点状变成片状。试验钢经890℃淬火并于200℃回火30 min后,其力学性能就可满足Q1100E高强钢的要求。

Heat treatment process of a Q1100E low-alloy steel without Ni was investigated, and then the steel was subjected to microstructure survey and mechanical property measurements. The results show that the grain size number of prior austenite is 9.5, and the inclusion is mainly spherical calcium-aluminate. All the microstructures of the investigated steel quenched from 890 % and tempered by different processes are uniform tempered martensite. As tempering temperature become higher amount of carbide in the steel increases and its shape changes from dot-like form to flake form. The mechanical properties of the investigated steel can conform with property requirements for Q1100E high strength steel after quenching from 890 ℃ followed by tempering at 200 ℃ for 30 min.