回火温度对热轧低碳贝氏体钢显微组织和力学性能的影响

Effect of Tempering Temperature on Microstructure and Mechanical Properties of As-rolled Low Carbon Baintic Steel

对低碳贝氏体钢进行了热轧和不同温度回火处理后,采用光学显微镜和多功能材料试验机研究了回火温度对其显微组织及力学性能的影响。结果表明:不同回火温度下试验钢的显微组织主要为由板条贝氏体、粒状贝氏体、准多边形铁素体等组成的混合组织,回火温度不同,各种组织所占的比例有很大不同;回火温度对低碳贝氏体钢的屈服强度有明显影响,但对抗拉强度的影响相对较小,随着回火温度的提高,屈强比明显增加。

A low carbon bainitic steel was hot rolled and tempered, the influence of tempering temperatures on the microstructure and mechanical properties of the steel was studied by using multi-function material testing machine and optical microscopy. The results indicate that the microstructure of the low carbon bainitic steel consisted of lath-shaped bainite, granular bainite and quasi-polygonal ferrite, and the proportion of each kind of microstructure changed with the tempering temperatures. Tempering temperatures had distinct effect on yield strength of the tested steel, and less effect on the ultimate tensile strength. The yield ratio increased with the increase of tempering temperature.