热处理对高强建筑用钢组织和力学性能的影响

Effect of Heat Treatment on Microstructure and Mechanical Properties of High Strength Construction Steel

采用箱式电阻炉对高强度建筑钢进行了不同温度的回火,并对回火试样进行了显微组织观察,对拉伸性能和冲击性能进行了检验。结果表明,试验钢回火后组织以铁素体+贝氏体为主,随着回火温度升高,M-A逐渐分解,粒状贝氏体含量减少,铁素体晶粒尺寸增加;抗拉强度、屈服强度、屈强比和冲击功均先升高后降低,伸长率增加,断面收缩率则先略有降低后升高。综合考虑力学性能试验结果,当试验钢回火时间为60 min时,最佳回火温度为600℃。

The tempering at different temperatures of high strength construction steel was carried out by the box type resistance furnace. And the microstructure of the tempered samples was observed. The tensile properties and impact properties were tested. The results show that, the microstructure of tested steel after tempering is mainly ferrite and bainite; with the increase of the tempering temperature, the M-A decomposes gradually, the content of granular bainite decreases and the grain size of ferrite increases; the tensile strength, yield strength, yield strength ratio and impact energy increase firstly and then decrease, the elongation increases, the section shrinkage rate firstly decreases and then increases. Comprehensively considering mechanical performance test results, the optimum tempering temperature for the test steel is 600 ℃ when the tempering time is 60 min.