回火温度和时间对2.25Cr-1Mo-0.25V钢组织和性能的影响

采用光学显微镜、扫描电镜、拉伸试验和冲击试验等方法,研究了2.25Cr-1Mo-0.25V钢分别在690 ℃和705 ℃回火1~150 h条件下的显微组织、力学性能及断口形貌的变化。结果表明,回火温度及回火时间对钢的显微组织、强度及韧性指标影响很大。在本试验温度范围内,显微组织中碳化物随着回火时间的延长由条状逐渐球化,并逐渐向晶界聚集;强度指标随着回火时间的延长呈现先急剧下降后逐渐稳定的趋势;韧性指标随着回火时间的延长先升高后下降并稳定的趋势。试验钢在回火温度690 ℃和705 ℃的断面收缩率及冲击韧性指标随回火时间的变化趋势相同。

Effects of tempering temperature and time on microstructure and properties of 2.25Cr-1Mo-0.25V steel

The microstructure,properties and fracture morphology of 2.25 Cr-1 Mo-0.25 V steel tempered respectively at 690℃and 705℃for 1-150 h were studied by using optical microscope,scanning electron microscope,tensile test and impact test.The results show that tempering temperature and tempering time have great influence on the microstructure,strength and toughness of the tested steel.In the studied range of temperature,the strip-like carbides in the microstructure are gradually spheroidized and gathering towards the grain boundary with the extension of tempering time.With the increase of tempering time,the strength index shows a tendency of gradual stability after a sharp decline,but the toughness index first increases,then decreases and stabilized.In this study,the reduction of area and the impact toughness with the change of tempering time show the same trend at tempering temperatures of 690℃and 705℃.