燃烧器喷嘴材料热疲劳性能和高温氧化性能研究

Study on High Temperature Oxidation and Thermal Fatigue Property of Materials Used in the Jet of the Burner

采用对比试验方法,通过热疲劳裂纹扩展速率和氧化增重试验,研究了燃煤锅炉燃烧器喷嘴常用的两种材料的热疲劳性能和高温氧化性能,结果表明,铬、锰、硅等元素含量高的新材料ZG40Cr26Ni4Mn3NRe的热疲劳性能和抗高温氧化性能均明显优于原燃烧器喷嘴材料ZG40Cr20Ni5.材料的抗热疲劳性能在很大程度上取决于材料的抗高温氧化性能,热疲劳裂纹在表面缺陷处最易出现,热循环过程中氧化膜的形成和破裂加剧了热疲劳裂纹的萌生和扩展.

In this paper, high temperature oxidation property and thermal fatigue property of ZG40Cr26Ni4Mn3NRe and ZG40Cr20Ni5 heat-resistant steels usually used in jet of the burner were studied through reference experiment in order to assess applicability of ZG40Cr26Ni4Mn3Nre and failure mechanism. The results indicate that thermal fatigue property and high temperature oxidation of ZG40Cr26Ni4Mn3Nre are much better than ZG40Cr20Ni5 because content of Cr,Mn,Si in the former steel are higher than that of the latter and thermal fatigue property of the materials depends on high temperature oxidation to a great extent. Thermal fatigue crack initiates most possibly from surface defects,and also the engendering and breaking of oxidation film during the process of thermal stress cycle result in fatigue crack initiation and propagation.