20Cr1Mo1VTiB钢螺栓断裂失效分析  

Fracture failure analysis of 20Cr1Mo1VTiB steel bolt

作　　者：刘飞 张雪超 孙常明 董云鹤 刘阳[1] 郑建军 Liu Fei;Zhang Xuechao;Sun Changming;Dong Yunhe;Liu Yang;Zheng Jianjun(Inner Mongolia Power(Group)Co.,Ltd.,Hohhot Inner Mongolia 010030,China)

机构地区：[1]内蒙古电力(集团)有限责任公司,内蒙古呼和浩特010030

出　　处：《金属热处理》2024年第12期306-311,共6页Heat Treatment of Metals

基　　金：内蒙古电力(集团)有限责任公司2022年科技计划项目(2022-38)。

摘　　要：某汽轮机组高压主汽门用20Cr1Mo1VTiB钢高温紧固螺栓服役1.29×10^(5)h后发生断裂失效故障。采用化学成分分析、SEM及TEM微观组织分析、XRD检测及力学性能测试等方法剖析了20Cr1Mo1VTiB钢螺栓的断裂失效原因。结果表明,20Cr1Mo1VTiB钢螺栓的断裂失效主要与服役工况的长时高温和高应力耦合环境所引发的蠕变损伤有关,微观上与两种蠕变孔洞的形成有关,一种是形成于粗大夹杂物尖角附近微裂纹区的蠕变孔洞,另外一种则是Laves相析出后沿其界面形成的孔洞。随着运行时间的累积,20Cr1Mo1VTiB钢螺栓基体中的蠕变孔洞数量不断增加并聚集长大,最终成为裂纹源,引发20Cr1Mo1VTiB钢螺栓的疲劳断裂失效。A high-temperature fastening bolt(20Cr1Mo1VTiB steel)for the high-stress main steam valve of a steam turbine unit cracked after serving for 1.29×10^(5)h.The cracking failure cause of the high-temperature fastening bolt was analyzed by means of chemical composition examination,SEM and TEM microstructure observation,XRD detection,and mechanical property testing.The results show that the fracture of the bolt is primarily due to creep damage from long-term high-temperature and high-stress conditions of serving.Additionally,the accumulation of creep damage is mainly due to two types of creep voids forming in microcrack zones near coarse inclusions sharp corners and along the interface of Laves phase.With the increase of running time,the number of creep voids in the 20Cr1Mo1VTiB steel bolt matrix continuously rises and aggregates,eventually forming crack sources that lead to fatigue rupture.

关 键 词：20Cr1Mo1VTiB钢螺栓 蠕变 断裂失效 夹杂物 LAVES相 

分 类 号：TG146[一般工业技术—材料科学与工程]