GH4033高温合金螺栓断裂原因分析

Fracture Analysis of Bolt Made of GH4033 Superalloy

催化装置滑阀螺栓使用时发生断裂,导致阀体导轨和阀板脱落。通过对滑阀导轨GH4033螺栓进行宏观观察、化学成分分析、显微组织检查、断口分析、微观观察,确定其断裂原因。结果表明:该螺栓是由高温蠕变损伤引起的沿晶脆性断裂;因热处理不当,螺栓组织中晶粒粗大,第二相和沿晶碳化物较少,弱化细晶强化、第二相强化和晶界强化作用,导致蠕变性能下降;长期高温服役,产生蠕变损伤,萌生微裂纹,损伤累积加速裂纹形成和扩展,使得螺栓过早断裂失效。

The slide valve bolt in a catalytic unit fractured during service,leading to the falling off of the valve body guide rail and the valve plate.The fracture cause of the GH4033 bolt was determined by macroscopic observation,chemical composition analysis,microstructure examination,fracture analysis and microscopic observation.The results show that the facture of the bolt is intergranular brittle fracture caused by high temperature creep damage.Improper heat treatment causes coarse grain in the bolt,and less second phase and intergranular carbide,which weaken the fine grain,the second phase and the grain boundary strengthen,leading to the decline of creep property.Long-term service at high temperature led to creep damage and micro-crack initiation,and damage accumulation accelerated the formation and expansion of crack,resulting in the early fracture of the bolt.