304H板材焊接接头蠕变疲劳失效分析

Failure Analysis of Creep-fatigue for 304H with Welded Joints

通过具有保持时间的高温蠕变疲劳试验研究了不锈钢304H材料在相同条件下母材、焊接过程中超声波消应力以及不消应力的失效行为,并对失效后断口宏微观形貌进行分析。结果表明,断裂位置均发生在距离焊缝一定距离的母材上,失效寿命基本一致,焊接时超声波消应力处理不能提高蠕变疲劳寿命,加载过程中循环应力应变不稳定、不封闭且向右推移,从而造成材料延性耗竭而断裂,失效断口为穿晶韧窝断裂。

The tests of creep-fatigue with hold time for the failure behavior of 304 H stainless steel base metal,the welding joint with eliminating stress by ultrasonic and non-eliminating during welding process under the same condition were researched,and fracture mechanism analysis were carried out. The result show that fracture occurred in the position with a certain distance away from the base metal material,the failure life was consistent,the failure life of welding joint with eliminating stress by ultrasonic was not improved. Cycle stress-strain curve during loading was unstable,unclosed and shifted to right,resulting in fracture due to depletion of ductile for 304 H. The fracture mode is transgranular dimple fracture.