过热器集箱三通焊缝裂纹原因分析

Analysis on the Weld Crack of Superheater Header Tee

通过成分分析、显微组织分析、断口检测和力学性能检测,对某火电厂过热器集箱三通焊缝裂纹原因进行了分析研究,认为焊缝失效形式为应力型蠕变脆性断裂。焊接接头焊后热处理不合格,母材和焊缝硬度高,在介质工作压力作用下发生焊缝材料提前老化;焊缝材料组织中存在较多的非金属夹杂、大的气孔等,加剧了材料开裂失效的速度,造成材料提前失效。提出了相应建议及处理措施。

The tee of superheater header of a tharmal power plant was analyzed and studied through composition analysis,micros structure analysis,fracture detection and mechanical property detection.Creep brittle fracture of stress type was considered as the failure mode.Weld perished early under work pressure because of unsuitable heat treatment and high hardness of base and weld.Many factors,such as inclusions,blowhole in weld intensified the speed of material negating.They promote the material failure ahead.The suggestions and countermeasures are put forward.