T91/TP347H高温再热器管焊缝开裂原因分析  

CAUSE ANALYSIS OF WELDED SEAM CRACKING OCCURRED ON TUBES OF T91/TP34H HIGH-TEMPERATURE REHEATER

作　　者：郑坊平[1] 马红[1] 王弘喆[1] 王碧磊[1] 

机构地区：[1]西安热工研究院有限公司,陕西西安710032

出　　处：《热力发电》2011年第11期95-99,共5页Thermal Power Generation

摘　　要：通过宏观检测、化学成分分析、金相及力学性能检验等方法,对某电厂T91/TP347H高温再热器管开裂原因进行的分析表明:高温再热器异种钢焊接接头焊缝两侧内壁12.5mm段削薄,化学成分符合ASME SA—213/SA—213M2008a要求,显微组织老化,抗拉强度符合要求。因此,T91侧管子的环向开裂是由于焊接接头两侧管子端部内壁削薄结构在特定条件下造成的工质流动变化引起了局部超温,使结构薄弱区域受较大的管圈热胀应力作用而致。Through some methods,such as macroscopic inspection,chemical composition analysis,metallographic examination,and mechanical performance examination etc.,the causes leading to welded seam cracking occurred on tubes of T91/TH347H high-temperature reheater in one power plant have been analysed.Results show that the inner wall in section 12.5 mm at two sides of the welded seam with different steels in the high-temperature reheater has been thinly peeled,the chemical composition conforms with the requirements specified in ASME SA-213M 2008a,the microstructure being aged,the tensile strength conforming with the requirements.Therefore,the cracking in annular direction at the side of P91 steel is due to local overtemperature resulted from the working medium flow variation caused by the thinly peeling of inner wall structure at tube ends of two sides concerning the welded joint under specific condition,making the area of thinly weakened structure to bear larger thermal expansion stress.

关 键 词：T91钢 焊接接头 焊缝 环向开裂 局部超温 蠕变开裂 

分 类 号：TG115[金属学及工艺—物理冶金]