裂解炉炉胆焊缝裂纹原因分析及焊接修复  

Analysis and Repair of Cracks in the Cracking Furnace of Ammonia Decomposition Unit

作　　者：张鹏 付一川 赵振旭 屈海东 刘杰 梁艳 冶维财 ZHANG Peng;FU Yichuan;ZHAO Zhenxu;QU Haidong;LIU Jie;LIANG Yan;YE Weicai(Gansu Iron and Steel Vocational and Technical College,Jiayuguan 735100,China;State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metal,Lanzhou University of Technology,Lanzhou 730050,China;Gansu Jiayuguan Hongsheng Electric Heating Co.,Ltd.,Jiayuguan 735100,China;The First Branch of China Nuclear Power 404 Co.,Ltd.,Jiayuguan 735100,China)

机构地区：[1]甘肃钢铁职业技术学院,甘肃嘉峪关735100 [2]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050 [3]甘肃嘉峪关宏晟电热有限公司,甘肃嘉峪关735100 [4]中核四〇四有限公司第一分公司,甘肃嘉峪关735100

出　　处：《电焊机》2023年第10期78-83,共6页Electric Welding Machine

基　　金：甘肃省自然科学基金(21JR7RA233)。

摘　　要：氨分解装置裂解炉炉胆为耐热不锈钢焊接制造,局部焊接接头在长期高温运行过程中产生裂纹。为保证耐热不锈钢炉胆的安全生产,分析炉胆裂纹的产生原因为S31008奥氏体不锈钢在长时间高温运行中沿晶界连续析出网状脆性Cr23C6碳化物,在工作应力作用下裂纹沿晶界扩展,造成沿晶界断裂。此外,裂解炉运行温度以及椭圆形封头与中间接管、中间接管与管束的尺寸不一致引起应力集中,造成无法同步收缩,从而形成残余拉应力。采用ER310焊丝和钨极氩弧焊进行焊接修复,选用合理的焊接工艺能够获得奥氏体+铁素体的焊缝组织,既可以提高金属的抗裂性能,又不降低焊缝金属的高温性能,焊缝无损检测后发现焊缝与母材熔合线清晰规则,熔合情况良好,修复后的炉胆能够达到正常使用要求。A furnace of cracking furnace of ammonia decomposition unit is made of heat-resistant stainless steel-welded,and the partial welded joint cracks in the process of long-term high-temperature operation.In order to ensure the safe production of heat-resistant stainless steel furnace liner,the reason for the occurrence of furnace liner cracks is that S31008 austenitic stainless steel continuously precipitates a network of brittle Cr23C6 carbides along the grain boundary during long-term high-temperature operation.Under the action of working stress,the cracks propagate along the grain boundary,causing fracture along the grain boundary.In addition,the operating temperature of the cracking furnace and the inconsistency in the dimen‐sions of the elliptical head and intermediate nozzle,as well as the intermediate nozzle and tube bundle,cause stress concen‐tration and prevent synchronous shrinkage,resulting in residual tensile stress.Using ER310 welding wire and tungsten argon arc welding for welding repair.After the non-destructive testing of the weld,it was found that the fusion line between the weld and the base metal was clear and regular,the fusion was good,and the furnace liner after welding repair could meet the requirements of normal use.

关 键 词：耐热不锈钢 焊缝裂纹 晶间腐蚀 焊接修复 

分 类 号：TG457[金属学及工艺—焊接]