摘要
介绍了国内外承压设备用材标准对不锈耐热钢晶粒度的规定,通过对几个失效案例的具体分析,明确了粗大晶粒会增加晶间腐蚀的敏感性,且在焊接热输入过大的情况下,粗大晶粒会阻碍焊缝收缩时的晶界滑移,增加焊接接头产生裂纹的风险。通过分析,认为晶粒粗大降低了晶界的总面积,随着晶界面积的减少,热影响区在焊接热循环过程中使碳化物更多地聚集于晶界,使得晶界熔合区和热影响区形成裂纹的可能性更大。提出了在严格按焊接工艺施工的前提下,对母材规定合理的晶粒度范围。建议对不锈耐热钢板材、管材和管件的晶粒度按4~9级,锻件的晶粒度按3~7级进行规定。
The grain size of stainless heat-resistant steel in the domestic and foreign standards of materials for pressure equipment was briefly summarized.Through the analysis of several failure cases,it was clear that coarse grain will increase the sensitivity of intergranular corrosion,and when the welding heat input is too large,the coarse grain will hinder grain boundary slip during weld shrinkage and increase the risk of cracking of the welded joint.It is considered that the coarse grain reduces the total area of grain boundary,with the decrease of the grain boundary area,the heat-affected zone makes the carbides accumulate more in the grain boundary during the welding thermal cycle,making a greater possibility of crack formation in grain boundary fusion zone and heat affected zone.It was put forward that reasonable grain size range of base metal should be stipulated on the premise of strictly following welding process.It is suggested that the grain size of stainless heat-resistant steel sheet,pipe and pipe fitting should be classified into 4~9 grades,and that of forgings should be classified into 3~7 grades.
作者
束润涛
SHU Runtao(Wuhan Runzhida Petrochemical Equipment Co.,Ltd.,Wuhan 430200,China)
出处
《压力容器》
北大核心
2023年第4期74-79,共6页
Pressure Vessel Technology
关键词
不锈耐热钢
晶粒粗大
失效
stainless heat-resistant steel
coarse grain
failure
