P92钢焊条电弧焊焊缝金属热裂纹及其特征  

Hot cracking and its characteristics in weld metal of P92 steel by shielded metal arc welding

作　　者：陈忠兵[1] 吕一仕[1] 侯志强 彭波[2] 祝国胜 赵明凯[3] 

机构地区：[1]苏州热工研究院有限公司,215004 [2]广东惠州平海发电厂有限公司,516363 [3]广东火电工程总公司,广州市510735

出　　处：《焊接》2013年第12期33-39,70,共7页Welding & Joining

摘　　要：采用工程试样和实验室试样,通过缺陷形貌观察和缺陷断面上合金元素能谱分析,研究P92钢焊条电弧焊焊缝金属中短小形缺陷的性质及其特征。结果表明,两种试样缺陷断面上均观察到方向性一致的树枝晶和自由凝固结晶晶胞,实验室试样还观察到缺陷产生于高温下,据此可确定该缺陷为焊接热裂纹且属结晶裂纹。裂纹位于焊道收弧处;在焊缝不同深度呈现星形状或线状不同形貌;裂纹中可以存在氧化层或夹渣;裂纹面上未观察到S,P,B的显著偏析,但发现W,Cr,Si,V等元素偏析。元素偏析可能影响最后结晶区域结晶模式与结晶组织,从而影响热裂纹的形成。The properties and characteristics of a kind of short and tiny defect in weld metal of P92 steel weld by shielded metal arc welding were studied by the defect morphology observation and energy spectrum analysis of alloy elements in defect surface with both engineering samples and laboratory samples.Results show that dendrites with uniform direction and cells with free solidification crystal were observed on the defects fracture surfaces.Moreover,it has been observed in the laboratory sample that the defect emerges at high temperature.According to the results,it can be concluded that the defect is welding hot cracking,and also belong to solidification cracking.The cracking located at the extinguishing position of arc in weld bead,and shows different morphologies such as star sharp or lamellar sharp in different weld depth.Oxidation layer or welding slag can be found in the crack.Significant segregation of S,P,B elements are not found,but Cr,W,Si,V elements segregation are observed on the cracking surface.Elements segregation may affect the solidification mode and metallurgical structure of the final solidification zone,and then affect the formation of hot cracking.

关 键 词：P92钢焊缝金属热裂纹 自由结晶面元素偏析 

分 类 号：TG401[金属学及工艺—焊接]