摘要
采用E630马氏体不锈钢焊条通过手工电弧焊对0Cr15Ni7Cu2Nb马氏体不锈钢与450 MPa级低合金钢进行焊接,并对异质焊接接头显微组织、接头硬度及冲击性能进行研究。研究结果表明:低合金侧熔合线两侧区域上存在Cr的浓度梯度,使熔合线左右两侧形成明显的增脱碳层,增碳层作为硬化层导致该区域韧性降低,使该区域呈现准解理断裂,而马氏体不锈钢侧熔合线无明显增脱碳层,因而仍保持良好的韧性;粗大的枝晶状马氏体以及复合型氧化物夹杂的存在均降低了焊缝区域的韧性。
OCr15Ni7Cu2Nb martensitic stainless steel and 450 MPa grade low alloy steel were welded by manual arc welding with E630 martensitic stainless steel electrode. The microstrueture, hardness and impact toughness of the dissimilar steel welded joints were investigated. The results show that there exists Cr concentration gradient on the two sides of low alloy fusion line which leads to a carbon- enriched layer and a decarburized layer in the fusion zone. As a result, the carbon-enriched layer brings about the decrease of toughness and shows a quasi cleavage fracture. But there is no carbon-enriched layer in the fusion line of martensitic stainless steel, and it keeps good toughness. The toughness of the weld area is reduced by the existence of the coarse martensite in dendritic and the composite oxide inclusions.
出处
《金属热处理》
CAS
CSCD
北大核心
2017年第5期68-74,共7页
Heat Treatment of Metals
