采用镍基和奥氏体焊材焊接Cr5Mo钢焊接接头的高温性能

通过热处理实验、持久实验以及焊缝附近微区变形的测量 ,对采用镍基焊材和奥氏体不锈钢焊材焊接的Cr5Mo钢焊接接头的高温性能进行研究。试验表明在高温条件下 ,奥氏体A30 2 /Cr5Mo焊接接头很快就发生碳迁移 ,且碳迁移的程度随着时间的延长而加剧 ;而镍基Inconel 1 82 /Cr5Mo焊接接头很难发生碳迁移。由于碳迁移的影响 ,在低应力的条件下 ,A30 2 /Cr5Mo焊接接头持久寿命大约只有Inconel 1 82 /Cr5Mo焊接接头的 5 0 % ,且镍基焊接接头的断裂位置大多位于远离焊缝的母材上 ,而A30 2 /Cr5Mo焊接接头的断裂位置大都在脱碳层附近。通过对焊缝附近微小区域变形的测量 ,发生断裂的脱碳层区域较其他位置具有较大的蠕变变形以及较高的蠕变变形速率

High Temperature Behavior of Cr5Mo Dissimilar Joints Welded by Nickel-based and Austenite Weld Metal

In the present paper, high temperature behavior of A302/Cr5Mo and Inconel 182/Cr5Mo welded joints were studied by thermal aging treatment, long term creep testing and measuring of small zone deformation. It was found that carbon migration in A302/Cr5Mo welded joints happen very soon during thermal aging treatment, and carbon migration pricks up with time prolong. while in Inconel 182/Cr5Mo welded joints, carbon migration does not almost occur. Because of the effect of carbon migration, creep rupture life of welded joints with austenitic weld metal is about 50% of that of Ni-based welded joints on low stress level, and the rupture position of Ni-based welded joints is located in base-metal far away from fusion line, while that of A302/Cr5Mo joints is located in decarburised zone. By measuring the deformation of small zone near fusion line, it is also show that the decarburised zone where rupture happened has larger creep deformation and faster creep strain rate than other zones.