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1.问题的提出 我厂制作的导辊,其辊身的材质为20CrMoV,辊颈为35钢(如图1所示),它们之间的焊接为异种金属之间的焊接。由于两种钢的物理性能、化学成分的差异及晶体组织和力学性能的不均匀性,在焊接时接头存在较严重的碳迁移及组织性能变化,加之两种钢的线膨胀系数不同,在焊接过程中近界面部位产生附加应力会导致焊缝断裂;同时焊接时由于合金元素(如Cr、Mo、V)的作用存在稀释问题,从而在焊缝及近缝区产生硬脆的马氏体组织,因此焊接困难。 为此,我们在焊前通过在35钢一侧堆焊一过渡层再与20CrMoV进行焊接,并在焊接时制定了合理的工艺措施,取得了满意的效果。
1. Question put forward I plant the guide roller, the roller body material 20CrMoV, roll neck 35 steel (shown in Figure 1), between the welding of dissimilar metals between the welding. Due to the difference of physical properties and chemical composition of the two steels and the non-uniformity of the crystal structure and mechanical properties, there is a serious carbon migration and structural change in the joints. In addition, the linear expansion coefficients of the two steels are different. In the process, additional stress will be generated near the interface, which will lead to the fracture of the weld seam. At the same time, due to the dilution effect of alloying elements (such as Cr, Mo and V) during welding, hard and brittle martensite will be formed in the weld and near seam area , So welding is difficult. For this reason, we welded a 20CrMoV welded layer by welding a transition layer on one side of 35 steel before welding, and made reasonable technological measures during welding, which achieved satisfactory results.