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利用Fe基药芯焊丝对失效的5CrNiMo模具进行多层堆焊修复,之后对堆焊试样进行空冷处理。利用显微观察及硬度分析方法研究了各层堆焊合金的显微组织形貌及显微硬度分布。结果表明:焊后空冷处理条件下各层显微组织形貌及硬度分布差异较大,堆焊合金由第一层到第三层细小的板条回火马氏体逐渐减少,粗大的板条回火马氏体逐渐增多,最外表层堆焊合金组织主要为粗大的片状马氏体,同时堆焊合金的显微硬度由第一层到外表层逐渐升高,出现梯度分布,最外层堆焊合金显微硬度平均值达到了540 HV。堆焊时后层堆焊对前层进行了高温回火是各层显微组织及硬度分布出现差异的主要原因。
The Fe-based flux cored wire was used to repair the failed 5CrNiMo molds by multi-layer surfacing, and then the overlay welding samples were air-cooled. The microstructure and microhardness distribution of surfacing alloy of all layers were studied by microscopic observation and hardness analysis. The results show that the microstructure and hardness distribution of each layer under the air-cooling condition after welding are quite different. The surfacing alloy gradually decreases from the first to the third layers of the small lath tempered martensite. The thick lath Tempered martensite gradually increased, the outermost surfacing alloy is mainly coarse sheet martensite, while the microhardness of surfacing alloy gradually increased from the first layer to the outer surface, a gradient distribution, the outermost The average microhardness of layer surfacing alloy reached 540 HV. Welding surfacing layer welding on the front of the high temperature tempering the various layers of the microstructure and hardness distribution of the main reasons for the difference.