超低碳氮强化药芯焊丝堆焊层组织与性能

Microstructure and properties of hard facing metal welding by ultralow carbon and nitrogen strengthened flux-cored wire

采用自主研制的超低碳氮强化药芯焊丝,利用明弧摆动堆焊技术,选择合适的堆焊工艺参数,在42CrMo板表面堆焊形成马氏体不锈钢堆焊层。通过超声波探伤仪、金相显微镜、EDS、显微硬度计分析测试堆焊层的组织、成分及性能。结果表明,堆焊层无裂纹、气孔等缺陷,与母材达到了冶金结合;堆焊层组织为单一的马氏体,其成分与所设计的药芯一致;堆焊层的硬度从底部到表层呈梯度变化,其平均硬度是基体的2.5倍,弥补了传统堆焊材料整体韧性不足的缺陷;氮化物均匀弥散分布在堆焊层表面。

Adopting the self-developed ultralow carbon and nitrogen strengthened Rux-cored wire, an martensitic stainless weld o- verlay is synthesized by open arc welding technology and appropriate overlaying parameters on 42CrMo steel. The microstructure, components and properties were analyzed by the ultrasonic flaw detector, optical microscopy, EDS and micro-hardness tester. The result shows that the hard facing layer was metallurgically bonded with the matrix materials without any crack and gas pore. The microstructure of the weld overlay is sole martensite, and the component is consistent with that of the welding wire; There is a grandient change for hardness of the weld overlay from bottom which makes up for the overall toughness defects of the tradition- al welding material. The hardness value of the weld overlay is 2. 5 times greater than that of the substrate, and the nitrides are e- venly distributed in the surface of the hard facing layer.