摘要
采用TIG-CO2复合焊接技术,在Q235 钢表面制备Fe-Cr-C-B堆焊层,研究不同焊接热输入下复合焊接堆焊层组织和性能的变化.结果表明:不同焊接热输入下堆焊层焊缝与母材形成良好的冶金结合,界面处融合良好,没有发现明显的气孔、裂纹等焊接缺陷.堆焊层组织由树枝状马氏体和硬质合金相共同构成.随着热输入的增大,热影响粗晶区形成大量的过热魏氏体组织,堆焊层区域各部分组织晶粒有所增大.使用TIG-CO2复合焊接技术在表面堆焊一层Fe-Cr-C-B堆焊层时,堆焊层硬度和耐磨性明显提高,当CO2焊接电流为120 A时,堆焊层硬度最大为55HRC,磨损失重为0.051 5 g,堆焊层具有良好耐磨性.
Abstract
TIG-CO2 composite welding technology is used to prepare Fe-Cr-C-B overlay layer on the surface of Q235 steel,and the changes in the structure and properties of composite welded overlay layer are studied under different welding heat inputs.The findings indicate that the weld seam of the cladding layer exhibits a robust metallurgical bond with the base material across a range of welding heat inputs,demonstrating effective fusion at the interface and an absence of significant welding defects such as porosity and cracks.The cladding layer structure is composed of dendritic martensite and cemented carbide phases.As the heat input is increased,a significant number of superheated Weinstein structure are formed in the coarse crystalline region of the heat-affected zone.Additionally,the grain size of the various parts of the cladding layer region increases.The utilization of TIG-CO2 composite welding technology for the purpose of affixing a layer of Fe-Cr-C-B cladding to a surface resulted in a notable enhancement in the hardness and wear resistance of the cladding layer.The hardness of the cladding layer reached a maximum of 55 HRC when the CO2 welding current is 120 A.The wear loss is 0.051 5 g,indicative of the layer's commendable wear resistance.
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