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通过选择合金粉料种类、激光输出功率、光斑扫描速度为影响因素,用正交试验方法在45钢基体上进行熔覆研究;使用剪切法测试熔覆层与基体的结合强度,分析评价各试验因素对结合强度的影响程度;测试了熔覆层的显微硬度,并使用高解析场发射扫描式电子显微镜进行熔覆层SEM成像和EDS成分分析。试验结果表明,激光熔覆层与基体的结合强度大于45钢基体的抗剪应力强度;镍基的熔覆层的抗剪强度为母材的2~3倍,铁基的抗剪应力强度为母材的5倍以上;粉料种类对结合强度的影响最大,光斑扫描速度次之,激光输出功率影响最小;靠熔覆层外部的硬度比结合部和中部的硬度均高,存在热影响区,硬度高于母材;熔覆层与基体之间形成了良好的冶金结合,组织均匀,无微裂纹等缺陷。激光熔覆层的结合强度能满足再制造的要求。
By selecting the type of alloy powder, laser output power and spot scanning speed as the influencing factors, the orthogonal experiment was used to study the cladding on the 45 steel substrate. The shear strength was used to test the bonding strength between the cladding and the substrate. The influence of experimental factors on the bonding strength was investigated. The microhardness of the cladding layer was tested. SEM and EDS analysis of the cladding layer were performed by using high resolution field emission scanning electron microscopy. The experimental results show that the bonding strength between the laser cladding layer and the substrate is greater than the shear strength of the 45 steel substrate. The shear strength of the nickel-based cladding layer is 2 to 3 times that of the parent material. The shear strength of the iron- 5 times more than that of the base metal. The types of the powder have the greatest influence on the bonding strength, the spot scanning speed is the second, and the laser output power has the least impact. The hardness outside the clad layer is higher than that of the bonding part and the middle part, , The hardness is higher than that of the base metal, the metallurgical bonding between the cladding layer and the substrate is formed, the structure is uniform, and no defects such as micro-cracks are formed. The bonding strength of laser cladding can meet the remanufacturing requirements.