45#钢表面激光熔覆梯度涂层的组织及性能

Microstructure and Properties of Laser Clad Gradient Coating on 45 # Steel Surface

在45#钢表面激光熔覆梯度涂层,其中底层材料分别为Ni60A和Fe基合金粉末,上层材料自熔性镍基碳化钨粉末,使用洛氏硬度计、蔡司高级金相显微镜和显微硬度计对比分析熔覆层的组织及性能。结果表明:当Ni60A粉末作为底层材料时,熔覆层宏观表面相对平整光滑,平均洛氏硬度是基体(HRC:22)的2.5倍,熔覆层厚度均匀且熔池深度基本保持不变,第一道与最后一道熔覆层的高度差仅为0.10mm,当Fe基合金粉末作为底层材料时,高度差0.28mm;熔覆层及界面处无裂纹、气孔等缺陷,沿熔覆层与基体交界处向外晶粒呈现枝状晶到等轴晶,基体与熔覆层间冶金结合比较牢固;熔覆层上层显微硬度分布均匀,约是基体的3倍。激光熔覆梯度涂层材料且上层材料为自熔性镍基碳化钨粉末时,底层材料选择Ni60A粉末,得到的涂层成形质量更佳。

Laser clad gradient is coated on 45# steel surface. Material of the underlying is Ni60A powder and Fe-based alloy powder. Material of the upper layer is self-fluxing Ni-based WC powder, using rockwell hardness, advanced microscope and micro hardness tester to analyze that microstructure and properties of cladding after completion of the experintent. The results show that macro surface of cladding relatively smooth and the average rockwell hardness is 2.5 times of the matrix （HRC： 22）, uniform thickness of the cladding layer and the depth of the molten pool remained basically unchanged, the height difference of the first and last line of the cladding layer is 0.10ram When Ni60A powder is used as the underlying. When Fe-based alloy powder is used as the underlying, the height difference is 0.28mnr Cladding layer and the interface without cracks, holes and other defects. Alang the junction of cladding layer and the substrate , grains exhibit columnar crystals and equiaxed. Cladding la？er between the substrate and the relatively strong metallurgical bond. The hardness of cladding layer distribution and it is 3 times of the matrix. When laser clapt grcutient coating and material of the upper layer is self-fluxing Ni-based WC powder, the underlying material is Ni60A powder, Cladding layer formed to give a better quality. It has a certain reference value in the fie ld of los e r cladding.