等离子堆焊工艺对新能源柴油机气阀机械性能的影响

Effect of Plasma Cladding Process on the Mechanical Properties of New Energy Diesel Engine Valves

采用等离子堆焊技术在42CrMo合金结构钢基体制备不同热输入条件下的Colmonoy56 SPL粉末合金堆焊层,通过金相显微镜、扫描电镜、硬度测试等手段对合金层的微观组织、成分、稀释率、洛氏硬度、显微硬度进行分析.结果表明:合金层主要由3种相组成,分别是γ-Ni基体相、富Cr的碳化物相、菊花状的共晶组织相;不同热输入条件下合金层的稀释率、微观组织存在差异,不同相的单相显微硬度差异明显,共晶组织的相比例影响合金层宏观洛氏硬度,随着共晶组织相比例的增大,合金层硬度呈减小的趋势.

Colmonoy56 SPL powder alloy cladding layer was prepared by plasma cladding technology on 42CrMo alloy structural steel substrate under different heat input conditions,and the microstructure,composition,dilution rate,Rockwell hardness,and microhardness of the alloy layer were analyzed by means of metallurgical microscope,scanning electron microscope,and hardness test.The results show that the alloy layer is mainly composed of three phases,namely,γ-Ni matrix phase,Cr-rich carbide phase,and chrysanthemum-like eutectic organization phase;there are differences in the dilution rate and microstructure of the alloy layer under different heat input conditions,and there are obvious differences in the single-phase microhardness of the different phases,and the phase ratio of the eutectic organization influences the macroscopic Rockwell hardness of the alloy layer,and with the increase of the phase ratio of the eutectic organization,the hardness of the alloy layer is on the trend of decreasing.The hardness of the alloy layer tends to decrease as the proportion of eutectic organization phase increases.