基于实时测量的等离子喷焊熔池温度对焊层组织性能的影响

等离子喷焊过程中熔池温度波动大，目前主要存在依赖人工干预、自动化程度低等问题，喷焊层质量受到很大影响。因此，喷焊过程熔池温度的实时控制是等离子喷焊技术发展的必然选择。为研究喷焊过程熔池温度变化对喷焊层组织性能的影响，开发实时监控技术打下基础，采用在线监测的方法，对喷焊过程熔池温度进行实时测量，分析了喷焊过程熔池温度对喷焊层宏观形貌、组织成分和显微硬度的影响。结果表明，等离子喷焊过程熔池温度控制在1400℃左右，喷焊层具有较好的组织与性能。喷焊过程熔池温度较低时，容易引起近熔合区形成氧化物夹杂；喷焊过程熔池温度过高时，容易造成喷焊层稀释率的增加。喷焊电流110 A时，前段喷焊层的显微硬度为(670±26) HV0.1,明显高于中段喷焊层的显微硬度(550±20) HV0.1;当喷焊电流为70、110和150 A时，喷焊层显微硬度呈由高到低的趋势。

Influence of plasma spray welding pool temperature on microstructure and properties of welding layer based on real-time measurement

Mainly due to the problems of relying on manual intervention and low level of automation, the molten pool temperature varies dramatically during plasma spray welding, and the quality of spray welding layers is significantly affected. As a result, real-time control of the molten pool temperature in the spray welding process is an unavoidable choice for the advancement of plasma spray welding technology. In order to study the influence of the temperature change of the molten pool on the microstructure and properties of the spray welding layers and to lay the groundwork for developing the real-time monitoring technology, the on-line monitoring method was adopted to measure the temperature of the molten pool during the spray welding process in real time, and the influence of the temperature of the molten pool on the macromorphology, microstructure composition and microhardness of the spray welding layers was analyzed. The results reveal that when the molten pool temperature is maintained at around 1400 ℃ in the plasma spray welding process, the spray welding layers have good microstructure and characteristics. When the molten pool temperature is too low during the spray welding process, it is easy to cause the formation of oxide inclusions in the near fusion zone. When the molten pool temperature is too high during the spray welding process, the dilution rate of the spray welding layer is likely to increase. When the spray welding current is 110 A, the microhardness of the front sprayed layer is (670±26) HV0.1, which is significantly higher than that of the middle sprayed layer as (550±20) HV0.1; when the spraying current changes from 70 to 110 and to 150 A, the microhardness of the spray welding layers shows a trend from high to low.