早期的核设施回路管道采用316L不锈钢,在核辐射条件下经过长时间的运行,面临着严重的晶间应力腐蚀隐患,提高核设施耐晶间腐蚀已经成为核电站需要解决的重要问题之一。材料的Cr含量对抵抗晶间应力腐蚀有明显作用,用CO₂和Nd∶YAG两种激光熔覆高Cr含量的Inconel 690合金,研究了获得高Cr熔覆层涉及的稀释率控制,激光波长、光束分布、工艺参数对稀释率的影响,熔覆层微观组织和耐腐蚀性能。研究证明,矩形光斑比圆形高斯光斑更容易获得低稀释率的涂层,高Cr含量能获得更好的耐腐蚀性能;Nd∶YAG激光比CO₂激光更容易获得高耐腐蚀熔覆层。

Early nuclear power plant components were normally made with stainless steel AISI 316L due to its good anticorrosion property. After long time running,316L nuclear components are facing severe intergranular stress corrosion under rigorous radiation conditions. To rejuvenate the as-eroded 316L components is vital for long-term sustainable and safe operation of the nuclear power plants. It is approved that the resistance to intergranular stress corrosion cracking and intergranular attack is significantly dependent on the Cr content in the material. In this paper,the coating was deposited by CO₂ and Nd∶YAG laser using Inconel 690. Investigation on main influence factors on the Cr content in the coating including the dilution rate,laser types,beam energy distribution and laser processing parameters,were discussed. A rectangular beam can achieve low dilution,high Cr content and high deposition efficiency than a Gaussian beam. The coating produced by Nd∶YAG laser shows more excellent properties than CO₂ laser.