Ni-Cr-Mo-Cu合金的固溶处理及其对耐蚀性的影响

Solution treatment and its effects on corrosion resistance of Ni-Cr-Mo-Cu alloy

基于扩散理论运用和具体分析,本工作对于所研制的Ni-Cr-Mo-Cu铸态合金的固溶处理工艺及其对成分、组织和腐蚀抗力的影响进行了试验研究。结果表明:手工电弧熔炼、真空感应熔炼和真空白耗电极熔炼的铸态组织有明显区别,分别为较细的胞状或网络状结构(其胞尺寸约20μm)、粗大的树枝晶(其枝晶间距80～100μm)和发达的方向性树枝晶组织(间距为60～80μm)。经1140～1170℃、2.5h的固溶处理后,上述胞状或枝晶组织消失、偏析组织达到均匀化。与铸态合金相比,固溶状态的合金在4种介质(50%HNO_3、30%HCl、15%FeCl_3和混合酸)中的耐蚀性都获得提高(15%～25%以上)。

Based on the application and analysis of diffusion theory in detail, the solution treatment and its effects on composition, microstructure and corrosion-resistance of newly-developed as-cast Ni-Cr-Mo-Cu alloy were studied and examined. The results show that the as-cast microstructures of three melting methods, hand-arc furnace, vacuum induction furnace and consumable electrode vacuum arc furnace, were fine cellular or network structures （about 20μm for its cell size）, coarse dendritic structures （80-100μm for its spacing） and well-developed directional dendrites （60-80μm for its spacing） respectively. After solution treatment at 1140~ 1170℃ for 2.5h, the above cellular or dendritic structures all disappeared and segregated microstructures were homogenized. Compared with the as-cast alloy, the corrosion resistance of the as-solution condition Ni-Cr-Mo-Cu alloy among four kinds of corrosive agents （50%HNO3, 30%HC1. 15%FeCl3 and mixed acid） was all improved （above 15%-25%）.