元素V对奥氏体焊缝金属晶间腐蚀敏感性的影响

Effevt of V on intergranular corrosion resistance of austenite weld metal

关键词:  晶间腐蚀  碳化物  熔敷金属

Key words:  intergranular corrosion  carbide  deposited metal

摘要:

采用透射电镜(TEM)分析技术研究了1Cr19Ni23N焊条熔敷金属中钒含量对组织及对熔敷金属抗晶间腐蚀性能的影响。结果表明,低钒含量焊条熔敷金属组织中沿奥氏体晶界析出M₂₃C₆型富铬碳化物,在晶界附近形成贫铬层,导致晶间腐蚀的发生;高钒含量焊条熔敷金属组织中,V优先于Cr与C形成细小弥散的碳化钒分布在晶粒内部,使得该焊条在保持原较高碳含量的基础上,通过改变碳化物形态和分布达到了保持高强度和改善晶间腐蚀敏感性的目的。

Abstract:

Variable microstructures of the deposited metals with different V content using 1Cr19Ni23N electrode were observed by transmission electron microscope.Thus the effect of V on the intergranular corrosion resistance of austenite deposited metal is discussed.The results showed that M₂₃C₆ carbide particles were formed at austenite grain boundaries and a poor-Cr zones were formed along grain boundaries in deposited metal with low V content.As a result,intergranular corrosion occurred at these zones.Increasing V content in deposited metal may result in small and dispersed V(C) precipitates distributing in austenite grain.V have a strong effect on the quantity,morphology and distribution of carbides.Holding high C content and high strength,intergranular corrosion resistance of the deposited metal with high V content was increased.Therefore,high V content increases the strength and intergranular comosion resistance of the deposited metal and does not change the C content.