摘要
采用自动钨极氩弧(TIG)焊对N263高温镍基合金进行焊接,研究焊接接头经过热处理及不同时效时间后微观组织的演变规律。结果表明:采用自动TIG焊接5mm厚N263薄板,采用单边V型坡口,预留1mm的钝边,并采用75%Ar+25%He混合气保护,焊接速度100mm/min,可以获得成形较好的焊缝。焊后接头在800℃下经8h热处理后,发现焊缝组织中枝晶间主要是块状富Ti、Mo碳化物MC,以及周围弥散的细小析出物,主要为富Cr、Mo碳化物M23C6;随后又在750℃进行长期时效,枝晶间M23C6碳化物尺寸和数量有所增加。该研究充分说明了N263焊接接头经过高温热处理及长期时效后,晶粒稳定性强,强化相数量增多,接头保持了良好的高温性能。
Automatic tungsten inert gas welding was utilized to weld N263 high temperature nickel base alloy,and the microstructure evolution of the welded joint after post-weld heat treatment(PWHT)and different aging time was investigated.The results confirmed that weld seam with excellent formation could be obtained when automatic TIG welding was used to weld N263 thin plate with thickness of 5 mm,and meanwhile with the application of single side V groove,truncated edge with thickness of 1mm and 75%Ar+25%He mixture gas protection with 100 mm/min welding speed.After 8 h heat treatment at 800℃,it was found that bulky Ti-Mo-rich carbides M 23 C 6 precipitated at inter dendritic region and tiny Cr-Mo-rich carbides M 23 C 6 in the surrounding area.Then long time aging was processed at 750℃,and size and amount of inter dendritic M 23 C 6 carbides increased.This research fully indicated that after PWHT and long time aging,N263 weld joint would have strong grain stability with increased number of strengthening precipitation,showing good high temperature performance.
作者
刘雷
LIU Lei(Shanghai Electric Power Generation Equipment Co.,Ltd.Turbine Plant,Shanghai 200240,China)
出处
《热力透平》
2018年第4期303-308,共6页
Thermal Turbine
关键词
高温镍基合金
钨极氩弧焊
时效
微观组织
high temperature nickel base alloy
tungsten inert gas welding
aging
microstructure
