GUO Xinfang, CUI Fengyou, FAN Hongju, et al.TIG+SMAW Process and Properties Analysis of Large Diameter Thick-walled G115 Heat-Resistant Steel Pipe[J].Electric Welding Machine, 2022, 52(8): 101-107. DOI： 10.7512/j.issn.1001-2303.2022.08.14.
TIG+SMAW Process and Properties Analysis of Large Diameter Thick-walled G115 Heat-Resistant Steel Pipe
TIG+SMAW method is used to weld large diameter thick-walled G115 heat-resistant steel pipe used for ultra-supercritical power plant boiler, and the microstructure and mechanical properties of the joint are analyzed. The results show that there are obvious microstructural transformation in weld zone (WZ), heat affected zone (HAZ) and fusion zone. The WZ is mainly composed of tempered martensite microstructure, HAZ is mainly composed of lath martensite microstructure, and base metal appears lamellar martensite microstructure. From the base metal to the weld, the grain gradually refines, the microstructure of weld is mainly equiaxed grain and columnar grain, and the joint hardness distribution gradually increases, but slightly decreases near the fusion line, in which the minimum value of joint hardness is 220.6 HV0.2 (HAZ) and the maximum value is 302.8 HV0.2 (WZ). In addition, the joint impact test shows that the impact absorption energy of the root of HAZ is significantly higher than that of the weld, while that of the filled zone is slightly lower than that of the weld. The average values of the impact absorption energy in WZ and HAZ are 43.89 J and 66.49 J respectively. The impact toughness of the welded joint is good, which can meet the actual application requirements.
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