A286 合金溶接材の 4K および 300K における機械的性質と低サイクル疲労強度

概要

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The tensile, Charpy impact and fatigue properties of TIG welded alloy A286 have been investigated at 4 and 300 K. The base material was forged plates of 35 mm thick of electroslag remelted A286 in which the composition of minor elements such as C, Si and B was tightly controlled. The plates were welded by using A286 filler metal without fusion zone hot cracking and HAZ fissuring except for a small amount of micro-defects dispersed in the weld metal. The yield and tensile strengths, ductility and fatigue strength of the weldment were lower than those of the base material owing to strain localization at the softened weld metal zone. The post-weld heat-treatment which consists of homogenization followed by aging restored the lowered strengths, ductility and the fatigue strength of notched specimen near to those of the base material. The absorbed energy at 4 K of the base material, weldment and heat-treated weldment was almost the same, about 60 J. Though the micro-defects in the weld metal slightly decreased the ductility and absorbed energy, they did not cause any harmful effects on the yield and tensile strengths of the weldment and heattreated weldment. The fatigue strength of smooth specimens after the post-weld heat-treatment was, however, sensitive to the size or the number of the micro-defects and the S-N data were dispersed among those for the smooth specimens of the base material at 4 and 300 K.
社団法人日本鉄鋼協会の論文
1987-10-01