Nb 含有オーステナイトステンレス鋼の溶接高温割れ感受性

概要

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Hot cracking of Nb-containing austenitic stainless steel was studied. The following results were obtained; 1) Hot cracking susceptibility of Nb-containing material increases detrimentally in both fully γ-phase and (γ+α)-phase weld metal when Nb content exceeds about 0.40%. 2) C improves hot cracking resistance in case of high Nb content (0.78%), but indicates hardly noticeable effect when the Nb content is low (0.26%). The effect of N on hot cracking is not so significant within the range of 0.015% to 0.12%. 3) Increase of hot cracking susceptibility is due to the segregation of Nb, C and N at grain boundaries, which was found on the crack fracture surfaces in the welds by Auger Electron Spectroscopy. Based on these results, 40mm thick plate of modified low-C, type 347 stainless steel was made and welded by GTAW, SMAW and SAW. Microcrack resistance of these welds proved to be quite satisfactory.
社団法人溶接学会の論文
1981-07-05