加圧下における湿式水中プラズマ溶接の冷却特性と溶接金属の組織

概要

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From the standpoint of welding application, effects of cooling characteristic on metallurgical and mechanical properties of weld metals were examined in underwater wet plasma welding (melt run in flat position) in pressurized city water. The test welding were carried out at ambient water pressure from 0.04kgf/(cm)^2 to 30kgf/(cm)^2 using 19mm thick JIS-SM41A steel plate as the base metal, and, the welding conditions were employed under which the weld metal having an excellent appearance and being free from blow-hole was produced by melt run. The main results obtained in this study are summarized as follows. (1) Cooling below 800℃ at each water pressure is rapid in comparison with that in air. And, cooling time tends to reduce up to 10kgf/(cm)^2 in ambient water pressure, while it has increasing tendency over that water pressure. (2) Effect of arc current on cooling characteristic is stronger than that of plasma gas flow rate. (3) Structure of weld metal becomes clearly different with the increase in water pressure up to 10kgf/(cm)^2,however, it is difficult to distinguish the difference between them at above that water pressure. (4) Hardness of weld metals have an increasing tendency up to 10kgf/(cm)^2,however, no difference in them is recognized at above that water pressure. Meanwhile, maximum hardness of HAZ is more than Hv 300 at each water pressure.
社団法人溶接学会の論文
1981-09-05