BONDED FLUX FOR FLAT FILLET SUBMERGED ARC WELDING

PROBLEM TO BE SOLVED: To provide a bonded flux for flat fillet submerged arc welding capable of providing preferable welding work efficiency and mechanical performance of weld metal even in large heat input.SOLUTION: The bonded flux for flat fillet submerged arc welding contains, by mass% to the whole mass% of the flux, 25 to 45% of SiO, 5 to 15% of CaO, 10 to 30% of MgO, 5 to 15% of AlO, 1 to 8% of one kind or the sum of two or more kinds of metal fluoride, 1 to 5% of one kind or the sum of two kinds of NaO and KO, 2 to 10% of metal carbonate as COequivalent, 1 to 10% of Mn, 0.1 to 0.8% of Al, 5 to 15% of Fe, and further contains 0.1% or less of Si and the balance of inevitable impurities.SELECTED DRAWING: Figure 1 【課題】大入熱においても良好な溶接作業性および溶接金属の機械的性能を得ることができる下向きすみ肉サブマージアーク溶接用ボンドフラックスを提供する。【解決手段】フラックスの全質量％に対する質量％で、ＳｉＯ２：２５〜４５％、ＣａＯ：５〜１５％、ＭｇＯ：１０〜３０％、Ａｌ２Ｏ３：５〜１５％、金属弗化物の１種または２種以上の合計：１〜８％、Ｎａ２ＯおよびＫ２Ｏの１種または２種の合計：１〜５％、金属炭酸塩のＣＯ２換算値：２〜１０％、Ｍｎ：１〜１０％、Ａｌ：０．１〜０．８％、Ｆｅ：５〜１５％を含有し、Ｓｉ：０．１％以下で、残部は不可避不純物であることを特徴とする下向きすみ肉サブマージアーク溶接用ボンドフラックス。【選択図】図１