| 摘要 |
<p>A fused flux for submerged arc welding which is suitable for use in, e.g., producing a UOE steel tubing. It can form a weld metal which stably has an oxygen amount of 250 ppm or smaller while retaining a tensile strength at least on the level of the 75 kgf/mm<SUP>2</SUP> grade (=750 MPa grade) and which combines strength with toughness. This flux has a chemical composition comprising 5-15 mass% SiO<SUB>2</SUB>, 1-10 mass% MnO, 10-30 mass% CaO, 40-50 mass% CaF<SUB>2</SUB>, 2-10 mass% MgO, 2-20 mass% Al<SUB>2</SUB>O<SUB>3</SUB>, 2-20 mass% TiO<SUB>2</SUB>, and 1-10 mass% BaO and optionally containing one or more of up to 3 mass% Na<SUB>2</SUB>O, up to 3 mass% K<SUB>2</SUB>O, and up to 1.0 mass% B<SUB>2</SUB>O<SUB>3</SUB>, the total amount of these ingredients being at least 95 mass%.</p> |
