| 摘要 |
PURPOSE:To provide a sintered flux for submerged arc welding which is superior in welding workability and forms weld zones of excellent mechanical performance and cracking resistance by granulating flux powder raw materials of specific compsns. with water glass as a binder. CONSTITUTION:This flux contains 15-30% CaCO3 or <50% BaCO3 (where CaCO3+1/2BaCO3 is 15-30%), 15-45% MgO, 10-30% Al2O3, 10-30% CaF2, <17% SiO2, <=5% alkali metal oxide such as Na2O or K2O, and <=3% Si or Al in the form of powder, wherein (0.56CaCO3+CaO)/MgO is <1.2. The molar ratio of SiO2 to alkali metal oxide in Na2O-K2O-Li2O-H2O water glass used as a binder is controlled to 1.8-2.2, the molar ratio of Na2O/(Na2O+K2O) to 0.5- 0.85 and the molar ratio of Li2O/(Na2O+K2O+Li2O) to 0.10-0.30. The material kneaded with the binder is granulated and calcined to the sintered flux for submerged arc welding. |
