| 摘要 |
PROBLEM TO BE SOLVED: To provide a bond flux for submerged arc welding and a manufacturing method therefor capable of reducing diffusible hydrogen in a welding metal and reducing the preheating temperature for stopping cracking. SOLUTION: The bond flux for the submerged arc welding is adjusted so as to have an specific surface area larger than 0.20 and less than 0.40 m<2> /cm<3> , a flux water content of 200 mas ppm or less, by containing 4-9 mass% in terms of CO2 of a metallic carbonate. And in the manufacturing method for the bond flux for the submerged arc welding, wherein flux raw material powder and water glass as a binder are mixed, thereafter granulated and burnt, the raw material powder for the flux contains the metallic carbonate wherein the particles having the particle size of 75μm or less occupies 75 mass% of the total grain structure.
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