| 摘要 |
PROBLEM TO BE SOLVED: To stably obtain a non defect welded part with high speed submerged arc welding by heating the flux raw material in which Fe-Si particles containing a specified quantity of Si and having a specified particle distribution are blended in a specified quantity as a deoxidizing agent, and sintering at a specified temp. SOLUTION: The calcined flux raw material powder which has a flux component having a composition consisting of, by weight, 30-70% SiO2, 5-40% Mn oxide (in term of MnO), 3-30% MgO, and 2-20% Al2O3, and 1-10% Fe-Si particles is blended as a deoxidizing agent, is granulated to about 12-200 mesh by using a water glass, etc., as a binder, and is calcined at a high temp. of >750 deg.C. The Fc-Si particles contain 30-80% Si, preferably having a particle distribution so that a particle size of >106μm is <=10% and a particle size of <45μm is <=50%. Further, for calcing the temp. is raised at speed of 5 deg.C/min in a temp. region of 700-(max temp. -50) deg.C. By this method, the calcined flux excellent in pock mark resistance and welding workability is stably obtained.
|
