The flux and flux which thermosetting metaplasia resin coat

摘要

PROBLEM TO BE SOLVED: To obtain a back-bead without weld defects by specifying a difference between the wt.% of the flux coated with a thermosetting resin remaining in a sieve based on the total flux quantity and the wt.% of the flux not coated in ≤ a specific ratio. ;SOLUTION: The difference is set not more than 5 wt.% between the wt.% of the flux coated with a thermosetting resin and that of the flux not coated. In addition, the difference of apparent density between the two is desirably ≤0.7 g/cm³. Welding is performed while the backing flux is supported with a copper plate on the reverse side 3 of the groove and the surface flux is supplied to the groove 2 side. The flux coated with the thermosetting resin is mixed with the flux not coated to make the backing flux, thereby improving gas release from inside the flux and the solidified state of the flux at the time of welding. Simultaneously, the phenomenon that the remaining flux sticks to the copper plate is prevented.;COPYRIGHT: (C)1999,JPO