| 摘要 |
PURPOSE:To obtain a backing strip for welding which has a wide range of the heat input to be used and can yield penetration beads having a good shape by using a refractory material contg. SiO2, Al2O3 and MgO at specific ratios as a stock. CONSTITUTION:The refractory material which contains, by weight %, 45-70% SiO2, 15-40% Al2O3, and 5-30% MgO so as to contain these materials at >=90% in total and is mixed with a small amt. of ZrO2, CaO or CaF2, LiF as the raw material for adjusting refractoriness is used as the backing strip for welding to be used for one-side arc welding. This backing strip for welding is the refractory material having SK11-SK15 refractoriness in the melt falling temp. range in the refractoriness test specified in JIS R 2204 and 20-40% porosity. The penetration beads which have the uniform shape, are free from overlaps and undercuts and have excellent quality are obtd. |
