| 摘要 |
PURPOSE:To improve the moisture absorption resistance of an electrode and the crack resistance of a weld zone by regulating the value of the average roughness Ra of the center line on the covered surface in the specified range. CONSTITUTION:The raw material of good wettability is used for the covered flux forming the covered surface of the low hydrogen material covered electrode for arc welding, which i made to be of the particle size structure close to the closest packing as well, moreover, the kneading conditions, coating pressure, drying speed, etc., are adjusted and the center line average roughness Ra on the covered surface is regulated in 3.0-6.5mum. A good correlation exists on the surface roughness to the amt. of the absorbed moisture of an electrode. The increasing trend of a moisture absorption amt. is lenient in case of Ra being 3.0mum min 6.5mum max but increased rapidly if exceeding 6.5mum. A coating crack is caused with Ra being <=3.0mum. With this method the moisture absorp tion resistance of an electrode can be improved with preventing the generation of a coating crack. Moreover, the crack resistance of a weld zone is improved with the improvement of the moisture absorption resistance. This electrode is taken as the low hydrogen material covered electrode for arc welding stipulat ed for in JIS B0601.
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