| 摘要 |
PURPOSE:To prevent high temp. cracking of a welded metal by welding at least the 1st layer by using a composite wire contg. C in a specific range of contents in electrogas welding method for extra low carbon steel. CONSTITUTION:In the stage of electrogas welding of steel for general structure purpose contg. 0.005-0.06wt% C and for low temp. of low alloy content such as dead soft steel, the steel is welded by using a composite wire contg. 0.11-0.35% C, then the weld metal formed by the welding contains about 0.07-0.15% C which is in the range stable to high temp. cracking. In the stage of multi-layered welding, it is necessary to weld at least the 1st layer thereof by using said composite wire. The content of C in the composite wire is determined by controlling the sheath material of the wire and the iron powder, deoxidizing agent, alloying agent, graphite, etc. of the packed flux. |
