BUTT WELDING METHOD FOR PIPING FOR HIGH PRESSURE

摘要

PURPOSE:To obtain the weld zone of the piping for high pressure improving a pressure resistant strength without spoiling the productivity by welding the initial layer of a groove with TIG welding and thereafter by welding the other groove part with an arc welding. CONSTITUTION:The initial layer of the mutual groove 2 of a piping 1, 1, namely the important part on the welding strength especially as shown by (a) is welded with TIG welding. The weld zone is formed thereafter by welding with an efficient arc welding the part (b) which requires other numerous depositing metals. As a result, no welding defect is caused on a TIG weld zone 4 and even if a defect 3 is caused on an arc weld zone 5 the welding strength becomes large as a whole and the piping resistant to the high pressure >=300kg/cm<2> can be realized.