BONDING METHOD OF DISSIMILAR MATERIAL JOINT BY ELECTRON BEAM WELDING

摘要

PURPOSE:To prevent the occurrence of various weld cracks by beforehand buttering-welding the specific steel materials to the welding surfaces of 26Ni-15Cr-Fe-base heat-resisting alloy and 12Cr martensite-base heat-resisting steel at the time of electron-beam-welding both members. CONSTITUTION:At the time of electron-beam-welding the 1st member 6 composed of 26Ni-15Cr-Fe-base heat-resisting alloy and the 2nd member 8 composed of 12Cr martensite-base heat-resisting steel, the covering part 20 of JISG303SUS308 steel is buttering-welded on the welding surface of the 1st member 6 by a low-heat-input TIG welding method. Also, preheating of 350-400 deg.C is applied on the welding surface of the 2nd member 8, after which the covering part 22 of SUS308 steel is buttering-welded by a TIG welding method and is annealed for 3 hours at 625 deg.C. Here, the thickness of the welding materials 20, 22 of the 1st member 6 and 2nd member 8 are made 2.1+0.015t, 4.1+0.015t or more respectively (t is the thickness of welding materials and unit is mm). Next, the both welding materials 20, 22 are electron-beam welded 24, whereby the weld zone free from various high-temperature cracks and hardening cracks is obtained.