| 摘要 |
PURPOSE:To obtain good appearance and sufficient welding strength by forming microholes penetrating from the outside surface of a hollow work to a hollow part to the hollow work and welding the work while suppressing the pressure increase in the work by the thermal influence at the time of joining the end faces of the work to each other. CONSTITUTION:The microholes 2 penetrating from the outside surface of the work 1 to the hollow part are formed to the this work. The end faces of the work are welded while the pressure increase in the work is suppressed by escaping the air or evaporating gas in the work from the microholes by the thermal influence at the time of joining the work. The air or steam gas flows out through the microholes of the work to the outside and the pressure in the work is maintained under the pressure nearly equal to the outdoor air pressure even if the the pressure tends to increase upon expansion of the air in the work or the evaporation of the cutting fluid, etc., sticking to the inside part of the work by heating up of the weld zone to a high temp. The welding quality is stabilized without generating the problem that the expanded air intrudes into the weld zone and generates blowholes. |
