| 摘要 |
PURPOSE:To perform TIG arc welding in such a way that the depth of penetration in a weld zone is approximately constant even if arc length varies largely by using a specifically composed gaseous mixture of gaseous hydrogen and inert gas as a shielding gas. CONSTITUTION:A DC voltage is impressed between an electrode 1 consisting of W or a W base alloy and a material 2 to be welded from a power source 3 to generate and sustain an arc 4 in tungsten inert gas (TIG) arc welding. The electrode 1 is moved in this state along the welding position to form successively a weld zone 5. A gaseous mixture composed of 3-60vol% gaseous hydrogen and the balance inert gas is used as a shielding gas. Then the gaseous hydrogen has a high reducing property and therefore said gas maintains the high temp. part in a reducing atmosphere, by which oxidation of the material 2 is prevented. The bead width and depth (l) of penetration are approximately constant even if arc length (d) varies.
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