| 摘要 |
<p>This invention aims at providing a welding method capable of preventing generation and re-deposition of metallic fumes at portions near the surface of a weld portion and capable of reducing a deposition quantity of chromium carbides. The present invention further aims at providing a welding stainless material free from deposition of fumes, a semiconductor fabrication apparatus, an ultra-pure water feeding apparatus and an ultrahigh-pure gas feeding piping system. In a method of connecting a plurality of stainless members by fusing and solidifying predetermined portions (weld portions) of these stainless materials, the welding method of this invention is characterized in that heat input quantity to the weld portions is set below 600 joule/cm. Furthermore, the welding method is characterized in that the welding rate is set to below 20 cm/min. The stainless material is characterized in that when the welded body is washed with ultra-pure water (at flow rate of 15 l/hr for 6 hours) after welding, the sum of elution quantities of Fe, Ni, Cr and Mn is not greater than 0.1 νg per cm of the weld length.</p> |
