| 摘要 |
PURPOSE:To decrease the dust and spatters to be generated at the time of welding by shielding an arc from the atm. by a shielding gas contg. carbon dioxide and gaseous oxygen at the time of welding. CONSTITUTION:The gaseous CO2 and gaseous O2 exist in the shielding gas at the time of welding of the galvanized steel sheets but the gaseous CO2 is decomposed by an arc to generate O and, therefore, the shielding gas enhances the performance as an oxidative gas by the presence of the gaseous O2 and the gaseous CO2. The size component in the plating layer is, therefore, oxidized to ZnO even in a range in excess of about 900 deg.C at the time of welding. 0The evaporation of zinc is suppressed and the amt. of the dust to be generated at the time of zinc evaporation is suppressed low. Since a good arc shielding effect is exhibited by the presence of the CO2, the arc is stabilized by the shielding gas and the molten metal is stabilized. The amt. of the spatters to be generated is simultaneously suppressed to a low level as well. |
