| 摘要 |
PURPOSE:To prevent generation of defects such as concave bead, overlapping etc. in welding in which slag is formed on molten metal and the molten metal solidifies on a downward slope by specifying solidifying temperature and viscosity of the slag. CONSTITUTION:Downward slope welding is performed forming slag of which solidifying temperature is 850-1,400 deg.C and viscosity at 1,450 deg.C is <=5 poise, and in case where solidifying temperature is 850-1,200 deg.C, viscosity at 1,200 deg.C is >=5 poise, on molten metal. When the solidifying temperature is below lower limit, generation of slag is increased and concave bead is formed. At the same time generation of defects such as overlapping etc. is increased remarkably. When the temperature is above upper limit, generation of concave bead is eliminated. However, defects such as slag inclusion, undercut etc. take place. When the viscosity exceeds the upper limit at 1,450 deg.C, that is, temperature of starting solidification of the molten metal, frequency of occurrence of defects such as slag inclusion, undercut etc. increases, and when it is below the lower limit at 1,200 deg.C, a temperature at which inside of the bead solidifies completely, concave bead is liable to be formed. |
