The authors have newly developed a Narrow-Gap One-side Horizontal CO2 Arc Welding Process (NOW-H Process) for on-site welding of column to column joints of steel structures of building.
In this paper, mechanism of the formation of reverse-side bead is discussed experimentally to establish the basis of the NOW-H Process. Formation of reverse-side bead in the horizontal position welding is different from that of the flat position, as already mentioned in the Report 2. In the horizontal position welding, concavity of the reverse-side bead is apt to occur at the root of upper side plate, and also the shape of 1st pass is prone to become convexity, resulting in the lack of fusion in the medium of 1st and 2nd layer.
Accordingly, in order to prevent these weld defects and obtain a steady reverse-side bead, adequate backing methods are needed.
Effects of diameter of wire, root-opening, arc voltage and other factors on the formation of reverseside head are described.
