Welding of Steel with Propane-Oxygen Flame (Report 3)

Effect of Aluminum in Welding Rod

Abstract

It was shown in previous report that the maximum intensity of propane-oxygen flame was given by a stoichiometrical gas mixture for complete combustion and also that the time to start melting a steel plate was shorter at the inside of the inner cone of flame than at any other part of flame.
Therefore in this paper, it is investigated if such a propane-oxygen flame, by which the shortest time to start melting steel plate is obtained, is available for welding. And aluminum-containing welding rods are used for bead-on-plate test of rimmed or killed steel plate under various flame conditions. Morover, porosity and mechanical properties of some butt-welded joints by aluminum-containing rods are examined.
The results obtained are summarized as follows :
1) The ratio of Si/Mn is also important to prevent porosity of weld metal, i.e. a too high content of silicon is detrimental to the prevention of porosity.
2) Aluminum in welding rod ranging from 0.20 to 0.35% is more effective for prevention of porosity than silicon and manganese, and such an aluminum content of rod gives good mechanical properties of welded joints.
3) Outside of inner cone of the flame the ratio of oxygen/propane less than 3.2 is most suitable for welding.