Effect of thermit composition on manual SHS welding for low carbon steel

Base on self-propagating high-temperature synthesis(SHS), a new method of welding called manual SHS welding is introduced.Since it is easy to carry and operate, this technique can be used in emergency maintenance.The effect of the thermit composition of the combustion welding rod on the welding of low carbon steel and the microstructure of weld were studied.The thermit was composed of (CuO+Al)and (Fe₂O₃ +Al).It is shown that when the content of (CuO +Al)is higher than 50%, welding can successfully proceed.And combustion velocity becomes higher with the increasing of (CuO+Al)content.This is due to the higher combustion temperature and larger combustion heat of (CuO+Al)thermit. The tensile strength of weld becomes higher with the increasing of (Fe₂O₃ +Al)content.This is due to the precipitation of the second phase rich in Fe, which can thin the Cu grain and strengthen the alloy.The combustion welding rod with 50% and 60% (CuO +Al) thermit is easy to operate and the tensile strength of weld are higher than 420MPa.