Effects of forming process of combustion welding rod on manual SHS welding

The influence of forming process of the combustion rod on manual self-propagating high-temperature synthesis(SHS) welding was investigated systematically,and the optimum parameters were obtained.Results showed that the particle size,the forming density and the mixing time had significant effects on the combustion reaction and the welding quality.As the particle size of the powder increased,welding spatter became severe and a lot of stomata generated in the seam.As the particle size decreased,the combustion velocity increased and the rod was difficult to operate.The optimum particle size to make combustion rod was -260 to +300 mesh.It was showed that there was a peak in the forming density and combustion velocity curve.The optimum forming density was between 2.74 and 3.05 g/cm³.Results also showed that when the mixing time increased,the reaction and spatter became violent.But if the mixing time was too short,the powder could not contact adequately and the heat generated was not enough to melt the metal.The optimum mixing time was 30 min.It was showed that the diameter of the rod had not obvious effect on the combustion,and it could be determined by the thickness of the weldment.