High melting point metals welding by concentrated solar energy

•Welding of steel has been achieved by means of concentrated solar energy.•Two high melting materials (H13 tool steel and AISI 316L stainless steel) has been used.•Three different welding geometries have been achieved: flush corner joint, T-joint, and V-grove butt joint.•Defect-free welded beads have been obtained by optimizing solar radiation and tracking speed.

Sound welding of high melting point metals, namely H13 tool steel and AISI 316L stainless steel, have been achieved by means of concentrated solar energy. Longitudinal weld track on 2 and 5 mm steel sheets with a thickness up to 60 mm, under argon atmosphere, has been performed on a variety of geometrical configurations. This work has been carried out in a 2 kW thermal power vertical axis parabolic concentrator at the PROMES–CNRS Solar facility (Odeillo-Font-Romeu, southeast France). Cross sections of welded specimens were characterized by optical microscopy, scanning electron microscopy, EDS analysis, and microhardness measurements. Various microstructures were observed in the melted zone, partially melted zone, and heat-affected zone due to the several metallurgical transformations (such as melting, solidification, solution and partial solution) induced by welding. Defect-free welded beads for both materials have been obtained by optimizing the geometrical configuration, solar radiation and tracking speed.