Properties of electron-beam-welded and laser-welded austenitic Fe-28Mn-5Al-1C alloy

Austenitic Fe-28Mn-5Al-1C alloy was welded by electron-beam and CW CO₂ laser techniques. Tensile tests, impact tests, potentiodynamic and cyclic polarization measurements were used to evaluate the mechanical properties and corrosion behaviour of the weld materials, Metallographic examination showed that the microstructure of the electron-beam-welded and laser-welded metals consisted mainly of the columnar and equiaxed austenitic structures. Grain growth in the heat-affected zone (HAZ) was minimal for welding with these two techniques. The tensile and impact tests indicated that the weld materials exhibited lower tensile strength, percentage elongation, percentage reduction in area and impact energy than those of the base alloy. The polarization measurements revealed that the anodic polarization behaviour of the HAZs of the electron-beam-welded and laser-welded materials was identical to that of the base alloy when exposed in 1M Na₂SO₄ solution. However, the electron-beam-welded and laser-welded metals exhibited a higher current density in the passive region than that of the base alloy when exposed to 1N H₂SO₄ acid solution.