Dry sliding wear of laser hardened low alloy steel at room and elevated temperatures

摘要

This paper discusses about the wear behaviour of as-received and laser hardened EN25 low alloy steel performed in dry sliding condition using a pin-on-disc method. A 2kW continuous wave neodymium yttrium-aluminium-garnet laser source is used for transformation hardening to improve the hardness and wear resistance. The laser transformation hardened steel samples are characterized by optical microscope, x-ray diffractometer and microhardness tester. The sliding wear study is conducted for different loads (10 N, 25 N, 40 N), sliding distances (1000 m, 2000 m, 3000 m) at various elevated temperatures (200℃, 400℃ and 600℃) with constant sliding speed of 0.15 m/s. The study at room temperature is also carried out for comparison. The friction and wear characteristics in sliding contact are evaluated and the worn surfaces are analysed through a scanning electron microscope. The experimental work indicates that wear resistance of laser hardened steel is five times higher than the as-received steel. The results also indicate that the wear resistance increases at 400℃ due to the oxide layer formation and decreases at 600℃ due to fracture of the oxide layer.