Wear Performance of a Laser Surface Hardened ASTM 4118 Steel


In this investigation ASTM 4118 steel was treated by using pulse Nd: YAGlaser with wave length 1064nm and pulse duration 100ns. In order to assess thenew tribological properties of laser surface hardened ASTM 4118 steel, the wearresistance between specimens treated with laser and those of conventionallyhardened under dry sliding conditions was compared. The change of wearmechanisms in laser hardened 4118 steel resulted in distinct difference in wearrates.The results showed that quenched zones not only had sufficient depth ofhardening and higher hardness, but had more retained austenite and finer carbidesbecause of a higher degree of carbide dissolution. Laser surface hardened ASTM4118 steel specimens exhibited superior wear resistance to their conventionallyhardened specimens due to the change in the microstructure hardening, highhardness. The wear mechanism for both the laser quenched layer andconventionally hardened layer was highly similar, generally involving adhesivewear mechanism , material transfer, wear induced oxidation and plowing. Also theresults of hardness show that increases with increasing of laser energy by 70%.