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