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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 rates. 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%.