الفهرس 
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Abstract
The composition and surface microstructure of a component play a decisive role in determining the surface dependent engineering properties (hardness, wear, fatigue, corrosionand oxidation resistance). Surface engineering process aims to control heating and cooling of metallic materials to alter their physical and mechanical properties without affecting the bulk material. Conventionally, surface treatment processes like flame hardening, induction hardening, arburizing, nitriding, carbonitriding and different hardfacing techniquesare usually employed in nhancing the wear resistance property of Fe-based alloys. These processes suffer from various estrictions, i.e., time and energy consumption, complex heat treatment schedule, non-ontrollable heat affected zone, lack of solid solubility limit, quenchingrequiredand slower kinetics. Furthermore, few of these conventional techniquesare not environment friendly. On the otherhand, when a high power laser beam is used as a source of heat for surface treatment, it will avert most of the restrictions as observed in conventional surface treatment.Martensitic stainless steels are widely used in engineering applications such as steamand water valves, pumps, screw machining parts, turbines, and many other applications which demand high strength and high resistance to wear and corrosion. Failure of such stainless steel components due to corrosion, oxidation, friction, fatigue and wear/abrasion is most likely to initiate from the surface. The engineering solution to minimize or eliminate such surface initiated failure lies in tailoring the surface composition and/or microstructure of the near surface region of a component without affecting the bulk.AISI 416 martensitic stainless steel grades have minimum sulfur content of 0.15 wt.%. Such stainless steel is commonly used in machining partsdue to its free machinability. This work aimsto gain improvement in both wear resistance and impact toughness that can be achieved via Laser Transformation Hardening (LTH)or Laser Surface Melting (LSM)particularly in view of the rather scarce studies reported in this respect.