Abstract
The milling of hard materials with a complex shape using conventional methods causes many tool based problems. However, a laser assisted milling process eliminates the tool-based problem because of the small, high intensity beam used. Laser engraving, which is one of milling methods, is an effective process for the machining of difficult to machine geometries and materials like hot work tool steels. This study focuses on recast layer formation and subsurface hardness as a function of distance. Power, scan speed and frequency were employed for the investigation. The highest hardness was detected at 201 HV, which measured at 800 mm s^-1 for scan speed and 40 kHz for frequency. XRD analysis showed that two different phases, Fe and Fe_2.96Si_0.05O₄, existed on the machined surfaces.

Key words
laser engraving, microstructure, hardness, recast layer

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