Improvement of Microstructure and Wear resistance of X12 Tool Steel by Using Laser Surface Re-Melting Technique

Abstract

Nd-YAG lasers have been successfully used in recent years as reliable heat source to surface modification of engineering materials such as laser surface re-melting. In the present study, X12 tool steel was surface modified by using pulse Nd-YAG laser technique. Laser parameters are selected of 12 J pulse energy, 15 Hz frequency, 20 mm defocus length, 6 ms pulse duration, and 5.6 mm /s mm scanning speed. These parameters were chosen after undertaking trials to give suitable parameters in this process. Optical microscopy and backscattered scanning electron microscopy (SEM) with EDS and X-ray diffraction techniques were used to analyse the microstructure changes of the surface of tool steel. Wear resistance test was achieved by using a pin on disk method. The reason for this work is to improve the wear resistance for surface layer of tool steel after changes the morphology of the structure by rapid solidification during laser re-melting. In general, the structure consists of the dendrite and cellular structures with δ ferrite formed under conditions of rapid solidification without the primary coarse carbides. After laser melting, the results of the structure at the surface layers show an increase in wear resistance.

Enhancement of Mechanical Properties and Corrosion Resistance of Cast Iron Alloy Using CO2 Laser Surface Treatment

“…Most of the constraints of traditional treatments, such as time, energy consumption, areas impacted by uncontrollable heat, non-contamination of the surface, the need for quenching, and complex heat treatment instances during the process, can be eliminated using this method [13]- [16]. the laser can be considered An excellent solution to modify the surfaces of solids, due to the ability of the high-power laser to locally melt the surface within a very short time, then rapid re-solidification by self-quenching (1×10 -3 °C/sec) which leads to a change in the surface properties [17]- [19]. This property makes the laser an excellent tool for acquiring certain qualities for metal surfaces as a result of microstructural changes or chemical composition changes (if a material or more is added to the molten pool).…”