Surface Hardening of an AISI D6 Cold Work Steel Using a Fiber Laser

Abstract

Laser surface treatments represent some of the most advanced and versatile processes for enhanced materials applications. Laser hardening is a technique to generate a hard wear-resistant surface microstructure in metals due to the rapid heating and cooling cycles imposed by a laser beam. This work intends to understand the influence of the laser variables on hardness after laser hardening of an AISI D6 steel. A fiber laser, which is a new source available for industrial applications, has been used. The overall absorptivity measured was ∼37 % and the laser treatment produced two different zones: Remelted and heat-affected. The surface layer was remelted and composed of martensite and retained austenite. The region next to the free surface is composed of primary austenite dendrites with martensite plates with hardness between 400 and 500 HV. The region called the heat-affect zone is composed of martensite, retained austenite, and carbides and has a hardness up to 800 HV. The case depth in laser treated samples was between 1 and 2 mm.

Surface microrelief and hardness of laser hardened and ultrasonically peened AISI D2 tool steel

“…Similar transformation hardening of 1045 steel and W-Cr-V steel was also reported in [7]. Microhardness (7.8 GPa) obtained after combined LSH + UIT process is higher than that observed after LSH of AISI H13 steel (5.3 GPa) [49] or comparable with that of AISI D6 steel (~6-8 GPa) [50]. A couple of works were dwelt with the laser melting treatment of chromium carbon steel [51] and tool steel [9].…”

An Optimal Genetic Algorithm for Fatigue Life Control of Medium Carbon Steel in Laser Hardening Process

“…In particular, the scan speed (i.e., peripheral speed) is calculated as the product between the rotational speed and the radius of the samples middle section. The laser focus and the number of passes were fixed, respectively, at 0 and 1, because defocusing the laser beam and increasing the number of times that the laser passed on the treated area reduced the resulting hardness [19,28,29]. For each condition investigated, i.e., 5 terms of P × 5 terms of Ss, the rotational speed and the beam feed were properly chosen to ensure no overlap in the laser scans during the thermal treatment, and therefore only one pass [29].…”

Laser hardening of copper-iron pseudoalloy

“…High rates of heating and cooling amounting to 104…106 °C/s leads to obtaining of superior physico-mechanical properties of surface layers (Ivanov et al, 2011;Tolochko., 1995). High-power fiber lasers are applied more and more widely in various technologies, replacing all other types of lasers (Turichin et al, 2012;Goia and Lima 2011). This is related with their high efficiency, high reliability and lower dimensions (Kraposhin et al, 1990).…”