High speed laser cladding of an iron based alloy developed for hard chrome replacement

Abstract

Tougher environmental legislations related to the usage of hexavalent chrome are forcing industries to search for new alternatives to replace conventional hard chrome plating [1]. In addition to the environmental aspects, the typical requirements of the coatings are smooth surfaces with high resistance to wear and corrosion [2]. Furthermore, to be attractive to any high volume industrial application, a replacement solution must not only have technical, but also cost benefits. High-speed laser cladding is such a process that can replace hard chrome plating [3,4]. If compared to conventional laser cladding, where the layer thickness normally range between 0.5 mm to 1.5 mm, the high-speed laser cladding process can produce layers between 25 µm and 500 µm in thickness. The resulting heat input as well as the dilution with the substrate is very low [4]. Until now, nickel based alloys have mostly been used as hard chrome replacement with high-speed laser cladding [3,5]. However, there is a need for new innovative coating materials. The novel iron based alloy in this study, consisting of 18% Cr and 2.5% Ni, features very good wear properties and high corrosion resistance. In combination with high-speed laser cladding, this alloy delivers an environmentally friendly and cost effective solution with complete metallurgical bonding to the substrate.