Laser surface alloying of carbon steel with FeCrSi3N4 powders

Abstract

Laser surface alloying (LSA) is a relatively new technique for producing a highly alloyed layer on metal surfaces. Surface failures such as corrosion and wear can be improved by modifying surface chemistry with LSA. It reduces the amount of scarce and costly alloying elements, while retaining the bulk properties of the substrate. The beneficial effect of nitrogen on enhancing mechanical properties and corrosion resistance, especially local corrosion, as compared with conventional austenitic stainless steels (SSs), has been reported. During the last decade, there have been intensive studies on introducing large amounts of nitrogen into the SSs. Mass alloying of nitrogen into SSs can be achieved by using techniques such as pressurized induction melting, plasma remelting, hot isostatic pressure (HIP) melting, and pressurized electroslag remelting (PESR). The PESR process in which nitrogen is added directly into the melt via a metal nitride addition has become commercially available. Whether surface modification of carbon steel with high nitrogen stainless steel is possible is of interest. In the present investigation, a technique used to produced a nitrogen-alloyed SS surface layer by laser melting the Fe-Cr-Si[sub 3]N[sub 4] powders on carbon steel is attempted. The chemical states and concentration of the alloying elements in themore » LSA layers are analyzed and presented.« less