Some studies on laser boriding of nickel and chromium electroplated AISI 1020 steel

Abstract

A carbon steel of grade AISI 1020 was selected as the base material The surface of the AISI 1020 steel was modified by three different boriding processes ie continuous pack boriding interrupted pack boriding and multicomponent laser boriding Continuous pack boriding was carried out in a muffle furnace at 950 C for 3 h in a boriding mixture Interrupted pack boriding is a modified pack process The packing procedure is similar to continuous pack boriding but the difference is in the heat treatment cycle of the process The specimens were subjected to heating at 950 C for 1 h After 1 h of boriding the stainless steel box containing mixture of SiC and specimens were removed from the furnace and allowed to cool in still air for 45 min and then it was again loaded in the muffle furnace This procedure was repeated 3 times Laser boriding was carried out on nickel and chromium electroplated specimens at different energy densities by keeping laser power at 500 W at different scanning speeds and at two different spot diameters 1 5 x 103 m and 1 62 x 10 3 m The energy densities of the laser beam were varied from 19 106 J m2 to 85 106 J m2 The structures of the multicomponent laser borided specimens obtained by different energy densities of laser beam treatment were evaluated by optical microscopy XRD SEM and EDS newline