1.4849 | GX40NiCrSiNb38-19 Magnetism in charging racks

Charging racks for the gas carburizing process became magnetic after some time in operation and magnetically attracted debris from shot peening. In the as-delivered condition , the 1.4849 alloy is completely non-magnetic. In the carburizing furnace, the rack was carburized to a depth of approx. 1.5 mm. As a result, in the surface (where 1.44 instead of 0.3-0.5% C is present) virtually all the chromium is first bound as carbide and subsequently oxidized. The chromium-depleted matrix is superficially changed into an almost pure iron-nickel alloy with up to 50% nickel
and thus becomes ferromagnetic.