Method for nitriding and nitrocarburizing rifle barrels in a fluidized bed furnace

Abstract

A method for nitriding and nitrocarburizing the bores of rifle barrels or similar elongated hollow objects in which a funnel is attached to the inlet end of each of rifle barrel prior to treatment. The rifle barrels are then loaded into a fluidized bed furnace in a substantially vertical position with the open end of the funnel facing the direction of flow of the reactant gases and fluidized particulate medium through the fluidized bed furnace. When the rifle barrels are submerged in the fluidized particulate medium, the rifle barrels are heated to a reaction temperature for a predetermined period of time. The funnels increase the quantity of reactant gases and fluidized particulate medium flowing through the bore of each rifle barrel. As a result, excellent nitrided and nitrocarburized surfaces have been obtained in the bores of rifle barrels made from ferrous and titanium alloys at reduced processing temperatures and times.

Dependencies are inferred from the claim text.