Abstract: In the decarburization annealing of steel strip, wherein the annealing atmosphere flows counter to the strip motion in the furnace, there is an undesirable buildup of carbon monoxide in the zone where the strip enters the furnace. Carbon monoxide is undesirable because it slows the decarburization of the strip by a back reaction. The carbon monoxide is removed from the buildup zone and catalytically converted to methane and water by a known reaction with hydrogen, and the water and methane are in-turn recycled near the buildup zone of the furnace. It was found that the presence of water at temperatures up to 1600.degree. F. prevents methane from acting as a carburizing agent.

Abstract: Method of nitriding steel surfaces by circulating thereover a ternary mixture of ammonia, hydrogen and water at an elevated temperature and atmospheric pressure. Most of the harmful effects of HCN formation are avoided by utilizing a furnace lining consisting of a coated nickel base alloy, and by adding from 1 to 3% water to the nitriding gas and flowing the nitriding gas at a rate as low as 5 to 20 cu. ft. per hour per 100 sq. ft. of steel surface area.

Abstract: Low carbon, low alloy, ferrous metal stock containing from 0.05 to 0.5 wt. percent uncombined group IVB or VB metal, is strengthened by a procedure comprising; gas phase nitrogenation at temperatures below 590.degree. C to form extremely fine dispersions of such group IVB or VB metal nitrides, followed by an additional treatment for removing excess nitrogen in solid solution.

Abstract: In the box annealing of ferrous metal sheets, the occurrence of carbon deposits and staining is materially reduced by initially heating the sheet in a protective atmosphere which is essentially a mixture of N.sub.2 and H.sub.2 and then modifying the atmosphere so that during the soak period it contains at least about 3% CO.sub.2, 3% CO, 4% H.sub.2 and 0.5% H.sub.2 O, balance N.sub.2. Atmosphere modification is effected only after the sheet portions, which are exposed to the protective atmosphere, reach a predetermined, minimum replacement temperature within the range 1000.degree. - 1400.degree.F.