Abstract: The present invention discloses novel nitrogen-hydrogen based atmospheres for sintering steel components in continuous furnaces with consistent quality and properties while prolonging the life of the wire mesh belts, reducing maintenance costs, and improving furnace productivity. Specifically, it discloses the use of a controlled amount of an oxidizing agent such as moisture, carbon dioxide, nitrous oxide, or mixtures thereof along with nitrogen-hydrogen atmospheres. The amount of an oxidizing agent added to the nitrogen-hydrogen atmospheres to pre-condition belt material prior to its use for sintering and to sinter steel components is controlled in such a way that atmospheres become oxidizing to the belt material but reducing to steel components being sintered, specifically in the high heating and cooling zones of continuous furnaces.

Abstract: The present invention discloses a novel, moisture-free atmosphere for brazing carbon steels that provides good braze flow and brazed joint quality with minimum or no formation of soot on brazed joints. According to the present invention, carbon steels are brazed in continuous furnaces using a moisture-free atmosphere containing a mixture of three gases including nitrogen, hydrogen, and carbon dioxide. The key features of the invention involve (1) formation of moisture, which is needed to facilitate braze flow and to minimize formation of soot on brazed joints, in-situ in the heating zone of the furnace by the reaction between hydrogen and carbon dioxide and (2) reduction in the overall amount of a reducing gas required for brazing carbon steels by keeping moisture out of the cooling zone.

Abstract: A process for producing low-cost atmospheres suitable for annealing, brazing, and sintering ferrous and non-ferrous metals and alloys, neutral hardening low, medium, and high carbon steels, sintering ceramic powders, and sealing glass to metal from non-cryogenically produced nitrogen containing up to 5% residual oxygen is disclosed. According to the process, suitable atmospheres are produced by 1) pre-heating the non-cryogenically produced nitrogen stream containing residual oxygen to a desired temperature, 2) mixing it with more than a stoichiometric amount a hydrocarbon gas, 3) passing it through a reactor packed with a platinum group of metal catalyst to reduce the residual oxygen to very low levels and convert it to a mixture of moisture and carbon dioxide, and 4) introducing the reactor effluent stream into the heating zone of a furnace and converting in-situ a portion of both moisture and carbon dioxide with a hydrocarbon gas to a mixture of carbon monoxide and hydrogen.

Abstract: A process for producing low-cost atmospheres suitable for decarburize annealing carbon steels from non-cryogenically generated nitrogen containing up to 1.54 residual oxygen by catalytically deoxygenating a non-cryogenically generated nitrogen stream at low temperatures with a hydrocarbon gas and mixing the deoxygenated stream with an economical amount of hydrogen prior to introduction into the furnace for annealing. The process includes the use of 1) hydrocarbon gas to convert residual oxygen to a mixture of carbon dioxide and moisture at low temperatures and 2) mixing the deoxygenated stream with a sufficient amount of hydrogen to maintain a pH.sub.2 /pH.sub.2 O ratio of at least 2 in the furnace.

Abstract: Method and apparatus for dispersing cryogenic inert gases over the surface of a bath of molten metal by separating vaporized cryogenic gas from the liquid phase of the gas and introducing the liquid phase and the gaseous phase onto the surface of the molten metal in a swirling pattern. Additional inert gas can be introduced into the middle of the liquid phase.

Abstract: Aluminum or aluminum alloys are brazed in the presence of a non-corrosive flux using a low-cost, substantially dry nitrogen atmosphere produced by a non-cryogenic air separation technique such as a pressure swing adsorption (PSA) or a selective permeation (membrane). The use of a substantially dry, non-cryogenically produced nitrogen atmosphere brazed aluminum or aluminum alloy components with consistent good brazed joint quality and appearance while utilizing low loading of the flux.

Abstract: A process for producing low-cost atmospheres suitable for annealing, brazing, and sintering non-ferrous metals and alloys from non-cryogenically produced nitrogen containing up to 5%, residual oxygen is disclosed. According to the process, suitable atmospheres are produced by 1) pre-heating the non-cryogenically produced nitrogen stream containing residual oxygen to a desired temperature, 2) mixing it with more than a stoichiometric amount a hydrocarbon gas, 3) passing it through a reactor packed with a platinum group of metal catalyst to reduce the residual oxygen to very low levels and convert it to a mixture of moisture and carbon dioxide, and 4) using the reactor effluent stream for annealing, brazing, and sintering non-ferrous metals and alloys in a furnace.

Abstract: A method is disclosed for the electric arc spraying of powder-filled cored wires to apply hard, wear-resistant coatings to various substrates. Inert gas, preferably nitrogen, is supplied to the arc spray gun such that the mass ratio of the wire feed rate to the gas feed rate is preferably between about 0.07 and about 0.11. Operation in this range yields an optimum combination of coating hardness properties and arc spray gun operating characteristics.

Abstract: Surfaces subject to wear and corrosion can have their service life increased by being coated with a composite coating applied by the electric arc thermal spray process using at least one titanium feed wire, optionally pre-nitrided, a second wire of a different metal, metal alloy ceramic or intermetalic compound and nitrogen in the arc spray gun.

Abstract: A process for heating steel under atmosphere for annealing or hardening wherein the atmosphere is generated by injecting a mixture of dimethyl ether and nitrogen into the furnace.

Abstract: A process for decarburizing ferrous metals and in particular electrical steels such as motor and transformer laminations wherein metal articles are treated at temperature under a furnace atmosphere generated by injecting N.sub.2 --CO.sub.2 --H.sub.2 mixtures or N.sub.2 -methanol-CO.sub.2 mixtures into the furnace.