Abstract: A new precipitation hardened, high strength plate product has been developed that attains 80 ksi minimum strength together with excellent toughness, high formability and weldability without heat treatment or the need to cool at rates faster than air cooling. The optimum mechanical properties are achieved by a critical balance of carbon in the range of from 0.20-0.26%, manganese in the range of from 1.0-1.7%, vanadium in the range of from 0.08-0.20%, and at least one of from 0.01 to 0.025 nitrogen and from 0.01 to 0.10 columbium, processing the steel to obtain interphase precipitation strengthening, and by a controlled rolling procedure in which there is no substantial rolling below the Ar.sub.3 temperature.

Abstract: An electrical resistance spot welding system and method is disclosed. The system has adjustable output power circuitry for applying electrical heating energy to a weld site by way of weld tips, in accordance with a welding operation. An energy monitor senses instantaneous accumulated energy applied during the welding operation, and terminates the operation when an adjustable predetermined total energy has been applied. Other circuitry monitors applied welding voltage, and derives therefrom a signal which is a function of the energy density per unit area applied at the weld site. Circuitry responds to the energy density sensing to control the energy monitor and the power circuitry to govern the total energy applied in the welding operation.

Abstract: A method for adding reactive elements to molten copper or copper base alloys is disclosed. This method prevents unwanted reactions and oxidation by adding the reactive elements to the molten metal in the form of a powder mixture placed within tubing which is compatible with said molten metal. This filled tubing is sealed and drawn down, if desired, to an appropriate size for rapid melting within said molten metal and consequent rapid dissolution of the reactive elements throughout the molten metal.

Abstract: Improved method for melting copper base alloys containing from 2 to 12% aluminum including the steps of covering a molten mass of said copper base alloy with an essentially continuous flux layer of a molten salt consisting essentially of from 10 to 90% by weight of potassium chloride, from 10 to 90% by weight of sodium chloride and less than 5% by weight of other materials, said salt having a melting point of from 660 to 800.degree. C, and adding additional amounts of said alloy through said flux layer.