METHOD AND APPARATUS FOR HEAT TREATING STRUCTURAL MEMBERS

摘要

METHOD AND APPARATUS FOR HEAT TREATING STRUCTURAL MEMBERS The present invention relates generally to an improved method and apparatus for induction heat treating and restraint quenching structural members of carbon steel, to a uniform martensitic structure, such that distortion of the member due to rapid quenching is controlled to a minimum. More specifically, the member is generally heated by induction in two stages generally to austenitizing temperature in the range of 1450.degree. to 1750.degree.F. Then the member is liquid quenched under restraint to below 1000.degree.F. to minimize distortion and finally tempered under restraint at a temperature in the range of 750.degree. to 1250.degree.F. Such structural members attain minimum physical properties after heat treating in the range of 110,000 psi yield strength and 125,000 psi tensile strength.