Abstract: A cutting element insert for an earth boring bit has one or more small projections formed on its bottom. The projections are offset from the axis of the insert. When the insert is pressed into the hole in the supporting structure of the bit, the projections will embed into the bottom of the hole to help retain the insert against rotation.

Abstract: In an earth boring tool an improved sintered tungsten carbide insert and surface conditioning method to improve retention within an interferringly sized hole and to decrease the frequency of fracture of the inserts. The insert has a randomly varied surface finish that is obtained from abrasive treatment with particles having hardness greater than 9.0 on Mohs' Scale. The particles are selected from the class consisting of silicon carbide, boron carbide, boron, and diamond. The resulting surface has asperities varying from a maximum value, smaller than that formed by grinding, to a minimum value, larger than the mat finish obtained by abrading with aluminum oxide.

Abstract: Apparatus for heat treating the weld and heat affected zone between a steel pipe and a steel connector, the apparatus including an induction coil to heat the weld and weld heat affected zone to a selected temperature. A ring shaped manifold having nozzle means to direct flow outwardly is connected with pumping means to pump gas simultaneously against the interior and exterior of the weld and heat affected zone.

Abstract: A method is disclosed for heat treating the weld and heat affected zone between a metal pipe and a metal connector. The overall strength of the assembly in the heat affected zone of the weld is brought to a value higher than, or at least matching, that of the strength of the pipe body in a manner to avoid cracking and to insure that the weld or the heat affected zone does not fail. After welding in the conventional manner, the weld is cooled below the transformation temperature, heated above the critical temperature, quenched at a selected rate that avoids cracking and refines the grain structure, followed by tempering, all of which improve the mechanical properties.