Abstract: A threaded steel coupling with an exterior coating and interior case and threads, wherein the coupling body consists primarily of bainite and the interior case and threads consist primarily of a mixture of martensite and bainite. Also provided is a method of fabrication, including selective carburization of the interior threaded portion of the steel coupling forming the case and austempering.

Abstract: A steel article which is made of carbon or low alloy steel, with a prescribed chemical composition, is heat treated so that its yield strength is increased to a minimum of 60,000 psi and is subsequently dipped or spray covered with aluminum and then heated to interdiffuse aluminum metal and the iron in the steel matrix, thereby forming a new intermetallic layer which is an integral part of the steel article and which is essentially an aluminum-iron alloy, all in a manner which does not lower the yield strength of the steel below 60,000 psi. In the preferred form of the invention, a steel article is austenitized above its critical temperature for about 15 minutes or more and is subsequently rapidly cooled to below 600.degree. F. to transform the austenite structure to a much stronger martensitic structure and is then reheated to below 1341.degree. F. to temper the martensite.

Abstract: The journal and/or pilot bearings of a rotary cone earth boring bit are constructed to include alternating areas of wear resistant materials and anti-galling materials. The bearing matrix is formed by compressing a powdered alloy in the shape of the desired bearing element. The bearing matrix is sintered, thereby forming a porous bearing element. An anti-galling material is infiltrated into the porous matrix of the bearing element and the bearing element is hardened. The resulting bearing element includes areas of wear resistant materials and areas of anti-galling materials.

Abstract: The journal and/or pilot bearings of a rotary cone earth boring bit are constructed to include alternating areas of wear resistant materials and anti-galling materials. The bearing matrix is formed by compressing a powdered alloy in the shape of the desired bearing element. The bearing matrix is sintered, thereby forming a porous bearing element. An anti-galling material is infiltrated into the porous matrix of the bearing element and the bearing element is hardened. The resulting bearing element includes areas of wear resistant materials and areas of anti-galling materials.