Hughes Tool Company LLC

Allen E Wisler

Herbert C Dill

Leo D Lane

A tool joint hardfacing containing sintered tungsten carbide granules embedded in an alloy steel matrix, with the surface substantially free of protruding granules to decrease casing wear during well drilling. The hardfacing is applied in a single application by rotating the drill pipe, providing an arc between a consummable steel wire and the pipe to create a weld puddle, and reciprocating the wire parallel to the pipe axis to create a band. Sintered tungsten carbide granules are gravity fed from an orifice directly into the arc and precipitate toward the bottom of the matrix to provide a smooth surface. The bottom of the matrix appears to be harder than the top.

Surface smoothed tool joint hardfacing

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.

Heat treatment of welds

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.

A metallurgical composition especially suitable for use as a hardfacing to increase the wear resistance of manufactured articles, such as for example tool joints used in earth drilling operations. This composition has cemented tungsten carbide particles dispersed in a matrix of air hardening alloy steel. Included in the alloy steel are carbon, chromium, molybdenum and vanadium. For weldability, manganese and silicon are added. Also disclosed are suitable ranges of proportions of constituents.

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Houston, TX, United States of America

Allen E Wisler