Hardening of selected areas of an earth boring rockbit
AssigneeDresser Industries, Inc.
InventorsRobert K. Sorensen, Starling Seaton
Life of this patent
Estimating the term…
Abstract
Bearing surfaces or other selected areas of component parts of a rotary cone earth boring rockbit are carburized or otherwise surface enriched by the sequential steps of coating the selected surface area to be enriched with a non-water based composition capable of effecting a corrosive protective seal thereabout; covering the coated area with a predetermined applied thickness of a carbonaceous paste; drying the paste and thereafter, subjecting the component part to an elevated temperature below which the coating is pyrolyzed to fully austenize the part and achieve a desired case depth followed by quenching, tempering, and finished machining as required.
Claims16
A method of surface-enriching a metal surface by application to said surface of a surface-enriching material and wherein said surface is susceptible to corrosion by said material in the as-applied condition comprising the steps of:
- (a) applying a protective coatig onto the metal surface to be enriched, said coating being effective to prevent direct contact of said material with said surface as applied, but permitting such contact at an elevated surface-enriching temperature;
- (b) applying over said coating a predetermined quantity of said material;
- and
- (c) heating said surface and material for a controlled time period to a predetermined elevated temperature sufficient to cause said material to become non-corrosive and expose said surface directly to said enriching material and to effect a desired case depth of enrichment on said surface from said material.
A method of surface-enriching a selected metal surface area of an earth boring rockbit by application to said surface of a surface-enriching material wherein said surface is susceptible to corrosion by said material in the as-applied condition and in which the rockbit comprises component parts including a body adapted for mounting onto the under end of a drill string and a rotatable cutter supported for rotation on said body, said method comprising the steps of:
- (a) applying a protective coating onto the metal surface to be enriched, said coating being effective to prevent direct contact of said material with said surface as applied, but permitting such contact at an elevated surface-enriching temperature;
- (b) applying over said coating a predetermined quantity of said material;
- and
- (c) heating said surface and material for a controlled time period to a predetermined elevated temperature sufficient to cause said material to become non-corrosive and expose said surface directly to said enriching material and to effect a desired case depth of enrichment on said surface from said material.
Dependencies are inferred from the claim text.