Rock bit with cobalt alloy cemented tungsten carbide inserts
AssigneeSmith International, Inc.
InventorsDah-Ben Liang, Madapusi K. Keshavan
Life of this patent
Estimating the term…
Abstract
A rock bit employs cemented tungsten carbide inserts for engaging a rock formation for drilling oil wells or the like. The cemented tungsten carbide inserts have as a binder phase a cobalt base alloy including from 10 to 35% by weight nickel, from 3 to 10% by weight chromium, from 1 to 6% by weight of molybdenum, and a balance primarily of cobalt. A particularly preferred composition has 6% by weight chromium, 17% by weight nickel, 4% by weight molybdenum and a balance of cobalt. Wear resistance is enhanced without loss of toughness in the inserts.
Claims29
A rock bit comprising:
- a body having a pin end for connection to a drill string and a downhole end;
- and
- a plurality of cutter inserts mounted adjacent to the downhole end of the rock bit for engaging a rock formation, at least a portion of the inserts comprising cemented tungsten carbide having as a binder phase a cobalt base alloy including from 10 to 35% by weight nickel, from 3 to 10% by weight chromium and a balance primarily of cobalt.
A rock bit as recited in claim 6 wherein the chromium content is in the range of from 6 to 8% by weight.
A rock bit comprising:
- a body having a pin end for connection to a drill string and a downhole end;
- and
- a plurality of cutter inserts mounted adjacent to the downhole end of the rock bit for engaging a rock formation, at least a portion of the inserts comprising cemented tungsten carbide having as a binder phase a cobalt base alloy including alloying metals in the range of from 15 to 45% by weight selected from the group consisting of nickel, chromium, molybdenum and tungsten.
A rock bit comprising:
- a body having a pin end for connection to a drill string and a downhole end;
- and
- a plurality of cutter inserts mounted adjacent to the downhole end of the rock bit for engaging a rock formation, at least a portion of the inserts comprising cemented tungsten carbide having as a binder phase a cobalt base alloy including from 10 to 35% by weight nickel, from 1 to 10% by weight of at least one additional alloying element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, and a balance primarily of cobalt.
A rock bit comprising:
- a body having a pin end for connection to a drill string and a downhole end;
- and
- a plurality of cutter inserts mounted adjacent to the downhole end of the rock bit for engaging a rock formation, at least a portion of the inserts comprising cemented tungsten carbide having as a binder phase a cobalt base alloy including from 3 to 10% by weight chromium and sufficient nickel for inhibiting transformation from a face centered cubic crystal structure.
Dependencies are inferred from the claim text.