Nano-reinforced wc-co for improved properties

Abstract

A drill bit that includes a bit body; and at least one cutting element for engaging the formation disposed on the bit body, the at least one cutting element comprising: a ductile phase; a plurality of carbide particles dispersed in the ductile phase; and a plurality of nanotubes integrated into the cutting element is disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application, pursuant to 35 U.S.C. § 119(e), claims the benefit of U.S. Patent Application No. 60 / 858,830 filed on Nov. 14, 2006, and U.S. Patent Application No. 60 / 953,755 filed on Aug. 3, 2007, both of which are incorporated by reference in their entirety.BACKGROUND OF INVENTION[0002]1. Field of the Invention[0003]Embodiments disclosed herein relate generally to composite materials used in cutting tools.[0004]2. Background Art[0005]Historically, there have been two types of drill bits used drilling earth formations, drag bits and roller cone bits. Roller cone bits include one or more roller cones rotatably mounted to the bit body. These roller cones have a plurality of cutting elements attached thereto that crush, gouge, and scrape rock at the bottom of a hole being drilled. Several types of roller cone drill bits are available for drilling wellbores through earth formations, including insert bits (e.g. tungsten carbide insert bit,...

AI Technical Summary

Benefits of technology

The patent text describes a drill bit with cutting elements that have a ductile phase with carbide particles dispersed in it. The cutting elements also have nanotubes integrated into them, which increases their toughness and wear resistance compared to a bit with just carbide particles. The text also describes a method for making a composite body for cutting tools by integrating nanotubes into carbide particles and a binder phase, which results in a stronger and more durable material.

Problems solved by technology

On the other hand, fine grain powders, e.g., grains less than 5 μm, do not infiltrate satisfactorily.

Although the fracture toughness of cemented tungsten carbide has been somewhat improved over the years, it is still a limiting factor in demanding industrial applications such as high penetration drilling, where cemented tungsten carbide inserts often exhibit gross brittle fracture that can lead to catastrophic failure.

Bit bodies formed from either cast or macrocrystalline tungsten carbide or other hard metal matrix materials, while more erosion resistant than steel, lack toughness and strength, thus making them brittle and prone to cracking when subjected to impact and fatigue forces encountered during drilling.

This can result in one or more blades breaking off the bit causing a catastrophic premature bit failure.

Additionally, the braze joints between the matrix material and the PDC cutters may crack due to these same forces.

The formation and propagation of cracks in the matrix body and / or at the braze joints may result in the loss of one or more PDC cutters.

A lost cutter may abrade against the bit, causing further accelerated bit damage.

However, bits formed with sintered tungsten carbide may have sufficient toughness and strength for a particular application, but may lack other mechanical properties, such as erosion resistance.

Further, as the bulk particles used in ceramic materials decrease in size with the increasing use of nanoparticles (grain sizes less than 100 nm), observed brittleness has limited potential applications for the resulting material.

However, incorporation of the fibrous materials, such as carbon fibers, has presented difficulties including resistance to wetting of the fibers and reaction between the metal and carbide.

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