Microwave sintering

Abstract

A carbide composite that includes carbide particles having an average particle size of less than about 100 nanometers and a metallic binder disposed around the carbide particles is disclosed. The carbide composite may also include carbide particles having an average particle size ranging from 3 to 10 microns.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority, pursuant to § 119(e), of U.S. Patent Provisional Ser. No. 60 / 739,703 filed on Nov. 23, 2005, which is herein incorporated by reference in its entirety.BACKGROUND OF INVENTION [0002] 1. Field of the Invention [0003] The invention relates generally to applications for microwave sintering. More specifically, the invention relates to microwave sintered cutting elements for use in drilling applications. [0004] 2. Background Art [0005] Drill bits used to drill wellbores through earth formations generally are made within several broad categories of bit structures, including roller cone bits, and drag or fixed cutter bits. [0006] Roller cone rock bits include a bit body adapted to be coupled to a rotatable drill string and include at least one “cone” that is rotatably mounted to the bit body. A plurality of cutting elements are positioned on each cone. Within the category of roller cone bits, there are two furt...

AI Technical Summary

Benefits of technology

The present invention relates to a cutting element made from a carbide composite that includes tungsten carbide particles and a metallic binder. The tungsten carbide particles have a small size, which increases the hardness of the composite. The invention also relates to a method for making a wear-resistant element by sintering a mixture of green carbide particles and a metallic binding material with microwave energy to form a composite with two different carbide regions. The first region has small carbide particles, while the second region has larger carbide particles. The invention also includes a carbide composite with two different carbide regions and a metallic binder phase. The first region has small carbide particles, while the second region has larger carbide particles. The composite is formed by a rapid consolidation process.

Problems solved by technology

Tungsten carbide cutting elements tend to fail by excessive wear because of their softness.

During manufacture of the cutting elements, the materials are typically subjected to sintering under high pressures and high temperatures.

These manufacturing conditions can lead to potential problems involving dissimilar elements being bonded to each other and the diffusion of various components, resulting in residual stresses induced on the composites.

The residual stress induced composites can often result in insert breakage, fracture or delamination under drilling conditions.

Additionally, the combination of the high temperature and high pressure for the length of time necessary to form the cutting elements inherently result in grain growth and thus larger carbide grain sizes.

However, the use of grain growth inhibitors typically produces undesirable side effects by altering the physical characteristics of the sintered carbide product, especially when the carbide product is to be brazed to a diamond layer or crown.

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