Drill Bits
Steel Tooth vs Tungsten Carbide Products
Tricone rockbits are divided into two major categories - Steel Tooth products and Insert products. Steel Tooth
(also called Milled Tooth) products have cutting elements which have been milled from the steel of
the cone itself and are strengthened by the application of tungsten carbide hard facing to the surfaces of the tooth.
Insert products have cutting elements which are actually tungsten carbide inserts which have been pressed into
holes drilled into the cone material. Insert products are much more durable than the steel tooth products, but
carry a higher cost to manufacture.
The cutting action changes as the rock formations become harder. In soft formations, the rock is drilled by using
gouging and scraping with lower loads to remove the rock, hence the cutting elements tend to be large and have lots
of protrusions and spacing to maximise the drilling action. In hard formations, the rock is crushed under high
compressive point loads, hence these cutting elements tend to be small, exhibit shorter protrusion and more densely
packed, which prevents the high compressive loads from breaking the insert before it breaks the the rock.
Steel teeth and insert cutting elements come in varying shapes, sizes and grades of tungsten carbide material. This
variety of cutting elements allows engineers to tailor products to address specific drilling conditions encountered
throughout the world. Within each of the two major categories, the cutting structure designs are grouped into several
series of bits which have similar characteristics and performance criteria.
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