Which term describes a drilling bit wear pattern where excessive weight dulls a tooth until the softer inner portion caves over the harder case area?

Which term describes a drilling bit wear pattern where excessive weight dulls a tooth until the softer inner portion caves over the harder case area?

• A. Bradding
• B. Spalling
• C. Pitting
• D. Erosion

Answer: (A)

Excessive weight on the bit pushes the softer inner portion of a tooth to yield and flow over the boundary of the harder outer case, causing the interior to cave into the edge and dull the tooth. This plastic deformation under overloading is the wear pattern described as bradding. It’s different from spalling, which is brittle chipping or flaking; pitting, which are small surface pits; and erosion, which is material removal by high-velocity abrasive fluids. To avoid bradding, keep weight-on-bit within recommended ranges and ensure the bit design and drilling parameters suit the formation.

Excessive weight on the bit pushes the softer inner portion of a tooth to yield and flow over the boundary of the harder outer case, causing the interior to cave into the edge and dull the tooth. This plastic deformation under overloading is the wear pattern described as bradding. It’s different from spalling, which is brittle chipping or flaking; pitting, which are small surface pits; and erosion, which is material removal by high-velocity abrasive fluids. To avoid bradding, keep weight-on-bit within recommended ranges and ensure the bit design and drilling parameters suit the formation.