Tungsten Carbide Buttons: Types, Grades, and Where Each One Works Best
1) What tungsten carbide buttons are
A tungsten carbide button (often called a carbide button insert) is a small, dense wear element installed into a drilling tool. The steel bit body delivers energy and holds geometry; the carbide button is the working contact point that faces abrasive wear and cyclic impact.
Most “Tungsten Carbide Buttons” used in rock drilling are a form of cemented carbide: tungsten carbide (WC) grains bonded by a metallic binder (most commonly cobalt; sometimes nickel in corrosion-driven environments).
2) Button types (by head geometry) and what each does
In drilling, button “type” usually means head geometry (the rock-contact profile). Geometry influences: contact stress, penetration behavior, chipping risk, and how wear changes bit performance over time.
| Type | Best at | Commonly used when | Tradeoff |
| Spherical / Domed | Impact survival and resisting catastrophic breakage | Formations are hard and/or abrasive and impacts are severe | Generally less “aggressive” than more pointed profiles |
| Ballistic / Semi-ballistic
| Penetration in softer or fractured formations | You want higher productivity where impact severity is lower | Typically less resistant to breakage in very harsh impact duty |
| Conical / Chisel-like | Localized “bite” and aggressive cutting action in certain designs | Tool designers want higher contact stress for penetration | Higher chipping risk if impact severity or misalignment is high |
| Flat-top
| Stable wear surface and broader contact area in specific cutting structures | The bit design benefits from a flatter wear land | Edge chipping can increase if grade/impact conditions are mismatched |
How our standard P / Z / X styles map to these geometries
On our product page we group common “catalog styles” as: P type (flat-top), Z type (coin-spherical), and X type (wedge/chisel-like). If you’re specifying against a drawing, these style names help align intent quickly with the bit designer. (See: Tungsten Carbide Buttons product page.)
3) Where carbide buttons are used
Carbide buttons appear across multiple drilling systems. Organizing your selection by tool family keeps decisions grounded in real load conditions.
| Drilling system | How buttons are used | What selection usually prioritizes |
| Roller cone (TCI) bits | Inserts form the cutting structure contacting rock under rolling contact | Wear stability + resistance to chipping under cyclic contact stress |
| DTH bits | Buttons arranged on bit face; geometry tuned to formation | Penetration vs service life under repeated impact cycles |
| Top hammer / drifter bits | Buttons installed in bits; shapes selected by rock conditions | Productivity, straight holes, and correct shape/grade matching |
| Geotechnical tools | Buttons handle variable duty in mixed soils/rock | Reliability in unpredictable conditions |
4) Grades: binder %, WC grain size, and microstructure quality
Engineers sometimes ask me, “What’s the best carbide button grade?” My honest answer: the best grade is the one that matches your formation and failure mode—and the one your supplier can produce consistently.
Grade lever #1: Binder type and percentage
In WC-based cemented carbides, the binder (often cobalt) strongly influences the hardness–toughness balance. Higher binder content typically increases toughness and impact tolerance, while lower binder content tends to increase hardness and wear resistance (assuming similar grain size and quality).
Grade lever #2: WC grain size (and distribution)
WC grain size is not just a marketing label (“fine grain”). It’s measurable and should be reportable by metallographic methods. Grain size affects wear behavior, crack initiation, and how “forgiving” the material is under impact.
Grade lever #3: Microstructure quality (porosity, carbon balance, eta phase)
Two buttons with the same binder % and nominal grain size can perform very differently if one batch has higher porosity or carbon defects. For critical drilling duty, ask your supplier how they characterize porosity and related microstructural defects, and request lot-level traceability.
5) Where each type works best (by drilling system)
“Where it works best” is usually a combination of: formation hardness/abrasiveness, impact severity, and how the bit delivers energy.
| Drilling system | What dominates | Button types commonly favored | Grade direction (rule-of-thumb) |
| DTH bits | Abrasion + cyclic impact at the face; performance tied to formation | Spherical/domed in hard & abrasive; ballistic/semi-ballistic in softer formations | Hard/abrasive → more wear resistance; unstable/impact-heavy → more toughness |
| Tophammer / drifter bits | High-frequency impact + alignment sensitivity | Often tougher geometries to survive impact; selection varies by formation | Favor toughness when chipping dominates; favor hardness when wear dominates |
| Roller cone (TCI) bits | Rolling contact + localized impact; insert retention and wear shape matter | Domed/spherical and other insert geometries designed for cutting structure intent | Match grade to abrasive wear vs breakage risk and retention design |
| Geotechnical tools | Mixed soil/rock; unpredictable wear modes | Balanced geometries and grades; spec by failure mode and soil/rock mix | Often a balanced grade unless abrasion or impact clearly dominates |
FAQ
| Question | Answer |
| What are tungsten carbide buttons? | Tungsten carbide buttons are cemented-carbide inserts installed in drilling tools to resist abrasive wear and cyclic impact while fracturing rock. |
| Which button shape is best for hard, abrasive rock? | Spherical and wear-stable rounded types are commonly selected for harsh, abrasive conditions because they prioritize service life and wear stability. |
| What does “grade” mean for carbide buttons? | Grade refers to microstructure and binder strategy (often WC grain size and cobalt-binder content/chemistry) that shifts the balance between wear resistance and toughness. |
| Why do carbide buttons chip or break? | Common drivers include impact overload, stress concentration from aggressive geometry, changing contact conditions as the bit wears, and retention/pocket or installation issues that allow cracks to initiate and grow. |
References
Definitions / material basics
● Sandvik Coromant – cemented carbide definition and manufacturing route (pressing/injection molding + sintering): https://www.sandvik.coromant.com/
● Hyperion Materials & Technologies (Precision by Hyperion) – cemented carbide structure overview (WC + Co binder, typical grain size ranges): https://www.precisionbyhyperion.com/resources/understandingcemented-carbide/
Test methods and microstructure characterization
● ISO 3738-1 – Hardmetals: Rockwell hardness test (scale A) – Test method: https://www.iso.org/obp/ui/en/
● ISO 4499-2 – Hardmetals: measurement of WC grain size (metallographic guideline): https://www.iso.org/
● ISO 4499-4 – Hardmetals: characterization of porosity, carbon defects, eta-phase content: https://www.iso.org/
● ISO 3327 – Hardmetals: determination of transverse rupture strength (TRS): https://www.iso.org/
Formation-based button profile guidance (industry example)
● Epiroc DTH product catalog (example of spherical vs ballistic selection language by formation): https://www.epiroc.com/