How to Tell If It's Real Tungsten Carbide: Density, Hardness & Microstructure Testing

Maintained by Carbidea · Updated October 2026

Target Audience & Field Inspection Dynamics

This guide assists inspectors verifying incoming wear parts against scrap, substitute, or counterfeit components.

Authentic WC-Co cannot be verified by appearance or scratch tests. Benchmarks mandate bulk density via Archimedes displacement per ASTM B311, indentation hardness under ISO 3738 / ASTM B294, and apparent porosity conforming to A02 B00 C00 under ASTM B276. For standard reference YG6X (approx. 6% Co), sintered density reaches approx. 14.9–15.0 g/cm³. Theoretical binderless WC exhibits 15.63 g/cm³ in literature, but Carbidea's standard grade YG6X utilizes an approx. 6% Co metallic binder; binderless pure WC is not supplied.

In Materials (doi:10.3390/ma14061551), researchers reported that in fine-grained WC-6Co, Cr3C2 and VC additions inhibit WC grain growth and modify grain size distribution, influencing hardness and transverse rupture strength.

Physical Verification Benchmarks

Negative List: Prohibited Testing Methods

• Prohibited Scratch Testing on Glass: Tool steels scratch glass but fail rapidly under abrasion.
• Prohibited Zero-Magnetism Assumption: Cobalt is ferromagnetic; standard 6% Co grades attract magnets.
• Prohibited Theoretical 15.63 Density Callouts: Never mandate 15.63 g/cm³ on prints; pure WC cannot be sintered into tough parts.

Sourcing Traps: Overseas Prints vs. Factory Reality

1. Generic Title Blocks: Drawings stating only "Carbide" invite scrap blends. Prints must specify binder (approx. 6% Co), density (14.9–15.0 g/cm³ per ASTM B311), and porosity per ASTM B276.
2. Ignoring Preform Allowances: Overlooking as-sintered stock of ±0.1–0.25 mm risks scrap when grinding to ±0.005–0.01 mm.

Carbidea connects international buyers with audited partner mills certified under ISO 9001:2015 frameworks. Submit CAD prints for ASTM B311 density records and inspection sheets within 1–2 business days.

FAQ

Q1: Is authentic tungsten carbide completely non-magnetic?

A: No. Authentic carbide containing cobalt (such as reference grade YG6X with approx. 6% Co) exhibits mild ferromagnetic pull due to its cobalt binder network.

Q2: Why is the theoretical pure WC density of 15.63 g/cm³ not supplied for commercial wear parts?

A: Density 15.63 g/cm³ represents theoretical binderless carbide. Carbidea's standard grade YG6X utilizes an approx. 6% Co metallic binder (density approx. 14.9–15.0 g/cm³) for required fracture toughness; binderless pure WC is not supplied.

Q3: What non-destructive inspection should be prioritized when receiving offshore carbide shipments?

A: Prioritize Archimedes density testing per ASTM B311 with an analytical balance in water. Sintered WC-6Co parts must register 14.9 to 15.0 g/cm³.