TECHNICAL GUIDE • HARDMETAL QUALITY CONTROL
Cemented Carbide Inspection and Test Methods
A practical procurement guide to density, hardness, transverse rupture strength, microstructure, porosity, coercivity, chemistry and traceability for cemented-carbide materials and components.
MNK-G.S.A coordinates inspection requirements against the governing material specification, drawing, product form, manufacturing route and intended duty. A test result is meaningful only when the method, specimen, batch identity and acceptance requirement are defined together.
Inspection Starts with the Governing Requirement
A method standard explains how to measure a characteristic. It does not automatically define the required grade, acceptance limit or suitability for service. The purchase specification should identify which characteristics control acceptance, which edition of each method applies and how the supplied lot is represented.
Material Identity
Grade designation, declared composition, binder system, permitted additions and referenced manufacturer or customer specification.
Lot Definition
Powder batch, sintering lot, production order, component batch and the traceability relationship between test pieces and delivered items.
Acceptance Plan
Test methods, specimen preparation, sampling frequency, units, acceptance values, certificate type and response to nonconforming results.
Hardmetal Test-Method Matrix
| Characteristic | Relevant method references | Procurement interpretation |
|---|---|---|
| Density | ISO 3369:2006; ASTM B311-22 | Useful for batch control and detecting gross composition or porosity differences, but density alone does not prove grade identity. |
| Hardness | ASTM B294-22; ISO 6507-1:2023 where the agreed Vickers route is applicable | Specify scale, load, surface preparation and reporting basis. Values from unlike scales or methods must not be treated as directly interchangeable without a justified conversion route. |
| Transverse rupture strength | ISO 3327:2009; ASTM B406-96(2025) | Specimen geometry, preparation and loading method matter. ISO 3327:2009 remains published while a revision project is active. |
| Porosity and carbon defects | ISO 4499-4:2016; ASTM B276-21(2026) | Acceptance classes and the examined area must come from the governing specification or agreed inspection plan. |
| Microstructure and WC grain size | ISO 4499-1:2020; ISO 4499-2:2020; ISO 4499-3:2016 | Use the part of the series that matches the material system and feature being evaluated. A commercial label such as “fine grain” needs a defined measurement basis. |
| Coercivity | ASTM B887-25 | A process-control indicator influenced by microstructure and binder state. It is not a stand-alone declaration of grain size or grade equivalence. |
| Metallic constituents by XRF | ASTM B890-25; ISO 4503:1978 where its fusion-method scope is applicable | Confirm elements, calibration, specimen preparation and reporting limits. XRF does not replace every carbon or phase-control method. |
| Palmqvist toughness | ISO 28079:2026 | Use the agreed indentation method and report basis. Do not compare the result directly with a different fracture-toughness method. |
This matrix is a method-selection guide, not a universal mandatory test list. The product specification, drawing and agreed quality plan determine which tests apply.
Certificate and Batch Traceability
- Manufacturer and manufacturing site identification where required by the purchase specification
- Exact material or proprietary grade designation and declared composition basis
- Powder, pressing, sintering or production-batch reference appropriate to the supply route
- Product form, drawing revision, dimensions, quantity and supplied condition
- Test methods, editions, units, individual or batch results and acceptance values
- Clear relationship between certificate, test specimens and delivered packages or components
- Authorized inspection release and any agreed independent inspection record
For repeat orders, the previous certificate is valuable reference evidence, but it does not authorize silent substitution. The new batch must still satisfy the current drawing, specification and approved source route.
Interpreting Results Without False Equivalence
What a Result Can Support
- Compliance with one stated characteristic and acceptance limit
- Consistency of a defined production batch
- Comparison with an approved reference when the same method is used
- Evidence for a controlled source-qualification decision
What It Cannot Prove Alone
- That ВК, WCo, YG and a proprietary grade are direct equivalents
- That an ISO 513 application group is a chemical material grade
- That identical nominal cobalt content produces identical performance
- That a laboratory coupon represents every delivered component without an agreed sampling route
Grade approval should combine designation evidence, composition, physical and mechanical results, microstructure, product geometry, manufacturing route and application validation.
Geometry, Sampling and Product Condition
The inspection route changes with the product. A ground rod, as-sintered blank, thin insert, large die, brazed assembly and finished wear component do not present the same sampling or measurement conditions. ISO 4489:2019 provides a framework for sampling and testing hardmetals, while the purchase specification must define how it applies to the actual lot.
- State whether test pieces are taken from production material, companion specimens or separately prepared samples.
- Define grinding, polishing, decarburized-layer removal and other surface-preparation requirements before testing.
- Separate bulk-material tests from dimensional, visual, surface-finish and non-destructive inspection of finished components.
- For coolant channels, holes, threads and near-net features, inspect the drawing-controlled geometry in addition to material properties.
- For brazed or assembled parts, distinguish hardmetal qualification from joint, substrate and assembly inspection.
Inspection Requirements by Supply Route
Standard Blanks and Rods
Confirm grade data, batch results, diameter, length, straightness, supplied finish and coolant-channel geometry where applicable.
Parts to Drawing
Add revision-controlled dimensional inspection, critical characteristics, finish, edge condition and any assembly or interface requirements.
Qualified Repeat Supply
Control approved source, grade revision, batch consistency, change notification, retained evidence and the relationship to the original qualification.
Hardmetal Inspection RFQ Checklist
- Material or proprietary grade
- Governing specification and edition
- Drawing and revision
- Product form and supplied condition
- Quantity and lot definition
- Target application and critical failure mode
- Required tests, methods and acceptance values
- Sampling and specimen requirements
- Dimensional and visual inspection plan
- Certificate and traceability requirements
- Third-party inspection or witness points
- Delivery destination and required date
Related Hardmetal and Standards Resources
- ВК / ТК Cemented Carbides — grade families, sourcing experience and application context.
- Cemented Carbide Cutting Tool Blanks and Rods — product forms, coolant channels and toolmaker RFQ controls.
- Carbide Dies for Cold Heading and Wire Drawing — forming-duty blanks and application-specific sourcing.
- Carbide Wear Parts to Drawing — finished components and assemblies for industrial equipment.
- MNK Technical Library — lawful reference architecture for standards and technical guidance.
MNK-G.S.A provides scope summaries and procurement guidance. Copyright-protected standards are not reproduced; the official document and licensed access remain controlling.
Send Your Hardmetal Inspection Inquiry
Send the grade, governing specification, drawing, quantity, required tests, acceptance values, certificate requirements and delivery destination.