EN ISO 4499-2:2020 PDF

Overview

EN ISO 4499-2:2020 - Hardmetals: Metallographic determination of microstructure - Part 2: Measurement of WC grain size (ISO 4499-2:2020) provides standardized guidelines for measuring tungsten carbide (WC) grain size in WC/Co hardmetals (cemented carbides, cermets) using metallographic techniques. The standard covers measurement by optical and electron microscopy and specifies the use of the linear‑intercept method to obtain representative mean grain‑size values and distributions for quality control and materials development.

Key topics and requirements

• Scope: Applies to WC/Co hardmetals (tungsten carbide as the primary hard phase). Not intended for full size‑distribution analysis or shape measurement; powders are excluded unless suitably mounted and sectioned.
• Microscopy methods: Allows optical microscopy and electron microscopy techniques (SEM, FESEM, TEM) and includes EBSD (electron backscatter diffraction) as an accepted method for characterization.
• Calibration: Specifies microscope calibration requirements to ensure accurate linear measurements.
• Linear‑intercept technique: Recommends sampling strategies, line placement and counting rules to collect statistically meaningful intercept data (LI = mean linear intercept).
• Measurement limits: Defines minimum measurable intercept lengths for different microscopes (note: the standard corrects SEM minimum visible intercept to 400 nm).
• Analysis and statistics: Describes calculation of representative average values (arithmetic mean linear intercept, equivalent circle diameter conversions) and addresses systematic and random errors.
• Reporting: Requires comprehensive reporting to meet modern quality requirements; includes a report proforma (Annex B) and a measurement case study (Annex A) to illustrate best practices.
• Grain‑size categories: Provides classification ranges (nano <0.2 µm, ultrafine 0.2–0.5 µm, submicron 0.5–0.8 µm, fine 0.8–1.3 µm, medium 1.3–2.5 µm, coarse 2.5–6.0 µm, extra coarse >6.0 µm).

Practical applications

• Quality control and process monitoring in sintered hardmetal production
• Metallurgical development and failure analysis for cutting tools, wear parts and cermet components
• Correlation of microstructure (WC grain size) with mechanical properties (hardness, toughness) and performance
• Research labs developing new powder metallurgy formulations or sintering cycles

Who should use this standard

• Materials engineers and metallurgists working with cemented carbides
• Quality, inspection and R&D laboratories performing metallographic measurement of WC grain size
• Standards committees and accreditation bodies specifying test methods for hardmetals

Related standards

• ISO 4499-1 (preparation of microstructure)
• ISO 4489:2019 (sampling and testing)
• ISO 3369, ISO 3738‑1/2, ISO 6507 series (referenced for related test methods and calibrations)

Keywords: EN ISO 4499-2:2020, WC grain size, hardmetals, tungsten carbide, metallographic measurement, linear‑intercept method, SEM, EBSD, cemented carbides.