Overview
ISO 6370-2:2020 - "Vitreous and porcelain enamels - Determination of the resistance to abrasion - Part 2: Loss in mass after sub-surface abrasion" - defines a standardized laboratory test method to evaluate the abrasion resistance of vitreous and porcelain enamel coatings. The test measures the loss in mass of enamelled specimens after controlled sub-surface abrasion using a mixture of abrasive grains, steel balls and water, providing a comparative classification of enamel performance rather than absolute field wear values.
Key topics and requirements
- Scope: Test method for abrasion by rubbing, grinding or other mechanical effects on enamel coatings.
- Test principle: Three similarly enamelled specimens and three float-glass reference plates are exposed simultaneously to an abrading charge for three periods of 30 minutes (9 000 oscillations ± 300). Mass loss is measured before and after testing.
- Abrasives and media:
- Sanidine (potassium feldspar, P100) is included as a standard abrasive; fused aluminium oxide (P80) may be used for higher abrasion.
- Steel balls of hardened stainless bearing steel in three diameters (2 mm, 3 mm, 4 mm) are specified in defined masses per test.
- Water and ethanol (for cleaning) of specified purity.
- Apparatus & metrology:
- Abrasion testing apparatus per ISO 6370‑1.
- Balance accurate to 0.2 mg, drying oven (120 °C ± 5 °C), desiccator, pipette.
- Reference float glass plates (100 × 100 × 3 mm); Annex A provides methods to identify the float‑bath surface (chemical, UV, energy-dispersion).
- Result expression & reliability:
- Relative wear w is calculated from mean mass losses of specimens and reference glass plates.
- Repeatability guidance and a statistical check (α values) require acceptable dispersion (α > 60) for reliable results.
- Annex B outlines uncertainty calculation; typical measurement uncertainty reported is ±5 % (comparative method).
- Specimen preparation: Follow relevant base-metal standards (e.g., ISO 28764 for sheet steel and cast iron).
Applications and users
Who uses ISO 6370-2:2020:
- Coating manufacturers and R&D teams developing vitreous/porcelain enamel formulations.
- Quality control and materials testing laboratories verifying product durability.
- Specifiers, procurement engineers and architects needing comparative abrasion data.
- Certification bodies and standards committees for product classification.
Practical uses:
- Comparative ranking of enamel types for wear resistance.
- Process control during enamel production and finishing.
- Supporting claims in product datasheets and technical specifications.
Related standards
- ISO 6370‑1: Abrasion testing apparatus (companion standard)
- ISO 28764: Specimen production for enamel testing on sheet metals
- ISO 6344‑2: Grain size analysis for abrasives
- ISO 648, ISO 3696: Laboratory equipment and water quality
Note: The standard includes safety warnings - users must observe local health, safety and environmental requirements when performing tests.
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