Overview
ISO 10081-4:2014 - “Classification of dense shaped refractory products - Part 4: Special products” defines a consistent system for classifying and designating dense shaped refractory materials of special composition. It covers oxide, mixed oxide/non-oxide, non-oxide silicon carbide or carbon-based products, and other special non-oxide products (e.g., borides, nitrides) that are designated but not fully classified within the tables.
The standard is part of the ISO 10081 series (dense shaped refractories) and is maintained by ISO/TC 33 (Refractories).
Key topics and technical requirements
- Six classification criteria: type of product; group (based on main chemical component content); principal raw materials; state of raw materials; nature of the bond; and any post-treatment.
- Product types and designations: standardized type codes (examples from the standard) include ACr (alumina‑chromia), ACrZ / ACrZS (alumina‑chromia‑zirconia[-silica]), AZS (alumina‑zirconia‑silica), AC / AMC / AFC / ASC (alumina‑carbon, alumina‑magnesia‑carbon, alumina‑fused silica‑carbon, alumina‑SiC‑carbon), ZC (zirconia‑carbon), SiC (silicon carbide), and C (carbon).
- Group levels by composition: numeric group codes specify mass-fraction ranges (e.g., ACr90/5 indicates % ranges of Al2O3 and Cr2O3). Chemical analyses are generally performed on calcined products (reference: ISO 12677).
- Raw-material classification: raw materials are identified by nature (natural, synthetic, fused, stabilized zirconia) and their state (raw, calcined, sintered).
- Bonding and post-treatment: bond types are categorized as oxide ceramic, non-oxide ceramic, inorganic chemical, or organic chemical; post-treatments include tempering (≤800 °C) and impregnation.
- Analytical references: where indicated, composition and residual carbon are assessed using established ISO methods (the standard references methods such as ISO 12677 and ISO 10060).
Applications and users
- Manufacturers of dense shaped refractories use ISO 10081-4 for product specification, labelling and quality control.
- Material and process engineers apply the classification when selecting refractories for high-temperature linings, furnaces, converters and other industrial installations.
- Procurement and specification writers reference the standardized designations to ensure material compatibility across suppliers.
- Testing laboratories and conformity assessors rely on the classification criteria and referenced analytical methods for reporting and verification.
- R&D teams use the classification to communicate new special-product compositions (e.g., SiC-rich, zirconia-stabilized) consistently.
Related standards
- ISO 10081 (Parts 1–3) - classification of dense shaped refractories for alumina‑silica and basic carbon-containing products.
- ISO 12677 - analytical method references for calcined product composition.
- ISO 10060 - carbonization procedures and analysis for residual carbon content.
Keywords: ISO 10081-4:2014, classification of dense shaped refractory products, special refractory products, alumina-chromia, AZS, silicon carbide refractory, carbon refractory, refractory raw materials, refractory bonding, post-treatment.
