Overview
ISO 2566-2:2021 - Steel: Conversion of elongation values, Part 2: Austenitic steels provides a standardised method to convert room-temperature percentage elongation after fracture measured on one gauge length to the equivalent value on another gauge length. The standard supports both proportional (e.g. 56.5√S0) and non‑proportional (fixed, e.g. 50, 80, 100, 200 mm) gauge lengths. Conversions are based on an empirically derived formula and are implemented through conversion tables, factors and figures included in the document.
Key topics and requirements
- Scope and applicability
- Intended for austenitic stainless steels in the solution‑treated condition with tensile strength 450–750 N/mm².
- Not applicable to: cold‑reduced steels, quenched & tempered steels, or non‑austenitic steels.
- Not permitted when gauge length exceeds 25·√S0 or when the specimen width/thickness ratio exceeds 20.
- Special caution for strip thicknesses under 3 mm (index may change).
- Conversion basis
- Conversions use a statistical formula (referred to as Formula (1)) supported by Tables 1–21 and Figures 1–5 for practical use.
- Simple multiplicative factors are provided for conversions between common proportional gauge lengths and between common fixed gauge lengths.
- Conversion between proportional and non‑proportional lengths depends on the cross‑sectional area of the test piece; tables give area‑dependent factors.
- Use and limitations
- Conversions are intended for acceptance purposes only by agreement between customer and supplier.
- In dispute, the elongation must be measured on the gauge length specified by the relevant contract or specification.
Applications and users
- Tensile testing laboratories converting test results between different gauge‑length conventions.
- Material suppliers and purchasers reconciling elongation requirements specified in different standards or contracts.
- Quality assurance & inspection teams ensuring compliance with product specifications when tests use differing gauge lengths.
- Design and materials engineers comparing mechanical properties across datasets with mixed test methods.
Related standards
- Part of the ISO 2566 series; users should consult other parts of the series and the relevant national tensile testing standards when applying conversions.
- Tables and worked examples in ISO 2566-2:2021 help implement conversions practically; always verify applicability limits (steel condition, strength range, specimen geometry) before use.
Keywords: ISO 2566-2:2021, conversion of elongation values, austenitic steels, tensile testing, gauge length, percentage elongation, proportional gauge length, non-proportional gauge length.