ISO 9327-5:1999

Overview

ISO 9327-5:1999 - "Steel forgings and rolled or forged bars for pressure purposes - Technical delivery conditions - Part 5: Stainless steels" defines the technical delivery conditions for austenitic and austenitic‑ferritic stainless steel forgings and rolled/forged bars intended for pressure applications. It complements ISO 9327‑1 (general requirements) and specifies chemical composition limits, mechanical properties and delivery conditions tailored to stainless steels used in pressure equipment.

Key topics and requirements

• Material coverage: Applies to the austenitic and austenitic‑ferritic stainless steels listed in the standard’s Table 1.
• Chemical composition: Limits for cast analysis are specified; product‑analysis tolerances are given (see Table 2) for alloying elements such as C, Si, Mn, P, S, Cr, Ni, Mo, N, Ti, Nb, Cu.
• Mechanical properties: Tensile properties at room temperature and indications of the usual heat‑treatment condition at delivery are defined.
• High‑temperature data: Minimum elevated‑temperature proof strength values are provided (Table 3).
• Creep/stress‑rupture estimates: Estimated average stress‑rupture properties are included (Table 4).
• Inspection, testing and conformity: Inspection, testing frequency, sampling and conformity procedures are referenced to ISO 9327‑1 and related technical reports.
• Ordering and marking: Delivery, ordering information and marking requirements follow ISO 9327‑1 provisions.
• Normative references: Includes related test methods and guides (for example, ISO 148 Charpy V‑notch test and ISO/TR 15461 on testing frequency).

Practical applications

ISO 9327-5 is intended for use where stainless steel forgings or bars are supplied for pressure‑bearing components. Typical applications include:

• Pressure vessels and boilers
• High‑pressure piping and flanges
• Valves, fittings and closures for petrochemical and chemical plants
• Food, pharmaceutical and hygienic pressure equipment where corrosion resistance of stainless steels is required
• Power generation and nuclear industry components subject to elevated temperatures

Using ISO 9327‑5 helps ensure predictable mechanical behaviour (room and elevated temperature), traceable composition and consistent delivery conditions for critical pressure‑bearing parts.

Who should use this standard

• Manufacturers and foundries producing stainless steel forgings and bars for pressure purposes
• Material purchasers and procurement engineers specifying delivery conditions
• Design and pressure‑equipment engineers validating material selection for temperature and creep requirements
• Quality inspectors, testing laboratories and certification bodies assessing conformity to delivery conditions

Related standards

• ISO 9327‑1 - Steel forgings and rolled or forged bars for pressure purposes - Part 1: General requirements
• ISO 148 - Charpy impact test (V‑notch)
• ISO/TR 15461 - Steel forgings - Testing frequency and sampling guidance

Keywords: ISO 9327-5, stainless steels, steel forgings, rolled bars, pressure purposes, technical delivery conditions, product analysis tolerances, elevated temperature proof strength, stress rupture properties.