ISO 9328-7:2018

Overview

ISO 9328-7:2018 - Steel flat products for pressure purposes - Part 7: Stainless steels specifies technical delivery conditions for stainless steel flat products intended for pressure applications. It applies to a range of stainless steels (including austenitic and austenitic-ferritic (duplex) creep‑resisting grades) in the nominal thicknesses listed in Tables 7–10 of the standard. The general requirements and definitions of ISO 9328‑1 are directly applicable.

This third edition (2018) updates grade designations, refines technical data tables and aligns certain requirements with EN standards. The document also notes potential patent claims on some grades and references ISO 3651‑2 for intergranular corrosion testing.

Key topics and technical requirements

• Scope and classification: Defines steel grade designations and classification rules for stainless steel flat products used under pressure.
• Chemical composition: Cast-analysis limits and permissible deviations for product analysis are given in Tables 1–5; corrosion‑related requirements reference ISO 3651‑2 for intergranular corrosion testing.
• Mechanical properties: Tensile and impact requirements at room and low temperatures; elevated-temperature proof and tensile strength values are provided (see Tables 11–15), with creep data and preliminary guidance in informative annexes.
• Delivery conditions and process routes: Specifies process routes and heat treatment options (Tables 6–10) and includes guidance for post‑weld heat treatment (Annex C) and further fabrication treatments (Annex B).
• Surface condition, dimensions and tolerances: Referenced to ISO 9328‑1 and ISO 18286 for dimensional tolerances and flatness options.
• Inspection, testing and sampling: Types of inspection documents, required tests (Table 16), sampling frequency, test methods and re‑test rules follow ISO 9328‑1 provisions.
• Informative annexes: Provide comparable national designations (Annex A), physical property data (Annex G), reference strength and creep data (Annexes D–F), and numbering in accordance with ISO 15510.

Practical applications and users

ISO 9328‑7 is intended for manufacturers, specifiers and users of stainless steel plates and sheets for pressure equipment, such as:

• Boiler and pressure vessel manufacturers
• Heat exchanger fabricators
• Oil & gas and chemical process equipment engineers
• Procurement and quality assurance teams specifying technical delivery conditions and inspection certificates

Using ISO 9328‑7 helps ensure material consistency, traceability, and conformity to mechanical, chemical and corrosion-resistance requirements for pressure‑retaining components.

Related standards

• ISO 9328‑1 - General requirements for steel flat products for pressure purposes (normative for Part 7)
• ISO 3651‑2 - Corrosion testing for stainless steels (intergranular corrosion)
• ISO 18286, ISO 10474, ISO 15510 - Referenced for tolerances, inspection certificates and grade numbering

Keywords: ISO 9328-7:2018, stainless steels, steel flat products for pressure purposes, technical delivery conditions, austenitic, duplex stainless steel, tensile properties, chemical composition, post-weld heat treatment.