Overview
ISO 9328-6:2018 - "Steel flat products for pressure purposes - Technical delivery conditions - Part 6" specifies delivery requirements for quenched and tempered, weldable fine grain steels used in pressure equipment. It supplements the general rules of ISO 9328‑1 and covers chemical composition, mechanical properties, weldability, inspection and testing for the flat products listed in Annexes A and B. The standard supports both European design codes and ASME-type design approaches.
Key topics and technical requirements
- Scope and classification
- Applies to alloyed, fine grain steels (ferritic grain size 6 or finer per ISO 643) supplied in the quenched-and-tempered condition.
- Chemical composition
- Cast (heat) analysis limits are given in Tables A.1 / B.1; permitted product-analysis deviations are defined.
- Option to specify a carbon-equivalent value (CEV) at order stage.
- Mechanical properties
- Tensile, yield and impact requirements are specified in Annexes A and B, with options for elevated- and low-temperature grades and optional 40 J impact levels.
- Weldability
- Products shall be suitable for current welding processes; manufacturers can supply welding condition data from weld procedure tests.
- Guidance on cold cracking risk, PWHT effects, and option to test simulated post‑weld heat‑treated samples.
- Delivery, inspection and testing
- Delivery condition = quenched and tempered. Dimensions, tolerances, internal soundness, sampling, testing, marking and inspection procedures align with ISO 9328‑1.
- Inspection documentation options include inspection certificate 3.1 per ISO 10474.
- Options for purchaser
- Several ordering options (e.g., test directions for impact tests, elevated temperature tensile properties, thicker product requirements).
Applications
- Design, manufacture and fabrication of pressure vessels, boilers, heat exchangers and piping components where high-strength, weldable plates are required.
- Use when components must meet specified mechanical behavior at ambient, low or elevated temperatures and when compatibility with European or ASME design methods is needed.
- Useful for specifying materials in procurement, quality control, and welding procedure development.
Who uses this standard
- Plate producers and steel mills
- Pressure equipment manufacturers and fabricators
- Welding engineers and procedure developers
- QA/QC inspectors and materials purchasers
- Design engineers who require conformity with European or ASME-type codes
Related standards
- ISO 9328-1 (General requirements for steel flat products for pressure purposes)
- ISO 643 (Ferritic grain size testing)
- ISO 10474 (Inspection documents - certificates)
- EN 10028-6 (aligned technical data for some grades)
- Welding guidance: EN 1011 and IIW/IIS documents referenced for weld procedures
Keywords: ISO 9328-6:2018, weldable fine grain steels, quenched and tempered, steel flat products for pressure purposes, pressure equipment steel, chemical composition, mechanical properties, weldability, ASME, EN 10028-6.