Overview
ISO 9329-4:1997 - Seamless steel tubes for pressure purposes: Technical delivery conditions - Part 4: Austenitic stainless steels - defines the delivery, testing and metallurgical requirements for seamless austenitic stainless steel tubes used in pressure applications. It replaces ISO 2604-2:1975 and covers tubes for service at room, low and elevated temperatures intended for pressure vessels, chemical plants, steam‑generating equipment and interconnecting piping.
Key topics
- Scope and exclusions: applies to seamless circular tubes (term “tube” = “pipe”). Does not cover casing, tubing and linepipe for oil/gas industries or tubes for water/gas/sewage transport.
- Purchaser information: mandatory/order details (dimensional standard reference, diameter/thickness, length, steel grade, test category, inspection document). Optional requirements include heat treatment, special tolerances, NDT requests, impact/corrosion tests and bar coding.
- Manufacture and delivery condition: tubes must be seamless and may be hot‑finished or cold‑finished. Delivery conditions include solution‑treated or specified hot‑finished conditions; heat‑treatment ranges and types are referenced in the standard.
- Chemical composition and analyses: heat analysis and optional product (check) analysis requirements are specified for defined steel grades (see table references in the standard).
- Mechanical properties: requirements for tensile, proof‑stress at elevated temperatures, room‑temperature mechanicals and optional low‑temperature toughness (impact) criteria.
- Inspection and testing: tensile, flattening, hydraulic, impact, proof‑stress and corrosion tests; non‑destructive testing (ultrasonic, electromagnetic) options for longitudinal/transverse and laminar defects; leak‑tightness verification and inspection documents (certificates).
- Dimensions, tolerances and marking: dimensional tolerances, length options, marking, protection and documentation requirements are specified.
- Informative annexes: Annex A (stress‑rupture properties at elevated temperature) and Annex B (typical low‑temperature impact properties) provide guidance.
Applications and users
- Manufacturers of seamless austenitic stainless steel tubes
- Specifiers and purchasers for pressure vessels, boilers, heat exchangers and chemical plant piping
- Fabricators, welding engineers and inspectors responsible for compliance and traceability
- QA/QC and testing laboratories conducting mechanical and metallurgical tests
Keywords: ISO 9329-4:1997, austenitic stainless steel tubes, seamless steel tubes, technical delivery conditions, pressure vessels, heat treatment, mechanical properties, inspection and testing, dimensional tolerances.
Related standards
Referenced standards include (among others): ISO 404, ISO 1127, ISO 1129, ISO 2037, ISO 6759, ISO 7598, ISO 9302/9303/9305, ISO 10332, ISO 10474, ISO 14284 - consult ISO 9329-4 for full normative references and cross‑requirements.
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