Overview
ISO 9330-5:2000 - "Welded steel tubes for pressure purposes - Technical delivery conditions - Part 5" specifies technical delivery conditions for submerged arc‑welded (SAW) welded steel tubes of circular cross‑section made from unalloyed or alloyed steels with specified low temperature properties. It applies where the tube material is used in pressure systems that also form part of low‑temperature piping (e.g., cryogenic or cold service). The standard defines manufacturing, heat treatment, chemical and mechanical property requirements, inspection and testing, marking and documentation for SAW tubes supplied for pressure purposes.
Key topics and technical requirements
- Scope and intended use: SAW tubes for pressure purposes when low‑temperature performance is required; “tube” and “pipe” are synonymous in the standard.
- Manufacturing: Tubes are formed from flat‑rolled products and welded longitudinally or helically. SAW process must include at least one inside and one outside weld run; welding procedures and operators should be qualified. Tubes can be hot‑ or cold‑finished prior to heat treatment.
- Delivery condition / Heat treatment: Tubes are supplied heat‑treated over full length - normalizing, normalizing + tempering, or quenching + tempering depending on grade and agreement between parties.
- Metallurgical requirements: Fully‑killed steels; heat analysis and product analysis requirements for chemical composition are specified (see standard tables). Grain size, deoxidation and residual element considerations are covered.
- Mechanical and low temperature properties: Tensile, impact (Charpy) and bend tests, and requirements for low‑temperature toughness are specified or referenced.
- Inspection & testing: Specifies ultrasonic and radiographic weld seam inspection, tube end and strip/plate laminar testing, hydraulic testing, and acceptance criteria. Inspection documents and test categories follow ISO 10474 and related ISO test methods.
- Purchaser information: Mandatory order data include denomination, dimensional standard reference, OD × wall thickness, length, reference to ISO 9330‑5 and steel grade; optional items include product analysis, weld testing, bevelled ends, marking, coatings and specific inspection levels.
Applications and users
ISO 9330‑5 is aimed at:
- Tube manufacturers and SAW mill operators
- Procurement and specification engineers (oil & gas, petrochemical, LNG, cryogenics, power plants)
- Pressure‑piping designers and fabricators requiring low‑temperature toughness
- Inspectors, testing laboratories and compliance officers verifying mechanical and non‑destructive testing (NDT) results
Using ISO 9330‑5 helps ensure welded steel tubes meet consistent technical delivery conditions for safe, reliable performance in cold and pressure‑containing piping systems.
Related standards
- ISO 404 - General technical delivery requirements
- ISO 4200 - Dimensions and masses for plain end tubes
- ISO 10474 - Inspection documents for steel products
- ISO 9765 / ISO 12096 - Ultrasonic and radiographic testing for SAW weld seams
- ISO 5730 - Pressure‑containing equipment (application guidance)
Keywords: ISO 9330‑5, submerged arc‑welded, SAW tubes, welded steel tubes, low temperature properties, pressure purposes, technical delivery conditions, inspection and testing.