ISO 9328-4:2018

Overview

ISO 9328-4:2018 - "Steel flat products for pressure purposes - Technical delivery conditions - Part 4: Nickel‑alloy steels with specified low temperature properties" - defines the technical delivery requirements for plates and strip used in pressure equipment when those products are made from nickel‑alloy steels with specified low‑temperature behavior. This 2018 fourth edition updates the series, adds new steel grades (e.g., X6Ni7, X9Ni7) and clarifies delivery, testing and marking rules. The document is intended to support both European design codes and ASME‑type design codes.

Key topics and requirements

• Scope & applicability: Covers nickel‑alloy steel flat products for pressure purposes; follows the general rules of ISO 9328‑1.
• Classification & designation: Steel grade classification per ISO 4948 and designation rules per ISO 9328‑1; Annex C maps comparable national/regional grades.
• Information to purchaser: Mandatory and optional ordering information (e.g., delivery condition, test directions, impact energy options); example ordering format is provided.
• Delivery conditions & heat treatment: Default and optional conditions (normalized, thermomechanically rolled +M, untreated +AR); Annex D gives heat‑treatment guidelines.
• Chemical composition: Cast (heat) analysis limits and permissible product analysis deviations (see Tables A.1/B.1 and Table 1).
• Mechanical properties: Tensile and impact requirements for low‑temperature performance are specified in Annexes A and B (European and ASME tables). Option to specify higher impact energy (40 J) for certain grades.
• Testing & inspection: Inspection levels, sampling, test methods and test-piece orientation (transverse by default; longitudinal possible by agreement); requirements follow ISO 9328‑1 with supplementing details in this part.
• Marking, handling and documentation: Requirements for marking, certificates (e.g., inspection certificate 3.1 per ISO 10474) and handling instructions.

Applications

• Design, procurement and manufacture of pressure vessels, boilers, cryogenic equipment and piping where low‑temperature toughness is critical.
• Use in industries such as oil & gas, petrochemical, LNG, power generation and specialty cryogenics.
• Useful when specifying materials to meet both European and ASME code requirements.

Who should use this standard

• Material manufacturers and mills producing plates and strip for pressure equipment
• Engineering designers and materials engineers specifying steels for low‑temperature service
• Procurement and quality inspectors responsible for certificates, testing and acceptance
• Welding and fabrication experts requiring compatibility with heat treatment and toughness requirements

Related standards

• ISO 9328‑1 (general requirements for steel flat products for pressure purposes)
• ISO 4948 (steel classification)
• ISO 10474 (inspection documents - certificates)
• Regional design codes (EN/European and ASME), welding guidance (EN 1011 / IIW documents)

Keywords: ISO 9328-4:2018, steel flat products for pressure purposes, nickel‑alloy steels, low temperature properties, plates and strip, technical delivery conditions, pressure equipment, ASME, European design codes, chemical composition, impact tests.