ISO 9400-1990 PDF

Full title and description

ISO 9400:1990 — Nickel-based alloys — Determination of resistance to intergranular corrosion. The standard defines nickel‑based alloys for the purpose of the tests and specifies apparatus, preparation of test specimens, four laboratory test procedures and criteria for evaluation to assess susceptibility to intergranular corrosion under controlled conditions.

Abstract

ISO 9400:1990 describes four laboratory methods to determine the susceptibility of nickel‑based alloys to intergranular (intercrystalline) corrosion: (A) iron(III) sulfate – sulfuric acid test; (B) copper – copper‑sulfate – sulfuric acid test (with added copper); (C) hydrochloric acid test; and (D) nitric acid test. The standard covers required apparatus, specimen preparation, test procedures and evaluation of results.

General information

• Status: Published (International Standard; confirmed in systematic reviews, most recently maintained in the ISO review cycle).
• Publication date: December 1990 (ISO edition 1, approved 29 November 1990 / published 1990-12).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 77.060 — Corrosion of metals and alloys.
• Edition / version: Edition 1 (1990).
• Number of pages: 11 pages (ISO bibliographic entry).

Scope

ISO 9400:1990 specifies four laboratory test methods intended to determine the relative susceptibility of nickel‑based alloys to intergranular corrosion. The procedures are intended for laboratory assessment and comparison; results do not automatically equate to performance in service unless the test medium and conditions match the operational environment. Selection of the appropriate test method, the sensitization treatment and acceptance criteria should be agreed between purchaser and supplier for any given alloy. The standard is applicable to nickel‑based alloys in the field of corrosion testing as referenced in related alloy listings (for example ISO 6207).

Key topics and requirements

• Definitions: terminology for "nickel‑based alloy" as used in the standard.
• Specified apparatus and materials required to carry out each method (containers, heating baths, reagents, specimen holders).
• Specimen preparation: geometry, surface condition, and sensitization (heat‑treatment) procedures where applicable.
• Four test procedures: (A) Fe(III) sulfate – H2SO4; (B) Cu/CuSO4 – H2SO4 (with added copper); (C) HCl immersion; (D) HNO3 immersion — with stepwise procedures and exposure times.
• Evaluation and interpretation: criteria for assessing degree of intergranular attack and guidance that acceptance criteria must be agreed contractually between supplier and purchaser.
• Limitation: methods are comparative/laboratory in nature and may not reflect in‑service behaviour unless test conditions match service conditions.

Typical use and users

ISO 9400 is used by metallurgists, corrosion engineers, materials laboratories, alloy producers, procurement/specification engineers and quality control departments to evaluate and compare the intergranular corrosion susceptibility of nickel‑base alloys in research, product qualification and supplier acceptance testing. The standard aids material selection and contract specification where intergranular corrosion is a concern.

Related standards

Typical related and harmonized documents include the ISO 6207 series (alloy designations and listings for nickel alloys) and corresponding EN/ISO adoptions (for example EN ISO 9400 published as an identical text by CEN member bodies in the mid‑1990s). Equivalent national adoptions (DIN EN ISO 9400, BS EN ISO 9400, ÖNORM EN ISO 9400, etc.) exist that reproduce ISO 9400:1990 text as normative publications.

Keywords

nickel‑based alloys; intergranular corrosion; intercrystalline corrosion; corrosion testing; laboratory methods; sensitization; Fe(III) sulfate test; Cu/CuSO4 test; hydrochloric acid test; nitric acid test.

FAQ

Q: What is this standard?

A: ISO 9400:1990 is an ISO International Standard that specifies four laboratory test methods to determine the resistance (susceptibility) of nickel‑based alloys to intergranular corrosion.

Q: What does it cover?

A: It covers definitions, required apparatus, specimen preparation, four specific chemical immersion test procedures (Fe(III) sulfate–H2SO4; Cu/CuSO4–H2SO4; HCl; HNO3) and criteria/guidance for evaluation and reporting of results.

Q: Who typically uses it?

A: Materials and corrosion laboratories, alloy manufacturers, design and procurement engineers, and quality/control personnel who need to assess or specify susceptibility of nickel alloys to intergranular attack typically use this standard.

Q: Is it current or superseded?

A: ISO 9400:1990 remains the ISO publication for this subject and has been maintained in ISO's periodic review process (confirmed through reviews). National and regional adoptions (EN ISO 9400) were published in the 1990s; users should check their national standards body for any country‑specific status updates or later replacements.

Q: Is it part of a series?

A: It is related to other ISO work on corrosion and alloy designation (for example ISO 6207 and other corrosion‑related ISO documents) and has been adopted identically by several national/regional bodies as EN ISO 9400.

Q: What are the key keywords?

A: Nickel‑based alloys, intergranular corrosion, intercrystalline corrosion, corrosion testing, Fe(III) sulfate test, Cu/CuSO4 test, hydrochloric acid test, nitric acid test.