ASTM A967/A967M-25 PDF

Full title and description

ASTM A967/A967M-25 — Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts. This document specifies accepted chemical and electrochemical passivation treatments (including nitric- and citric-acid methods), rinsing and neutralization practices, and qualitative acceptance tests used to confirm effective passivation of stainless steel components.

Abstract

This specification covers several types of chemical passivation treatments for stainless steel parts (immersion using nitric acid, immersion using citric acid, and electrochemical treatments), required rinsing procedures, and a set of qualitative verification tests (water immersion, high-humidity, salt spray, copper sulfate, potassium ferricyanide–nitric acid, damp-cloth, and boiling water immersion options) to confirm removal of free iron and other exogenous contamination. The standard provides acceptance criteria and guidance for selecting appropriate treatments for various stainless steel grades.

General information

• Status: Active (current specification).
• Publication date: 01 January 2025.
• Publisher: ASTM International.
• ICS / categories: 77.140.20 (Steels of high quality).
• Edition / version: A967/A967M‑25 (2025 revision).
• Number of pages: 10 pages.

Scope

The standard establishes procedures and acceptance tests for chemical and electrochemical passivation of stainless steel parts to remove exogenous iron and other surface contaminants and to promote formation of a corrosion‑resistant passive oxide film. It includes multiple alternative treatment types (nitric, citric, electrochemical), rinsing/neutralization recommendations, and a set of qualitative tests and acceptance criteria to verify effectiveness; SI and inch‑pound units are given as separate systems.

Key topics and requirements

• Recognized passivation treatments: immersion in nitric acid solutions, immersion in citric acid solutions, and electrochemical methods.
• Rinsing and neutralization: thorough rinsing immediately after treatment (stagnant, countercurrent, or spray washes) to stop chemical reactions and reduce residual contaminants.
• Acceptance tests (qualitative): water immersion, high‑humidity, salt spray, copper sulfate, potassium ferricyanide–nitric acid, damp‑cloth, and boiling‑water immersion options to confirm removal of free iron and surface cleanliness.
• Visual inspection criteria: passivated parts must show a chemically clean surface with no etching, pitting, or frosting.
• Unit systems: values stated in SI and inch‑pound units are treated separately and independently.

Typical use and users

Used by fabricators, finishers, passivation service providers, QA/QC engineers, inspectors, and purchasers who require documented passivation of stainless steel parts. Common industries include aerospace, medical and surgical implants, pharmaceutical and food processing equipment, semiconductor and electronics, oil & gas, chemical processing, and architectural stainless applications where corrosion resistance and surface cleanliness are critical.

Related standards

Commonly referenced companion and alternative documents include ASTM A380/A380M (Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems) for broader cleaning and descaling practices and AMS2700 (aerospace passivation requirements) for aerospace‑class passivation controls and classifications; these standards are often used together or specified by purchasers depending on sector requirements.

Keywords

passivation, stainless steel, citric acid, nitric acid, electrochemical passivation, copper sulfate test, potassium ferricyanide, water immersion test, salt spray test, surface cleanliness, corrosion resistance.

FAQ

Q: What is this standard?

A: ASTM A967/A967M‑25 is the ASTM International standard specification that defines accepted chemical and electrochemical passivation treatments, rinsing practices, and qualitative acceptance tests for passivating stainless steel parts.

Q: What does it cover?

A: It covers immersion treatments (nitric and citric), electrochemical treatments, rinsing/neutralization guidance, and several qualitative tests to verify removal of free iron and other contaminants; it also sets basic visual acceptance criteria.

Q: Who typically uses it?

A: Manufacturers, contract passivation shops, procurement/specification writers, inspectors, and quality engineers across industries that require verified stainless steel passivation (aerospace, medical, food/pharma, semiconductor, chemical processing, etc.).

Q: Is it current or superseded?

A: The A967/A967M‑25 edition (published 01 January 2025) is the current active version of the specification. Purchasers should cite the 2025 edition when specifying requirements.

Q: Is it part of a series?

A: It is commonly used in conjunction with practice documents such as ASTM A380/A380M (cleaning and descaling) and industry/aerospace specifications (e.g., AMS2700) that provide complementary or more stringent passivation controls for specific sectors.

Q: What are the key keywords?

A: Passivation, citric acid, nitric acid, electrochemical passivation, surface cleanliness, free iron test, copper sulfate test, potassium ferricyanide test, salt spray, water immersion.