ASTM A967 Stainless Steel Passivation Standard: Nitric & Citric
Able Electropolishing provides stainless steel passivation services that meet the rigid standards of the American Society for Testing and Materials (ASTM). The standards that collectively make up the ASTM A967 passivation specification ensure that nitric and citric stainless steel passivation is performed properly and with quality results.
What is ASTM A967 Passivation?
The ASTM A967 passivation standard applies to the cleaning, passivation and testing of stainless steel parts. Chemical passivation removes free iron and other surface contaminants from stainless steel parts, improving corrosion resistance. Stainless steel passivation performed to the ASTM A967 standards meets these standards by passing tests that confirm its effectiveness, particularly as it pertains to removing free iron from the cold-worked surfaces. These ASTM-approved tests may include:
- Water immersion testing
- Salt spray testing
- Copper sulfate testing
- High humidity testing
The ASTM A967 standard provides instructions and acceptance criteria for these and other tests that can verify the quality of a stainless steel passivation operation.
Electropolishing vs. Passivation
Electropolishing Before & After Example
While passivation is useful for removing free iron and contaminants from stainless steel and is more well known, electropolishing is often a better option and can be used on far more metal alloys.
Electropolishing removes a microscopically precise layer of surface material, to tolerances as low as +/-.0001″, depending on the alloy. This degree of precision and consistency, along with the ability to remove a variety of surface imperfections in one process, is why electropolishing is so often specified for critical parts used in medical implants and surgical instruments, aerospace components and fragile or critical parts used in other industries. Electropolishing is a one-stop process for a micro-smooth, ultraclean, corrosion and pathogen-resistant surface finish – with 30 times more corrosion resistance than passivation.
Electropolishing also eliminates the need for additional metal finishing processes like hand deburring, tumbling, pickling, and cleaning.
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