Is QQ-P-35 obsolete?
QQ-P-35 has been cancelled and superseded by ASTM A967 or AMS-QQ-P-35. AMS-QQ-P-35 has been cancelled and superseded by AMS 2700. Not Specified Use type appropriate for alloy, subject to purchaser acceptance.
What is the passivation process for stainless steel?
Passivation is a widely-used metal finishing process to prevent corrosion. In stainless steel, the passivation process uses nitric acid or citric acid to remove free iron from the surface. The chemical treatment leads to a protective oxide layer that is less likely to chemically react with air and cause corrosion.
What supersedes QQ-P-35?
QQ-P-35 was superseded by AMS-QQ-P-35 for aerospace products and AMS-QQ-P-35 was cancelled and superseded by AMS2700.
What is passivate per ASTM A967?
The ASTM A967 passivation standard applies to the cleaning, passivation and testing of stainless steel parts. Per passivation standard, ASTM A967 requires the parts to be immediately neutralized post immersion followed by a chemical treatment to treat the surface of the part.
What is AMS2700?
SAE AMS2700, Revision F, March 2018 – Passivation of Corrosion Resistant Steels. Purpose. This specification covers the requirements for a process to assure removal of free iron or other less noble contaminants from the surfaces of corrosion resistant steel parts.
How much citric acid is needed to passivate?
4-10% citric
The Method 2 citric acid passivation standard specifies solution strengths of 4-10% citric acid (by weight of composition), with shorter treatment times at higher temperatures.
How do you mix citric acid for passivation?
Passivation can be accomplished at a 4-10% citric acid concentration in warm water in about 30 minutes. Again you want to air dry and let the oxygen do its work overnight before you rinse any residual acid off.
Can 316 stainless steel be passivated?
What types of stainless steel are compatible with the passivation process? The passivation process includes but is not limited to these types of SST: 303, 304, and 316 alloys. It is typically performed to ASTM A9367 and similar industry specifications for chemical passivation.
What chemicals are used in passivation?
There are three chemicals broadly used for passivating stainless steel; phosphoric acid, nitric acid, and citric acid. Each has its relative strengths compared to the others making them more suitable to certain applications over others.
What is passivation in stainless steel?
The process of passivation, is a post-fabrication acid treatment that removes “free iron” contamination left behind on the surface of the stainless steel wire from machining and fabricating. It is not a scale removal treatment, nor is it like a coat of paint.
How do you passivate corrosion-resistant steel?
3.3 Passivation treatment. Corrosion-resistant steel parts shall be passivated by immersing them in one of the following aqueous solutions (see 6.2) and maintaining them within the temperature ranges and times described below and in Table I.
What are the types of passivation treatment in engineering drawing?
Engineering drawings and specifications should specify classification type (passivation treatment) which should De used in accordance with 1.2.1. 1.2.1 Types. II- Medium temperature nitric acid solution with sodium dichromate additive VI- Low temperature nitric acid solution VII- Medium temperature nitric acid solution
What are the pretreatment requirements for passivation?
The pretreatment methods and procedures used prior to the passivation treatment shall be either in accordance with ASTM A380 or MIL-S-5002. The surface of the parts shall be free of oil, grease, rust, scale and other foreign matter and shall have no deleterious effect on material properties.