EMI RFI Shield Plating Inc

Passivation Corrosion Resistant Steel In Canada

Passivation of corrosion resistant steel in accordance with QQ-P-35, AMS-QQ-P-35, ASTM A967, AMS 2700

QQ-P-35 spec denotes the changes nitric acid content as well as Type II containing (2%-2.5%) by weight sodium dichromate. Type VI is a higher concentration of nitric acid with a low temperature as extreme nitric acid will cause hydrogen embrittilment across the parts. Type VII is a higher temperature treatment for a shorter period of time and Type VIII is a high concentration in high temperatures.

QQ-P-365
Passivation of Corrosion resistant steels
ASTM A967
Table Header Table Header
QQ-P-35 / AMS-QQ-P-35
Types
II
Medium temperature nitric acid solution with sodium dichromate additive.
VI
Low temperature nitric acid solution.
VII
Medium temperature nitric acid solution.
VIII
Medium temperature high concentration nitric acid solution.
AMS 2700
Methods
1
2
Types (for Method 1)
1
Low temperature nitric acid with sodium dichromate.
2
Medium temperature nitric acid with sodium dichromate.
3
High temperature nitric acid with sodium dichromate.
4
40% nitric acid for free machining steels.
6
Low temperature nitric acid.
7
Medium temperature nitric acid.
8
Medium temperature, high nitric acid concentration.
ASTM A967
Treatments in Nitric Acid Solutions
Nitric 1
20-25% by vol. Nitric Acid and 2.5±0.5 % by wt. Sodium Dichromate. Immersion time: 20 minutes min. Temp: 120-130⁰F (49-54⁰C)
Nitric 2
20-45% by vol. Nitric Acid Immersion time: 30 minutes min. Temp: 70-90⁰F (21-32⁰C)
Nitric 3
20-25% by vol. Nitric Acid Immersion time: 20 minutes min. Temp: 120-140⁰F (49-60⁰C)
Nitric 4
45-55% by vol. Nitric Acid Immersion time: 30 minutes min. Temp: 120-130⁰F (49-54⁰C)
Nitric 5
Other combinations of temperature, time and concentration of Nitric Acid, with or without other chemicals including accelerants, inhibitors, or proprietary solutions, capable of producing parts that pass the specified test requirements.
Treatments in Citric Acid
Citric 1
4-10% by weight Citric Acid Immersion time: 4 minutes min. Temp: 140-160⁰F (60-71⁰C)
Citric 2
4-10% by weight Citric Acid Immersion time: 10 minutes min. Temp: 120-140⁰F (49-60⁰C)
Citric 3
4-10% by weight Citric Acid Immersion time: 20 minutes min. Temp: 70-120⁰F (21-49⁰C)
Citric 4
Other combinations of temperature, time and concentration of Citric Acid, with or without other chemicals to enhance cleaning, including accelerants, inhibitors, or proprietary solutions, capable of producing parts that pass the specified test requirements.
Citric 5
Other combinations of temperature, time and concentration of Citric Acid, with or without other chemicals to enhance cleaning, including accelerants, inhibitors, or proprietary solutions, capable of producing parts that pass the specified test requirements. Immersion bath to be controlled at a pH of 1.8-2.2.