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Letter 26009
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Lee Gearhart |
REF AMS-QQ-P-35C AND/OR CURRENT SPECS FOR PASSIVATION;
DO ANY OF THE PASSIVATION SPECIFICATIONS ACTUALLY REQUIRE TESTING
SUCH AS HIGH HUMIDITY? (TYPE II, VI, VII, VIII) MIL-F-14072 E300 -
DOES THIS DIFFER FROM OTHER PASSIVATION SPECIFICATIONS? IS TESTING A
REQUIREMENT?
THIS IS A GREY AREA FOR ME. I AM NOT WILLING TO PURCHASE ALL OF THE
RELATIVE SPECS AS WE USE OUTSIDE VENDORS FOR ALL APPLIED FINISHES. I
AM MOSTLY CURIOUS ABOUT THE ADDED COST FOR TESTING THAT I AM NOT
CERTAIN IS A REQUIREMENT.
RICHARD GOULDMAN
JOB SHOP MACHINING - RICHMOND, VA, USA
AMS-QQ-P-35 has been superseded by AMS-2700C. The standard lists
Method 1 Type 6 as "Low Temperature Nitric Acid". Basically, this is
20%-45% HNO3 with 30 minutes minimum immersion time at 70F-90F. The
Method 1 Type 7 is considered "Medium Temperature Nitric Acid". This
type is 20%-25% HNO3 with 20 minutes minimum immersion time at
120F-140F.
The AMS-2700C states that three types of testing for corrosion
resistance verification are acceptable. They are:
Humidity - 95% Min. relative humidity at 100-115F for not less than
24hours. No red rust.
Copper Sulfate Test
Salt Spray - 2 hours exposure in salt spay environment in accordance
to ASTM B 117. No red rust.
Our company used the Salt Spray for our PPAP testing. It only cost us
50 dollars for a minimum run charge since the time is so low.
Clay O'Shell
- Tyrone, PA, USA

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