TASK 70-16-80-700-009
1 . General.
A.Suitability control tests should be performed on all products used for temporary marking, wipe cleaning, or any product that comes into contact with hardware and is not cleaned prior to re-entry into service or proceeding to a heat generating process (like weld, heat treatment, or thermal spray).
B.The control tests will identify temporary marking and other products likely to deteriorate engine parts during engine operation or shop maintenance.
C.Specific control tests can also be appropriate when temporary marking products are applied to nonmetallic materials. The markers appropriate for nonmetals must be established on a case-by-case basis.
D.Removal of temporary marking products must be performed using a method (thinners, solvents, abrasives, etc.) that does not deteriorate the base material of the engine part.
E.The ink used in temporary markers should be lot controlled.
F.The analysis and testing defined in this section can be used for determining the acceptability of certain other products that are used and subsequently left on engine hardware. An example of such a product would be penetrating oil used during disassembly.
2 . Requirements.
Subtask 70-16-80-700-091
G.Temporary marking and other materials must be tested for composition and temperature resistance, and must meet the requirements of the performed test. If the product is used on Ti alloys the product must pass ASTM F945 (“Stress Corrosion on Titanium”) on AMS 4911 and AMS 4916 alloys.
3 . Composition Testing.
Subtask 70-16-80-700-093
H.Purpose: To evaluate the marking material compatibility on jet engine components in the area of potential contamination from residual elements.
I.Procedure: Testing should be done per ASTM methods for elemental analysis.
(1)Obtain samples of the materials to be tested for the following elements:
NOTE:
Levels of elements are controlled by a maximum concentration per element as well as a total maximum for the group (I. and III.).
 
Element
Limit
 
Group I
Composition (Maximum concentration)
 
Lead
25 ppm
 
Cadmium
25 ppm
 
Antimony
25 ppm
 
Bismuth
25 ppm
 
Mercury
25 ppm
 
Zinc
25 ppm
 
Tin
25 ppm
 
Selenium
25 ppm
 
Silver
25 ppm
 
Thallium
25 ppm
 
Copper
25 ppm
 
Total Group I
Not to exceed 100 ppm
 
Group II
Composition (Maximum concentration)
 
Sulfur
100 ppm
 
Sodium
100 ppm
 
Potassium
100 ppm
 
Group III
Composition (Maximum concentration)
 
Fluorine
50 ppm
 
Chlorine
50 ppm
 
Bromine
50 ppm
 
Iodine
50 ppm
 
Total Group III
Not to exceed 100 ppm
(2)Metals (group I. of the elements) do not need to be individually analyzed if the ash content on 25 ml of the sample is less than or equal to 0.0025 wt percent. The sample can be dried at a low temperature then ashed by firing at 650°F (343°C) in a porcelain or platinum crucible to constant weight.
(3)The product must pass the elemental analysis requirements above for the material to be approved for use on engine components.
4 . Hot Corrosion Test for Metals.
Subtask 70-16-80-700-092
J.Test Equipment.
(1)Test part.
Raw material (metal sheet, tubes, test panels) of the same metal as parts to be marked, or a specimen taken from a large part or rod can be used for the test part.
(2)Test materials. As required.
(3)Equipment.
The convection ovens, used for the hot corrosion tests, must have an electrical heating system capable of temperature control and programming and be able to maintain the test parts at specified temperatures.
K.Method of Test.
(1)Apply the product to the test parts or test specimens and heat the test part for 8 hours ± 30 minutes at the temperature appropriate for the metal being tested, as indicated below:
 
Metal
Temperature
°F(± 25°F)
Temperature
°C(± 15°C)
Test Panel
Material
 
Magnesium alloys
700
371
AMS 4375
 
Aluminum alloy
700
371
AMS 4037
 
Steel
1700
927
AMS 5510
 
Nickel alloys
1700
927
AMS 5596
 
Cobalt alloys
2000
1093
AMS 5608
 
Titanium alloys
900
482
AMS 4911
L.Test Validation.
(1)Visual check of the sample must show no evidence of corrosion, contamination, or intergranular attack. Maximum allowable intergranular attack when examined under 400X magnification is 0.0002 inch (0.005 mm).
5 . Stress Corrosion on Titanium.
Subtask 70-16-80-700-094
M.Do the tests required on AMS 4911 and AMS 4916 alloys. Refer to ASTM F945 “Standard Test Method for Stress-Corrosion of Titanium Alloys by Aircraft Engine Cleaning Materials”
NOTE:
The product must be tested at maximum operating concentration. If the product must be mixed with water use deionized water.
N.The product must pass the requirements of ASTM F945.