Preliminary Requirements

Procedure

1. SUBTASK 70-11-29-200-001 Test the Solution

   1. Use the materials given below on which the solution is to be tested.

      Material: Aluminum casting alloy for high temperature.

      Form: Cast.

      Symbol or Code: LAF.

      MSRR Spec No.: 8010.

      Acceptable US Spec: AMS4225.

      Material: Low silicon aluminum alloy for high temperature.

      Form: Bar forged.

      Symbol or Code: LAJ.

      MSRR Spec No.: 8007.

      Acceptable US Spec: AMS4132.

   2. Prepare the test piece to a convenient and measurable size with the end faces ground flat and parallel to each other to facilitate micrometer measurement.

   3. Abrade the test piece using CoMat 05-020 WATERPROOF SILICON CARBIDE and CoMat 05-021 WATERPROOF SILICON CARBIDE.

   4. Measure the test piece across the ground faces using a 1in. micrometer graduated in 0.0001in. (0 to 25 mm graduated in 0.0025 mm).

   5. Throughly clean the test piece by immersion in two seperate baths of CoMat 01-060 ACETONE (CH3)2CO.

   6. On removal from the second bath of acetone place the test piece on a clean sheet of CoMat 02-011 FILTER PAPER in a desiccator ensuring that they are kept seperate.

   7. NOTE

      The balance zero should be checked before and after each set of weighings.

      Using a laboratory balance, weigh each test piece to the nearest milligram.

   8. Suspend each test piece on a thread of inert material and re-clean with CoMat 01-060 ACETONE (CH3)2CO.

   9. Suspend the test piece in the solution or solutions being tested at the appropriate temperature and for a period of time no less than the equivalent of the total immersion time required for cleaning the parts during five overhauls (2.5 hours).

   10. Remove the test piece from the solution, at the end of the selected period, wash it throughly in clean, cold running water and dry off from an immersion in CoMat 01-060 ACETONE (CH3)2CO.

   11. Having first removed the suspension material, place the test piece on a sheet of clean CoMat 02-011 FILTER PAPER in a desiccator.

   12. Weigh and measure the test piece as described in Step and Step.

   13. Examine the test piece for corrosion, pitting and intergranular penetration.

2. SUBTASK 70-11-29-200-002 Assess the Test

   1. The test pieces must be unaffected by corrosion products, pitting or intergranular penetration; light staining is acceptable.

   2. A measurement loss of 0.0001in. (0.0025 mm) on diameter is acceptable provided that this loss is not exceeded for the total cleaning time required for five overhauls.

   3. If there is no visible change in the appearance of the surface and dimension but there is an unacceptable weight change the test should be repeated.

   4. The subsequent weight changes, uncoated test pieces of material LAF and LAJ have a maximum weight change of 0.03 (gm/sq dm) each. These are equivalent to a dimensional loss of 0.0001in. (0.0025 mm) on diameter. The weight loss figures quoted must not be exceeded for a total immersion time required equivalent to the cleaning time for five overhauls.