Standard Practice for Measuring Intergranular Attack or End Grain Pitting on Metals Caused by Aircraft Chemical Processes

Importancia y uso:

4.1 If not properly qualified, chemicals and chemical processes can attack metals used during aircraft maintenance and production. It is important to qualify only processes and chemical formulas that do not have any deleterious effects on aircraft metallic skins, fittings, components, and structures. This test procedure is used to detect and measure intergranular attack or pitting depth caused by aircraft maintenance chemical processes, hence, this test procedure is useful in selecting a process that will not cause intergranular attack or end grain pitting on aircraft alloys.

4.2 The purpose of this practice is to aid in the qualification or process conformance testing or production of maintenance chemicals for use on aircraft.

4.2.1 Actual aircraft processes in the production environment shall give the most representative results; however, the test results cannot be completely evaluated with respect to ambient conditions which normally vary from day to day. Additionally, when testing chemicals requiring dilutions, water quality and composition can play a role in the corrosion rates and mechanism affecting the results.

4.2.2 Some examples of maintenance and production chemicals include: organic solvents, paint strippers, cleaners, deoxidizers, water-based or semi-aqueous cleaners, or etching solutions and chemical milling solutions.

Subcomité:

F07.07

Volúmen:

15.03

Número ICS:

19.040 (Environmental testing), 49.025.01 (Materials for aerospace construction in general)

Palabras clave:

aircraft maintenance chemicals; end grain pitting; intergranular attack; metallographic inspection; pit; pitting corrosion; pitting depth;