ABMA 13416:1997(R2008) pdf free
ABMA 13416:1997(R2008) pdf free.Aerospace – Airframe needle track roller, yoke type,single-row, sealed – Metric series
The test shall be made prior to the application of any corrosion preventative compound or after vapor degreasing.Black oxide coated rings shall be visually inspected under strong light to assure a satisfactory appearance. Each sample shall also be wiped with a clean white cloth for indications of smut (see 2.5). A slight amount of smut which is inherent in the process is acceptable and shall not be cause for rejection.
The black oxide coated rings, prior to the application of a preservative, shall be handled with clean cotton gloves or equivalent. Each sample shall have deposited, on one flat spot of black oxide coated surtace, three drops (0,2 mI) of a 5 % solution of oxalic acid. The reaction shall be observed after 30 s and up to 8 min. After 8 min, the ring shall be rinsed and inspected. A light gray centre with a lighter border colour or a gray-black centre with a light border indicated unacceptable coating. A black or dark brown centre with a light border indicates a good quality coating. A good quality coating may show a light border, indicating exposure of metal around the drops. Parts shall therefore be judged only on the colour and exposure of the metal under the drops.
To test for embritlement, the use of notched tensile samples may be used. The samples shall be held under the load for at least 200 h unless otherwise specified and then examined for cracks. The lot shall be rejected if any coated part develops cracks or fails by fracture.
Contractors may employ one of a number of tradename black finishing oxidizing materials or prepared chemical mixtures to apply the black oxide coating. The processing details shall be as recommended by the raw material supplier. Table A.1 provides an example of a process.ABMA 13416 pdf free download.
