ABMA 13413:1997(R2008) pdf free

ABMA 13413:1997(R2008) pdf free.Aerospace – Airframe needle track roller, yoke type,double-row sealed – Inch series
The materials for the blackening processes shall be selected by the contractor. he selected materials shall result in black coatings meeting all the applicable requirements of this annex.
Prior to the application of the black coatings, the basis metal shall be thoroughly cleaned with materials and methods at the option of the contractor. The cleaning process shall be performed without measurable abrasion or erosion. The cleaned surfaces shall be free of rust, scale, grease, oil, paint or other foreign matter.
AlI rings which are cold formed or which contain residual tensile stress, such as may be produced by cold straightening, shall be given a stress relief. The stress relief may be conducted before or atter cleaning and coating at the discretion of the contractor.
The specified black coating shall be applied under controlled time and temperature conditions. AIll equipment, together with solutions or baths, shall be property maintained and kept free of dirt or possible contaminants.
The selected process shall not reduce the hardness of the rings being processed or expose the rings to temperatures in the temper britle range of the material, nor shall it cause embrittlement of the steel.
The process shall not result in any attack of the surface, either piting or intergranular. During processing, daily determination for this behaviour shall be made using a microscopic method and examined at a magnification which will clearty establish the condition. Rings with pitted surfaces or showing intergranular attack shall be rejected.
After the cold rinse, the rings shall be dipped for a minimum of 30s in a 0,06 % solution of chromic acid (240 cc chromic acid per 380 I of water) maintained at a temperature of 66°C to 88°C and a pH of 2 to 3. After the chromic acid dip, parts shall be dried without further rinsing by using wam dry air.
Due to hazardous waste resulting from the use of chromic acid, an altemative dip process may be used at the option of the contractor provided it sufficiently neutralises any residuals from the coating process.
Coatings shall cover the basis metal completely and pass the smut test. Colour shall be a uniform black. A slight amount of smut, which is inherent in the process, shall not be cause for rejection. There shall be no indication of any reddish-brown or green smut when tested (see A.3.3.1). Smut “spottiness” shall be classified as unsatisfactory requirnng reprocessing.ABMA 13413 pdf free download.