NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 GENERAL MAINTENANCE, OVERHAUL, AND REPAIR PROCEDURES—Continued 0005 00 DIAGNOSTIC AND AUTOMATED TEST EQUIPMENT - Continued (5) Inspection and Evaluation of Indications. (a) Material processed with type I fluorescent penetrant will be inspected using a black light (ultra- violet light). (b) Material processed with type II visible dye penetrant will be inspected using white light. (c) Irrelevant (false) indications can be caused by inadequate cleaning or improper application and removal of materials. Irrelevant indications will also appear where parts are press-fitted together. (d) Observation for indications should begin as soon as the developer is applied. (e) The extent of the indication will show the extent of the discontinuity and the brilliance will be a measure of its depth. (f) Deep cracks will hold more penetrant and will therefore be broader and more brilliant. (g) Size may be determined by persistence of indication to reappear on repeated application of developer. (h) Line indications may appear as straight, curved, jagged, or intermittent and denote cracks, laps, cold-shuts, seams, lack of fusion in welds, or similar defects. (i) Isolated spot indications may appear rounded or irregular and denote shrinkage, pinholes, porosity, and similar defects. (j) Defects which are repairable will be completely retested after completion of repairs. (6) Post Cleaning. All parts which have been subjected to liquid penetrant inspection processes must be cleaned before being put into use. All penetrant materials and developers must be removed. e. Leak Detection Procedure. This inspection process works extremely well through thin sections such as welded sheet metal and thin castings. Inspection efficiency drops, however, when inspecting materials with a cross section over one-half inch thick. CAUTION In welded seams, the defects may not go entirely through and may only appear as a fine line on the side where the penetrant is applied. In this case, the regular liquid penetrant inspection should be used. (1) Preclean and dry surfaces if evidence of soil is present. (2) Apply penetrant to one side of the material being inspected by brushing or spraying, with the latter preferred. Observe proper dwell time. 0005 00-20 Change 1