MIL-STD-867 Temper Etch InspectionThis standard establishes requirements and test for performing temper etch inspection of carburized steels and tool and low alloy steels, which are heat treated above 1.24 x 109 Pascal PA 1.26 x 102 kilogram - force/square millimeter Kgf/mm2 or 1.8 x 105 pound - force/square inch psi. This standard applies to aircraft and missiles structural and propulsion system components when MIL-HDBK-6870 for guidance only and/or MIL-STD-866 are reference documents in the solicitation or contract.

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MIL-STD-867C

tolerance requirements and, if necessary, allow sufficient material remaining after machining or grinding to account for the material removed during the etch process.

4.4   Record of inspection.  The results of the etch inspection shall be appropriately recorded and filed.

4.5   Qualification and certification.  Before performing temper etch inspection on production parts inspection personnel shall be qualified and certified in accordance with SAE-ARP-1923.

4.5.1    Initial qualification.  At qualification inspection personnel shall pass physical, written, and practical tests.

4.5.2   Re-certification.  Personnel performing temper etch inspection shall be re- qualified and re-certified as specified in this section at intervals not to exceed three (3) years.  Physical tests are required yearly.

4.5.3   Re-examine for qualification.   Personnel examined and not meeting qualification standards must wait 30 days and show evidence of having taken suitable corrective action, additional training or self-study before re-examination.

4.5.4   Certification.   Records for all qualified personnel shall be maintained and include:  Date of qualification, results of physical, written and practical test, and experience as a temper etch inspector.

5.   DETAILED REQUIREMENTS

5.1   Process.  Temper etch inspection may be accomplished utilizing a process procedure as listed in Tables I, II, III or IV for the type of steel to be inspected.  The entire surface of the feature in question shall be etched and inspected.

5.2   Cleaning.  Parts shall be cleaned to a water break free condition just prior to the etch process by vapor degreasing, hot ultrasonic cleaning or water based hot

alkaline cleaning.  To obtain a uniform surface for optimum temper etch on rough surfaces, grit blasting or liquid honing is recommended.

5.3   Solution concentrations.   The acid solution concentrations listed in the tables that follow are a percent of the concentrated solution used in the makeup.  For example:  Solution 1 in TABLE I is 3-5% of the concentrated nitric acid solution used. That is, 3 to 5 gallons of concentrated nitric acid diluted to 100 gallons.

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