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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STEP

PROCESS

SOLUTION

TIME

TEMPATURE

REMARKS

1.

Solvent clean

Acetone

(ASTM-0329)

or cleaner

(A-A-59281)

As necessary

Ambient

Wipe surface with

commercial cheese cloth

saturated with solvent.  Wipe dry with

cheese cloth.

2.

Etch

Ammonium

Peroxydisulfate

10% by weight in water.

15 - 60 seconds

Ambient

Make solution just before

use. Swab with commercial

cheese cloth saturated with

solution.

3.

Rinse

Clear water

As required to remove etch solution

Ambient

Swab area with commercial

cheese cloth saturated with

water.

4.

Neutralization

Any alkali solution with a

pH of 10 minimum

As required to neutralize

etchant

Ambient

Swab area with

commercial cheese cloth

saturated with alkali solution.

5.

Rinse

Clear water

As required to

remove alkali solution

Ambient

Swab with

commercial cheese cloth saturated with water.

6.

Rinse

Alcohol or acetone

To remove water

Ambient

Swab with commercial

cheese cloth saturated with

alcohol.  Wipe dry.

7.

Inspect and evaluate per appropriate criteria.

**8.

Oil

Rust preventative

(MIL-PRF-

16173)

Swab only

Ambient

To prevent corrosion.

*This process may also be used as an immersion technique, provided pre-cleaning is in accordance with

para 5.2. (However see NOTE 2 below.)

Steps 1 thru 7 shall be completed without interruption.

NOTE 1:  No bake required after etching using this process.

NOTE 2:  Make solution up just before use as it becomes inactive after 72 hours.

** This step may be omitted if the facility can show evidence that corrosion during the queue between

process steps is not an issue.  This could be the case in a low humidity environment.