G-J301_REV_B.pdf

CAGE 77751 G-J301

Revision B

19 December 2018

Data contained on this sheet is subject to the restrictions on the title page of this document.

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TABLE OF REVISIONS

Symbol Section Description Date Approval

– – Original 10/15/73

– – Revision A 2/21/79

1.1 added cleaning reqt.

1.2 added new para.

1.3 was 1.2

1.4 was 1.3

3.1.1 added clean. equip.

3.2.1 deleted etching sol. control & make up

3.2.3 added clean. sol.

3.3 added general reqt. for cleaning

3.4 added clean. process procedures & reqts.

3.4.1 added clean. procedure; omit 3.4.1.1–3.4.1.4

3.4.2 was 3.4.1

3.4.3 was 3.4.2

3.4.3.2 was 3.4.2.2, reword para.

3.4.3.4 was 3.4.2.4, reword para.

3.4.2.5 omit para.

3.4.4 was 3.4.3

5.0 added new etch rates

Revision Changes Reason for Change Approval

12/19/2018

Incorporated Amendment A1;

reformatted; removed references to “FRC” (Fairchild Republic Company) throughout; made minor grammatical corrections throughout.

Specification requirements.

Changed document title; was:

“Cleaning and Etching Prior to Penetrant Inspection, Process for.”

Clarity, per Air Force direction.

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Revision Changes Reason for Change Approval

Revision B (continued)

Rewrote 1.1 entirely; was “This specification establishes the requirements for cleaning and etching specific metal alloys prior to penetrant inspection.”

To improve linkage of scope to the Engineering requirements.

Moved and modified the last sentence of 1.3 into a new 1.4;

was: “Chem-milled surfaces do not require etching”; renumbered original 1.4 as 1.5.

Per Air Force direction.

In 1.5 [formerly 1.4], replaced “both FRC Quality Engineering and Materials Engineering” with “the A-10 SPO.”

To assign this responsibility to the appropriate entity.

Reorganized 2.0; added order of precedence; updated documents, including references elsewhere.

Clarity; specification requirement; to reflect current document numbers and titles.

In 3.1.1, changed “FRC” to “A-10 program.”

Current appropriate designation.

In 3.2.1.b., in last sentence, changed “and” to “and/or.”

Clarity, per Air Force direction.

In 3.2.1.c., changed “Turco Aluminetch #3” to “Bonderite C- AK Alum Etch 3 (known as Turco Aluminetch #3).”

Current product designation.

In 3.2.1.d., updated material identities; relocated NOTE to beneath 3.2.1.c.

To reflect current document numbers; NOTE is applicable only to 3.2.1.c.

In 3.2.2, deleted second sentence in entirety.

No longer applicable.

In 3.2.3.b., changed “Ridolene 53” to “Bonderite C-AK 53 AERO (known as Turco Ridolene 53).”

Current product designation.

In 3.2.3.c., deleted Amchem 4-14 in its entirety.

No longer available.

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Revision Changes Reason for Change Approval

Revision B (continued)

In 3.2.3.c., changed “Amchem 7- 17” to “Bonderite C-AD Deoxidizer 7-17 Toner (formerly known as Turco Deoxidizer 7-17 Toner)”;

deleted NOTE in its entirety; in right-most column, added “or” between “Ambient” and “100– 120.”

Current product designation;

NOTE is no longer applicable;

clarity.

In 3.3.a., rewrote second clause of second sentence in entirety.

Clarity, per Air Force direction.

In 3.3.d., added “as determined per ASTM F2111” at the end of the sentence.

To require that testing for surface damage conforms to

ASTM F2111.

In 3.4, added second sentence in its entirety.

To permit alternate processes if approved by the A-10 SPO.

In 3.4.1.b., changed “Ridolene 53” to “Bonderite C-AK 53 AERO (known as Turco Ridolene 53).”

Current product designation.

In 3.4.1.d., deleted “Amchem 4- 14”; changed to “Bonderite C-AD Deoxidizer 7-17 Toner (formerly known as Turco Deoxidizer 7-17 Toner).”

No longer available; current product designation of suitable replacement.

In 3.4.1.d., deleted “for 5–10 minutes”; added second sentence in its entirety

Previous deoxidizing time may not be appropriate for replacement material.

In 3.4.3.2, at beginning of last sentence, changed “ Quality Engineering” to “The supplier’s Quality Assurance Department”;

at end of last sentence, added “part and” between “given” and “situation.”

Both for clarity.

In 3.4.3.3, added “(see Section 5.0)” between “... etching rate” and “and the requirements of Section 3.3.”

To direct user to the location of the appropriate information.

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Revision Changes Reason for Change Approval

Revision B (continued)

In the NOTE beneath 3.4.4.1.b., changed “Turco Aluminetch” to “Bonderite C-AK Alum Etch 3 (known as Turco Aluminetch #3)”;

changed “Amchem 4-14” to “Bonderite C-AD Deoxidizer 7-17 Toner (formerly known as Turco Deoxidizer 7-17 Toner).”

Current product designation; no longer available; current product designation of suitable replacement.

In the NOTE beneath 3.4.4.1.b., deleted “for for 2–5 minutes”;

added second sentence in its entirety.

To direct user to the location of the appropriate information.

In 5.0, changed “Turco Aluminetch #3 per 3.2.3.c.” to “Bonderite C-AK Alum Etch 3 (known as Turco Aluminetch #3) per 3.2.1.c.”

Current product designation (3.2.3.c. was a typo).

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TABLE OF CONTENTS

TABLE OF REVISIONS ...................................................................................................... ii

1.0 SCOPE

2.0 APPLICABLE DOCUMENTS

2.1 Government Documents

2.1.1 Federal

2.1.2 Military

2.2 Non-Government Documents

2.2.1 A-10 Program

2.2.2 Industry

3.0 REQUIREMENTS

3.1 Facilities and Equipment

3.2 Cleaning and Etching Solutions

3.3 General Requirements for Cleaning and Etching

3.4 Cleaning and Etching Process Procedures and Requirements

4.0 QUALITY ASSURANCE PROVISIONS

5.0 GUIDE TO ETCH RATES

1.0 SCOPE

1.1 This specification establishes the requirements for cleaning and etching specific metal alloys, prior to penetrant inspection, when called out on the applicable drawings or other associated Engineering documentation.

1.2 The cleaning practice is intended to make penetrant inspection more sensitive by the removal of oils, greases and scale, all of which could mask defects.

1.3 The etching practice is intended to make penetrant inspection more sensitive by the removal of worked or disturbed metal, which could mask crack-like defects. All mechanically finished surfaces including as-forged and as-extruded surfaces are covered.

1.4 Chem-milled surfaces do not require etching prior to conducting a post-production penetrant inspection.

1.5 Other processes meeting the cleaning and etching requirements of this specification may also be used if approved by the A-10 SPO. Standard industrial chemical descaling processes for forgings and extrusions do not require approval for use prior to inspecting as-forged and as-extruded surfaces, provided the processor briefly describes the process and notes that it meets Section 3.3, Parts a., d. and e. of this specification.

2.0 APPLICABLE DOCUMENTS

The following documents of the issue in effect on the effective date of contract shall form part of this specification. In the event of conflict between the documents referenced herein and the requirements of this specification, the documents referenced herein shall govern.

2.1 Government Documents

2.1.1 Federal

A-A-55827 Chromium Trioxide, Technical

A-A-59105 Nitric Acid, Technical

TT-N-95 Naphtha, Aliphatic

2.1.2 Military

MIL-DTL-24641 Acid, Hydrofluoric, Technical

2.2 Non-Government Documents

2.2.1 A-10 Program

A-F201 Chem-Milling of Aluminum Alloys, Process for

G-R301 Cleaning, Chemical (Acid or Alkaline) and Mechanical (Abrasive) – Metal, Process for

G-R302 Solvent Cleaning of Metals

T-R201 Cleaning, Descaling, and Chemical Surface Treatment of Titanium and Titanium Alloys

2.2.2 Industry

ASTM F2111 Standard Practice for Measuring Intergranular Attack or End Grain Pitting on Metals Caused by Aircraft Chemical Processes

3.0 REQUIREMENTS

3.1 Facilities and Equipment

3.1.1 Immersion Cleaning and Etching – Immersion cleaning and etching will be performed with materials, facilities and equipment such as described in A-10 program specifications A- F201, G-R301, G-R302, and T-R201.

3.1.2 Manual Etching – Manual etching shall be performed in areas and under conditions suitable for strong chemicals and copious water rinsing. Special attention must be given to the use of chemically resistant application tools, to providing protection for personnel, and to environmental pollution effects. Guidance should be sought from appropriate Engineering and Safety personnel. Refer to T-R201 Paragraph 5.0 on general safety precautions. Use only when immersion is impractical.

3.2 Cleaning and Etching Solutions

3.2.1 Etching Solutions for Aluminum Alloys – The following solutions may be used, if convenient for manufacturing, provided all requirements are met:

a. Aluminum deoxidizer solutions in accordance with G-R301. These are slow-etching solutions and will require long periods of immersion.

b. Chem-milling etchant solutions in accordance with A-F201. These are normally rapid-etching solutions that must be used at temperatures well below those specified in A-F201 for acceptable etch rates to result. These solutions are also more likely for acceptable rates to result. These solutions are also more likely to produce problems of excess intergranular and/or pitting attack.

c. Bonderite C-AK Alum Etch 3 (known as Turco Aluminetch #3) – This solution, as described below, is the etchant that is preferred for use when container size and part size are compatible.

Chemical Concentration Temperature, °F

Bonderite C-AK Alum Etch 3 (known as Turco Aluminetch #3)

6–10 oz./gal. of water 130–145

NOTE: Aluminetch #3 may be used at ambient temperatures, which will require longer immersion times, until such time that heating apparatus is installed.

d. HNO3, CrO3, HF Solution (Tri-Acid Etch)

Chemical Concentration Temperature, °F

Nitric Acid (HNO3), 42° Bé (A-A-59105)

9.3–10.5 gallons

70–100

Chromic Acid Flakes (CrO3) (A-A-55827, Type I)

38–42 lbs.

Hydrofluoric Acid, 70% Tech.

(MIL-DTL-24641)

0.85–1.0 gal.

Water, Tap To make 100 gallons

3.2.2 Etching of Titanium and Titanium Alloys – Use the nitric-fluoride solution of specification T-R201.

3.2.3 Cleaning Solutions for Aluminum Alloys – The following solutions may be used for cleaning aluminum alloys:

a. Degreasing solvent in accordance with G-R302.

b. Alkaline cleaner in accordance with G-R301.

Name Description Concentration Temperature, °F

Bonderite C-AK 53 AERO (known as Turco Ridolene 53)

Alkaline Cleaner 2–4 oz./gal. 140–160

c. Deoxidizer solution in accordance with G-R301.

Name Description Concentration Temperature, °F

Bonderite C-AD Deoxidizer 7-17 Toner (formerly known as Turco Deoxidizer 7-17 Toner)

Heavy Duty Alum. Deoxidizer

2.0–6.0 oz./gal.

10–20% by Volume 42° Bé Nitric Acid

Ambient or 100–120

3.3 General Requirements for Cleaning and Etching

a. Material removal from an etched surface shall be 0.0002 to 0.0005 inch on mechanically finished parts. Parts having as-forged or as-extruded surfaces may be etched in excess of 0.0004 inch, provided dimensional tolerances on the Engineering drawing and all applicable requirements of this specification are met.

b. Etching shall be performed for periods exceeding two minutes and the period shall be long enough to ensure that all regions have been uniformly wetted and etched.

The etching period is defined as extending from the time when the part is fully immersed or contacted by etchant to that time when the last contacted region is separated away from the etchant.

c. It follows from a. and b. above that the etching rate on a surface shall not exceed

0.0002 inch/minute/surface.

d. Etching removal of metal shall not introduce surface damage such as pits or intergranular attack extending beyond 0.0002 inch below the local surface, as determined per ASTM F2111.

e. Parts shall be free of corrosion products, discolorations, or other adverse conditions that would interfere with visual and penetrant inspection or subsequent processing.

3.4 Cleaning and Etching Process Procedures and Requirements

Process procedures and requirements are the steps of cleaning, cleaning prior to etching, etching in a solution or gel of known etch rate, and rinsing after etching. Alternate cleaning and etching processes may be used provided they are approved by the A-10 SPO.

3.4.1 Cleaning – Cleaning shall refer to cleaning of aluminum alloys not to be etched prior to penetrant inspection.

a. Degrease per G-R302 if required. Parts must be thoroughly dried before the next step.

b. Soak in Bonderite C-AK 53 AERO (known as Turco Ridolene 53) alkaline cleaner for 5 to 15 minutes.

c. Transfer the part while wet into rinse water at 140–160°F. Rinse for 2–5 minutes.

Rinsed parts shall be free of smut, soil and most marking inks. Check for a water break-free surface.

d. Immerse in Bonderite C-AD Deoxidizer 7-17 Toner (formerly known as Turco Deoxidizer 7-17 Toner) for deoxidation. Time of immersion shall be in accordance with manufacturer’s recommendations and Section 5.0.

e. Rinse in cold water.

f. Air dry.

3.4.2 Cleaning Prior to Etching – Cleaning prior to etching shall be done as necessary to remove interfering surface conditions that would inhibit uniform etching of the part.

3.4.2.1 Parts that are heavily contaminated with oils, greases or other organic residues shall be cleaned in accordance with G-R302.

3.4.2.2 Parts that are lightly contaminated with organic or inorganic materials and those that require further cleaning after solvent cleaning per G-R302 shall, in the case of aluminum alloys, be alkaline cleaned per G-R301 and, in the case of titanium alloys, per T-R201.

3.4.2.3 Aluminum parts that may contain thermally produced oxide layers shall be deoxidized per G-R301.

3.4.2.4 Parts that cannot be conveniently immersed fully or by sections into available tanks to accomplish Paragraphs 3.4.2.2 and 3.4.2.3 may be hand scrubbed with detergents and/or abrasively treated to accomplish the required removal of surface conditions that could interfere with etching. Such practice shall not violate dimensional or other limitations inherent to the part or the alloy.

3.4.3 Etching – Etching shall be accomplished with a solution selected from Section 3.2.

3.4.3.1 Etching will be accomplished only after a current etching rate has been established for the particular tank or batch of etchant at the temperature of use.

3.4.3.2 Etch rate determinations shall be made by manufacturing personnel by using the direct measurement of metal surface removal on etched test pieces. A dated log shall be maintained describing the calculations performed, the test material and the solution conditions. The supplier’s Quality Assurance Department shall review the adequacy of etch rate determination practice and ensure that it is appropriate and correct for the given part and situation.

3.4.3.3 The etchant immersion time shall be calculated from the etching rate (see Section 5.0) and the requirements of Section 3.3.

3.4.3.4 Manual etching may be performed on parts or sections of parts. Ensure continuous etching action by constant application of fresh etchant solution during the etching period.

Maskants, tapes and plugs may be used as necessary to confine the etching action only to required areas.

3.4.4 Rinsing After Etching

3.4.4.1 Aluminum Alloys – Immediately after etching, parts will be:

a. Rinsed in room temperature water.

b. Deoxidized per G-R301 (except when no smut results from etching).

NOTE: Parts etched in Bonderite C-AK Alum Etch 3 (known as Turco Aluminetch #3) shall be deoxidized in Bonderite C-AD Deoxidizer 7-17 Toner (formerly known as Turco Deoxidizer 7-17 Toner). Time to be determined per Section 5.0.

c. Rinsed in room temperature water.

d. Rinsed in hot water (140–190°F).

e. Dried thoroughly.

3.4.4.2 Titanium Alloys – Immediately after etching, parts will be:

a. Rinsed in room temperature water.

b. Rinsed in hot water (140–190°F).

c. Dried thoroughly.

3.4.4.3 Manual Rinsing – Manual rinsing after manual etching shall be by repeated swabbing or flushing with room temperature water. Manual rinsing will be judged sufficient when common litmus paper (blue for acid etchant or red for alkaline etchant), applied wet to the surface, shows no color change different from its response to the rinse water. Drying shall be accomplished by blotting with clean paper or cloth toweling and/or by the use of blown clean air to minimize drying stains.

4.0 QUALITY ASSURANCE PROVISIONS

4.1 Quality Assurance shall monitor and enforce all requirements of this specification and the referenced specifications as they apply.

4.2 Visual examination will normally be sufficient to verify the absence of objectionable surface conditions; however, when defects are suspected, examination at 10x or by metallographic means shall be used for evaluation.

5.0 GUIDE TO ETCH RATES

The below-listed approximate etch rates are presented only as an aid to selection of the more-appropriate etching medium and should not be used in establishing the etching period:

Deoxidizer solution per 3.2.1.2.a. 0.000005 in./minute/surface

Chem-milling solution per 3.2.1.b. Use temperatures below 150°F to get rates less than 0.0002 in./minute (0.001 in./minute at 195°F) (0.0005 in./minute at 150°F)

Bonderite C-AK Alum Etch 3 (known as Turco Aluminetch #3) per 3.2.1.c.

0.0004 in. to 0.0008 in./minute/surface

HNO3, CrO3, HF (Tri-Acid Etch) solution per 3.2.1.d.

0.00001 in. to 0.00003 in./minute/surface