1.SCOPE:
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TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)
Tel: 724-776-4970 (outside USA)
2.APPLICABLE DOCUMENTS:
The issue of the following documents in effect on the date of the purcha order forms a part of this specification to the extent specified herein. The supplier may work to a subquent revision of
a document unless a specific document issue is specified. When the referenced document has
been canceled and no superding document has been specified, the last published issue of that document shall apply.
2.1SAE Publications:
Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001 or
AMS 2759/9 Hydrogen Embrittlement Relief (Baking) of Steel Parts
2.2ASTM Publications:
Available from ASTM, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA
19428-2959 or
ASTM B 117 Practice for Operating Salt Spray (Fog) Apparatus
ASTM B 253 Guide for Preparation of Aluminum Alloys for Electroplating
ASTM B 487 Test Method for Measurement of Metal and Oxide Coating Thickness
by Microscopical Examination of a CrossSection
ASTM B 499 Test Method for Measurement of Coating Thickness by the Magnetic
Method: Nonmagnetic Coatings on Magnetic Basis Metals ASTM B 504 Test Method for Measurement of Thickness of Metallic Coatings by the
Coulometric Method
ASTM B 568 Test Method for Measurement of Coating Thickness by X-Ray
Spectrometry
ASTM B 571 Test Methods for Adhesion of Metallic Coatings
ASTM E 376 Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-
Current (Electromagnetic) Examination Methods
ASTM F 519 Test Method for Mechanical Hydrogen Embrittlement Evaluation of
Plating Process and Service Environments
3.TECHNICAL REQUIREMENTS:
3.1Preparation:
3.1.1Steel parts having a hardness of 40 HRC or higher and which have been straightened,
formed, or ground after heat treatment shall be suitably stress relieved before cleaning and
plating. Temperatures to which parts are heated shall be such that maximum stress relief is
obtained without reducing hardness of parts below drawing limits, but, unless otherwi
specified, not less than 275 °F ± 10 (135 °C ± 6) for not less than five hours for parts 55 HRC or greater, or 375 °F ± 25 (191 °C ± 14) for not less than four hours for other parts.
3.1.2Parts shall have clean surfaces free of water break prior to immersion in the plating solution.
3.1.3Electrical contact between the parts and power source shall be made to prevent chemical or
immersion deposition, electrical arcing, and overheating. If parts are to be plated all over,
contact points shall be located where specified or where agreed upon by purchar and
processor. If parts are not required to be plated all over, contact points shall be located on
areas on which plating is not required or is optional.
3.1.4Prior to deposition of the zinc-nickel alloy, parts may be given an electrodeposited nickel
strike, or may be dry or wet abrasive blasted. Mechanical finishing, if employed, shall be
completed prior to application of a nickel strike, when ud, and shall be accomplished in a
manner that will not affect the appearance or quality of the finished part.
3.2Procedure:
3.2.1The zinc-nickel alloy plate shall be electrodeposited from a suitable electrolyte. Stress-
reducing agents shall not be ud unless approved by purchar.
3.2.1.1Aluminum alloys may be zincate treated in accordance with ASTM B 253 before plating.
3.2.1.2Parts which specify Type 2 plating shall be given a supplementary chromate conversion
coating, which will meet the requirements of 3.4.4.2. Any post thermal treatment shall be
done prior to application of the chromate conversion treatment. Steel parts requiring a post
thermal treatment as in 3.3 may require reactivation prior to application of the conversion
coating.
3.2.1.3Parts which specify Type 3 plating shall, after hydrogen embrittlement relief baking, be given
a supplementary zinc phosphate conversion coating, which meets the requirements of
3.4.4.3. Steel parts requiring post thermal treatment as in 3.3 may require reactivation prior
to application of the conversion coating.
3.3Hydrogen Embrittlement Relief:
Treatment of steel parts shall be in accordance with AMS 2759/9.
3.4Properties:
Zinc-nickel alloy plate shall conform to the following requirements. (Composition and thickness for Types 2 and 3 apply prior to conversion coating).
3.4.1Composition: The zinc-nickel alloy plate shall contain 6 to 20% nickel and the balance
esntially zinc, determined by a method acceptable to purchar.
3.4.2Thickness: Shall be as follows, determined on reprentative parts or test panels in
accordance with ASTM B 487, ASTM B 499, ASTM B 504, ASTM B 568, ASTM E 376, or
other method acceptable to purchar (See 8.3).
3.4.2.1Nickel Strike: When applied, shall be 0.0001 inch (2.5 µm) maximum.
3.4.2.2Zinc-Nickel Alloy Plate:
3.4.2.2.1Parts Without External Threads (other than washers): Shall have total plate thickness of
0.0003 to 0.0007 inch (8 to 18 µm).
3.4.2.2.2Washers and Parts With External Threads: Shall have total plate thickness of 0.0002 to
0.0004 inch (5 to 10 µm).
3.4.2.2.3Except for external threads, thickness shall be considered only where surfaces of parts
can be touched by a sphere 0.75 inch (19 mm) in diameter. No requirements are
established for minimum plating thickness on surfaces of holes, recess, internal
threads, contact areas of parts plated all over, and other areas where a controlled deposit
cannot be obtained under normal plating conditions, but such areas shall not be masked
to prevent plating.
3.4.3Adhesion: Shall meet the requirements of ASTM B 571 for zinc plating.
3.4.4Corrosion Resistance:
3.4.4.1Type 1 plated parts or reprentative specimens, plated to a thickness of 0.0004 to 0.0007
inch (10 to 18 µm) shall show no visual evidence of red corrosion on the basis metal in
controlled thickness areas, determined by exposure for 500 hours to salt spray corrosion
test conducted in accordance with ASTM B 117 (See 4.3.1.3).
3.4.4.2Type 2 plated parts or reprentative specimens, plated to a thickness of 0.0004 to 0.0007
inch (10 to 18 µm) shall show no visual evidence of white corrosion product after 96 hours
and no evidence of red corrosion on the basis metal in controlled thickness areas after 500 hours, determined by exposure to salt spray corrosion testing in accordance with ASTM B
117. (See 4.3.1.3).
3.4.4.3Type 3 plated parts or reprentative specimens, which have received a supplementary
Type 3 phosphate conversion coating shall be uniform in texture, evenly deposited, and
medium gray to black in color. The coating shall not show smut, powder, or white stains.
Corrosion test not required; visual requirement only.
3.4.5Hydrogen Embrittlement: The plating process shall not cau hydrogen embrittlement in steel
parts, after baking, determined in accordance with ASTM F 519 (See 4.3.1.4).
3.5Quality:
Plating, as received by purchar, shall be smooth, continuous, adherent to the basis metal, and visually free from porosity, blisters, nodules, pits, and other imperfections detrimental to performance of the plating. Slight staining or discoloration is permissible. There shall be no evidence of double plating or spotting-in.
4.QUALITY ASSURANCE PROVISIONS:
4.1Responsibility for Inspection:
The processor shall supply all samples for processor’s tests and shall be responsible for the performance of all required tests. Parts, if required for tests, shall be supplied by purchar.
Purchar rerves the right to sample and to perform any confirmatory tests deemed
necessary to ensure that processing conforms to the specified requirements.
4.2Classification of Tests:
4.2.1Acceptance Tests: Thickness (3.4.2), adhesion (3.4.3), and quality (3.5) are acceptance tests
and shall be performed to reprent each lot.
4.2.2Periodic Tests: Composition (3.4.1), corrosion resistance (3.4.4.2) (white corrosion product
only), hydrogen embrittlement (3.4.5), and tests of preparatory and plating solutions (See 8.7) to ensure that the deposited metal will conform to specified requirements are periodic tests
and shall be performed at a frequency lected by the processor unless frequency of testing is specified by purchar, except corrosion resistance (3.4.4.2), which shall be conducted not less than monthly.
4.2.3Preproduction Tests: All technical requirements are preproduction tests and shall be
performed prior to or on the initial shipment of plated parts to a purchar, when a change in material and/or processing requires reapproval by the cognizant engineering organization
(See 4.4.2), and when purchar deems confirmatory testing to be required.
4.3Sampling and Testing:
Shall be not less than the following: A lot shall be all parts of the same material and part number or similar part configuration, plated to the same range of plate thickness using the same
solutions, plated in a single, continuous plating cycle, not to exceed 16 hours, and prented for processor’s inspection at one time.
4.3.1Sample Configuration:
4.3.1.1Nondestructive testing shall be performed wherever practical and authorized herein. Except
as noted, actual parts shall be lected as samples for tests.
4.3.1.2Thickness and Adhesion: Separate test panels of the same generic class of alloy and heat
treat condition as the parts, distributed throughout the lot, cleaned, plated, and post treated
with the parts reprented shall be ud when plated parts are of such configuration or size
as to be not readily adaptable to the specified tests, when nondestructive testing is not
practical on actual parts, or it is not economically acceptable to perform destructive tests on
actual parts.
