ASTM B816-00(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B816 −00 (Reapproved 2021)
Standard Specification for
Coatings of Cadmium-Zinc Mechanically Deposited
This standard is issued under the fixed designation B816; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 General—Thisspecificationcoverstherequirementsfor
2.1 ASTM Standards:
a coating that is a mixture of cadmium and zinc deposited on
B117Practice for Operating Salt Spray (Fog) Apparatus
metallic products by mechanical deposition. The coating is
B183Practice for Preparation of Low-Carbon Steel for
provided in four thickness classes (see Table 1) and several
Electroplating
finish types (see Table 2).
B242Guide for Preparation of High-Carbon Steel for Elec-
1.2 Toxicity—Warning: Cadmium is toxic; therefore these
troplating
coatingsshouldnotbeusedonarticlesthatwillcontactfoodor
B320Practice for Preparation of Iron Castings for Electro-
beverages, or for dental and other equipment that may be
plating
inserted into the mouth.Also, the coatings should not be used
B322Guide for Cleaning Metals Prior to Electroplating
on articles that will be heated to high temperatures, because
B374Terminology Relating to Electroplating
cadmiumwillformtoxicfumes.Similarly,ifcoatedarticlesare
B487Test Method for Measurement of Metal and Oxide
welded, soldered, or otherwise heated during fabrication,
Coating Thickness by Microscopical Examination of
adequate ventilation should be provided to exhaust toxic
Cross Section
fumes.
B499Test Method for Measurement of CoatingThicknesses
1.3 Similar Documents—Other kinds of mechanically de-
by the Magnetic Method: Nonmagnetic Coatings on
posited coatings are covered by Specifications B635, B695,
Magnetic Basis Metals
and B696.
B571Practice for Qualitative Adhesion Testing of Metallic
1.4 The following precautionary caveat pertains only to the Coatings
test method portion, Section 9, of this specification. This
B602Test Method for Attribute Sampling of Metallic and
standard does not purport to address all of the safety concerns,
Inorganic Coatings
if any, associated with its use. It is the responsibility of the user
B635Specification for Coatings of Cadmium-Tin Mechani-
of this standard to establish appropriate safety, health, and
cally Deposited
environmental practices and determine the applicability of
B695Specification for Coatings of Zinc Mechanically De-
regulatory limitations prior to use.
posited on Iron and Steel
1.5 This international standard was developed in accor-
B696Specification for Coatings of Cadmium Mechanically
dance with internationally recognized principles on standard-
Deposited
ization established in the Decision on Principles for the
B697Guide for Selection of Sampling Plans for Inspection
Development of International Standards, Guides and Recom-
of Electrodeposited Metallic and Inorganic Coatings
mendations issued by the World Trade Organization Technical
B762Test Method of Variables Sampling of Metallic and
Barriers to Trade (TBT) Committee.
Inorganic Coatings
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
B08.06 on Soft Metals. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2021. Published May 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approvedin1991.Lastpreviouseditionapprovedin2015asB816–00(2015).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/B0816-00R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B816 − 00 (2021)
TABLE 1 Thickness Classes
5.1.3 Coating type (see 4.2), including required color if
Coating Type IIc is used, and required lubricant or organic finish if
Class Thickness Typical Applications
Type IId is used,
Minimum, µm
5.1.4 Nature of the substrate, for example: high-carbon
7 7 Automotive fasteners
steel, mild steel, copper, brass:
12 12 Increased corrosion resistance (for ex-
ample, bellville washers)
5.1.4.1 State if precoating stress relief heat treatment is
25 25 Exterior hardware
required and the time and temperature to be used if different
50 50 Pole line hardware in severe envi-
from the standard values (see section 12.1),
ronments
5.1.4.2 State if special pretreatments are required to modify
the surface of the article (see Note 1),
TABLE 2 Coating Types 5.1.4.3 If special cleaning precautions are to be followed
(see A1.1), and
Type Description Typical Applications
5.1.5 Identification of significant surfaces (see 7.4.2).
I As-coated, without supplemen- Lowest cost where white corro-
ary treatments. ion products are acceptable.
5.1.6 Requirements and methods of testing one or more of
For elevated temperature ap-
the following:
lication that will degrade
5.1.6.1 Need for and type of special test specimens (see
Type II coatings (see 1.2).
IIa With yellow to bronze color sup- Delay the appearance of white
9.1),
lementary chromate coating. corrosion products. Increase
5.1.6.2 Appearance (see 7.3),
total corrosion protection.
IIb With brown to olive drab color Greater corrosion resistances 5.1.6.3 Deposit composition (see 9.2),
supplementary chromate than IIa. To provide a match
5.1.6.4 Thickness (see 9.5),
coating. to military equipment.
5.1.6.5 Adhesion (see 9.6),
IIc Type IIa, dyed. Color coding
Decorative purposes 5.1.6.6 Corrosion resistance (see 9.7),
IId Type IIa with an added lubricant Lubricity
5.1.6.7 Absence of hydrogen embrittlement, waiting time
or organic finish (oil, wax, lac- Maximum corrosion resistance
prior to testing and testing loads (see 9.8), and
uer, etc.)
5.1.7 The sampling plan to be used (see 8.1) and responsi-
bility for inspection (see section 13.1).
6. Significance and Use
E27Method for Spectrographic Analysis of Zinc and Zinc
Alloys by the Solution-Residue Technique (Withdrawn
6.1 Corrosion Resistance, General—Thisfunctionalcoating
1985)
isusedtoprovidecorrosionresistance.Theperformanceofthis
E396Test Methods for Chemical Analysis of Cadmium
coating depends largely on its thickness and the kind of
E536Test Methods for ChemicalAnalysis of Zinc and Zinc
environment to which it is exposed. Published results of
Alloys
environmental corrosion studies have demonstrated that the
F1470Practice for Fastener Sampling for Specified Me-
coating provides corrosion resistance greater than equivalent
chanical Properties and Performance Inspection
thicknesses of zinc coatings in industrial environments and
greater corrosion resistance than equivalent thicknesses of
3. Terminology
cadmium coatings in marine environments.
3.1 Definitions—Some of the terms used in this are defined
6.2 Galvanic Corrosion Resistance—The galvanic couple
in Terminology B374.
that results in the corrosion of steel and aluminum parts in
contact with each other in corrosive environments can also be
4. Classification
minimized by plating the steel parts with this mechanically
4.1 Thickness Classes—The coating is classified in four
deposited coating.
thickness classes, as defined in Table 1.
6.3 Hydrogen Embrittlement, Absence of—The mechanical
4.2 Coating Types—The coating is classified by type, as
coating process does not produce any permanent hydrogen
defined in Table 2.
embrittlement in products made from high-strength steels, for
example, fasteners or lock washers.
5. Ordering Information
7. Coating Requirements
5.1 In order to make the application of this specification
complete, the purchaser needs to supply the following infor-
7.1 Nature of Coating—Thecoatingshallbeamechanically
mation to the seller on the purchase order or other governing
deposited mixture of cadmium and zinc with the composition
documents:
45 to 75 mass % zinc, remainder cadmium.
5.1.1 The name, designation, and year of issue of this
7.2 Coating Process:
specification,
7.2.1 Coating—The cadmium-zinc coating shall be pro-
5.1.2 Thicknessclass(see4.1),includingamaximumthick-
ducedbymechanicaldepositioninaccordancewiththeprocess
ness if appropriate,
description given in Annex A1.
3 4
The last approved version of this historical standard is referenced on Holford, Raymond N., Jr., “Five Year Outdoor Exposure Corrosion
www.astm.org. Comparison,” Mechanical Finishing, July 1988.
B816 − 00 (2021)
7.2.2 Supplementary Treatments—Type II coatings shall be 7.6.1 Type I Coatings on Ferrous Articles—Type I coated
produced by treatment with acidic solutions that contain ferrous articles shall not develop red corrosion products
hexavalent chromium compounds and anions that act as (“rust”) when submitted to the 5% salt spray test for the
catalysts or film-forming compounds. following times:
Class 7 36 h
7.3 Appearance:
Class 12 72 h
7.3.1 General—The coating on all readily visible surfaces
Class 25 192 h
shall be uniform in appearance, well compacted, and complete Class 50 300 h
in coverage. Superficial staining from rinsing and drying and
7.6.2 Type II Coatings, White Corrosion—Type II coatings
mild variations in color and luster are acceptable.
shall not develop white corrosion products when submitted to
7.3.2 Surface Defects—Defects and variations in appear-
the salt spray test for 72 h. The organic coating or lubricant
ance in the coating that arise from surface conditions of the
shall be removed from Type IId coatings before the test or the
substrate(scratches,pores,rollmarks,inclusions,etc.)andthat
test can be run on articles that are withdrawn from processing
persist in the coating despite the observance of good metal
before the organic coating is applied.
finishing practices shall not be cause for rejection.
7.6.3 Type II Coatings on Ferrous Articles—Type II coated
ferrous articles shall not develop red corrosion products
NOTE 1—Coatings generally perform better in service when the
(“rust”) when submitted to the 5% salt spray test for the
substrate over which they are applied is smooth and free of torn metal,
inclusions, pores, and other defects. The specifications covering the
following times:
unfinished products should provide limits for these defects. A metal
Class 7 72 h
finisher can often remove defects through special treatments, such as
Class 12 96 h
grinding, polishing, abrasive blasting, chemical etches, and electropolish-
Class 25 192 h
ing. However, these are not normal in the treatment steps preceding the
Class 50 300 h
application of the coating. When they are desired, they are the subject of
TheorganiccoatingorlubricantshallberemovedfromType
special agreement between the purchaser and the seller.
IId coatings before the salt spray test or the test can be run on
7.4 Thickness:
articles that are withdrawn from processing before the organic
7.4.1 Conformance to Specified Class—Thethicknessofthe
coating is applied.
coatingeverywhereonthesignificantsurfacesshallconformto
NOTE 4—In many instances, there is no direct relation between the
the requirements of the specified class as defined in 4.1.
results of an accelerated corrosion test and the resistance to corrosion in
7.4.2 Significant Surfaces—Significant surfaces are usually
other tests or actual environments, because several factors that influence
definedasthosenormallyvisible(directlyorbyreflection)that
the progress of corrosion, such as the formation of protective film, vary
are essential to the appearance and serviceability of the article
greatly with the conditions encountered. The results obtained in the test
when assembled in normal position; or that can be the source should not, therefore, be regarded as a direct guide to the corrosion
resistanceofthetestedmaterialsinallenvironmentswherethesematerials
of corrosion products that deface visible surfaces on the
may be used. Also, performance of different materials in the test cannot
assembled article. Significant surfaces are further defined at
always be taken as a direct guide to the relative corrosion resistance of
those surfaces that are identified as such by the purchaser, for
these materials in service.
example, by indicating them on an engineering drawing of the
product or by marking a sample item of product.
8. Sampling
7.4.3 Minimum Thickness Requirement—The coating re-
8.1 The purchaser and producer are urged to employ statis-
quirement of this specification is a minimum requirement; that
tical process control in the coating process. Properly
is, the coating thickness is required to equal or exceed the
performed, statistical process control will assure coated prod-
specified thickness everywhere on the significant surfaces.
ucts of satisfactory quality and will reduce the amount of
Variation in the thickness from point to point on an article and
acceptance inspection. The sampling plan used for the inspec-
from article to article in a production lot is inherent in
tion of the quality coated article shall be agreed upon between
mechanically deposited coatings. Therefore, if all of the
the purchaser and producer.
articles in a production lot are to meet the thickness
8.1.1 When a collection of coated articles (inspection lot,
requirement, the average coating thickness for the production
see 8.2) is examined for compliance with the requirements
lot as a whole will be greater than the specified minimum.
placed on the articles, a relatively small number of the articles
NOTE2—Thethicknessofmechanicallydepositedcoatingsvariesfrom
(sample)isselectedatrandomandisinspected.Theinspection
point to point on the surface of a product, characteristically tending to be
lot is then classified as complying with the requirements based
thicker on flat surfaces, and thinner at exposed edges, sharp projections,
on the results of the inspection of the sample. The size of the
shielded or recessed areas, and interior corners and holes, depending on
sample and the criteria for compliance are determined by the
the dimensions, with such thinner areas often being exempted from
thickness requirements. application of statistics. The procedure is known as sampling
NOTE3—ProcessesusedtoproduceTypeIIfinishesremovesomeofthe
inspection. Test Method B602, Guide B697, and Test Method
coating. Because thickness requirements apply to the finished article,
B762 contain sampling plans that are designed for sampling
additionalthicknessesmayhavetobeappliedtocompensateforthemetal
inspectio
...