ASTM B449-93(2015)
(Specification)Standard Specification for Chromates on Aluminum
Standard Specification for Chromates on Aluminum
ABSTRACT
This specification covers the requirements relating to rinsed and non rinsed chromate conversion coatings on aluminum and aluminum alloys intended to give protection against corrosion and as a base for other coatings. Aluminum and aluminum alloys are chromate coated in order to retard corrosion; as a base for organic films including paints, plastics, and adhesives; and as a protective coating having a low electrical contact impedance. The materials are classified according to its coating thickness: Class 1; Class 2; Class 3; and Class 4. Chromate conversion coatings are normally applied by dipping: the coating may also be applied by inundation, spraying, roller coating, or by wipe-on techniques.
SCOPE
1.1 This specification covers the requirements relating to rinsed and nonrinsed chromate conversion coatings on aluminum and aluminum alloys intended to give protection against corrosion and as a base for other coatings. This edition of the specification has been coordinated with ISO/DIS 10546 and is technically equivalent.
1.2 Aluminum and aluminum alloys are chromate coated in order to retard corrosion; as a base for organic films including paints, plastics, and adhesives; and as a protective coating having a low electrical contact impedance.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B449 −93 (Reapproved 2015)
Standard Specification for
1
Chromates on Aluminum
This standard is issued under the fixed designation B449; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
3
1. Scope 2.2 ISO Standards:
ISO 2409 Paint and Varnishes—Cross-Cut Test
1.1 This specification covers the requirements relating to
ISO 3768 Metallic Coatings—Neutral Salt Spray Test (NSS
rinsed and nonrinsed chromate conversion coatings on alumi-
Test)
num and aluminum alloys intended to give protection against
ISO 3892 Conversion Coatings on Metallic Materials—
corrosion and as a base for other coatings. This edition of the
Determination of Mass Per Unit Area—Gravimetric
specification has been coordinated with ISO/DIS 10546 and is
Method
technically equivalent.
ISO 4519 Electrodeposited Metallic Coatings and Related
1.2 Aluminum and aluminum alloys are chromate coated in
Finishes—Sampling Procedures for Inspection by Attri-
order to retard corrosion; as a base for organic films including
butes
paints, plastics, and adhesives; and as a protective coating
ISO/DIS 10546 Chemical Conversion Coatings—Rinsed
having a low electrical contact impedance.
and Nonrinsed Chromate Conversion Coatings—On Alu-
1.3 The values stated in SI units are to be regarded as minum and Aluminum Alloys
4
standard. No other units of measurement are included in this 2.3 Federal Standard:
standard.
Fed. Std. No. 141 Paints, Varnish, Lacquer, and Related
Materials; Methods of Inspection
1.4 This standard does not purport to address all of the
4
2.4 Military Specification:
safety concerns, if any, associated with its use. It is the
MIL-DTL-5541 Chemical Films forAluminum andAlumi-
responsibility of the user of this standard to establish appro-
num Alloys
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
3. Terminology
2. Referenced Documents 3.1 Definitions:
2
3.1.1 nonrinsed—chromate coatings that are dried immedi-
2.1 ASTM Standards:
ately after the chromating step without receiving a water rinse.
B117 Practice for Operating Salt Spray (Fog) Apparatus
3.1.1.1 Discussion—This special type of coating is typically
B602 Test Method for Attribute Sampling of Metallic and
used on long coils of aluminum sheet stock that receive an
Inorganic Coatings
immediate subsequent paint or adhesive coating.
B767 Guide for Determining Mass Per Unit Area of Elec-
trodeposited and Related Coatings by Gravimetric and
NOTE 1—Nonrinsed chromate coatings are finding increased usage on
Other Chemical Analysis Procedures fabricated parts and castings.
D1730 Practices for Preparation of Aluminum and
3.1.2 rinsed—chromate coatings that are rinsed in water
Aluminum-Alloy Surfaces for Painting
prior to drying.
D3359 Test Methods for Measuring Adhesion by Tape Test
3.1.2.1 Discussion—Thistypeofcoatingistypicallyapplied
to extruded aluminum fabricated parts and castings.
4. Classification
1
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
4.1 Chromate finishes can be applied ranging in color from
B08.07 on Conversion Coatings.
brown, thick coatings (Class 1) providing maximum corrosion
Current edition approved March 1, 2015. Published April 2015. Originally
ε1
approved in 1967. Last previous edition approved in 2010 as B449 – 93 (2010) .
DOI: 10.1520/B0449-93R15.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 4th Floor, New York, NY 10036, http://www.ansi.org.
4
Standards volume information, refer to the standard’s Document Summary page on Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
the ASTM website. Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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B449−93 (2015)
protection to yellow, intermediate thickness coatings (Class 2) film,and,therefore,thetypeofconversioncoating,dependson
suitable as an organic film base or to colorless, thin coatings the composition of the chromating solution, but it is also
(Class 3) suitable for low electrical contact resistance. The affected by the pH and temperature, the duration of the
yellow coatings vary from golden y
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: B449 − 93 (Reapproved 2010) B449 − 93 (Reapproved 2015)
Standard Specification for
1
Chromates on Aluminum
This standard is issued under the fixed designation B449; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1
ε NOTE—Updated format of the military specification in Section 2.4 editorially in June 2010.
1. Scope
1.1 This specification covers the requirements relating to rinsed and nonrinsed chromate conversion coatings on aluminum and
aluminum alloys intended to give protection against corrosion and as a base for other coatings. This edition of the specification
has been coordinated with ISO/DIS 10546 and is technically equivalent.
1.2 Aluminum and aluminum alloys are chromate coated in order to retard corrosion; as a base for organic films including
paints, plastics, and adhesives; and as a protective coating having a low electrical contact impedance.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
B117 Practice for Operating Salt Spray (Fog) Apparatus
B602 Test Method for Attribute Sampling of Metallic and Inorganic Coatings
B767 Guide for Determining Mass Per Unit Area of Electrodeposited and Related Coatings by Gravimetric and Other Chemical
Analysis Procedures
D1730 Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting
D3359 Test Methods for Measuring Adhesion by Tape Test
3
2.2 ISO Standards:
ISO 2409 Paint and Varnishes—Cross-Cut Test
ISO 3768 Metallic Coatings—Neutral Salt Spray Test (NSS Test)
ISO 3892 Conversion Coatings on Metallic Materials—Determination of Mass Per Unit Area—Gravimetric Method
ISO 4519 Electrodeposited Metallic Coatings and Related Finishes—Sampling Procedures for Inspection by Attributes
ISO/DIS 10546 Chemical Conversion Coatings—Rinsed and Nonrinsed Chromate Conversion Coatings—On Aluminum and
Aluminum Alloys
4
2.3 Federal Standard:
Fed. Std. No. 141 Paints, Varnish, Lacquer, and Related Materials; Methods of Inspection
4
2.4 Military Specification:
MIL-DTL-5541 Chemical Films for Aluminum and Aluminum Alloys
1
This specification is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.07 on
Conversion Coatings.
Current edition approved April 1, 2010March 1, 2015. Published June 2010April 2015. Originally approved in 1967. Last previous edition approved in 20042010 as
ε1
B449 – 93 (2004).(2010) . DOI: 10.1520/B0449-93R10E01.10.1520/B0449-93R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
4
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
B449 − 93 (2015)
3. Terminology
3.1 Definitions:
3.1.1 nonrinsed—chromate coatings that are dried immediately after the chromating step without receiving a water rinse.
3.1.1.1 Discussion—
This special type of coating is typically used on long coils of aluminum sheet stock that receive an immediate subsequent paint
or adhesive coating.
NOTE 1—Nonrinsed chromate coatings are finding increased usage on fabricated parts and castings.
3.1.2 rinsed—chromate coatings that are rinsed in water prior to drying.
3.1.2.1 Discussion—
This type of coating is typically applied to extruded aluminum fabricated parts and castings.
4. Classification
4.1 Chromate finishes can be applied ranging in color
...
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