ASTM D7396-14(2020)
(Guide)Standard Guide for Preparation of New, Continuous Zinc-Coated (Galvanized) Steel Surfaces for Painting
Standard Guide for Preparation of New, Continuous Zinc-Coated (Galvanized) Steel Surfaces for Painting
SIGNIFICANCE AND USE
4.1 This guide describes procedures that can be used to prepare new zinc-coated surfaces for painting and improve the bond of paint to the zinc surface.
SCOPE
1.1 This guide covers surface cleaning and various methods for treating new, continuous zinc-coated (galvanized) steel surfaces produced by either the hot-dip method or by electroplating. This guide is applicable to only surface preparation for application of liquid paint and coating products, and not for powder coating applications. This guide covers surfaces that have not been treated previously at the mill to provide temporary protection against staining by moisture other than by easily removed protective oils (see Appendix X1). For preparing surfaces of new or weathered items of zinc-coated steel produced by batch processing, refer to Practice D6386.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 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.
General Information
Relations
Standards Content (Sample)
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: D7396 − 14 (Reapproved 2020)
Standard Guide for
Preparation of New, Continuous Zinc-Coated (Galvanized)
Steel Surfaces for Painting
This standard is issued under the fixed designation D7396; 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.
1. Scope D6386 Practice for Preparation of Zinc (Hot-Dip Galva-
nized) Coated Iron and Steel Product and Hardware
1.1 This guide covers surface cleaning and various methods
Surfaces for Painting
for treating new, continuous zinc-coated (galvanized) steel
D6492 Practice for Detection of Hexavalent Chromium On
surfaces produced by either the hot-dip method or by electro-
Zinc and Zinc/Aluminum Alloy Coated Steel
plating.This guide is applicable to only surface preparation for
2.2 SSPC—The Society for Protective Coatings Standards:
application of liquid paint and coating products, and not for
Surface Preparation Specification No. 1 Solvent Cleaning
powder coating applications. This guide covers surfaces that
Surface Preparation Specification No. 2 Hand Tool Cleaning
have not been treated previously at the mill to provide
Surface Preparation Specification No. 3 Power Tool Clean-
temporaryprotectionagainststainingbymoistureotherthanby
ing
easily removed protective oils (see Appendix X1). For prepar-
Surface Preparation Specification No. 16 Brush-Off Blast
ing surfaces of new or weathered items of zinc-coated steel
Cleaning of Coated and Uncoated Galvanized Steel,
produced by batch processing, refer to Practice D6386.
Stainless Steel, and Non-Ferrous Metals
1.2 The values stated in SI units are to be regarded as the
Paint Specification No. 27 Basic Zinc Chromate-Vinyl Bu-
standard. The values given in parentheses are for information
tyral Wash Primer
only.
3. Summary of Guide
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 This guide describes surface cleaning and treatment
responsibility of the user of this standard to establish appro-
methods that provide galvanized surfaces suitable for painting,
priate safety, health, and environmental practices and deter-
specifically so that an applied coating system can develop the
mine the applicability of regulatory limitations prior to use.
adhesion necessary for satisfactory service life.
1.4 This international standard was developed in accor-
3.2 Eight methods of treatment (Note 1 and Note 2) are
dance with internationally recognized principles on standard-
covered as follows:
ization established in the Decision on Principles for the
3.2.1 Method A—Zinc Phosphate Treatment.
Development of International Standards, Guides and Recom-
3.2.2 Method B—Chromate Treatment.
mendations issued by the World Trade Organization Technical
3.2.3 Method C—Aqueous Chromic-Organic Treatment.
Barriers to Trade (TBT) Committee.
3.2.4 Method D—Acid-Curing Resinous Treatment.
3.2.5 Method E—Annealing Heat Treatments.
2. Referenced Documents
2 3.2.6 Method F—Amorphous Complex-Oxide Treatment.
2.1 ASTM Standards:
3.2.7 Method G—Abrasive Blast Cleaning.
A780 Practice for Repair of Damaged and Uncoated Areas
3.2.8 Method H—Fluro-Titanic/Zirconic Polymer Treat-
of Hot-Dip Galvanized Coatings
ment.
D4285 Test Method for Indicating Oil or Water in Com-
pressed Air NOTE 1—Materials employed in these methods of treatment are
available from a number of sources as proprietary compounds or methods.
Selection may be made from available sources.
This guide is under the jurisdiction of ASTM Committee D01 on Paint and
NOTE 2—The use of solvents containing volatile organic compounds to
Related Coatings, Materials, and Applications and is the direct responsibility of
prepare or treat the surface of metal components contributes to air
Subcommittee D01.46 on Industrial Protective Coatings.
pollution in the same manner as the use of solvent containing paints and
Current edition approved Feb. 1, 2020. Published February 2020. Originally
coatings. The user of this guide must determine the applicability of
approved in 2007. Last previous edition approved in 2014 as D7396 – 14. DOI:
appropriate regulations governing the volatile organic compound content
10.1520/D7396-14R20.
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 Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,
the ASTM website. Pittsburgh, PA 15222-4656, http://www.sspc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7396 − 14 (2020)
of the materials used in a shop application (Miscellaneous Metal Parts),
185°F). After cleaning, rinse thoroughly in hot water or water
field painting (Architectural), or specific process industry.
under pressure. Allow to dry completely before proceeding.
3.3 Variationsinsurfacepreparationproduceendconditions Whenever galvanized steel is rinsed, heated drying to acceler-
that differ and hence do not necessarily yield identical results atethecompleteremovalofwaterfromthesurfaceisdesirable.
when paints are subsequently applied. Service conditions will 3.6.2 Solvent Cleaning—Typical cleaning solvents, such as
dictate the type of surface preparation to be selected, although mineral spirits or high-flash naphtha, can be used to remove oil
the quality produced by any individual method may vary with and grease. The procedure to be used is as specified in SSPC
different zinc coatings. Surface Preparation Specification 1. Proper rags or brushes
shouldbeusedtowipethegalvanizedparts.(Warning—These
3.4 Galvanized surfaces are treated by using various meth-
rags or brushes should be cleaned or recycled often, since oil
ods and apparatus; satisfactory application may be made at the
can accumulate on their surfaces and be transferred back to the
following locations:
galvanized part. Small parts may be dipped or cleaned in
Mill Plant Field
ultrasonic baths of solvents.) After cleaning, rinse thoroughly
Method A Y Y Y
Method B Y Y . in hot water or water under pressure. Allow to dry completely
Method C Y Y .
before proceeding.Whenever galvanized steel is rinsed, heated
Method D Y Y Y
drying to accelerate the complete removal of water from the
Method E Y . .
Method F Y Y . surface is desirable.
Method G Y Y Y
3.6.3 Hand or Power Tool Cleaning—Hand or power tool
Method H Y Y .
cleaning may be used to clean light deposits of zinc reaction
3.5 This guide does not describe the cleaning necessary to
by-products, such as wet storage stain or salts, as specified in
provide a zinc-coated (galvanized) surface suitable for the
SSPC Surface Preparation Specification 2 or 3.
application of the treatments. Many cleaning methods are
4. Significance and Use
applicable and the preferred method should be agreed upon
between the purchaser and the supplier.
4.1 This guide describes procedures that can be used to
prepare new zinc-coated surfaces for painting and improve the
NOTE 3—Most producers of zinc-coated (galvanized) steel sheets and
bond of paint to the zinc surface.
coils have adopted the practice of applying an inhibitor to the zinc surface
to give temporary protection against staining by moisture during shipping
5. Processes
or storage. Some of these inhibitors interfere with proper reaction of most
ofthetreatmentsdescribedinthesemethods,andanunsatisfactorysurface
5.1 MethodA,ZincPhosphateTreatment—Thisconversion-
for painting results. It is strongly recommended that the purchaser consult
coating method consists of reacting the zinc surface in a zinc
thesupplierofthechemicaltreatmenttobeusedastothesuitabilityofthe
acid phosphate solution containing oxidizing agents and other
zinc surfaces for treatment by any of these methods.
salts for accelerating the coating action. The zinc surface is
3.6 Surface Cleaning—Galvanized surfaces must be clean
converted to a crystalline phosphate coating of the proper
and free of soluble salts, oil and grease before they are treated.
texture to inhibit corrosion and increase the adherence and
Adhesion problems have been experienced with newly galva-
durability of the paint film. Such treatments are recommended
nized articles that have been water quenched or treated with
for product finishes and may be carried out by immersion,
chromate conversion coatings. These two post-galvanizing
spray, or brush application.
processes, water quenching and chromate conversion coating,
are not recommended for galvanized articles that are to be 5.2 Method B, Chromate Treatment—This treatment con-
treat
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.