ASTM B630-88(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: B630 − 88 (Reapproved 2021)
Standard Practice for
Preparation of Chromium for Electroplating with Chromium
This standard is issued under the fixed designation B630; 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 4. Preparation of Surface
1.1 This practice is intended to serve as a process guide (not 4.1 Surface Finishing—The smoothness of the chromium
asastandardprocedure)forproducingadherentelectrodeposits coating before electroplating with chromium should closely
of chromium on chromium for engineering use. approximate the requirements of the finished part. It is usually
achieved by appropriate grinding with a diamond wheel.
1.2 Only well-known, generally practical methods using
hexavalent chromium plating baths have been included. Some 4.2 Stripping and Basis Metal—With previously electro-
of the newer proprietary chromium plating processes produce plated parts where the chromium deposit has been worn
chromium plating for which this process is unsuitable. Suppli- through, or where grinding has exposed the basis metal,
ers of the processes should be consulted. preferred results are obtained by stripping the remaining
chromium completely. However, it is possible to obtain satis-
1.3 The values stated in SI units are to be regarded as
factory deposits on such substrates by careful attention to
standard. No other units of measurement are included in this
details in the pretreatment and electroplating process steps.
standard.
4.3 Stripping may be done by several methods, including
1.4 This standard does not purport to address all of the
proprietary processes or inhibited hydrochloric acid solution
safety concerns, if any, associated with its use. It is the
(10 to 20 % by volume), or anodic treatment at 55 to 800A/m
responsibility of the user of this standard to establish appro-
(5 to 75 A/ft ) in a solution of 35 to 50 g/L (5 to 7 oz/gal) of
priate safety, health, and environmental practices and deter-
sodium hydroxide or 60 to 75 g/L (8 to 10 oz/gal) of sodium
mine the applicability of regulatory limitations prior to use.
carbonate at 20 to 25°C (70 to 80°F).
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4.4 Process Outline:
ization established in the Decision on Principles for the
4.4.1 Preclean (see 5.1.1 and 5.1.2),
Development of International Standards, Guides and Recom-
4.4.2 Alkaline electrolytic clean (see 5.1.3),
mendations issued by the World Trade Organization Technical
4.4.3 Rinse (cold water),
Barriers to Trade (TBT) Committee.
4.4.3.1 Rinse (hot water),
4.4.3.2 Dry,
2. Referenced Documents
4.4.3.3 Mask (see 5.2),
4.4.4 Activate (see 5.3),
2.1 ASTM Standards:
4.4.5 Chromium electroplate,
B177 Guide for Engineering Chromium Electroplating
4.4.6 Rinse (cold water),
3. Significance and Use
4.4.7 Rinse (hot water), and
4.4.8 Dry.
3.1 Electrodepositsofchromiumonchromiumareproduced
in cases where it is desired to obtain a better performing
5. Procedure
coating, to reclaim plated parts that are defective, or restore
5.1 Cleaning—The following cleaning treatments may be
worn chromium coatings to original dimensions.
used for all conditions and types of electrodeposited chro-
mium. The choice of the procedures will be governed largely
This practice is under the jurisdiction of ASTM Committee B08 on Metallic
by the condition of the surface.
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on
5.1.1 Precleaning—When considerable amounts of grease
Pre Treatment.
and oil are present on the surface, precleaning (emulsion or
Current edition approved Oct. 1, 2021. Published October 2021. Originally
alkaline spray or soak) is necessary to remove the bulk of the
approved in 1977. Last previous edition approved in 2017 as B630 – 88 (2017).
DOI: 10.1520/B0630-88R21.
soil.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1.2 Abrasive Cleaning—Oxide and other films may be
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
removedbymechanicaltechniquesusingsuchabrasivesasfine
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. emery on a cloth or a wheel, pumice slurry, or
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