ASTM B630-88(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B630–88(Reapproved 2006)
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 factory deposits on such substrates by careful attention to
details in the pretreatment and electroplating process steps.
1.1 This practice is intended to serve as a process guide (not
4.3 Stripping may be done by several methods, including
asastandardprocedure)forproducingadherentelectrodeposits
proprietary processes or inhibited hydrochloric acid solution
of chromium on chromium for engineering use.
(10 to 20 % by volume), or anodic treatment at 55 to 800A/m
1.2 Only well-known, generally practical methods using
(5 to 75 A/ft ) in a solution of 35 to 50 g/L (5 to 7 oz/gal) of
hexavalent chromium plating baths have been included. Some
sodium hydroxide or 60 to 75 g/L (8 to 10 oz/gal) of sodium
of the newer proprietary chromium plating processes produce
carbonate at 20 to 25°C (70 to 80°F).
chromium plating for which this process is unsuitable. Suppli-
4.4 Process Outline:
ers of the processes should be consulted.
4.4.1 Preclean (see 5.1.1 and 5.1.2),
1.3 This standard does not purport to address all of the
4.4.2 Alkaline electrolytic clean (see 5.1.3),
safety concerns, if any, associated with its use. It is the
4.4.3 Rinse (cold water),
responsibility of the user of this standard to establish appro-
4.4.3.1 Rinse (hot water),
priate safety and health practices and determine the applica-
4.4.3.2 Dry,
bility of regulatory limitations prior to use.
4.4.3.3 Mask (see 5.2),
2. Referenced Documents
4.4.4 Activate (see 5.3),
4.4.5 Chromium electroplate,
2.1 ASTM Standards:
4.4.6 Rinse (cold water),
B177 Guide for Engineering Chromium Electroplating
4.4.7 Rinse (hot water), and
3. Significance and Use
4.4.8 Dry.
3.1 Electrodepositsofchromiumonchromiumareproduced
5. Procedure
in cases where it is desired to obtain a better performing
5.1 Cleaning—The following cleaning treatments may be
coating, to reclaim plated parts that are defective, or restore
used for all conditions and types of electrodeposited chro-
worn chromium coatings to original dimensions.
mium. The choice of the procedures will be governed largely
4. Preparation of Surface
by the condition of the surface.
5.1.1 Precleaning—When considerable amounts of grease
4.1 Surface Finishing—The smoothness of the chromium
and oil are present on the surface, precleaning (emulsion or
coating before electroplating with chromium should closely
alkaline spray or soak) is necessary to remove the bulk of the
approximate the requirements of the finished part. It is usually
soil.
achieved by appropriate grinding with a diamond wheel.
5.1.2 Abrasive Cleaning—Oxide and other films may be
4.2 Stripping and Basis Metal—With previously electro-
removedbymechanicaltechniquesusingsuchabrasivesasfine
plated parts where the chromium deposit has been worn
emery on a cloth or a wheel, pumice slurry, or greaseless
through, or where grinding has exposed the basis metal,
buffing compounds. Grit blasting, shot blasting, wet blasting,
preferred results are obtained by stripping the remaining
or vapor honing may also be used. Abrasive cleaning is
chromium completely. However, it is possible to obtain satis-
generally not necessary when suitable mechanical finishing
procedures have been used.
This practice is under the jurisdiction of ASTM Committee B08 on Metallic
5.1.3 Cathodic Alkaline Cleaning—Removal of final traces
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on
of dirt, grease, and oil is best accomplished by cathodic
Pre Treatment.
Current edition approved April 1, 2006. Published April 2006. Originally alkaline cleaning. Cathodic electrocleaning is necessary be-
approved in 1977. Last previous edition approved in 2001 as B630 – 88 (2001).
cause anodic electrocleaning will strip chromium and may
DOI: 10.1520/B0630-88R06.
expose the basis me
...