TT-C-490E
July 22, 2002 __
SUPERSEDING
TT-C-490D
March 31, 1993
FEDERAL SPECIFICATION
CHEMICAL CONVERSION COATINGS AND PRETREATMENTS
FOR FERROUS SURFACES (BASE FOR ORGANIC COATINGS)
This specification was approved by the Assistant Administrator
Office of Federal Supply and Services, General Services
Administration, for the use by all Federal Agencies.
1. SCOPE AND CLASSIFICATION
1.1 Scope. This specification covers cleaning, surface conditioning for crystal refinement and pretreatment
by chemical conversion of ferrous metals and zinc/zinc alloy coated metals. The application of chemical
conversion and pretreatment coatings provides uniformly textured substrates for receiving and retaining
paint, lacquer, etc. In addition, this specification covers suitable cleaning processes for nonferrous surfaces
(see 6.1, 6.1.2).
1.2 Classification. This specification covers the following cleaning methods and surface preparation
processes:
1.2.1 Surface cleaning. Surface cleaning should be by any of the following methods as specified (see 6.4):
Method I Mechanical or abrasive cleaning.
Method II Solvent cleaning by immersion, spray or vapor.
Method III Hot alkaline cleaning by immersion, spray or electrolytic methods.
Method IV Emulsion with or without added water.
Method V Alkaline derusting.
Method VI Phosphoric acid (alcohol, detergent or solvent type with detergent).
1.2.1.1 Ozone depleting chemicals. The cleaning material should not contain any chemical, which is
classified in the Clean Air Act Amendments of 1990 as a Class I or Class II ozone depleting substance.
1.2.2 Conversion coatings and pretreatments. Chemical conversion and pretreatment coatings should be of
the following types as specified (see 6.4).
Type I Zinc phosphate spray application (150 mg/ft
2
min - 500 mg/ft
2
max)
Zinc phosphate immersion or dip application (300 mg/ft
2
min - 500 mg/ft
2
max)
Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in
improving this document should be addressed to: Director, U.S. Army Research Laboratory, Weapons and
Materials Research Directorate, ATTN: AMSRL-WM-M, Aberdeen Proving Ground, MD 21005-5069 by
using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this
document or by letter.
AMSC N/A AREA MFFP
INCH-POUND
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