ASTM C703-72(1999)

Standard Test Methods for Spalling Resistance of Porcelain Enameled Aluminum

SCOPE
1.1 These test methods cover accelerated determination of the resistance of porcelain enamel coatings on aluminum alloys to spalling from exposure to moisture or weathering. Method A,  using a 5% solution of ammonium chloride, requires 96-h immersion while Method B,  using a 1% solution of antimony trichloride, is completed after 20 h of immersion. The spalling tendency is evaluated by the same criteria in both methods. While either method is suitable for magnesium silicon alloys, such as 6061, Method B is preferred for simple alloys or commercially pure aluminum, such as 1100.  
1.2 The methods appear in the following order:  Sections Method A---Ammonium Chloride 4 to 9 Method B---Antimony Trichloride 10 to 15

General Information

• Status: Historical
• Publication Date: 09-Mar-1999
• ICS: 25.220.50 - Enamels
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.12 - Materials for Porcelain Enamel and Ceramic-Metal Systems

Relations

• Replaced By: ASTM C703-72(2006) - Standard Test Methods for Spalling Resistance of Porcelain Enameled Aluminum
• Effective Date: 01-Apr-2006

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:C703–72(Reapproved1999)
Standard Test Methods for
Spalling Resistance of Porcelain Enameled Aluminum
This standard is issued under the fixed designation C 703; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope mL of solution per square centimetre of the immersed surface.
No metal other than the base metal of the specimen may be
1.1 These test methods cover accelerated determination of
exposed to the test solution.
theresistanceofporcelainenamelcoatingsonaluminumalloys
to spalling from exposure to moisture or weathering. Test
5. Reagent
Method A, using a 5 % solution of ammonium chloride,
3 5.1 Ammonium Chloride Solution (5 %)—The test solution,
requires 96-h immersion while Test Method B, using a 1 %
freshly prepared, shall consist of 5 parts, by mass, of ammo-
solution of antimony trichloride, is completed after 20 h of
nium chloride (NH Cl) (technical grade is adequate) dissolved
immersion. The spalling tendency is evaluated by the same
in 95 parts, by mass, of water. Deionized or distilled water is
criteria in both methods. While either method is suitable for
preferred, but in the case of very large production pieces, tap
magnesium silicon alloys, such as 6061, Test Method B is
water may be used. Sufficient solution shall be prepared to
preferred for simple alloys or commercially pure aluminum,
permit complete immersion of the specimens.
such as 1100.
1.2 The test methods appear in the following order:
6. Test Specimens
Sections
6.1 Full-size production pieces should be tested. When this
Test MethodA—Ammonium Chloride 4-9
Test Method B—Antimony Trichloride 10-15
is not practical, specimens approximately 4 by 6 in. (102 by
152 mm), cut from production parts should be tested. At least
2. Terminology
one representative specimen from each “job” or each 1000 ft
2.1 Definitions:
(93 m ) of production, whichever is applicable, should be spall
2.1.1 spalling—a defect characterized by separation of the
tested. Spall-tested pieces should not be shipped.
porcelain enamel from the aluminum base metal without
6.2 Test production parts in as-produced condition.
apparent external cause. Spalling can result from the use of
improper alloys or enamel formulations, incorrect pretreatment 7. Procedure
of the base metal, or faulty application and firing procedures.
7.1 Immerse the test specimens completely in the NH Cl
solution at room temperature. Large production pieces may be
3. Significance
immersed in a container made by lining a packing box with
3.1 It is difficult to overemphasize the importance of the
polyethylene plastic sheeting.
spall test. Porcelain enameled aluminum that fails this test will
7.2 Make a visual inspection after 96 h of immersion.
probably spall in service if subjected to moisture or weather-
NOTE 1—Variations of this test may be used for studies of processing
ing.
variables.These include scored or deformed samples, 24 h inspection, and
multiple cycles of 96 h each.
TEST METHOD A—AMMONIUM CHLORIDE
8. Evaluation
4. Apparatus
8.1 Any of the following types of spall that develop within
4.1 Container, glass or plastic, large enough to immerse the
96 h shall constitute failure:
test area of the specimen completely and hold a minimum of 3
8.1.1 Any spall area (revealing bare metal) extending ⁄8 in.
(3 mm), or more, in from an edge and more than 1 in. (25 mm)
These test methods are under the jurisdiction of ASTM Committee B-8 on in length,
Metallic and Inorganic Coatings and are the direct responsibility of Subcommittee
8.1.2 Any spall area on the interior surface (not touching an
B08.12 on Materials for Porcelain Enamel and Ceramic-Metal Systems.
edge) that is more than ⁄8 in. (3 mm) to its maximum
Current edition approved April 3, 1972. Published May 1972.
dimension, or
Method A is based on Bulletin AL-1a, Recommended Test Methods for
2 2
Evaluation and Control of Quality of Porcelain Enamel on Aluminum ,ofthe
8.1.3 Morethansixvisiblespallspotsper1ft (929cm )on
Porcelain Enamel Institute.
the interior surface.
Method B is based on Bulletin T-51, Antimony Trichloride Spall Test of
Porcelain Enameled Aluminum, of the Porcelain Enamel Institute.
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C703
9. Report 13. Procedure
13.1 Immerse as much of the test specimen as practical in
9.1 The report shall include the following:
the SbCl solution at room temperature. If a sample has been
9.1.1 Evaluation of the specimen as passing or failing the
bent over a mandrel, the bent portion must be immersed in the
immersion test in 96 h,
solution.
9.1.2 Complete identification of the specimen, including the
13.2 After 20 h of immersion, rinse the sample in water and
basis metal, metal pretreatment, enamel slip formulation, firing
scrub with a spong
...