ASTM C614-20

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C614 − 10 (Reapproved 2015) C614 − 20
Standard Test Method for
Alkali Resistance of Porcelain Enamels
This standard is issued under the fixed designation C614; 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.
INTRODUCTION
Although all porcelain enamels are highly resistant to attack by cold alkaline solutions, some
compositions are affected by hot solutions of the type encountered in automatic laundry and
dishwashing equipment. Tests to eliminate porcelain enamels of poor resistance have been developed
and used by various laboratories. In general, these tests consist of subjecting specimens to a boiling
solution of either sodium pyrophosphate or sodium hydroxide for a period of two or more hours. The
specimens are weighed before and after exposure to the test treatment and the loss-in-weight is taken
as a measure of alkali attack. In some tests representing milder exposure conditions, the 45 degree
specular gloss is measured before and after exposure, and the percentage of initial gloss retained is
used as an indicator of alkali resistance. While such tests have served a useful purpose in developing
more resistant porcelain enamel compositions and in manufacturing control operations, agreement
between laboratories has left something to be desired. The present test was designed to provide the
reproducibility between laboratories that is so essential to any standard test procedure.
1. Scope
1.1 This test method covers the measurement of the resistance of a porcelain enamel to a hot solution of tetrasodium
pyrophosphate. Although the specific alkali mentioned herein is tetrasodium pyrophosphate, the equipment and techniques are
equally applicable to other alkali solutions.
1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
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 safety, health, and healthenvironmental 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.
2. Significance and Use
2.1 This test method is intended specifically for testing the resistance to alkaline attack of porcelain enamels to be used as a final
This test method is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
Materials for Porcelain Enamel and Ceramic-Metal Systems.
Current edition approved May 1, 2015Nov. 1, 2020. Published May 2015December 2020. Originally approved in 1968. Last previous edition approved in 20112015 as
C614 – 10(2011).(2015). DOI: 10.1520/C0614-10R15.10.1520/C0614-20.
This test was developed at the National Bureau of Standards under the sponsorship of The Porcelain Enamel Institute, Inc., and published as P. E. I. Bulletin T-25.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C614 − 20
finish on washing machines, dishwashers, combination washer-dryers, and similar appliances where the surface is normally
exposed to an alkaline environment at elevated temperatures.
3. Apparatus
3.1 Test Chamber, of a type illustrated in Fig. 1, Fig. 3, and Fig. 6. This part of the equipment consists of a stainless steel beaker
fitted with an O-ring sealed cover which supports an immersion heater, a stirring device, thermometer and thermistor wells; three
specimen holders; a reflux condenser; a flow channeling shield to slide over and be supported by the immersion heater; and a
stirring motor. The beaker, heater sheath, stirring device, thermometer and thermistor wells, specimen holders, and the flow
channeling shield shall be made from stainless steel alloys from the AISI 300 Series.
3.2 Temperature Controller, thermistor-actuated, capable of maintaining the temperature of the alkali solution in the beaker at
96.00 6 0.20°C.0.20 °C.
3.3 Thermometer, calibrated, approximately 15 in. (380 mm) (380 mm) long and ⁄32 in. (7.1 mm) in diameter, with 0.1° divisions.
3.4 Drying Oven, electrically heated.
3.5 Balance, having a sensitivity of 0.1 mg and a capacity of not less than 200 g.
3.6 Desiccator.
3.7 Hot Plate, or burner suitable for heating the test solution.
3.8 Sponge, soft, cellulose.
1 1 1
3.9 Aluminum Alloy Sheets, approximately 3 ⁄2 by 3 ⁄2 by ⁄8 in. in. (89 by 89 by 3.1 mm).3.1 mm).
NOTE 1—Test solution is in stainless steel beaker.
FIG. 1 Alkali Equipment in Operation
See the appendix for drawings of the equipment. This equipment may be purchased from the Hoover Instrument Service, Inc., 401 N. Home Rd., Mansfield, OH 44906.
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Dimension in. mm
A 9 229
B ⁄4 6.4
C—Thermistor well ⁄32 8.7 OD
8 ⁄8 206 length
D—Thermometer well ⁄8 9.2 OD
8 ⁄8 206 length
E ⁄2 12.7
F 1 ⁄2 38.0
G—Heater chuck ⁄8 15.9
H 1 ⁄4 32.0
I 1 ⁄32 39.0
J 1 ⁄8 41.5
K ⁄8 22.2
L 3 ⁄8 98
M 1 ⁄32 37.5
N 2 ⁄8 54
FIG. 2 Cover for Alkali Equipment
4. Reagents and Materials
4.1 Tetrasodium Pyrophosphate, hydrated (Na P O ·
4 2 7
10H O), recrystallized, reagent grade.
4.2 Trisodium Phosphate (Na PO ·12H O).
3 4 2
5. Test Specimens
5.1 Preparation of Specimens—The test specimens shall be 3 ⁄2 in. (89 mm) square and may be prepared by enameling metal
blanks of that size or by cutting from a larger piece. Hanging holes, if necessary for firing or weighing, or both, may be placed
at the corners. The specimens shall be sufficiently flat to permit sealing in the holders. The edges of cut specimens shall be stoned
or filed to remove any sharp or loosely adhering fragments of metal or porcelain enamel. It is recommended that the specimens
be permanently marked on the back side for identification.
5.2 Number of Specimens—Six specimens shall be tested simultaneously.
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A— Empty specimen holder in position.
B— Immersion heater.
C— Thermometer well.
D— Thermistor well.
E— Stirrer.
F— Circular shield (lowered for clarity).
FIG. 3 Cover Assembly
5.3 Cleaning of Specimens Before Alkali Exposure —Exposure—The specimens shall be rinsed with running tap water and washed
with a soft cellulose sponge dampened with a 1 % solution of trisodium phosphate. A light pressure and a back-and-forth motion
in two directions, 90° apart, shall be used in the washing. After washing, the specimens shall be rinsed first with running tap water,
next with distilled water, and then allowed to drain in a near vertical position prior to oven-drying at 110°C110 °C for 15 min. The
specimens shall be cooled in a desiccator for 30 min 30 min prior to weighing.
5.4 Weighing of Test Specimens—The specimens shall be weighed immediately upon removal from the desiccator. Weights shall
be recorded to 0.0001 g. The
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