ASTM B915-22

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Designation: B915 − 01 (Reapproved 2017) B915 − 22
Standard Test Method for
Measuring Static Heat Resistance of Self-Cleaning Oven
Coating
This standard is issued under the fixed designation B915; 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
The purpose of this test is to qualitatively and quantitatively determine the resistance of a porcelain
enamel to thermal conditions encountered in pyrolytic self-cleaning oven in an accelerated laboratory
evaluation.
1. Scope
1.1 This test method covers the procedure for the qualitative and quantitative evaluation of static heat effects on porcelain enamel
coatings.
1.2 This test method is adaptable to various temperatures and times, since the requirements in the porcelain enameling industry
differ between manufacturers.
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. Referenced Documents
2.1 ASTM Standards:
D523 Test Method for Specular Gloss
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 blistering, n—a defect caused by gas evolution consisting of a bubble that protrudes on the surface of the glass.
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, 2017May 1, 2022. Published May 2017May 2022. Originally approved in 2001. Last previous edition approved in 20132017 as B915 – 01
ɛ1
(2013) .(2017). DOI: 10.1520/B0915-01R17.10.1520/B0915-22.
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B915 − 22
3.1.2 color and gloss change, n—this is determined by the color and gloss delta values calculated between each heat test cycle.
3.1.3 copper heads/stickers, n—protrusions of iron oxide crystals permeated from the steel substrate or conglomerated metal
components in the enamel.
3.1.4 crazing, n—a defect appearing as one or more fine cracks in the porcelain enamel from thermal contraction and expansion
in the glass.
3.1.5 edge burn off, n—this may occur in the first 24 to 72 h and appears as a thin dull discolored gray line around the entire edge
of the test plate.
3.1.6 enamel breakdown, n—the point at which the glass composite has disintegrated. Microscopic examination will show loss of
enamel bubble structure and devitrification of the enamel. This stage reveals metallic type elements derived from the glass
composition and the iron oxide from the steel substrate that has completely permeated the glass.
3.1.7 hazy appearance/scumming, adj—the glass will develop an opaque film that exhibits low gloss on the surface of the
porcelain enamel.
3.1.8 metalizing, n—enamel on test plates will have a reflective copper color from condensed metals in the enamel that may
increase with the deterioration of the glass during the heat test cycle.
4. Significance and Use
4.1 This test method is intended for testing the porcelain enamel finish on oven parts of self-cleaning ranges.
4.2 The numerical values and visual evaluation derived by this test method are used to measure differences in heat resistant
characteristics between enamel formulas intended to meet oven manufacturer specifications.
5. Apparatus
5.1 Furnace, capable of holding a constant temperature of 920°F (493°C)920 °F (493 °C) minimum.
5.2 Standing Bracket, approximately 10 by 10 by 6 in. 6 in. (25.4 by 25.4 by 15.24 cm). 15.24 cm). Dimensions may vary
according to test plate size.
5.3 Two Heavy-Gauge Steel Rods, approximately 12 in. (30.48 cm) 12 in. (30.48 cm) long and ⁄8 in. (0.32 cm) in. (0.32 cm) in
diameter.
3 3
5.4 Standard Size ⁄8-16 or ⁄8-24 (0.96-cm) in. (0.96 cm) Nuts, used for spacers between heat test plates.
5.5 Spectrocolorimeter, Spectrocolorimeter—capable of reading color by reflection of enameled plates on reflectance 45°/0° and
L*, a*, b* color space.Equipment available for making color readings is an instrument that reads Spectrocolorimeter on the L, a,
b scale such as Macbeth Color Eye or a Hunter Lab ColorQUEST.to calculate a color difference per subsection 6.2.3 of Practice
D2244.
5.6 Gloss Meter, capable of reading 60° ASTM gloss measurements (see Test Method D523).
6. Procedure
1 1
6.1 Punched holes are located ⁄4 in. (0.63 cm) in. (0.63 cm) down from the top and ⁄2 in. (1.2 cm) in. (1.2 cm) from the right
3 3
and left sides on a 5 ⁄8- by 5 ⁄8-in. (13.65- in. (13.65 by 13.65-cm)13.65 cm) uncoated metal plate.
60° ASTM gloss measurements: “The 60° optical head reads the angles of incidence (i) and view (v) are 60° as measured from perpendicular to the specimen.”
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6.2 The metal plate is processed in the enamel formula that is to be subjected to static heat testing.
6.3 Before placing the test plate on heat test, initial color (L, a, b) and gloss (60°) readings are recorded, dated, and established
as 0 h.0 h.
6.4 The enameled plate should be clean and free of any fingerprints or smudges. To clean a soiled plate, a lint-free paper towel
dampened with alcohol is rubbed back and forth on the surface until plate is clean. To prevent further smudging, handle test plates
on the edges.
6.5 A steel rod is passed through each hole of the test plate. The test plates are suspended across the top of the standing bracket
by the steel rods.
6.6 If more than one test plate is required, a spacer is placed on the rods between each test plate. This allows a ⁄4-in. (0.63-cm) in.
(0.63 cm) space between each test plate. Approximately
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