ASTM C385-58(2022)

Standard Test Method for Thermal Shock Resistance of Porcelain-Enameled Utensils

ABSTRACT
This test method covers the determination of the resistance of porcelain-enameled utensils to thermal shock. A hot plate, timing device, container, and sponge shall be used. The surface temperature of the hot plate, determined by any suitable surface temperature measuring device, may be varied by changing the wattage input to the hot plate. If the hot plate surface temperature be calibrated to wattage input, the desired temperature may then be set by adjusting wattage input. The wattage input or similar calibration shall be made for each surface temperature. In preparation for the test, the hot plate shall be leveled and the surface temperature shall be adjusted to a certain level. Quenching water shall be placed in a large container and its temperature shall be adjusted to a certain level. The amount of water required to fill a test utensil to a certain depth shall be measured. A dry utensil shall be centered directly on the preheated hot plate. After a certain time, the utensil shall be removed from the hot plate and the utensil immediately shall be filled to some depth with quenching water. After a few seconds, the quenching water shall be poured out and the inside of the utensil shall be wiped with a wrung-out damp sponge. After some time, the utensil on the hot plate shall be replaced. Immediately after centering the utensil on the hot plate, the input to the hot plate shall be adjusted so that the hot plate surface temperature will reach a certain level. The utensil shall be allowed to heat dry for a few minutes with the hot plate adjusted so the new surface temperature will be reached. After a certain heating period, the utensil shall be removed. This procedure shall be repeated according to the schedule given. The test shall be continued until the utensil fails or has withstood quenching after a certain heating temperature.
SCOPE
1.1 This test method covers the determination of the resistance of porcelain-enameled utensils to thermal shock. This test method is adaptable to any porcelain-enamel utensil that can be filled with water to a depth of 1 in. (25 mm).  
1.2 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, health, and environmental 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2022
• ICS: 25.220.50 - Enamels
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.12 - Materials for Porcelain Enamel and Ceramic-Metal Systems

Overview

ASTM C385-58(2022): Standard Test Method for Thermal Shock Resistance of Porcelain-Enameled Utensils establishes procedures to determine how well porcelain-enameled utensils withstand rapid and repeated temperature changes. This widely recognized ASTM standard is essential for quality control and product durability evaluation in both manufacturing and laboratory environments. The method is suitable for any porcelain-enameled utensil capable of being filled with water to a depth of 1 inch (25 mm).

Thermal shock resistance is a crucial property that affects the longevity, safety, and usability of porcelain-enameled kitchenware. Failure to meet minimum resistance can result in cracking or enamel detachment, directly impacting product performance and consumer safety.

Key Topics

• Thermal Shock Resistance Testing:
  The standard details how to expose utensils to cycles of rapid heating followed by immediate quenching with water, simulating temperature changes experienced in actual use.

• Test Apparatus and Materials:

  • Hot plate with adjustable and calibrated surface temperature
  • Timing device for accurately controlling heat exposure
  • Containers for holding and applying quenching water
  • Sponge for cleaning the utensil after each cycle

• Test Procedure Highlights:

  • Utensils are heated on a pre-calibrated hot plate, then rapidly quenched with water to assess resistance
  • The process includes controlled heating cycles at incrementally higher temperatures, specified in a test schedule
  • Testing continues until failure (enamel detachment or cracking) or endurance through all cycles

• Rating and Results:

  • Results are reported based on the number of heating-quenching cycles each utensil passes without failure
  • An average value for five identical utensils provides a representative measure of product quality

• Safety Considerations:
  Users are responsible for following appropriate safety, health, and environmental practices when performing this test.

Applications

Implementing ASTM C385 delivers practical value to a range of stakeholders:

• Quality Assurance in Manufacturing:
  Ensures consistency and high thermal shock resistance in porcelain-enameled products, reducing the risk of premature failure.

• Product Development:
  Allows manufacturers to benchmark new formulations and production processes with standardized performance criteria.

• Supplier Evaluation:
  Assists buyers in comparing different suppliers or batches for compliance and reliability.

• Consumer Safety:
  Helps minimize risks associated with thermal failure in utensils, such as cracking or loss of enamel that could cause injury or contamination.

• Research and Material Testing:
  Serves as a foundation for laboratory studies on thermal durability and improvements in enamel technology.

Related Standards

For broader testing and evaluation of porcelain-enameled and ceramic-coated utensils, consider the following standards:

• ASTM C282: Standard Test Method for Tensile Strength of Porcelain Enamels
• ASTM C674: Standard Test Method for Flexural Properties of Ceramic Whitewares Materials
• ASTM C927: Standard Terminology of Glass and Glass Products

These standards, alongside ASTM C385, support robust quality control practices and material performance evaluations in the ceramic and porcelain-enamel industry.

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By adhering to ASTM C385-58(2022), manufacturers and quality professionals can ensure their porcelain-enameled utensils meet rigorous standards for thermal shock resistance, supporting safe, reliable, and long-lasting kitchenware.

Standards Content (Sample)

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.
Designation: C385 − 58 (Reapproved 2022)
Standard Test Method for
Thermal Shock Resistance of Porcelain-Enameled Utensils
This standard is issued under the fixed designation C385; 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 2.3 Container, suitable for holding approximately 4 gal of
water.
1.1 This test method covers the determination of the resis-
tance of porcelain-enameled utensils to thermal shock. This 2.4 Container, for pouring water into utensil.
test method is adaptable to any porcelain-enamel utensil that
2.5 Sponge, for wiping utensil dry.
can be filled with water to a depth of 1 in. (25 mm).
3. Quenching Water
1.2 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
3.1 Either tap or distilled water shall be used.
conversions to SI units that are provided for information only
NOTE 1—In areas where tap water is extremely hard, distilled water is
and are not considered standard.
recommended.
1.3 This standard does not purport to address all of the
4. Test Specimens
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 The test specimens shall consist of five identical uten-
priate safety, health, and environmental practices and deter-
sils.
mine the applicability of regulatory limitations prior to use.
NOTE 2—“Identical utensils” signifies utensils of the same size, shape,
1.4 This international standard was developed in accor-
and finish.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 5. Preparations for Test
Development of International Standards, Guides and Recom-
5.1 Level the hot plate. Switch on the hot plate and adjust
mendations issued by the World Trade Organization Technical
the surface temperature to 475 6 10 °F (245 6 5.5 °C).Allow
Barriers to Trade (TBT) Committee.
the hot plate to preheat at this temperature for at least1hto
obtain a uniform temperature over the entire heating surface.
2. Apparatus
5.2 Place the quenching water in a large container. Adjust
2.1 Hot Plate, capable of maintaining over its entire surface
the temperature of the water to 70 6 2 °F (21 6 1 °C). Mea-
a uniform temperature, that is, less than 20 °F (−6.7 °C)
sure out the amount of water required to fill a test utensil to a
variationovertheentiresurface.Surfacetemperatureofthehot
depth of 1 in. (25 mm); this amount of water shall be used for
plate shall be capable of being adjusted from 475 to
quenching.
825 6 10 °F (245 to 440 6 5.5 °C). The surface temperature
of the hot plate, determined by any suitable surface tempera- NOTE 3—The test utensils must be at room temperature at the start of
the test.
ture measuring device, may be varied by changing the wattage
input to the hot plate. If the hot plate surface temperature be
6. Procedure
calibrated to wattage input, the desired temperature may then
6.1 Center a dry utensil directly on the preheated hot plate.
be set by adjusting wattage input. The wattage input or similar
After 3 min remove the utensil from the hot plate and
calibration shall be made for each surface temperature (see 6.2
immediately fill the utensil to a depth of 1 in. (25 mm) with
and 6.3).
quenching water.After 10 s pour out the quenching water and
2.2 Timing Device, a clock or similar instrument having a
wipe the inside of the utensil with a wrung-out damp sponge.
sweep second hand and an integrating minute hand.
Afteratotalnonheatingperiodof20sreplacetheutensilonthe
hot plate.
6.2 Immediately after centering the utensil on the hot plate,
ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
adjust the input to the hot plate so that the hot plate surface
Materials for Porcelain Enamel and Ceramic-Metal Systems.
temperature will reach 500 6 10 °F (260 6 5.5 °C).Allow the
Cu
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