ASTM C374-70(2004)e1

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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e1
Designation:C 374–70(Reapproved2004)
Standard Test Methods for
Fusion Flow of Porcelain Enamel Frits (Flow-Button
Methods)
This standard is issued under the fixed designation C 374; 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.
e NOTE—Keywords were added editorially in September 2004.
1. Scope TEST METHOD A
1.1 These test methods cover evaluation of the relative
3. Apparatus
fusion flow characteristics of samples of a given porcelain
3.1 Mortar, of hard steel, resistant to abrasion by the
enamel frit by comparison with an established standard for that
porcelainenamelfrit,andconformingtothedimensionsshown
frit.
in Fig. 1.
1.2 Two test methods are included, differing only in certain
details of the samples and in the apparatus and procedure for
NOTE 1—Suitable mortars are available commercially under the desig-
preparation of test specimens. Both test methods give equally nation “tool steel crushing mortar.”
reproducible results and provide a satisfactory basis for com-
3.2 Sieves—No. 12 (1.70-mm) and No. 200 (75-µm) sieves
parisonoffusionflowofthesamplewiththatoftheestablished
conforming to Specification E 11.
standard.
NOTE 2—Tyler Standard Series sieves No. 12 (0.0060-in. (0.152-mm)
1.2.1 Test Method A employs granular particles of frit to
openings) and No. 200 (0.029-in. (0.07-mm) openings) correspond to
which a bonding agent has been added. Button specimens are
ASTM sieves Nos. 12 and 200 (U.S. Standard Sieves series numbers).
formed under high pressure in a hydraulic press.
3.3 Hydraulic Press, capable of developing 3500-lbf
1.2.2 Test Method B employs crushed, sized particles of frit
(15 600 N) force (Fig. 2).
to which a bonding agent has been added. Button specimens
3.4 Steel Mold Assembly, consisting of a die and plunger,
are formed in a steel mold by hand.
and having an inside diameter of ⁄2 in. (12.7 mm) over its
1.3 This standard does not purport to address all of the
length of 2 ⁄8 in. (54 mm) as illustrated in Fig. 3.
safety concerns, if any, associated with its use. It is the
3.5 Fusion Flow Rack, preferably constructed of heat-
responsibility of the user of this standard to establish appro-
resisting alloy and conforming to the detailed requirements
priate safety and health practices and determine the applica-
shown in Fig. 4.
bility of regulatory limitations prior to use.
4. Sample
2. Referenced Document
4.1 A representative sample of the frit to be tested shall be
2.1 ASTM Standards:
obtained, mixed thoroughly, and reduced by quartering to
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
about 25 g. This sample shall be crushed in a hard steel mortar
poses
to pass a No. 12 (1.70-mm) sieve and be retained on a No. 200
(75-µm) sieve.
These test methods are under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and are the direct responsibility of Subcommittee
5. Test Specimen
B08.12 on Materials for Porcelain Enamel and Ceramic-Metal Systems.
5.1 Weigh 3.5 6 0.05-g samples of the standard frit and of
Current edition approved Aug. 1, 2004. Published September 2004. Originally
approved in 1955. Last previous edition approved in 1998 as C 374 – 70 (1998).
the material to be tested and thoroughly mix each of these
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
samples with 4 or 5 drops of a 1 % gum arabic solution. Mold
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
fusion button test specimens of the standard and of the sample
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. as directed in 5.2.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C 374–70 (2004)
the groundcoat plate shall have a median firing temperature no
morethan50°F(28°C)belowthemedianfiringtemperaturefor
the most refractory frit being tested. Place the groundcoat plate
with fusion buttons in place in a horizontal position on the
fusion flow rack, which shall previously have been heated to
furnace temperature, and place the entire test assembly in the
furnace immediately.
6.2 Firing—Fire in a furnace in which the atmosphere is
oxidizingandentirelyfreeofanyproductsofcombustion.Heat
distribution within the furnace shall be such that no portion of
the fusion buttons will vary more than 65°F (63°C) from any
other button or portion thereof. The temperature shall approxi-
mate the median firing temperature for the standard that is used
as a basis for comparison. Allow the buttons to remain in the
horizontal position (Fig. 5(a)) until such time as fusion of the
NOTE—1 in. = 25.4 mm.
buttons is evident from the rounded appearance of the tops of
FIG. 1 Mortar
the buttons. Then release the groundcoat plate to the vertical
position (Fig. 5(b)) and allow the fusion buttons to flow a
minimumof50mm,followingwhichremovethetestassembly
from the furnace and allow the buttons to cool. When the flow
is completed, the sides of the fusion buttons should be
approximately parallel; that is, there should be no excessive
spreading of the fusion buttons in the horizontal position,
indicating that the buttons were allowed to remain in the
horizontal position for too long a time.
6.3 Measuring Flow—Measure the greatest length of the
fusion flow to the nearest 1 mm for each fusion button,
including the standard.
7. Report
7.1 Report the length of the fusion flow for each test
specimenincomparisonwiththestandardrunatthesametime.
For example, if a given specimen flows 50 mm agai
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