1、Designation: C374 14Standard Test Methods forFusion Flow of Porcelain Enamel Frits (Flow-ButtonMethods)1This standard is issued under the fixed designation C374; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis test provides a procedure to compare the fluidity of a glass frit or a porcelain enamel powderto a standard reference mate
3、rial at a fixed temperature above the samples glass temperature.1. Scope1.1 These test methods cover evaluation of the relativefusion flow characteristics of samples of a given porcelainenamel frit by comparison with an established standard for thatfrit.1.2 Two test methods are included, differing o
4、nly in certaindetails of the samples and in the apparatus and procedure forpreparation of test specimens. Both test methods give equallyreproducible results and provide a satisfactory basis for com-parison of fusion flow of the sample with that of the establishedstandard.1.2.1 Test Method A employs
5、granular particles of frit towhich a bonding agent has been added. Button specimens areformed under high pressure in a hydraulic press.1.2.2 Test Method B employs crushed, sized particles of fritto which a bonding agent has been added. Button specimensare formed in a steel mold by hand.1.3 The value
6、s stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with i
7、ts use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Document2.1 ASTM Standards:2E11 Specification for Woven Wire Test Sieve Cloth and TestSievesTEST ME
8、THOD A3. Apparatus3.1 Mortar, of hard steel, resistant to abrasion by theporcelain enamel frit, and conforming to the dimensions shownin Fig. 1.NOTE 1Suitable mortars are available commercially under the desig-nation “tool steel crushing mortar.”3.2 SievesNo. 12 (1.70-mm) and No. 200 (75-m) sievesco
9、nforming to Specification E11.NOTE 2Tyler Standard Series sieves No. 12 (0.0060-in. (0.152-mm)openings) and No. 200 (0.029-in. (0.07-mm) openings) correspond toASTM sieves Nos. 12 and 200 (U.S. Standard Sieves series numbers).3.3 Hydraulic Press, capable of developing 3500-lbf(15 600 N) force (Fig.
10、2).3.4 Steel Mold Assembly, consisting of a die and plunger,and having an inside diameter of12 in. (12.7 mm) over itslength of 218 in. (54 mm) as illustrated in Fig. 3.3.5 Fusion Flow Rack, preferably constructed of heat-resisting alloy and conforming to the detailed requirementsshown in Fig. 4.1The
11、se test methods are under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and are the direct responsibility of SubcommitteeB08.12 on Materials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved May 1, 2014. Published June 2014. Originallyapproved in 1955
12、. Last previous edition approved in 2009 as C374 70 (2009)1.DOI: 10.1520/C0374-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary pag
13、e onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Sample4.1 A representative sample of the frit to be tested shall beobtained, mixed thoroughly, and reduced by quartering toabout 25 g. This sample shall be crushe
14、d in a hard steel mortarto pass a No. 12 (1.70 mm) sieve and be retained on a No. 200(75 m) sieve.4.2 For wet-ground enamels the sample shall be evaporatedto dryness in an evaporation dish. After cooling, the driedenamel shall be loosened and again pulverized using a pestleand mortar or similar appa
15、ratus.4.3 Dry ground samples of frit, ready-to-use powder, orenamel powder for dry electrostatic application may also betested.5. Test Specimen5.1 Weigh 3.5 6 0.05-g samples of the standard frit and ofthe material to be tested and thoroughly mix each of thesesamples with four or five drops of a 1 %
16、gum arabic solution.Mold fusion button test specimens of the standard and of thesample as directed in 5.2. For dry electrostatic powder samples,use four to five drops of acetone instead of the aqueous gumarabic solution.5.2 Place the sample in the steel mold. Place the moldassembly containing the sa
17、mple in a hydraulic press and bringthe press up to 3000 to 3500 lbf (13.3 to 15.6 kN) total load,and immediately release (Fig. 2). Force the formed button outof the mold with the plunger, taking care not to damage thebutton in any way that might change the dimensions.5.3 Dry the test specimens in a
18、suitable oven at 212F(100C) for 1 h.NOTE 3Special care must be exercised in drying buttons formed bythis method, before firing, in order to prevent bloating and possibleeruption of the button when first placed in the furnace.6. Procedure6.1 MountingPlace the dried fusion buttons on a firedgroundcoat
19、 plate. The location of the test specimens withrespect to the standard may be modified as desired. Althoughthe gage of metal used for the ground-coated plate is not ofcritical importance, most satisfactory results will be obtainedwhen the metal is not heavier than 18 gage nor lighter than 22gage (1.
20、02 to 0.044 mm). Use the same gage of metalconsistently from test to test in order to reduce the number ofvariables to a minimum. The groundcoat enamel used to coatthe groundcoat plate shall have a median firing temperature nomore than 50F (28C) below the median firing temperature forthe most refrac
21、tory frit being tested. Place the groundcoat platewith fusion buttons in place in a horizontal position on thefusion flow rack, which shall previously have been heated tofurnace temperature, and place the entire test assembly in thefurnace immediately.6.2 FiringFire in a furnace in which the atmosph
22、ere isoxidizing and entirely free of any products of combustion. Heatdistribution within the furnace shall be such that no portion ofthe fusion buttons will vary more than 65F (63C) from anyother button or portion thereof. The temperature shall approxi-mate the median firing temperature for the stan
23、dard that is usedas a basis for comparison. Predetermine, by one or morepre-tests, the holding time, i. e. the time required from placingthe fusion buttons in the furnace in the horizontal position (Fig.5(a) until such time as fusion of the buttons is evident from therounded appearance of the tops o
24、f the buttons. For all tests ofthe same materials, the fusion buttons shall remain in thehorizontal position for the predetermined holding time. At theend of the holding time, release the groundcoat plate to thevertical position (Fig. 5(b) and allow the fusion buttons toflow a minimum of 50 mm, foll
25、owing which remove the testassembly from the furnace and allow the buttons to cool. Whenthe flow is completed, the sides of the fusion buttons should beapproximately parallel; that is, there should be no excessivespreading of the fusion buttons in the horizontal position,indicating that the buttons
26、were allowed to remain in thehorizontal position for too long a time.6.3 Measuring FlowMeasure the greatest length of thefusion flow to the nearest 1 mm for each fusion button,including the standard.NOTE 11 in. = 25.4 mm.FIG. 1 MortarFIG. 2 Hydraulic PressC374 1427. Report7.1 Report the length of th
27、e fusion flow for each testspecimen in comparison with the standard run at the same time.For example, if a given specimen flows 50 mm against a flowfor the standard of 55 mm, the results shall be reported as“50/55 mm.” If the width of the test specimen is observed tovary more than 10 % from the widt
28、h of the standard, length-times-width values shall be calculated for the comparison.TEST METHOD B8. Apparatus8.1 MortarSee 3.1.8.2 SievesNo. 60 (250 m) and No. 200 (75 m) sievesconforming to Specification E11.NOTE 4Tyler Standard Series sieves No. 60 (0.0097 in. openings) andNo. 200 (0.0029 in. open
29、ings) correspond to ASTM sieves Nos. 60 and200 (U.S. Standard Sieve series numbers).8.3 Steel Mold Assembly, consisting of a die, plunger, andbackup disk as shown in Fig. 6. The inside diameter of themold shall be12 in. (12.7 mm) over its length of 114 in. (31.8mm).8.4 Fusion Flow RackSee 3.5.9. Sam
30、ple9.1 A representative sample of the frit to be tested shall beobtained, mixed thoroughly, and reduced by quartering toNOTE 1Metric Equivalentin. mm in. mm0.010 0.0338 9.5 134 44.01332 10.3 218 54.012 12.7 212 63.5FIG. 3 Mold for Test SpecimensTest Method AC374 143about 25 g. This sample shall be c
31、rushed by impact in a hardsteel mortar to pass a No. 60 (250 m) sieve and be retained ona No. 200 (75 m) sieve. In order to avoid the excessivereduction of fines, they shall be removed frequently during theprocess of reduction by throwing the sample on the sieve andNOTE 1in. = 25.4 mm.FIG. 4 Fusion
32、Flow RackNOTE 1(a) Fusion Buttons in Horizontal Position (b) Fusion Buttons in Vertical PositionFIG. 5 Fusion Test AssemblyC374 144continuing the crushing of the coarser particles until all thesample passes through the sieve.9.2 For wet-ground enamels the sample shall be evaporatedto dryness in an e
33、vaporation dish. After cooling, the driedenamel shall be loosened and again pulverized using a pestleand mortar or similar apparatus.9.3 Dry ground samples of frit, ready-to-use powder, orenamel powder for dry electrostatic application may also betested.10. Preparation of Test Specimens10.1 Weigh 3.
34、5 6 0.05 g samples of the standard and of thematerial to be tested and thoroughly mix each of these sampleswith 4 or 5 drops of a 1 % gum arabic solution. Mold fusionbutton test specimens of the standard and of the sample asdirected in 10.2.10.2 Place the mixture in the steel mold with the plunger i
35、nplace and tamp the mixture to form a solid button (Note 5).Force the formed button out of the mold, taking care not todamage the button in any way that might change the dimen-sions.NOTE 5Since the height of the button will generally be controlled bythe density of the material, for materials of appr
36、oximately the samedensity such as leadless frits or lead-bearing frits, it will be foundconvenient to score the side of the plunger at a point representing theaverage height of the button for materials of the same density and tamp thepowder to this mark each time a button is formed.10.3 Dry the test
37、 specimens (Note 3).11. Procedure11.1 Mount and fire the fusion buttons and measure the flowas directed in Section 6.12. Report12.1 Report the results of the test as directed in Section 7.13. Precision and Bias13.1 No statement is made for precision or bias of these testmethods because the results a
38、re used to compare the relativefusion flow characteristics of a given porcelain enamel frit,with those of an established standard to determine anticipatedperformance.NOTE 1in. = 25.4 mm.FIG. 6 Details of Mold for Test SpecimensTest Method BC374 14514. Keywords14.1 comparative test; fusion flow; glas
39、s coating; moltenflow; porcelain enamel fritsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, an
40、d the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revisi
41、on of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you sh
42、ouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C374 146
