1、Designation: C285 10 (Reapproved 2015)1Standard Test Methods forSieve Analysis of Wet-Milled and Dry-Milled PorcelainEnamel1This standard is issued under the fixed designation C285; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTESections 4 and 10 corrected editorially in May 2015.INTRODUCTIONThese test methods provide a rapid means of determ
3、ining the fineness of glass frit in wet- ordry-milled porcelain enamel coating materials by sieve analysis. Fineness is a key predicator offusibility, tearing, gloss, opacity, suspension in the slip, and ease of spraying because of the directrelationship to surface area.1. Scope1.1 These test method
4、s cover the determination of thefineness of frit in wet- or dry-milled porcelain enamels andother ceramic coatings for metals by means of the No. 200(75-m) or No. 325 (45-m) sieve.1.2 The two methods appear as follows:SectionsMethod AReferee MethodMethod BRoutine Method4to910 to 141.3 Method A is in
5、tended for use where a referee method ofhigher accuracy is required, while Method B is intended tomeet the needs of normal enamel plant production controloperations where a rapid, simplified method of sieve testing isrequired. The accuracy of the simplified method has proved tobe entirely adequate f
6、or this use. The simplified test, however,is not recommended where high accuracy is required.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health prac
7、tices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Significance and Use3.1 The fineness of the frit has a direct bearing on many ofits properties, such as fusibili
8、ty, tearing, gloss, opacity, suspen-sion in the slip, and ease of spraying.METHOD AREFEREE METHOD4. Apparatus4.1 BalanceThe balance or scale shall be of at least 500-gcapacity, and accurate to 0.1 g.4.2 SievesThe sieves shall conform to Specification E11.They shall include the No. 40 (425-m) sieve a
9、nd also the No.200 (75-m) or the No. 325 (45-m) sieve, or both. A No. 325sieve shall be used when the fineness is such that, from asample containing 100 g of dry solids, less than2gisretainedon a No. 200 sieve. An 8-in. (203-mm) full-height sieve isrecommended. This height is preferred because there
10、 is lesstendency to flood or splash, and also because it fits commercialautomatic tapping and shaking machines. All sieves used for1These test methods are under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and are the direct responsibility of SubcommitteeB08.12 on Materia
11、ls for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved May 1, 2015. Published May 2015. Originallyapproved in 1951. Last previous edition approved in 2010 as C285 10. DOI:10.1520/C0285-10R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
12、omer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1testing shall be standardized initia
13、lly and after every 50 testsagainst a reference sieve tested by the National Bureau ofStandards and bearing its precision seal. The correction for thesieve used in this test shall be determined by sieving tests madein conformity with the procedure of this test method. Identicalsamples shall be sieve
14、d through the reference sieve and the testsieve. Test materials shall be chosen so that 5 to 10 % of thematerial will be retained on the reference sieve. The differencebetween the percentage residue on the reference sieve and thaton the test sieve is the amount of correction which shall bealgebraica
15、lly added to, or subtracted from, the correction forthe reference sieve to obtain the final correction (Note 1). TheNo. 40 sieve need not be calibrated.NOTE 1For example, when comparing the reference sieve with a testsieve, should 8.5 g be retained on the reference sieve and 7.5 g on the testsieve,
16、the total correction for the test sieve would then be 8.5 7.5,or + 1.0.4.3 DryerA suitable means for drying the sieves and slipsample, without exceeding a temperature of 250F (122C),shall be provided. No dryer is needed for sieve tests ofdry-milled enamel.4.4 Mechanically Operated Sieve Shaker The m
17、echanicalshaking device shall be such as to produce a lateral and verticalmotion of the sieve, accompanied by a jarring action so as tokeep the sample moving continuously over the surface of thesieve. If a machine shaker is to be used, the thoroughness ofsieving shall be tested by comparing and cali
18、brating with thehand method of sieving, as described in Section 6.5. Sample5.1 Wet-Milled EnamelSelect a sample of slip representa-tive of the material to be tested. Protect samples from evapo-ration. Determine the water content of the slip by drying arepresentative 100-g sample of slip to constant
19、weight at atemperature not exceeding 250F (122C). Pass the samplethrough a No. 40 sieve before weighing, and discard thematerial retained on the sieve. Sample the slip after stirring byweighing out to the nearest 0.1 g, a quantity calculated tocontain 100 g of dry solids.5.2 Dry-Milled EnamelSelect
20、a sample representative ofthe material to be tested and containing 100 g of dry solids,weighed to the nearest 0.1 g.6. Procedure for Wet-Milled Enamel6.1 Wet SievingTransfer the weighed sample to the No.200 or No. 325 sieve. Wash the sample through the sieve witha gentle flow of water from a rubber
21、hose until the waterpassing through the sieve appears clear and free of cloudiness.This usually requires 2 min. Exercise care to prevent any lossof sample because of splashing or overflowing. Dry the sievewith its residue until the residue easily moves about as a drypowder when the sieve is shaken.
22、Complete the sieving andweighing operation in accordance with 6.2 or 6.3. Make tests induplicate.6.2 Hand SievingHold the sieve, with pan and coverattached, in one hand at an angle of about 20 from thehorizontal. Move the sieve up and down in the plane ofinclination at a rate of about 150 times per
23、minute, and strikeagainst the palm of the other hand at the top of each stroke.After every 25 strokes, turn the sieve about one sixth of arevolution in the same direction. Continue the operation untilnot more than 0.05 g passes through the sieve in 1 min ofcontinuous sieving. Weigh the portion of th
24、e sample retainedon the sieve to the nearest 0.1 g.6.3 Machine SievingIf a mechanically operated sieveshaker is used, vary the time during which the sieve (with panand cover attached) and the sample are shaken, and note thelength of time necessary to operate the sieve shaker in order toget the same
25、result as that obtained with hand sieving.Calibrate the machine-sieving operation in terms of handsieving.7. Procedure for Dry-Milled Enamel7.1 Transfer the sample quantitatively to the No. 200 or 325sieve. Complete the sieving and weighing operation in accor-dance with 5.2 or 5.3. Make tests in dup
26、licate.8. Calculation and Report8.1 Using the average of duplicate runs, report the finenessof the frit in percentage by mass (to the nearest 0.1 %) of thedry solids content of the sample retained on the No. 200 or 325sieve. The weight in grams is equivalent to weight percentage.9. Precision and Bia
27、s9.1 PrecisionIt is generally accepted within the porcelainenamel industry that duplicate tests run by the same operator inthe same laboratory should show a precision of 60.5 or less.Failure to duplicate determinations within this limit indicatesthe necessity for repetition of the test. The precisio
28、n ofduplicate tests is negatively influenced by variations in opera-tor technique, sieve binding and wear, and, when it is used, thecondition of mechanical sieving equipment. It is also influ-enced by changing conditions in the test sample which occurover time and which result in particle agglomerat
29、ion due tochemical reactions.9.2 BiasNo justifiable statement on bias can be madesince the true value of sieve analysis cannot be established byan acceptable standard sample.METHOD BROUTINE METHOD10. Apparatus10.1 BalanceThe balance or scale shall be at least 200-gcapacity, and accurate to 0.1 g.10.
30、2 SievesThe sieves shall conform to Specification E11and shall include the No. 40 (425-m) and the No. 200 (75-m)sieves. An 8-in. (203-mm) full-height sieve is recommended.This height is preferred because there is less tendency to floodor splash, and also because it fits commercial automatictapping a
31、nd shaking machines. A sieve properly cared for willhave 500 tests. It should, however, be compared from time totime with a master standard or reference sieve. It is recom-mended that an extra sieve be purchased and preserved as amaster standard against which all sieves in use or subsequentlypurchas
32、ed can be standardized.C285 10 (2015)1210.3 ContainerA container suitable for weighing a 100-gsample.10.4 DryerSee 4.310.5 Mechanically Operated Sieve ShakerSee 4.4.11. Sample11.1 Select a sample of slip from the mill before unloadingand pass it through a No. 40 sieve before weighing. Discard themat
33、erial retained on the sieve. The sample shall consist of 100g of slip for wet-milled porcelain enamel or 100 g of groundfrit for dry-milled porcelain enamel.12. Procedure12.1 Wet-Milled Porcelain EnamelTransfer the 100-gsample of slip to the No. 200 sieve. Wash the sample throughthe sieve with a str
34、eam of gently running water, care beingexercised to prevent splashing or overflowing of the sieve.Continue washing until the water passing through the sieveappears clear and free from cloudiness. This usually requires atleast 2 min. Dry the sieve with its residue until the residueeasily moves about
35、as a dry powder when the sieve is shaken(Note 2). Shake the sieve in an automatic shaking and tappingmachine, or by hand, until no further material passes throughthe meshes. This usually requires from 5 to 7 min. Transfer theresidue remaining on the sieve to the balance and weigh to thenearest 0.1 g
36、.NOTE 2It is recommended that, at this point, the residue be transferredto another sieve for shaking. The use of a second sieve minimizes the errorcaused by the clogging when both washing and shaking are accomplishedwith the same sieve.12.2 Dry-Milled Porcelain EnamelPlace the 100-g sampleof frit po
37、wder in a No. 200 sieve and shake in an automaticshaking and tapping machine, or by hand, until no furthermaterial passes through the meshes (Note 3). This usuallyrequires from 5 to 7 min. Transfer the residue remaining on thesieve to the balance and weigh to the nearest 0.1 g.NOTE 3The end point is
38、 usually taken as the time at which not morethan 0.1 g of material passes through the sieve with 1 min shaking.Alittleexperience will indicate to the operator when the shaking operation iscomplete.13. Calculation and Report13.1 Report the weight in grams of the residue on thescreen as equivalent to
39、weight percentage of the original slip,or frit powder, specimen.14. Precision and Bias14.1 PrecisionIt is generally accepted within the porcelainenamel industry that duplicate tests run by the same operator inthe same laboratory should show a precision of 60.5 or less.Failure to duplicate determinat
40、ions within this limit indicatesthe necessity for repetition of the test. The precision ofduplicate tests is negatively influenced by variations in opera-tor technique, sieve binding and wear, and, when it is used, thecondition of mechanical sieving equipment. It is also influ-enced by changing cond
41、itions in the test sample which occurover time and which result in particle agglomeration due tochemical reactions.14.2 BiasNo justifiable statement on bias can be madesince the true value of sieve analysis cannot be established byan acceptable standard sample.ASTM International takes no position re
42、specting 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, and the riskof infringement of such rights, are entirely their own responsibility.This
43、 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 revision of this standard or for additional standardsand should be addressed to ASTM Inter
44、national 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 shouldmake your views known to the ASTM Committee on Standards, at the address shown b
45、elow.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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 10 (2015)13
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