1、Designation: C181 11Standard Test Method forWorkability Index of Fireclay and High-Alumina RefractoryPlastics1This standard is issued under the fixed designation C181; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the work-ability index of fireclay and high-alumina refractory plastics byme
3、asuring the plastic deformation of a molded test specimenwhen subjected to impacts.1.2 The values 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、3 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 practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Doc
5、uments2.1 ASTM Standards:2D2906 Practice for Statements on Precision and Bias forTextiles33. Significance and Use3.1 Workability index serves as a measure of the facilitywith which refractory plastic materials can be rammed,gunned, or vibrated into place.3.2 Workability index is commonly used to con
6、trol consis-tency of plastics during manufacture. It has also been founduseful for specification acceptance by the consumer.3.3 The workability index determination can provide infor-mation for developing a plastic body. When a sample splitsunder impact at various water contents, it is an indication
7、thatthe material is “short” or lacking in plasticity.3.4 Determinations on samples that split during impact willbe difficult to reproduce. If the sample splits, the measurementis not a true indication of deformation. This should be noted inthe report.4. Apparatus4.1 RammerThe apparatus shall consist
8、 of the deviceknown as the sand rammer for refractories (see Fig. 1). It shallconsist essentially of a steel cylindrical mold (specimen tube)2.00 in. (50.8 mm) in inside diameter and 4.75 in. (120.6 mm)in length, supported in a vertical position on the same axis asa shaft to which shall be fastened
9、a plunger that fits inside themold. A 14-lb (6.4-kg) cylindrical weight slides on the sameshaft and is arranged to fall a distance of 2 in. (51 mm) beforeengaging a collar fastened to the shaft. As shown in Fig. 1, theweight may be raised by a manually rotated cam. Provisionshall be made by the equi
10、pment manufacturer to support theweight, thereby removing the load from the vertical shaft(example shown in Fig. 2). The sand rammer will include alinear scale capable of measuring sample height to 0.02 in. (0.5mm) with a typical range of 1.72.5 in. (Note 1). The portionof the scale to be used shall
11、 be adjusted so that when thevertical shaft is measuring a 3.00 in. standard, 3.00 in. is readon the scale.NOTE 1The apparatus as described in this section is capable ofmeasuring workabilities up to about 32 %. For products of higherworkability a suitable spacer block may be installed under the spec
12、imen.4.1.1 Mounting for RammerIt is recommended the ram-mer be mounted on sand rammer base sold by the manufactureror a concrete column to isolate the rammer from vibrationvariations. The rammer is to be secured onto the base orcolumn using steel bolts. Variable results are obtained from thetest unl
13、ess the described mounting or an acceptable alternativemounting is used for the rammer. An acceptable mountingmethod is one that can be calibrated using the manufacturerscalibration rings described below in 4.1.2.4.1.2 Maintenance and CalibrationAs needed, dependingon use, clean all moving parts and
14、 lubricate with SAE 10 oil.1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility of Subcommittee C08.09 on Monolith-ics.Current edition approved Oct. 1, 2011. Published November 2011. Originallyapproved in 1943. Last previous edition approv
15、ed in 2009 as C181 09. DOI:10.1520/C0181-11.2For 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 page onthe ASTM website.3Withdrawn. The l
16、ast approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Make periodic checks of the height that the weight drops toinsure the weight is being raised 2 in. (51 mm).
17、 Inspect therammer to determine whether it and the foundation areproducing full ramming energy. This is accomplished by usingcalibrated impact rings.4Inspect the specimen tube (Note 2).NOTE 2Variation in the smoothness and dimensions of the specimentube may cause variation in workability values. For
18、 referee testing thespecimen tube may require periodic comparison with a master precisionspecimen tube sold by manufacturer.5. Test Specimens5.1 Temperature of Refractory Plastic Since the work-ability index may vary with a wide spread of temperature, thetemperature of the material to be tested must
19、 be between 65and 75F (18 and 24C) to reduce this variable. Record thetemperature of material before forming the cylinder.NOTE 3As much as a 3-point change in the workability index mayoccur within the 10F (6C) stated range.5.2 Number of SpecimensFive cylindrical test specimensshall be molded from th
20、e sample of refractory plastic.5.3 Molding of SpecimensThe interior of the mold shallbe cleaned and coated with a light film of suitable parting agentprior to the preparation of each specimen. To facilitate filling4Manufacturers calibration rings consist of a set of precision steel rings thatdeform
21、within a specified range to determine full ramming energy; the anvil ispositioned in the specimen tube locating hole in the base of the rammer. A test ringis then placed in the center of the anvil with the axis of the ring being horizontal.The ring is then subjected to 3 impacts of the rammer head.
22、A measurement acrossthe center of the deformed ring is then made and compared to the limits specified onthe box containing the rings. Detailed instructions are included in the calibration kit.FIG. 1 Apparatus for Workability-Index TestFIG. 2 Example of Provision to Suspend WeightC181 112the mold, th
23、e sample shall be broken into pieces varying insize, the largest dimension being about 1 in. (25 mm). Thesample weight shall be chosen to provide a sample height of2.5 6 0.1 in. (64 6 3 mm). For a super-duty plastic, the sampleweight is approximately 300 g; for an 85 to 90 % aluminaplastic, approxim
24、ately 375 g. After placing the material in themold, it shall be subjected to ten impacts by turning the handle,which causes the weight to be raised 2 in. (51 mm) and thendropped upon the collar attached to the plunger shaft. The moldcontaining the sample shall then be upended and an additionalten im
25、pacts given to the specimen. The formed test specimenshall then be extruded from the mold by the use of a suitableauxiliary plunger.6. Procedure6.1 Remove the load on the plunger of the mold bysuspending the weight from the framework in accordance withthe manufacturers instruction. Typically this is
26、 done byslightly rotating the weight while engaging the hooks on thepins (Fig. 2) or engaging the screw head into the slot in theframework. Raise the vertical shaft using raising device (Fig.1), place the test specimen on the bottom of the mold and lowerthe shaft until the plunger is in firm contact
27、 with the specimen.Obtain the length of the specimen to the nearest 0.02 in. (0.5mm) by sighting on the rule and the end of the shaft. Disengagethe weight from its support and carefully lower it until it is atrest in its normal position. Then apply three impacts from theweight to the test specimen.
28、Read the final length of thespecimen from the scale, and record the difference in inches ormillimeters between the two measurements.7. Calculation and Report7.1 Calculate the percentage deformation for each of thefive test specimens on the basis of the original length and reportthe average value as
29、the workability index. The workabilityindex shall be calculated by the following equation, and shallbe rounded off to one decimal place.W 5L 2 L1L3 100whereL = length of specimen prior to deformation,L1= length of specimen after deformation, andW = workability index.7.2 State the temperature of the
30、sample, the specimenweight used, and whether any test specimen crumbled as aresult of the three impacts.8. Precision and Bias8.1 Interlaboratory Test Data5An interlaboratory test wasrun in 1975, in which two laboratories each tested ten speci-mens from each of two plastic materials: a super-duty and
31、 ahigh-alumina phosphate-bonded plastic. Samples were selectedfrom the same container of plastic and tested in each laboratoryat the same time. The components of variance for workabilityindex results calculated by the procedures given in PracticeD2906 are as follows:Within-laboratory component 4.1 %
32、 of the averageBetween-laboratory component 5.1 % of the average8.2 PrecisionFor the components of variance given in 8.1,two averages of test values should be considered significantlydifferent at the 95 % probability level if the difference equals orexceeds the critical difference listed as follows
33、(for t = 1.96):Critical Difference, % of Grand Average ofWorkability IndexNumber of Samples inEach AverageWithin-LaboratoryPrecisionBetween-LaboratoryPrecision3 6.6 15.65 5.1 15.010 3.6 14.615 2.9 14.38.3 BiasNo justifiable statement on bias is possible sincethe true value of the workability index c
34、annot be established byan accepted reference material.9. Keywords9.1 refractories; refractory plastic; workabilityASTM 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 adv
35、ised that determination of the validity of any such patent rights, and 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
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37、f 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 below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Indivi
38、dual 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/).5Supporting data are available from ASTM International Headquarters. RequestRR: C8 1003.C181 113
