1、Designation:C903151Standard Practice forPreparing Refractory Specimens by Cold Gunning1This standard is issued under the fixed designation C903;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in par
2、entheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorial changes were made throughout in April 2016.1.Scope1.1 This practice covers a procedure for preparing refractoryspecimens usually containing calcium
3、aluminate cement withor without metal fibers by cold nozzle-mix gunning.Specimensprepared in accordance with this practice are intended for usein standardASTM test methods required for evaluating gunnedmaterials.1.2 The values stated in inch-pound units are to be regardedas standard.The values given
4、 in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 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
5、-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C401 Classification of Alumina and Alumina-SilicateCastable RefractoriesC865 Practice for Firing Refractory Concrete Specimens3.Significance and Use3.
6、1 The properties of refractories can be affected by theirmethod of installation.This practice attempts to minimize thevariables encountered during installation by pneumatic gun-ning.3.2 This practice provides parameters to produce gunnedspecimens for use in other ASTM test methods.3.3 This practice
7、may be used to produce specimens foracceptance testing,service evaluation,manufacturing control,and research and development.3.4 Differences between various kinds of equipment and thedifferences in procedures and operator techniques may result insignificant variations in the physical properties of t
8、he gunnedspecimens.It is recommended that the same operator use thesame equipment to produce specimens for referee testingagreed to by the involved testing parties.The specific operatingparameters should be shown in the report.3.5 Although this practice is specifically designed for re-fractories con
9、taining calcium aluminate cement,it may be usedwith minor modifications for gun mixes containing other bondsystems.4.Apparatus4.1 Gun,pneumatic nozzle-mix.At least 50 ft(15.2 m)ofhose should be available.Acceptable nozzle diameters rangefrom 1 to 2 in.(25 to 51 mm).4.2 Air Compressor,capable of deli
10、vering sufficient pres-sure and volume to adequately move refractory to the gun.Thecompressor should be able to supply at least 250 ft3(7 m3)/min.4.3 Forms,suitable nonabsorbent type,which will vary insize in accordance with the number and size of samples beingprepared,but are at minimum 12 by 12 by
11、 4 in.(305 by 305 by100 mm).Forms should be sized to prevent rebound entrap-ment.The use of12inch hardware cloth as sidewalls of theform allows most of the rebound to pass through.5.Procedure5.1 Store the refractory to be gunned at 70 to 85F(20 to27C)for 24 h prior to gunning.5.2 Place the form agai
12、nst a rigid surface at an angle of 80to 90 to the horizontal.5.3 If recommended by the supplier,predampen the refrac-tory by mixing with potable water in a paddle mixer for 1 to 5min or follow manufacturers specific instructions.In general,regular(dense)refractories require 2 to 4%of predampeningwat
13、er and lightweight(insulating)refractories require 5 to 8%.NOTE1Refractories that contain a high-purity cement may benefit by1This practice is under the jurisdiction ofASTM Committee C08 on Refractoriesand is the direct responsibility of Subcommittee C08.09 on Monolithics.Current edition approved Oc
14、t.1,2015.Published December 2015.Originallyapproved in 1979.Last previous edition approved in 2010 as C903 10.DOI:10.1520/C0903-15E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume informat
15、ion,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 States1 aging for 5 to 10 min after dampening before gunning.This“agingprocedure should be used if gunning without it produces exc
16、essiverebound,dusting,or slumping.NOTE2Treat refractories containing metal fibers in a normal manner.If metal fibers are to be added to the gunning material,add them to thepaddle mixer before any water is introduced.The amount of fiber to beadded and the methods of reporting this amount shall be agreed upon bythe parties involved.To prevent clumping of the fibers they should beadded slowly through a suitable screen of12in.mesh.Fibers larger than1 in.may require larger openings.If any predampenin
