1、Designation:F48408(Reapproved 2013)Standard Test Method forStress Crazing of Acrylic Plastics in Contact with Liquid orSemi-Liquid Compounds1This standard is issued under the fixed designation F484;the number immediately following the designation indicates the year of originaladoption or,in the case
2、 of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test metho
3、d covers determination of the crazingeffect that a liquid or semi-liquid test compound will have ontransparent acrylic plastic material that is under bending stress.1.2 Three types of acrylic material are covered.One,two,orall of the materials shall be used in the test,as specified by theprocuring a
4、gency.When not specified otherwise,all three typesof acrylic shall be used in the test.1.3 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
5、.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 practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Docu
6、ments2.1 ASTM Standards:2D1193 Specification for Reagent Water2.2 Military Standards:MIL-PRF-5425 Plastic Sheet,Acrylic,Heat Resistant3MIL-PRF-8184 Plastic Sheet,Acrylic,Modified3MIL-PRF-25690 Plastic,Sheets and Formed Parts,ModifiedAcrylic-Basic,Monolithic,Crack Propagation Resistant33.Terminology3
7、.1 Definitions:3.1.1 crazea minute surface crack,sometimes hairline insize.NOTE1Hairline craze cracks are very difficult to see except withcareful inspection under properly oriented light.3.1.2 cracka fracture or tear.4.Types4.1 Type A,cast acrylic material shall conform to MIL-PRF-5425,Finish A.4.2
8、 Type B,cast acrylic material shall conform to MIL-PRF-8184,Finish B.4.3 Type C,stretched acrylic material shall conform toMIL-PRF-25690.5.Apparatus5.1 Stress ApparatusThe means of stressing the acrylicplastic test specimen bars shall be as shown in Fig.1.6.Test Specimens6.1 The test specimens shall
9、 be machined from 0.25 60.025 in.(6.4 6 0.64 mm)thick polished acrylic plastic sheetconforming to the applicable specification.6.2 The test specimens shall be 1 6 0.03 in.(25.4 6 0.8mm)wide by 7 6 0.05 in.(177.8 6 1.27 mm)long by 0.25 60.025 in.(6.4 6 0.64 mm)thick.Edges shall be a smoothmachined su
10、rface without cracks.7.Conditioning7.1 Do not anneal Type C acrylic specimens.7.2 Anneal Type A and Type B acrylic test specimens aftermachining by heating in a circulating air oven at 195 6 5F(916 3C)for 512h.Cool the specimens to room temperature inthe oven using a uniform cooling rate of 50F(28C)
11、/h.7.3 Condition all specimens at 75 6 10F and 50 6 5%relative humidity for a minimum of 24 h just before testing.8.Procedure8.1 Test two specimens of each acrylic material specified foreach of the test compounds being evaluated.1This test method is under the jurisdiction of ASTM Committee F07 onAer
12、ospace and Aircraft and is the direct responsibility of Subcommittee F07.07 onQualification Testing of Aircraft Cleaning Materials.Current edition approved Dec.1,2013.Published December 2013.Originallyapproved in 1977.Last previous edition approved in 2008 as F484 08.DOI:10.1520/F0484-08R13.2For ref
13、erenced 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.3Available from Standardization Documents Order Desk,Bldg.4 Section D,700R
14、obbins Ave.,Philadelphia,PA 19111-5098,Attn:NPODS.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.2 Conduct the test at a temperature of 75 6 10F(23 65C).8.3 Carefully load the acrylic specimen as a cantilever beamas shown in Fig.1.Unle
15、ss otherwise specified,the followingare recommended stress levels:8.3.1 Type A specimens shall be stressed to an outer fiberstress of 3000 psi(20 685 kPa).8.3.2 Type B specimens shall be stressed to an outer fiberstress of 3500 psi(24 132 kPa).8.3.3 Type C specimens shall be stressed to an outer fib
16、erstress of 4500 psi(31 027 kPa).8.4 Allow the specimen to remain under the designatedstress for 10 min;then examine under the lighting and visualinspection conditions shown in Fig.1 to be sure no crazing hasinitiated.If crazing has occurred,substitute another acrylic testspecimen.8.5 With the test specimen again under the designated load,place an absorbent cotton or flannel swatch,12to58in.(12.7to 15.9 mm)square,on the tension surface(top)of the crazetest specimen directly over the fulcrum.Posi
