1、Designation:D 1939-94 AMERICAN SOCIETY FOR TESTING Ah3 MATERIALS 1916 Race St Ph,ladelph,a.Pa 19103 Reprmted from the Annual Book ot ASM Skwdards Ccpyrlght ASTM If nc!Itsled 8”lhe current combmed Index will appear,n the nexl ednlon Standard Practice for Determining Residual Stresses in Extruded or M
2、olded Acrylonitrile-Butadiene-Styrene(ABS)Parts by Immersion in Glacial Acetic Acid This standard is issued under the fixed designation D 1939;the number immediately followmg the designatton indicates the year of original adoptlon or,in the case of revision,the year of last revision.A number in pare
3、ntheses indicates the year of last reapproval.A superscript epstlon(6)indtcates an edttonal change stnce the last revtsion or reapproval.1.Scope 1.1 This practice covers the evaluation of residual stresses in extruded profiles,as extruded,or in molded ABS parts,as molded.Residual stresses are indica
4、ted by the presence of cracking of the specimen upon immersion in glacial acetic acid.1.2 This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices an
5、d determine the applica-bility of regulatory limitations prior to use.Specific precau-tionary statements are given in Section 7.NOTE l-There is no equivalent IS0 standard.2.Referenced Documents 2.1 ASTM Standards:D 883 Terminology Relating to Plastics D 1600 Terminology for Abbreviated Terms Relatin
6、g to Plastics*D 4673 Specification for Acrylonitrile-Butadiene-Styrene(ABS)Molding and Extrusion Materials3 3.Terminology 3.1 General-Definitions are in accordance with Termi-nology D 883 and abbreviations are in accordance with Terminology D 1600,unless otherwise indicated.4.Significance and Use 4.
7、1 This practice is applicable for distinguishing between specimens that are highly stressed and specimens that are not,provided that other conditions are the same.4.2 No direct correlation has been established between the results of the acetic acid immersion test and other properties.For this reason
8、,acetic acid immersion is not recommended as a substitute for other tests,nor is it intended for use in purchasing specifications.However,despite this limitation,this practice does yield information of value in indicating the presence of residual stresses in extruded and molded ABS parts.4.3 This pr
9、actice is useful for extruders and molders who t This practice is under the jurisdiction of ASTM Committee D-20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials(Section D20.15.03).Current edition approved June 15,1994.Published August 1994.Originally pub
10、lished as D 1939-62.Last previous edition D 1939-84(1989)“.2 Annual Book of ASTM Standards,Vol 08.01.3 Annual Book of ASTM Srandards,VolO8.03.wish to evaluate residual stresses in ABS parts.This can be accomplished in two ways:(1)by visual examination after immersion in glacial acetic acid to see wh
11、ether or not cracking occurs,and(2)by determining the time necessary to develop cracks.Stresses will relax rapidly after molding or extrusion.Accordingly,both immersion in the test medium and visual comparison must be made at identical times and conditions after processing.5.Apparatus 5.1 Container,
12、of sufficient size to ensure complete im-mersion of specimen(s).6.Reagent 6.1 Acetic Acid,glacial,American Chemical Society Re-agent grade,99.7%assay.NOTE 2-An uncovered container may allow absorption of sufficient moisture to lower the concentration and affect results.7.Safety Precautions 7.1 Glaci
13、al acetic acid may cause severe skin bums.Protective equipment and clothing should be utilized to avoid contact with the skin or eyes.Use adequate ventilation to remove noxious or toxic fumes,or both.8.Test Specimen 8.1 Size of Specimen-The specimen shall be a complete molding or a cut piece of the
14、extrusion or molding of sufficient size to not influence the stresses being observed.Twisting and breaking must be avoided in separating the cut pieces since the slightest amount changes stresses and may cause false results.9.Procedure 9.1 Test at a temperature of 23 st 2C(73.4 f 3.6”F).(See precaut
15、ions in section 7.)9.2 At a fixed time after the actual molding or extrusion operation,immerse the specimen in glacial acetic acid for 30 s.At the end of this time,remove and rinse the specimen at once in running water,wipe dry,and carefully examine for cracking.Rate the degree of cracking as follow
16、s:no cracking,slight cracking,moderate cracking,extensive cracking.NOTE 3-Fixed time,meaning whatever time after production is convenient for the individual operation.Time should be consistent from test to test.NOTE 4-Slight cracking is defined here as cracking that is percep tible with diffkulty.Moderate cracking is cracking that is readily NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest informa
