(高清版)GB∕T 39542.3-2020 技術(shù)制圖活動鉛筆 第3部分：黑鉛芯HB 鉛芯彎曲強度

技術(shù)制圖活動鉛筆第3部分：黑鉛芯HB鉛芯彎曲強度Part3:Blackleads—BendingstrengthsofHBlea國家市場監(jiān)督管理總局國家標準化管理委員會GB/T39542.3—2020/ISO9177-3:1994——第2部分：黑鉛芯分類和尺寸； 本部分為GB/T39542的第3部分。本部分使用翻譯法等同采用ISO9177-3:1994《活動鉛筆第3部分：黑鉛芯HB鉛芯彎曲強 I1GB/T39542.3—2020/ISO9177-3:1994第3部分：黑鉛芯HB鉛芯彎曲強度GB/T39542的本部分規(guī)定了技術(shù)制圖活動鉛筆用硬度等級為HB的黑鉛芯彎曲強度和試驗方法。GB/T39542.2—2020技術(shù)制圖活動鉛筆第2部分：黑鉛芯分類和尺寸(ISO9177-2:1989,GB/T39542.2—2020界定的以及下列術(shù)語和定義適用于活動鉛筆的HB鉛芯的彎曲強度按第5章試驗，應(yīng)符合4.2的要求。4.2活動鉛筆HB黑鉛芯的彎曲強度鉛芯類型公稱直徑/mm最小彎曲強度(o)/MPa樹脂(P)0.35*1*石墨(C)2·通常在活動鉛筆和包裝上可以標志為0.3和0.9。使用者應(yīng)注意采用新標準化標志的鉛芯完全適用于舊標志的活動鉛筆，反之亦然，即0.35和1分別對應(yīng)0.3和0.9。2GB/T39542.3—2020/ISO9177-3:19945試驗方法隨機取樣的鉛芯，其彎曲強度應(yīng)按如下方法試驗。如圖1和圖2所示放置鉛芯試樣，并按如下速率(±10%)在兩支座間的中點對鉛芯施加載荷：——公稱直徑為2mm的鉛芯，加載速率為0.5N/s;——公稱直徑為0.35mm、0.5mm、0.7mm、1mm的鉛芯，加載速率為0.1N/s。上述加載速率應(yīng)預(yù)先用剛性的測試件代替鉛芯予以驗證。測得鉛芯斷裂時的載荷(F),按公式(1)計算彎曲強度(o):d彎曲強度，單位為兆帕(MPa);l——跨度，單位為毫米(mm),按表2設(shè)置；d——鉛芯的實測直徑，單位為毫米(mm)?！瓐D1彎曲強度試驗示意圖說明：說明：R0.2±0.022R0.2±0.022——支座。圖2彎曲強度試驗的支座表2兩支座間的跨度單位為毫米鉛芯類型公稱直徑跨度P0.35;0.5;0.7;1C2GB/T39542.3—2020/ISO9177-3:1994a)依據(jù)本部分檢測(即GB/T39542.3);b)鉛芯類型(P或C);c)被測鉛芯的實際直徑(對應(yīng)于公稱直徑);e)根據(jù)第5章所得的彎曲強度；GB/T39542.3—2020/ISO9177-3:1994中國標準出版社出版發(fā)行北京市朝陽區(qū)和平里西街甲2號(100029)北京市西城區(qū)三里河北街16號(100045)開本880×12301/16印張0.5字數(shù)10千字2020年7月第一版2020年7月第一次印刷版權(quán)專有侵權(quán)必究舉報電話：(010)68510107STANDARDPorte-mine—rCoovriahtIntemafonalOroarizationforStandardzationISO9177-3:1994(E)ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISOmemberbodies).TheworkofpreparingInternationalStandardtechnicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehrepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmental,inliaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnicalCommission(IEC)onallmattersofelectrotechnicalDraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesforvoting.PublicationasanInternationalavote.tation,SubcommitteeSC9,MediaandequipmentfordrawingandrelatedISO9177consistsofthefollowingparts,underthegeneraltitleMechan-—Part1:Classification,dimensions,performancerequirementsand—Part2:Blackleads—Classificationanddimensions—Part3:Blackleads—BendingstrengthsofHBleadsAllrightsreserved.Unlessothenwisespecified,nopartofthispublicationmaybereproducedorutiizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwritingfromthepublisher.二二CoovnahtIntematonalOroanlzationforStandardzatonatestmethodforblackleadsofHBhardnessdegreeusedformechanicalpencilsfortechnicaldrawings.Thefollowingstandardcontainsprovisionswhich,throughreferenceinthistext,constituteprovisionsofthispartofISO9177.Atthetimeofpublication,theeditionindicatedwasvalid.Allstandardsaresubjecttorevision,andpartiestoagreementsbasedontpossibilityofapplyingthemostrecenteditionofthestandardindicatedbelow.MemmaintainregistersofcurrentlyvalidInternationalISO9177-2:1989,Mechanicalpencils—Part2:Blackleads—Classificationanddimensions.strengthasdeterminedbybendingthebreakingpoint,usingaprescribedtestmethodformula.pencilsshallbetesteandshallsatisfytherequirementsspecifiedin4.2.definitionapplyvaluespecifiedintablspectivenominaldiameter.1CooyrahtIntermatonalOroanlzatonforStandardizaton2Onaleadsampletakenatrandom,bendingstrengthshallbetestedasfollows:2andapplyaloadonthebetweenthetwosupportinganvilsatthefollowingrates(士10%):0,5N/sfor2mmnominaldiameandusethisvaluetocalculatethebendingstrength(o)accordingtothefollowingformula:where1isthedistance,inmilthetwosupportinganvilsaccordingtota-distheactuaF((2(2Figure1—Arrangementforbendingstrengthtest2CoovrahtIntematonalOroanizationforStandardzationDimensionsinmillimetresTable2—DistancebetweenthetwosupportinganvilsDimensionsinmillimetresP0,35;0,5;0,7and1C2Thetestreportshallcontainthefollowinginformation:a)referencetothispartofISO9177;d)testvaluesforFandl;e)bendingstrengthasevaluatedaccordingtoclause5;f)nameoftestcentre,dateandsignatureofpersoncarryingoutthetest.3CoovriahtIntemationalOraanizafonforSta