(高清版)GB∕T 39542.3-2020 技术制图活动铅笔 第3部分：黑铅芯HB 铅芯弯曲强度

技术制图活动铅笔第3部分：黑铅芯HB铅芯弯曲强度Part3:Blackleads—BendingstrengthsofHBlea国家市场监督管理总局国家标准化管理委员会GB/T39542.3—2020/ISO9177-3:1994——第2部分：黑铅芯分类和尺寸； 本部分为GB/T39542的第3部分。本部分使用翻译法等同采用ISO9177-3:1994《活动铅笔第3部分：黑铅芯HB铅芯弯曲强 I1GB/T39542.3—2020/ISO9177-3:1994第3部分：黑铅芯HB铅芯弯曲强度GB/T39542的本部分规定了技术制图活动铅笔用硬度等级为HB的黑铅芯弯曲强度和试验方法。GB/T39542.2—2020技术制图活动铅笔第2部分：黑铅芯分类和尺寸(ISO9177-2:1989,GB/T39542.2—2020界定的以及下列术语和定义适用于活动铅笔的HB铅芯的弯曲强度按第5章试验，应符合4.2的要求。4.2活动铅笔HB黑铅芯的弯曲强度铅芯类型公称直径/mm最小弯曲强度(o)/MPa树脂(P)0.35*1*石墨(C)2·通常在活动铅笔和包装上可以标志为0.3和0.9。使用者应注意采用新标准化标志的铅芯完全适用于旧标志的活动铅笔，反之亦然，即0.35和1分别对应0.3和0.9。2GB/T39542.3—2020/ISO9177-3:19945试验方法随机取样的铅芯，其弯曲强度应按如下方法试验。如图1和图2所示放置铅芯试样，并按如下速率(±10%)在两支座间的中点对铅芯施加载荷：——公称直径为2mm的铅芯，加载速率为0.5N/s;——公称直径为0.35mm、0.5mm、0.7mm、1mm的铅芯，加载速率为0.1N/s。上述加载速率应预先用刚性的测试件代替铅芯予以验证。测得铅芯断裂时的载荷(F),按公式(1)计算弯曲强度(o):d弯曲强度，单位为兆帕(MPa);l——跨度，单位为毫米(mm),按表2设置；d——铅芯的实测直径，单位为毫米(mm)。……图1弯曲强度试验示意图说明：说明：R0.2±0.022R0.2±0.022——支座。图2弯曲强度试验的支座表2两支座间的跨度单位为毫米铅芯类型公称直径跨度P0.35;0.5;0.7;1C2GB/T39542.3—2020/ISO9177-3:1994a)依据本部分检测(即GB/T39542.3);b)铅芯类型(P或C);c)被测铅芯的实际直径(对应于公称直径);e)根据第5章所得的弯曲强度；GB/T39542.3—2020/ISO9177-3:1994中国标准出版社出版发行北京市朝阳区和平里西街甲2号(100029)北京市西城区三里河北街16号(100045)开本880×12301/16印张0.5字数10千字2020年7月第一版2020年7月第一次印刷版权专有侵权必究举报电话：(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