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

技術制圖活動鉛筆第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。上述加載速率應預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設置；d——鉛芯的實測直徑，單位為毫米(mm)。……圖1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(對應于公稱直徑);e)根據第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月第一次印刷版權專有侵權必究舉報電話：(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