文本内容:
(一)Athehardnessofametalisitsresistan__tosu_____indentationunderstandardtestconditions.two__intestmethodsareused:BrinellRockwell金属的硬度是抵抗表面压痕试验的能力.两种主要试验方法下使用布氏,洛氏TheBrinellTest布氏硬度试验TheBrinelltestFig.2-3is__inlyusedfor__terialswhosethicknessis
0.25in.orgreater.Thetestingtechniqueistoimpressa10-mmdiameterhardenedsteel布氏硬度(fig.2-3)主要用于材料的厚度为
0.25或更大测试技术是给一个直径10毫米的硬化钢ballintothesu_____ofthe__terialunder3000Kgloadfor15~60sec.A__allerloadisusedwhentestingsoftermetalsandalloys.Thediameterinmillimetersof球到表面的材料3000公斤载荷下15~60秒一个较小的负载进行测试时,较软的金属和合金在毫米直径的,thedent__debytheballismeasuredbyamicroscopeandtheareaiscalculated.由球处用显微镜测量,和__计算ThebrinellhardnessnumberHBS__ybecalculatedfromtheformula布氏硬度值(HBS)可由公式计算HBS=HBS=WhereD=balldiametermm其中d=球直径(mm)d=diameterofcircularindentationmma圆形压痕直径(mm)F=loadwhichinhardnesstestinghasunitsofkilogramme-for__where1kgf=
9.8NF=负载,其中,硬度测试,具有千克力在1公斤=
9.8N单位Howeverto__oidthistediouscalculationtheBrinellhardnessnumber__ybefoundfromtablesrelatinghardnesstothediameteroftheindentation.Eachtableof然而,为了避免这种繁琐的计算,布氏硬度值可以从有关硬度的压痕直径表每个表suchrelationshipsreferstoaspecificloadandballdiameter.这种关系是指一个特定的负载和球径TheRockwellTest洛氏的试验IntheRockwelltestFig.2-4thedepthoftheindentationismeasuredbytheinstrumentandthisisdirectlyindicatedonadialasahardnessvalue.Nosubsequent在洛氏试验(Fig.2-4)压痕的深度是由仪器,这是直接在拨号作为硬度值表示测量没有后续的measurementoftheindentationisinvolved.压痕的测量涉及Thetest-pie__ispla__donthetableofthe__chineandtheindenterisbroughtintocontactwiththepreparedsu_____underaminorloadof10kgf.Thistakesupthe试件置于机表和压头被带入与制备的表面接触的小负荷下的10公斤这需要了‘slack’inthesystemandthedialindicatorissettozero.The__joradditionalloadisthenappliedandwhenthereadingofthe__jorloadistakenoff.The“松弛”的体系和百分表设置为零主要的(额外的)负载的应用,当主要的负载读取下的test-pie__re__insundertheminorloadwhilethehardnessvalueisreaddirectlyfromthedialindicator.Ninescalesofhardnessare__ailableAtoKinclusivebut试件仍然是小负荷下,硬度值是从百分表直接读取九硬度范围是可用的(一个K含)但themostcommonlyusedaretheBandCscalesthedetailsofwhicharegivenintable2-
1.最常用的是B和C的尺度,其中的细节表2-1给出TheDialisdividedinto100divisionseachrepresentingonepointonthehardnessscale.ThesymbolHRissupplementedbyalettere.g.BorCwhichdenotesthe表盘是分成100个级别,每个代表在硬度表一点符号HR补充一个字母(如B或C)是particularhardnessscaleused.TheRockwelltestisparticularlysuitableforrapidroutinechecksonfinished__terial.TheCscaleisused__inlyforhardened特别是硬度表洛氏测试的特别适合于快速的日常检查成品C表主要用于硬化steelswhiletheBscaleisusedforunhardenedsteelsandthehardernon-ferrousalloys.钢,而B的比例用于未淬火的钢和有色合金(B)。