量具材料及工艺范文

量具材料及工艺范文量具材料及工艺范文 量具材料及工艺Measuring tools materials andprocess I working conditionsof measuring tools andperformance requirements of steelfor measuring tools Themeasure isused tomeasure thesize ofworkpiece tool such ascaliper micrometer gauge andgauge etc Because themeasuring toolis alwayssubject tofriction andcollision during the use the raingauge itselfmust havevery highsize auracy andconstancy so the following performanceis required 1 high hardnessand high wear resistance This ensuresthat itwill not be quicklyworn outfor longterm useand willlose itsauracy 2 high dimensional stability to ensure that the gaugekeeps itsshape andsize constantduring useand storage 3 sufficient toughnesstoensurethat the gauge is not damagedby aidentalcollision duringuse 4 corrosion resistanceunder specialconditions Two monly usedmeasuringtool steel Differenttypes of steel canbe usedaording tothe typeand auracyrequirementsof measuring tools 1 a measuringtool withsimple shapeand low precision requirements Carbon toolsteel canbe used such asT10A andTllA T12A Because thehardenability ofcarbon toolsteel islow water quenchingwith largesize willcause greaterdeformation Therefore this kind of steel can onlybe made of smallsize simple shape lowprecisioncaliper sample plate gauge andother measuring tools 2 measuring highprecision such asgauge gauge materialis usuallyused inhigh carbonlow alloytoolsteel Such asCr2 CrMn CrWMn andbearing steel GCr15and soon Because thiskindofsteel ismadeofalloy elementssuch asCr Mn andW inhigh carbon steel it canimprove hardenability reduce quenchingdeformation improve wear resistance anddimensional stabilityofsteel 3 for measuringthe shapeis simple the auracyisnothigh so thevulnerable such assimple flatruler andlarge sample calipers gauges the carburizingsteel15 20and15Cr and20Cr etc But the gauge shallbe usedafter carburizing quenching andlow temperaturetempering After theabove treatment the surfacehas high hardness high wearresistance and theheart maintainsenough toughness Can alsouse mediumcarbonsteel50 5560 65manufacturing tools but must be quenchedand temperedtreatment and thenby high frequency quenching tempering afteruse Also ensurethe auracyof measuring tools 4 measuring workunder corrosiveconditions canbe madeof stainlesssteel4Cr13and9Cr18manufacturing After quenching and tempering treatment canincrease the hardness ofHRC56 58 and canguarantee themeasuring instrumenthas goodcorrosion resistance and abrasionresistance enough If themeasuringtoolrequires exceptionallyhigh abrasionresistance anddimensional stability the nitridedsteel38CrMoAl orcold workdie steelCr12MoV isoptional 3CrMoAl steelis processedby quenching and tempering and thentreated bychlorination Finally it needsgrinding Surface nitridingor carbonitridingof Cr12MoV steelafter quenching and temperingor quenching and tempering After overheatingtreatment the twokinds ofsteelcanmake thegauge withhighwearresistance high corrosionresistanceand high dimensional stability Three heat treatment ofmeasuringsteel Themain featureof heat treatmentofgage steelis tokeep allkinds ofmeasures tokeep thedimension stablein long term usewhile maintaininghighhardnessandhighwearresistance The phenomenonthatthegauge changeswith timeduringtheuse of thegaugeis calledthe agingeffect of thegauge This isbecause theover eutectoidsteel usedto makemeasuring toolscontains acertain amountof retained austenite after quenching and theretained austenitebees martensite causing volumeexpansion II The martensitecontinued todepose duringits use The reductionofthesquareness caused the volumeshrinkage The existenceand redistributionof residualinternal stresscausedtheelastic deformationto partlychange intoplastic deformation resulting indimensional change Therefore thefollowingheat treatmentmeasures shouldbe adoptedfor theabove reasonsin theheat treatmentofthemeasuring tools 1 quenchingand temperingtreatment The objectiveis toobtain temperedbainitic structuresto reducequench deformationand improvemechanical finish 2 quenchingandlow temperaturetempering Measuring steelfor hypereutectoidsteel Usually inpletequenchingandlow temperaturetempering isnow underthe premiseof ensuringthehardness reduce thequenching temperature and preheating to reducetemperatureandquenching heatingand coolingprocess ofstress The quenchingmethod ofmeasuringtoolsis oilcooling 20 30DEG C and classificationquenchingandAustempering shallnotbeadopted Itis onlyconsidered inexceptional circumstances Generally uselow temperaturetempering tempering temperatureof150 160degrees tempering timeshould notbe lessthan4 5h 3 cold treatment High precisionmeasuringtoolsmustbesubjected tocold treatment after quenchingto reducethe residualaustenite andthus toincrease dimensionalstability The coldtreatment temperatureis generallyone to70 80degrees and itis carried out immediatelyafter quenchingand coolingto roomtemperature soas toavoid theaging ofretainedaustenite 4 aging treatment In orderto furtherimprove thedimensionalstability afterquenchingand tempering the24 36h aging treatment iscarriedoutat120 150DEG C which eliminatesthe residualinternal stressand greatlyincreases thedimensionalstabilitywithout reducingits hardness In theheat treatmentfor measuringsteel inaddition toa normal heat