简介：Drillpipeproductsarethemostcriticalservicerequirement,thehighestperformancerequirementandthehighestqualityreliabilityOCTGproducts.Throughthecontinuousresearchonsteelmaking,upset,hearttreatment,straighteningandfrictionwelding,Baosteelimprovesthekeytechnicalparameterswhichaffectthequalityofdrillpipe,suchasmaterialpurity,Miuofinternalupsettransitionarea,toughnessandstraightness.Baosteeldrillpipeproductshavemetthedemandingrequirementofdrillingoperations.ByBRPdephosphorizationandLFdesulfurization,theP,ScontentofBaosteeldrillpipeisverylow.TheScontentofS-135drillpipecanbecontrolledinlessthan10ppm.Baosteeldesignsanewclosed-loopcontrolsystemofupsetendinductionheatingsystem.Thesystemusetemperaturemeasurementinsidetheovenandclosed-loopcontrol.Thetemperatureaccuracyofthesystemcanbeguaranteedwithinthe±15℃togetastableupsetquality.TheupsettingprocessofthedrillpipeisoptimizedbyusingpatentedtechnologyandmadetheMiufrom100mmto140mm.Thismakeasubstantialincreaseinfatiguelifeofthedrillpipe.Toimprovetheimpacttoughnessofthedrillpipebody,thedrillpipebodymaterialischangedfromCr-Ni-MosystemtoCr-Mo-Vsystemandtheheattreatmentischangedfromoilquenchingtowaterquenching.Toimprovetheimpacttoughnessofthetooljoint,thetooljointfurnaceisupgradedtoimproveheatingcapacity.Toimprovetheimpacttoughnessoftheweldzone,anewfuzzycontrolsystemofweldzoneheattreatmentisdeveloped.Thetemperatureaccuracyofthesystemcanbeguaranteedwithinthe±5℃togetastableheattreatmentquality.Anewdrillpipestraightnessautomaticdetectiondevicesandself-learningmethodofstraighteningaredevelopedtoachieveautomatedstraightening.Aweldingprocesswithhighspeed,single-stagepressureandhighforgingforceisappliedtoinertiafrictionwelding.Aweldingprocesswithlowspeed,three-stagepressureandlowforgingforceisappli

简介：Thestressanalysisofthehumanfemurisconsiderablycomplicated.Inadditiontothemotionalpostureandtheloadingconditionofthefemur,itisgreatlyrelatedtoitsgeometryandbonystructureindifferentparts.Inpreviousresearches,themeansoffemoralshapeusinginthefinite-element-analysiswasobtainedbymeansofapply-ingtheradiographswhichweretheninputincomputer.Obviously,theresultswereneitherrealnorprecise.Inthispaper,thecomputerimageprocessingwasusedtogetthegeometryandthesizeofthehumanfemur,whichcouldmakethefinite-ele-

简介：Influenceofthermo-mechanicalcontrolledprocessing(TMCP),includingtwo-stagerollingwithlaminarcooling,aircoolingandultra-fastcooling,onthemicrostructureandmechanicalpropertiesofthreekindsofNb-microalloeyedsteelswasinvestigatedbyhot-rollingexperiment.Effectofchemistrycompositionsandmicrostructureonmechanicalpropertiesandtherelationshipbetweenthemultiphasemicrostructure’sformationwithTMCPwereanalyzed.Theresultsshowedthatthemixedmicrostructurecontainingferrite,bainite,martensiteandasmallamountofretainedaustenitecanbeobtainedbythermo-mechanicalcontrolledprocessing.Size,quantityanddistributionoftheconstituents(ferritegrain,bainitepacketandM-Aislands)significantlyaffectthemechanicalpropertiesofthreekindsofNb-microalloyedsteels.UndertheconditionofsimilarTMCPparameters,thereisagraduallydecreasingtendencyintensilestrengthfromhighsiliconNbsteel,highsiliconNb-TisteeltolowsiliconNb-Tisteel,andanoppositetendencyintotalelongationandproductoftensilestrengthandductility.Totalelongationandproductoftensilestrengthandductilityreachthemaximumvalues(41%and25256MPa%respectively)forlowsiliconNb-Tisteel.

简介：Havingawiderangeofmotion,thecervicalspineisratherpredisposedtotrau-maandotherdisorderswithseriousconsequences.Themotionofcervicalspineisacomplexonecomposedofmicromotions,includinghorizontaldisplacementsalongallthreeaxesandrotationsaroundthemwithsixfreedomdegreesofmovement.Reportonprecisemeasurementofthethree-dimensionalmotionofthecervicalsectionof