Extrusion yog txheej txheem compressive deformation nyob rau hauv uas ib tug block ntawm hlau yog nyem los ntawm ib tug orifice los yog tuag qhib nyob rau hauv thiaj li yuav kom tau ib tug txo nyob rau hauv txoj kab uas hla thiab nce nyob rau hauv ntev ntawm cov hlau thaiv.Cov khoom tshwm sim yuav muaj qhov xav tau hla ntu.Extrusion suav nrog kev tsim cov axisymmetric qhov chaw.Kev tuag ntawm cov voj voog ntawm qhov tsis yog voj voog hla ntu yog siv rau extrusion.Feem ntau, extrusion muaj ntau zog tsim.Loj hydrostatic kev nyuaj siab nyob rau hauv extrusion pab nyob rau hauv cov txheej txheem los ntawm kev txhim kho cov ductility ntawm cov khoom.Cov hlau zoo li aluminium, uas yooj yim ua haujlwm, tuaj yeem raug extruded ntawm chav tsev kub.
Hom ntawm extrusion:
Direct extrusion:Direct extrusion, tseem hu ua rau pem hauv ntej extrusion, yog ib tug txheej txheem nyob rau hauv uas yog lub billet txav raws tib txoj kev raws li lub ram thiab punch ua.zawv zawg ntawm billet yog tiv thaiv cov thawv ntim khoom ruaj ruaj.Friction ntawm lub thawv thiab billet yog siab.Yog li ntawd, yuav tsum muaj zog ntau dua.Ib tug dummy block ntawm me ntsis qis dua txoj kab uas hla ntawm billet yog siv los tiv thaiv oxidation ntawm billet nyob rau hauv kub extrusion.Hollow seem zoo li cov hlab tuaj yeem raug extruded los ntawm txoj kev ncaj qha, los ntawm kev siv hollow billet thiab ib tug mandrel txuas rau lub dummy block.
Indirect extrusion:Indirect extrusion (rov qab extrusion) yog ib qho txheej txheem uas cov punch txav rov qab mus rau ntawm cov pob zeb.Ntawm no tsis muaj qhov txheeb ze ntawm lub thawv thiab billet.Yog li ntawd, muaj kev sib txhuam tsawg dua thiab yog li txo qis zog yuav tsum tau rau indirect extrusion.Rau extruding khoom, hollow punch yog yuav tsum tau.Hauv hollow extrusion, cov khoom raug yuam los ntawm qhov chaw annular ntawm cov khoom punch thiab lub thawv.Qhov txawv ntawm extrusion siab nyob rau hauv indirect extrusion yog qhia saum toj no.Raws li pom, extrusion siab rau indirect extrusion yog qis dua li qhov ncaj qha extrusion.Ntau yam khoom yog tsim los ntawm kev sib txuas ncaj qha thiab tsis ncaj qha extrusion.Indirect extrusion tsis tuaj yeem siv rau extruding ntev extrudes.
Hydrostatic extrusion:Nyob rau hauv hydrostatic extrusion lub thawv yog ntim nrog ib tug kua.Extrusion siab yog kis los ntawm cov kua mus rau lub billet.Kev sib txhuam yog tshem tawm hauv cov txheej txheem no vim tias tsis muaj kev sib cuag ntawm cov pob zeb thiab cov thawv ntim.Cov ntaub ntawv brittle tuaj yeem raug extruded los ntawm cov txheej txheem no.Cov ntaub ntawv nkig heev tuaj yeem raug extruded rau hauv lub siab chamber.Kev txo qis ntau dua tuaj yeem ua tau los ntawm txoj kev no.Lub siab koom nrog hauv cov txheej txheem yuav siab li 1700 MPa.Lub siab yog txwv los ntawm lub zog ntawm lub thawv, punch thiab tuag cov ntaub ntawv.Cov roj zaub xws li roj castor yog siv.Feem ntau cov txheej txheem no yog nqa tawm ntawm chav tsev kub.Ob peb qhov tsis zoo ntawm cov txheej txheem yog: to ntawm cov roj pressurized thiab uncontrolled ceev ntawm extrusion ntawm tawm, vim yog tso tawm ntawm lub zog cia los ntawm cov roj.Qhov no yuav ua rau muaj kev poob siab hauv cov tshuab.Qhov teeb meem no tau kov yeej los ntawm kev ua kom cov punch tuaj rau hauv kev sib cuag nrog lub billet thiab txo cov roj kom tsawg los ntawm kev tshem tawm tsawg dua ntawm cov pob zeb thiab cov thawv.
Kev cuam tshuam extrusion:Hollow seem xws li khob, ntim tshuaj txhuam hniav yog tsim los ntawm kev cuam tshuam extrusion.Nws yog ib tug variation ntawm indirect extrusion.Lub punch yog tsim los ntaus lub slug ntawm kev kub ceev los ntawm kev cuam tshuam load.Tubes ntawm cov phab ntsa me me tuaj yeem ua tau.Feem ntau cov hlau xws li tooj liab, txhuas, txhuas yog cuam tshuam extruded.
Tube extrusion:Ua haujlwm hollow billet thiab ib lub mandrel ntawm qhov kawg ntawm tus ram, hollow seem xws li cov raj tuaj yeem raug extruded kom ze zog.Lub mandrel txuas mus rau qhov nkag ntawm qhov tuag.Clearance ntawm lub mandrel thiab tuag phab ntsa txiav txim siab phab ntsa thickness ntawm lub raj.Lub mandrel yog tsim los mus nrog rau cov ram thiaj li ua kom cov hlab ntsha concentric los ntawm extrusion.
Txias thiab kub extrusion:
Txias extrusion tuaj yeem tsim qhov chaw nrog qhov zoo ntawm qhov tiav, lub zog siab vim muaj zog tawv, txhim kho qhov tseeb, siab ntau lawm.Txawm li cas los xij, cov txheej txheem yuav tsum muaj siab dua thiab cov cuab yeej raug rau kev ntxhov siab ntau dua.Kev tsim nyog lubrication yog tsim nyog los tiv thaiv kev qaug dab peg ntawm cov cuab yeej thiab cov khoom ua haujlwm.Phosphate coated billets yog lubricated nrog xab npum.
Kub extrusion tuaj yeem ua haujlwm rau ntau dua extrusion piv.Inhomogeneous deformation tuaj yeem tshwm sim vim tuag phab ntsa chilling ntawm billet.Hlau yuav tau oxidized.Cov txheej oxide tuaj yeem ua rau muaj kev sib txhuam ntxiv nrog rau cov khoom ntws.iav yog siv los ua lubricant rau kub extrusion.Molybdenum disulfide los yog graphite yog cov khoom lubricants siv nyob rau hauv kub extrusion.Cov kaus poom extrusion siv nyias phab ntsa cov kaus poom ua los ntawm tooj liab los yog tin feem ntau yog siv rau extruding heev reactive hlau thiab hlau hmoov.
Extrusion xovxwm:
Hydraulic presses ntawm ntsug los yog kab rov tav hom yog siv rau extrusion.Vertical presses muaj peev xwm ntawm 3 mus rau 20 MN.Kab rov tav presses nyob qhov chaw tsawg dua, tab sis cov billets tau txias tsis sib xws.Kab rov tav presses mus txog 50 MN muaj peev xwm raug siv.Tubular extrusion feem ntau yog ua nyob rau hauv ntsug presses, thaum kab rov tav presses yog siv rau bar extrusion.
Post lub sij hawm: Apr-03-2017