Polycrystalline pob zeb diamond thiab carbide composite inserts (PCD / CC)
PCD / CC yog cov pob zeb diamond siv dav tshaj plaws rau kev ua cov hlau matrix composites. Nws yog tsim los ntawm sintering los yog nias ib txheej ntawm polycrystalline pob zeb diamond PCD nrog ib tug tuab ntawm {{0}} 5-1 hli rau saum npoo ntawm cemented carbide substrate nrog zoo zog thiab toughness. Lub zog dabtsi yog khoov ntawm cov hniav sib xyaw no yog qhov zoo ib yam li cov cemented carbide, thiab qhov hardness ntawm qhov chaw ua hauj lwm yog ze rau ntawm cov khoom polycrystalline pob zeb diamond PCD, thiab weldability yog zoo, regrinding yog ib qho yooj yim, thiab tus nqi yog. qis. Ib tug raug polycrystalline pob zeb diamond-tungsten carbide insert yog tiaj los yog daim ntawv zoo li, thiab tom qab ntawd laser-txiav mus rau qhov xav tau cov duab thiab qhov loj ntawm cov ntxig. PCD / CC feem ntau yog welded los yog tshuab-clamped, thiab ua rau ntau yam cuab yeej xws li tig, drilling, milling, xuas nrig ntaus, reaming, tho txawv thiab sawing. Kev ua tau zoo ntawm PCD / CC muaj feem xyuam rau qhov loj ntawm pob zeb diamond nplej. De Beers tsim PCD inserts nyob rau hauv 002, 010 thiab 025 ntau yam, nrog nruab nrab grain loj ntawm 2µm, 10µm thiab 25µm, feem. Qhov loj ntawm cov nplej loj, qhov sib sau ntawm pob zeb diamond ntau dua, qhov zoo dua qhov hnav tsis kam thiab lub neej ntev ntawm cov cuab yeej, tab sis qhov zoo ntawm cov ntug txiav yog me ntsis zuj zus, ua rau nws nyuaj rau kev ua cov cuab yeej siab. Ntawm qhov tsis sib xws, cov cuab yeej nplua nuj muaj lub vojvoog ntawm qhov txiav (feem ntau 1-2 ntawm PCD cov cuab yeej), thiab cov tshuab ua haujlwm zoo yog qhov zoo. Yog li ntawd, cov khoom siv lead ua ntawm polycrystalline tau ua tiav tas li, thiab muaj cov muaju zoo nrog 1 acid lossis tsawg dua 0.5 acid. Txog rau qhov kawg no, lub neej ntawm lub cuab yeej thiab qhov zoo ntawm lub tshuab ua haujlwm yuav tsum tau txiav txim siab los xaiv cov qib tsim nyog ntawm polycrystalline pob zeb diamond thiab cemented carbide composite inserts.
CVD pob zeb diamond
CVD pob zeb diamond yog cov khoom siv pob zeb diamond ntshiab uas muaj kev hnav tsis kam, tsis muaj binders, uas tau npaj rau qhov tsis tshua muaj siab (<0.1MPa). CVD diamond comes in two forms: CVD thin film coating (CD) and CVD thick film (TFD).
CD yog tsim los ntawm depositing ib txheej ntawm zaj duab xis zoo li pob zeb diamond nrog ib tug tuab ntawm tsawg tshaj li 50µm (feem ntau 10 ~ 30µm) muaj li ntawm polycrystals ntawm ib tug cemented carbide substrate (feem ntau hu ua K-hom alloy) los ntawm CVD (chemical vapor deposition) txheej txheem . Kev siv tau pom tias CD pob zeb diamond-coated cov cuab yeej tsis haum rau kev ua cov hlau matrix sib xyaw, vim tias cov khoom nyuaj hauv cov khoom sib xyaw tuaj yeem hnav los ntawm txheej txheej ntawm cov cuab yeej hauv lub sijhawm luv luv.
TFD yog tso rau cov pob zeb diamond substrateless cov yeeb yaj kiab tuab nrog lub thickness txog li 3-5 hli, thiab tom qab ntawd txiav cov zaj duab xis tuab rau hauv me me ntawm cov duab raws li qhov xav tau, thiab tom qab ntawd welded rau ntawm cemented carbide rau daim ntawv. ib tug composite hniav los yog cuab yeej.
TFD muaj kev ua tau zoo, nws tsis muaj qhov tsis zoo ntawm anisotropy ntawm ntuj pob zeb diamond, vim tias tsis muaj hlau daim ntawv cog lus, cov ntsiab lus impurity tsawg, thiab purity yog ze li ntawm 100 feem pua, yog li cov hardness thiab thermal conductivity siab dua PCD. , qhov kev sib txhuam me me, tshuaj lom neeg kev ruaj ntseg zoo dua, thiab kev ua haujlwm ntawm cov hlau matrix composites yog qhov zoo heev.
Qhia yog cov cuab yeej hnav nkhaus rau 40 feem pua SiCP A356MMC nrog ob lub pob zeb diamond, PCD thiab TFD. Cov kev txiav txim siab siv hauv kev sim hauv daim duab 2 yog: txiav ceev ntawm 400m / min, pub tus nqi ntawm 0.05mm / r, rov qab txiav nyiaj (txiav qhov tob) ntawm 0.5mm, thiab txiav cov kua dej. Nws tuaj yeem pom los ntawm daim duab 2 tias cov tuab-zaj duab xis pob zeb diamond TFD yog qhov zoo tshaj plaws rau kev ua 40 feem pua SiCP hlau matrix composites; PCD025 yog qhov thib ob, thiab PCD002 muaj lub neej qis tshaj plaws. Table 1 qhia txog kev txiav tsis pom zoo los ntawm De Beers rau machining hlau matrix composites nrog polycrystalline pob zeb diamond qib SYNDITE 025 inserts. Kev tshawb fawb qhia tau hais tias nrog kev nce ntawm kev txiav ceev thiab txo tus nqi pub, tus nqi Ra ntawm machined nto roughness yuav txo qis, thaum tus nqi ntawm cov cuab yeej txiav rov qab tsis muaj qhov cuam tshuam loj rau Ra. Yog li ntawd, thaum ua tiav, txiav ceev yuav tsum coj tus nqi loj dua hauv Table 1, thiab tus nqi pub yuav tsum coj tus nqi me dua.
Lub machining ntawm hlau matrix composites nrog pob zeb diamond yuav qhuav txiav los yog ntub txiav. Txawm li cas los xij, vim tsis muaj thermal stability ntawm pob zeb diamond, nws yuav carbonized (xws li graphitized) ntawm 700-800 degree C, uas yuav txo tau cov cuab yeej lub neej. Yog tias cov kua txiav yog siv rau kev txiav ntub dej, qhov txiav tuaj yeem txo qis thiab lub cuab yeej lub neej tuaj yeem nce ntxiv. Txawm li cas los xij, ua ntej lub cuab yeej txiav rau hauv lub workpiece, cov kua txiav yuav tsum tau nchuav kom txog thaum txiav tiav. Cov kua txiav yuav tsum tau muab nkag mus tas li, tsis tu ncua, txwv tsis pub nws yuav yooj yim ua rau lub cuab yeej puas lossis chipped. Nyob rau hauv tib txoj kev, thaum lub sij hawm txiav, nws yog ib qho tsim nyog yuav tsum tsis txhob tso tseg lossis hloov cov txiav txiav kom ntau li ntau tau.