Lub ntsiab
Hmoov kav hlau nrog txaus me me particle (<45 μm), high powder loading in polymers, and high density after sintering can be used for metal injection molding, with powders having an average particle size of less than 22 μm being the most ideal. Numerous methods exist for powder preparation, but powders prepared by different methods possess different properties, which ultimately affect the density, size, and deformation of the injected parts. Because small particles are used to characterize powder properties, many characterization methods (such as sieving) are insufficient to accurately monitor and predict the results of the metal injection molding process. This chapter mainly introduces powders used in metal injection molding, different powder preparation methods, the properties of metal injection molding powders, and the influence of powder geometry or manufacturing methods on the metal injection molding process.
Cov txheej txheem npaj sib txawv rau Mim hmoov
Muaj ntau txoj hauv kev rau kev npaj hmoov rau kev txhaj tshuaj tiv thaiv hlau (mim), suav nrog roj atomization, cua decomposition, thiab txo cov tshuaj lom neeg.
Thaum nws yog qhov tsim nyog los ntxiv ib qho me me ntawm hmoov rau ib tug alloy lossis los npaj tej yam tshwj xeeb ntawm cov txheej txheem hmoov, xws li cov tshuab crushing / sib tsoo, feem ntau yog siv. Lub carburizing ntawm ntshiab tungsten hmoov los tsim tungsten carbide {}}}} qib ua hmoov yog qhov kev zam. Cov Lus 3.1 qhia txoj kev npaj thiab cov yam ntxwv ntawm Mim hmoov; Lwm cov txheej txheem npaj khoom muaj sia tuaj yeem pom lwm qhov.
Qhia qhov me me thiab qhov loj me faib cov hmoov MIM yog ib kauj ruam tseem ceeb hauv cov hmoov av ntawm cov hmoov uas muaj qhov sib txawv me me; Yog li ntawd, nws yog qhov tseem ceeb kom ua kom muaj kev sib xws ntawm mim hmoov thoob plaws.
Rooj 3.1 Npaj txoj kev txoj kev thiab cov yam ntxwv ntawm Mim hmoov
| Kev npaj txoj kev | Tus nqi txheeb ze | Hlau lossis Alloy Piv Txwv | Particle Loj / μm | Particle picat |
|---|---|---|---|---|
| Roj Atomization | Siab | Stainless Hlau, Superalloy F75, MP35N, Titanium, Master Alloy Additives | 5 ~ 45 | Tus kheej |
| Dej atomization | Nruab nrab | Tib yam li roj atomization tsuas yog rau titanium thiab hlau alloys | 5 ~ 45 | Elliptical, tsis xwm yeem |
| Thermal Decomposition | Nruab nrab | Hlau, npib tsib xee | 0.2 ~ 20 | Kheej kheej, koob -} zoo li tus |
| Tshuaj txo qis | Siab / Nruab Nrab | Tungsten, molybdenum | 0.1 ~ 10 | Polygonal, spherical |
Roj Atomization
Cov roj atomization yog ib txoj kev npaj hmoov los ntawm melting hlau los yog lwm txoj hauv kev los ntawm kev hais lus cua kub thiab ntxiv rau ntawm lub ntsej muag. Tom qab tawm ntawm lub nozzle, cov hlau lossis alloy yog cuam tshuam los ntawm qhov siab- ceev cov roj txaus, tawg rau hauv cov yaj ua kom zoo. Cov tee dej no ua tau zoo rau hauv kev sib zog ua rau lub caij nplooj zeeg dawb. Lub siab - Ceev muab roj ceev tau yog feem ntau nitrogen, argon, lossis nitrogen; huab cua kuj tseem siv tau los ua qee cov hmoov tshwj xeeb. Huab cua - atomized omass muaj qib siab ntawm cov xim oxidation; Yog li, huab cua atomization tsis pom zoo rau cov ntaub ntawv engineering, tshwj xeeb yog cov neeg ua yeeb yaj kiab oxide nyuaj rau tshem tawm thaum xa tawm thaum xa tawm thaum lub sijhawm tshaj tawm {} sintering. Lub atomized tej yam poob dawb hauv ib lub taub loj, yog li muaj kev sib tw ua ntej hu rau cov thawv phab hlau. Thaum lub sij hawm atomization, yog tias muaj kev kub ntxhov nyob ze ntawm lub nozzle, cov khoom me me tuaj yeem rov qab} nkag rau hauv cov khoom me me, cov hmoov av me, cov khoom sib txawv. Cov dej tsis xwm yeem cuam tshuam nrog cov hmoov ntim ntom ntom ntom ntom ntom thiab cov khoom ua kom txaus siab rau cov khoom noj khoom haus. Dav - loj} {14 14 14 14 14}} Distribution omdized hmoov tuaj yeem tsim los ntawm sieving lossis huab cua sorting. Oversized hais qhia tuaj yeem rov qab- atom} atom los ua me- loj loj. Daim duab 3.4 qhia tau tias yog Electron lub tshuab ntsuas hluav taws xob qub (sem) duab ntawm cov duab atomized stainless hlau, uas muaj qhov sib txawv, thiab cov ntom ntom ntom.
Dej atomization
Cov ntsiab cai ntawm dej atomization thiab roj atomization yog qhov zoo sib xws. Qhov sib txawv yog tias dej, hloov roj, yog siv los tsoo cov hlau ua rau hauv cov khoom zoo. Nws siv lub siab high- Lub dav hlau dej siab los cuam tshuam rau cov hlau molten hlau ntws, nrawm tsoo nws thiab ua rau nws hmoov. Superheated yaj, tom qab ua atomized los ntawm lub siab- Lub dav hlau dej siab, tsim cov khoom siv tau siab ntau, kheej kheej. Yog li ntawd, siv dej atomization los npaj cov hmoov hlau hauv superheate kub thiab cov dej siab nias yog qhov tseem ceeb rau MIM (kev txhaj tshuaj hlau). Zoo ib yam li roj atomization, particle loj ntawm dej {{} omemized hmoov yog ib kauj ruam tseem ceeb hauv mim hmoov ntau lawm. Daim duab 3.5 qhia tau tias muaj cov duab semi ib txwm muaj dej {{} atomized stainless hlau hmoov. Cov lus no muaj cov duab tsis xwm yeem, thiab piv rau roj atomization, cov nplaim dej ntawm dej {} omolized hmoov xau yog qhov hnyav dua. Irregatally cov hais muaj qhov zoo dua hauv kev tswj cov duab thaum daws teeb meem ntawm kev txhaj tshuaj {{}} moulded seem. Dej atomization muaj ntau dua ntau dua kev ua haujlwm ntau dua li roj ing {16} omalized cov hmoov ntau dua li ntawm cov roj {} om atom} atomized hmoov.
Thermal Decomposition
Thermal decomposition yog ib qho tshuaj lom neeg cov tshuaj lom neeg los ntawm tshav kub, feem ntau yog siv los ua cov nickel thiab cov hmoov hlau rau kev txhaj tshuaj hlau. Tungsten thiab Cobalt cov hmoov tseem tuaj yeem npaj tau siv cov thev naus laus zis no. Cov hmoov uas tau ua los ntawm kev ua kom lub thermal muaj kev coj dawb huv ntau dua 99% thiab qhov loj me me los ntawm 0.20 txog 20 μm. Hauv cov txheej txheem no, cov hlau reacts nrog carbon monoxide nyob rau hauv kev kub siab thiab kub kom tsim cov carbon {}}} bead hlau. Cov pa roj carbon -} Cov kua yog huv, txias, thiab tom qab ntawd rov qab ua haujlwm ntawm qhov kev ua yeeb yam, ua rau lub vapor kom ua rau cov hmoov. Daim duab 3.6 qhia tau ib qho Sem sem duab ntawm thermally decomposed carbon -} Raws li cov hmoov av. Cov hmoov no feem ntau muaj cov roj carbon impurities thiab yuav tsum tau txo qis hauv hydrogenities ua ntej siv lossis thaum muaj kev suav nrog kev sib xyaw ua ke rau qis-}}}}}}} alllo. Yog hais tias cov hmoov tau txo ua ntej kev txhaj tshuaj tiv thaiv kev sib xyaw ua ntej, cov nplais yuav tsum yog kev tshem tawm agglomeration vim tias lawv sib tsoo ua ke thaum lub sijhawm txo qis. Tsis tas li ntawd, cov hmoov nplej sintering ntawm cov hmoov uas txo qis dua li ntawm cov hmoov tsis zoo vim tias cov hmoov av uas tsis muaj txiaj ntsig los ntawm cov khoom loj dua thaum txo qis.
Kev txo cov tshuaj txo cov tshuaj
Cov kev txo tshuaj txo cov tshuaj yog ib qho ntawm cov txheej txheem ntau tshaj plaws uas paub ntau lawm. Cov qauv no ua ntej cov oxide, tom qab ntawd siv cov neeg sawv cev txo xws li cov pa roj carbon monoxide nrog nws kom tsim cov pa roj carbon monoxide lossis carbon dioxide txo. Hydrogen kuj tseem siv tau los txo cov oxide rau cov hmoov av hlau. Txhawm rau txo qhov loj me me, cov tshuaj tiv thaiv kev txo qis yog nqa tawm ntawm qhov kub tsawg, tab sis tus nqi tshuaj tiv thaiv tsawg. Siv qhov kub siab dua tuaj yeem nrawm dua cov txheej txheem ntawm no, tab sis siab dua tuaj yeem ua rau sib tsoo, uas yuav tsum tau muab tshem tawm los ntawm kev sib tsoo lossis sib tsoo kom txaus. Yog hais tias cov lus tsis tau tsoo, cov hmoov sib xyaw ua ke tsis tuaj yeem thauj mus rau hauv cov khoom siv, ua rau muaj kev kub ntxhov thaum lub sij hawm txhaj tshuaj molding. Daim duab 3.7 qhia ib qho sem duab tungsten tsim los ntawm kev txo tshuaj lom neeg.
