Kev nqis peev casting yog txheej txheej ntau txheej ntawm refractory coatings rau saum npoo ntawm cov quav pwm. Tom qab nws yog hardened thiab qhuav, cov ciab pwm yog melted los ntawm cua sov kom tau ib lub plhaub nrog ib tug kab noj hniav sib xws rau cov duab ntawm cov quav ciab pwm. Tom qab ci, nws yog poured rau hauv Ib txoj kev tau txais castings, yog li nws tseem hu ua poob ciab casting. Nrog rau kev txhim kho tas mus li ntawm cov cuab yeej tsim khoom, cov txheej txheem tshiab wax molding tseem tshwm sim, thiab ntau yam khoom siv rau molding yog nce. Tam sim no txoj kev tshem tawm pwm tsis txwv rau melting, thiab molding cov ntaub ntawv tsis txwv rau cov ntaub ntawv siv quav ciab. Cov pwm yas kuj tseem siv tau. Vim tias cov castings tau los ntawm txoj kev no muaj qhov tseeb dua qhov tseeb thiab qis dua qhov roughness qhov tseem ceeb, nws tseem hu ua precision casting.
Basic feature ntawmpeev castingyog tias cov pwm pov tseg meltable yog siv thaum ua lub plhaub. Vim tias tsis muaj qhov yuav tsum tau kos pwm, lub plhaub yog ib qho tsis muaj qhov sib cais, thiab lub plhaub yog ua los ntawm cov khoom siv refractory nrog kev ua haujlwm kub zoo heev. Kev nqis peev casting tuaj yeem tsim cov txheej txheem zoo li cas, nrog qhov tsawg kawg nkaus phab ntsa thickness ntawm 0.3 hli thiab qhov tsawg kawg nkaus txoj kab uas hla ntawm lub qhov casting ntawm 0.5 hli. Qee lub sij hawm hauv kev tsim khoom, qee qhov chaw tsim los ntawm ntau qhov chaw tuaj yeem ua ke rau hauv tag nrho los ntawm kev hloov cov qauv thiab ncaj qha tsim los ntawm peev casting. Qhov no tuaj yeem txuag kev ua cov txiv neej-teev thiab cov khoom siv hlau siv, thiab ua rau cov qauv ntawm cov khoom sivcasting qhov chawtsim nyog dua.
Qhov hnyav ntawm castings tsim los ntawm peev casting feem ntau yog li ntawm kaum ntawm grams mus rau ob peb kilograms, los yog txawm kaum kilograms. Cov khoom hnyav dhau lawm tsis haum rau kev nqis peev casting vim qhov kev txwv ntawm kev ua haujlwm ntawm cov khoom siv molding thiab qhov nyuaj ntawm kev ua lub plhaub.
Castings tsim los ntawm peev castingtsis txwv los ntawm hom alloys, tshwj xeeb tshaj yog rau cov alloys uas nyuaj rau kev txiav los yog forge, uas tuaj yeem qhia nws qhov zoo tshaj plaws. Txawm li cas los xij, peev casting ntau lawm kuj muaj qee qhov tsis txaus, feem ntau yog vim muaj cov txheej txheem ntau, kev ua haujlwm ntev, cov txheej txheem thev naus laus zis, thiab ntau yam cuam tshuam rau qhov zoo ntawm castings, uas yuav tsum tau nruj me ntsis tswj kom ruaj khov ntau lawm.
Piv nrog rau lwm txoj hauv kev casting, qhov zoo tshaj plaws ntawm kev peev casting yog siv cov pwm meltable los ua lub plhaub. Ib lub peev pwm tau noj txhua zaus thaum lub plhaub tsim. Qhov tsim nyog yuav tsum tau ua ua ntej kom tau txais cov khoom zoo tshaj plaws nrog qhov siab qhov tseeb thiab qhov tsis zoo ntawm qhov roughness qhov tseem ceeb yog cov peev txheej pwm nrog qhov siab qhov tseeb thiab qhov tsawg ntawm qhov roughness qhov tseem ceeb. Yog li ntawd, kev ua tau zoo ntawm cov khoom siv molding (xws li cov khoom siv pwm), qhov zoo ntawm molding (tus qauv siv los nias lub peev) thiab cov txheej txheem molding yuav cuam tshuam ncaj qha rau qhov zoo ntawm cov peev txheej casting.
Kev nqis peev casting pwm yog tam sim no feem ntau siv hauv lub plhaub ua los ntawm cov khoom siv refractory multilayer. Tom qab lub module yog dipped thiab coated nrog refractory txheej, sprinkle lub granular refractory khoom, thiab ces qhuav thiab harden, thiab rov ua cov txheej txheem no ntau zaus kom txog rau thaum lub refractory txheej mus txog qhov yuav tsum tau thickness. Nyob rau hauv txoj kev no, lub plhaub ntau txheej yog tsim rau ntawm lub module, uas feem ntau yog nres rau lub sijhawm kom qhuav thiab tawv, thiab tom qab ntawd demolded kom tau txais lub plhaub ntau txheej. Qee lub plhaub ntau txheej yuav tsum tau ntim nrog xuab zeb, thiab qee qhov tsis ua. Tom qab ci, lawv tuaj yeem nchuav ncaj qha, uas yog hu ua lub plhaub muaj zog.
Qhov zoo ntawm lub plhaub yog ncaj qha ntsig txog qhov zoo ntawm qhov casting. Raws li kev ua haujlwm ntawm lub plhaub, kev ua haujlwm ntawm lub plhaub feem ntau suav nrog:
1) Nws muaj qhov kub thiab txias lub zog, haum rau lub zog kub thiab tsis tshua muaj zog.
2) Nws muaj huab cua zoo permeability (tshwj xeeb tshaj yog kub cua permeability) thiab thermal conductivity.
3) Lub linear expansion coefficient yog me me, thermal expansion yog tsawg thiab expansion yog uniform.
4) Kev tiv thaiv zoo heev rau txias txias thiab kub thiab thermal stability.
Cov khoom ntawm lub plhaub no zoo sib xws rau cov khoom siv hauv lub plhaub ua thiab cov txheej txheem ua lub plhaub. Plhaub cov ntaub ntawv muaj xws li cov ntaub ntawv refractory, binders, cov kuab tshuaj, hardeners, surfactants, thiab lwm yam. Ntawm lawv, cov khoom siv refractory thiab cov binder ncaj qha tsim lub plhaub, uas yog lub plhaub tseem ceeb. Cov ntaub ntawv refractory siv hauv peev casting yog silica xuab zeb, corundum thiab aluminosilicate refractories (xws li refractory av nplaum thiab txhuas banadium, thiab lwm yam). Tsis tas li ntawd, qee zaum siv zircon xuab zeb thiab magnesia xuab zeb.
Powdered refractory khoom thiab binder yog npaj rau hauv refractory txheej, thiab cov khoom siv refractory granular yog sprinkled rau ntawm lub refractory txheej thaum lub plhaub yog ua. Binders siv nyob rau hauv refractory coatings mas muaj xws li ethyl silicate hydrolysate, dej iav thiab silica sol. Cov xim npaj nrog ethyl silicate muaj cov txheej txheem zoo, lub plhaub siab lub zog, me me thermal deformation, siab qhov tseeb ntawm qhov tau txais castings, thiab zoo nto zoo. Nws yog feem ntau yog siv los tsim cov hlau tseem ceeb hlau castings thiab lwm yam castings nrog qhov zoo ntawm qhov yuav tsum tau ua. SiO2 cov ntsiab lus ntawm ethyl silicate ua nyob rau hauv Tuam Tshoj yog feem ntau 30% mus rau 34% (qhov loj feem), yog li nws yog hu ua ethyl silicate 32 (32 sawv cev rau qhov nruab nrab loj feem ntawm SiO2 hauv ethyl silicate). Ethyl silicate tuaj yeem ua lub luag haujlwm khi tsuas yog tom qab hydrolysis.
Lub plhaub txheej npaj nrog dej iav yog yooj yim rau deform thiab tawg. Piv nrog ethyl silicate, cov castings uas tsim muaj qhov tsawg qhov tseeb thiab qhov siab ntawm qhov roughness. Dej iav binder yog tsim rau zus tau tej cov me me zoo tib yam steel castings thiabnon-ferrous alloy castings. Dej iav rau peev casting feem ntau muaj ib qho qauv ntawm 3.0 ~ 3.4 thiab qhov ceev ntawm 1.27 ~ 1.34 g / cm3.
Silica sol binder yog aqueous tov ntawm silicic acid, tseem hu ua silica sol. Nws tus nqi yog 1/3 ~ 1/2 qis dua li ntawm ethyl silicate. Qhov zoo ntawm castings tsim los ntawm kev siv silica sol raws li ib tug binder yog siab tshaj ntawm cov dej iav. Tus neeg sawv cev khi tau zoo heev. Silica sol muaj kev ruaj ntseg zoo thiab tuaj yeem khaws cia rau lub sijhawm ntev. Nws tsis xav tau tshwj xeeb hardeners thaum ua cov plhaub. Lub siab kub lub zog ntawm lub plhaub yog zoo dua li ntawm ethyl silicate plhaub, tab sis cov silica sol muaj tsis zoo wettability rau cov peev thiab yuav siv sij hawm ntev zog. Cov txheej txheem tseem ceeb ntawm lub plhaub ua muaj xws li module degreasing, txheej thiab xuab zeb, ziab thiab hardening, demoulding thiab roasting.
Post lub sij hawm: Feb-11-2021