Refractory castablesfeem ntau muaj qhov txo qis hauv lub zog ntawm qhov kub nruab nrab (feem ntau 800℃-1000℃lossis siab dua). Qhov no feem ntau yog vim lub cev qhuav dej, recrystallization, thiab lub cev shrinkage ntawm hydrates nyob rau hauv lub binder, ua rau ib tug ntxeem tau qauv. Txhawm rau txhim kho qhov nruab nrab-kub lub zog ntawm cov khoom siv refractory castables, ib tus tuaj yeem tsom mus rau ntau qhov loj me: raw khoom proportioning, binder system optimization, additives use, thiab kev tsim kho. Cov hauv qab no yog cov tswv yim txhim kho tshwj xeeb:
I. Optimizing Raw Materials and Compensating for Chemical Reactions
Qhov no yog txoj kev ncaj ncees thiab ua tau zoo tshaj plaws. Lub hauv paus yog siv lub ntim expansion generated los ntawm cov tshuaj tiv thaiv los offset lub shrinkage thaum sintering.
1. Ntxiv Al₂O₃ Fine Powder: Ntxiv qhov tsim nyog ntawm Al₂O₃ (alpha alumina) hmoov zoo rau aluminate refractory castables yog qhov tseem ceeb. Nyob rau nruab nrab kub, nws undergoes ib tug expansion nyhuv tshuaj tiv thaiv, compensating rau lub zog txo los ntawm ntim shrinkage. Tshwj xeeb tshaj yog thaum lub binder yog CA-70 siab- alumina cement, ntxiv cov hmoov zoo no tuaj yeem ua rau lub zog nruab nrab ntawm qhov kub thiab txias tsis txhob txo nws.
2. Taw qhia txog cov khoom ua kom muaj zog: Ntshiab aluminate cement yog ua ke nrog silica fume. Ntawm 800-1200 degree, silica fume reacts nrog calcium oxide los ua ib qho anorthite reinforcing theem, uas tuaj yeem ua kom muaj zog nruab nrab ntawm qhov kub thiab txias li ntawm 20%.
II. Ntxiv cov sintering agents thiab expanding agents
Los ntawm kev qhia txog cov khoom siv ntxhia tshwj xeeb, tus cwj pwm sintering lossis ntim ruaj khov ntawm cov khoom ntawm qhov kub nruab nrab tuaj yeem hloov pauv.
1. Ntxiv cov av nplaum mos (sintering tus neeg sawv cev): Ntxiv 3%-6% av nplaum mos tuaj yeem txhawb nqa sintering ntawm cov castable ntawm qhov kub thiab txias, hloov cov microstructure thiab yog li ua rau nruab nrab- qhov kub thiab txias, txawm tias ntau tshaj qhov cub-qhuav lub zog.
2. Siv andalusite (siab- qhov kub thiab txias): Txawm hais tias andalusite feem ntau ua haujlwm ntawm qhov kub thiab txias (siab tshaj 1300 degree), yog tias cov qauv tsim tau zoo (ntxiv rau hauv cov hmoov zoo), cov mullite thiab ntau dhau SiO₂ generated thaum lub sij hawm nws decomposition ntawm qhov kub thiab txias muaj peev xwm tsim tau ob qho tib si mullitization ntawm qhov kub thiab txias.
3. Siv boron carbide: Boron carbide softens ntawm qhov kub thiab txias thiab adheres rau particle nto, pab kom densification. B₂O₃ oxide zaj duab xis tsim rau ntawm nws qhov chaw muab oxidation tsis kam, thaum lub columnar crystals generated txo porosity thiab txhim kho nruab nrab kub zog.
III. Txhim kho qhov sib txuas system:
Lub binder yog "skeleton" ntawm cov refractory castables. Xaiv ib tug haum binder tuaj yeem hloov pauv qhov tsis muaj zog hauv nruab nrab qhov kub thiab txias.
1. Siv cov qib siab -kev ua tau zoo cement: Ntshiab calcium aluminate cement (CA-70 lossis qib siab dua) yuav tsum tau siv thaum twg los tau. Piv nrog rau CA-50 cement zoo tib yam, nws muaj lub zog tuav tau zoo dua nyob rau theem nruab nrab kub.
2. Composite Binders: Cement yog ua ke nrog tshuaj binders (xws li phosphates), los yog cohesive binders (xws li silica sol thiab alumina sol) yog siv. Cov kev sib koom ua ke no tsim cov qauv kev sib txuas ruaj khov ntawm qhov nruab nrab ntawm qhov kub thiab txias, tsis zoo li cov dej ntshiab huv binders uas muaj feem cuam tshuam vim lub cev qhuav dej.
IV. Microstructure thiab Particle Loj Optimization:
Kev siv lub cev yog siv los ua kom cov qauv sab hauv ntawm cov khoom siv ntau dua thiab txo qhov tsis xws luag.
1. Tsim nyog Particle Size Distribution: Optimize particle tis ntawm aggregates (xws li corundum thiab mullite), ua raws li lub hauv paus ntsiab lus ntawm cov ntim ze tshaj plaws kom txo cov porosity sab hauv.
2. Taw qhia txog Micropowder Technology: Ntxiv cov nqi tsim nyog ntawm activated alumina micropowder los yog silica micropowder, siv cov nyhuv filling ntawm micropowder kom txo cov porosity pom, nce cov khoom ntom ntom, thiab yog li txhim kho lub zog.
V. Kev tsim kho thiab kev tswj xyuas:
Txawm tias qhov zoo tshaj plaws refractory castables cov ntaub ntawv formulation, kev tsim kho tsis zoo yuav txo tau lub zog.
1. Kev tswj xyuas nruj ntawm cov dej ntxiv: Kev sib ntxiv dej ntau dhau yuav ua rau muaj qhov porosity thiab txo qhov ntom. Cov dej ntxiv yuav tsum nruj me ntsis raws li cov neeg tsim khoom pom zoo cov nyiaj thaum sib tov.
2. Standardize cov txheej txheem ci: Thaum cua sov ntawm qhov nruab nrab kub theem (tshwj xeeb tshaj yog 900℃-1200 degree), lub sij hawm tuav txaus yuav tsum tau ua kom cov hydrates kom tag nrho lub cev qhuav dej thiab recrystallize, tsis txhob tawg los yog xoob qauv vim cua sov ntau dhau.
