1. Macroscopic Factors pab txhawb kev sib tsoo
1.1 Thaum lub sij hawm ib nrab-nruab nruam casting, dej txias yog ncaj qha mus rau ntawm qhov chaw ingot, tsim kom muaj qhov kub siab gradient nyob rau hauv lub ingot. Qhov no ua rau tsis sib xws ntawm cov cheeb tsam sib txawv, ua rau muaj kev sib koom ua ke thiab ua rau muaj kev ntxhov siab thermal. Hauv qee qhov kev ntxhov siab, cov kev ntxhov siab no tuaj yeem ua rau ingot tawg.
1.2 Hauv kev tsim khoom, ingot cracking feem ntau tshwm sim nyob rau hauv thawj theem casting los yog originates li microcracks uas tom qab propagate thaum lub sij hawm txias, muaj peev xwm kis mus rau tag nrho cov ingot. Ntxiv nrog rau kev tawg, lwm yam tsis xws luag xws li txias kaw, warping, thiab dai kuj tseem tuaj yeem tshwm sim thaum lub sij hawm pib casting, ua rau nws yog ib qho tseem ceeb nyob rau hauv tag nrho cov txheej txheem casting.
1.3 Lub susceptibility ntawm ncaj qha chill casting rau kub tawg yog ho cuam tshuam los ntawm cov tshuaj muaj pes tsawg leeg, master alloy ntxiv, thiab ntau npaum li cas ntawm grain refiners siv.
1.4 Lub kub tawg rhiab heev ntawm cov hlau yog feem ntau yog vim muaj kev ntxhov siab sab hauv uas ua rau cov voids thiab tawg. Lawv tsim thiab tis yog txiav txim los ntawm alloying ntsiab, yaj metallurgical zoo, thiab semi-nruam casting tsis. Tshwj xeeb, qhov loj me me ntawm 7xxx series aluminium alloys tshwj xeeb tshaj yog ua rau kub tawg vim muaj ntau yam alloying ntsiab lus, dav solidification ranges, siab casting stresses, oxidation segregation ntawm alloy ntsiab, kuj tsis zoo metallurgical zoo, thiab tsawg formability ntawm chav tsev kub.
1.5 Kev tshawb fawb tau pom tias electromagnetic teb thiab alloying cov ntsiab lus (xws li cov nplej refiners, loj alloying ntsiab, thiab kab kawm) cuam tshuam rau cov microstructure thiab kub cracking susceptibility ntawm semi-nruam nrum 7xxx series alloys.
1.6 Tsis tas li ntawd, vim cov complex muaj pes tsawg leeg ntawm 7050 aluminium alloy thiab muaj cov ntsiab lus oxidized yooj yim, cov yaj yuav nqus tau ntau hydrogen. Qhov no, ua ke nrog oxide inclusions, ua rau coexistence ntawm roj thiab inclusions, uas ua rau ib tug siab hydrogen ntsiab lus nyob rau hauv lub yaj. Cov ntsiab lus hydrogen tau dhau los ua qhov tseem ceeb cuam tshuam rau kev tshuaj ntsuam xyuas, kev coj tus cwj pwm tawg, thiab kev qaug zog ntawm cov khoom siv ua tiav. Yog li ntawd, raws li lub mechanism ntawm hydrogen nyob rau hauv lub yaj, nws yog tsim nyog los siv adsorption media thiab filtration-refining khoom kom tshem tawm hydrogen thiab lwm yam inclusions ntawm lub yaj kom tau ib tug heev purified alloy yaj.
2. Microscopic ua rau tawg tsim
2.1 Ingot kub cracking feem ntau txiav txim siab los ntawm tus nqi ntawm solidification shrinkage, pub tus nqi, thiab qhov tseem ceeb loj ntawm lub mushy cheeb tsam. Yog hais tias qhov loj ntawm lub cheeb tsam mushy tshaj ib tug tseem ceeb pib, kub tawg yuav tshwm sim.
2.2 Feem ntau, cov txheej txheem solidification ntawm alloys yuav muab faib ua ob peb theem: bulk feeding, interdendritic feeding, dendrite sib cais, thiab dendrite bridging.
2.3 Thaum lub sij hawm dendrite sib cais theem, dendrite caj npab ua kom zoo dua ntim thiab cov kua ntws yog txwv los ntawm qhov nro. Lub permeability ntawm thaj chaw mushy yog txo, thiab txaus solidification shrinkage thiab thermal stress yuav ua rau microporosity los yog kub tawg.
2.4 Nyob rau hauv lub dendrite bridging theem, tsuas yog ib tug me me ntawm cov kua nyob rau hauv triple junctions. Nyob rau ntawm lub sijhawm no, cov khoom siv semi-tshuaj muaj ntau lub zog thiab plasticity, thiab cov khoom siv hauv lub xeev yog tib lub tswv yim los them nyiaj rau kev sib zog ua kom lub zog thiab thermal stress. Ob theem no yog cov feem ntau yuav tsim shrinkage voids los yog kub tawg.
3. Kev Npaj Ua Haujlwm Zoo Tshaj Plaws Ingots Raws Li Cov Txheej Txheem Txheej Txheem Ua Haujlwm
3.1 Qhov loj-loj slab ingots feem ntau pom cov kab nrib pleb, sab hauv porosity, thiab inclusions, uas cuam tshuam rau cov neeg kho tshuab tus cwj pwm thaum lub sij hawm alloy solidification.
3.2 Cov khoom siv kho tshuab ntawm cov hlau thaum lub sij hawm khov kho feem ntau yog nyob ntawm cov txheej txheem sab hauv, suav nrog cov nplej loj, cov ntsiab lus hydrogen, thiab qib kev suav nrog.
3.3 Rau aluminium alloys nrog cov qauv dendritic, qhov thib ob dendrite caj npab sib nrug (SDAS) cuam tshuam rau ob qho tib si cov khoom thiab cov txheej txheem solidification. Finer SDAS ua rau ua ntej porosity tsim thiab ntau dua porosity feem, txo cov kev ntxhov siab tseem ceeb rau kub tawg.
3.4 Qhov tsis xws luag xws li interdendritic shrinkage voids thiab inclusions ua rau tsis muaj zog ntawm cov pob txha pob txha thiab txo cov kev ntxhov siab tseem ceeb uas yuav tsum tau ua rau kub tawg.
3.5 Grain morphology yog lwm qhov tseem ceeb ntawm microstructural yam cuam tshuam rau tus cwj pwm kub tawg. Thaum cov nplej hloov los ntawm columnar dendrites mus rau globular equiaxed nplej, cov hlau muaj qhov qis qis qis qis thiab txhim kho cov kua permeability ntawm interdendritic, uas suppresses pore kev loj hlob. Tsis tas li ntawd, cov nplej nplua nuj tuaj yeem ua kom haum cov kab mob loj dua thiab cov kab mob sib kis thiab nthuav tawm txoj hauv kev sib tw ntau dua, yog li txo qhov kev kub ntxhov tag nrho.
3.6 Nyob rau hauv kev tsim khoom, optimizing yaj tuav thiab casting cov txheej txheem - xws li nruj me ntsis tswj kev suav nrog thiab hydrogen cov ntsiab lus, nrog rau cov qauv nplej - tuaj yeem txhim kho cov kev tiv thaiv sab hauv ntawm slab ingots kom kub tawg. Ua ke nrog kev tsim cov cuab yeej zoo tsim thiab kev ua tiav, cov kev ntsuas no tuaj yeem ua rau kev tsim cov khoom lag luam siab, loj-loj, zoo slab ingots.
4. Grain Refinement ntawm Ingot
7050 aluminium alloy feem ntau siv ob hom nplej refiners: Al-5Ti-1B thiab Al-3Ti-0.15C. Cov kev tshawb fawb sib piv ntawm kev siv hauv kab ntawm cov refiners no qhia:
4.1 Ingots refined nrog Al-5Ti-1B nthuav qhia qhov loj me me ntawm cov nplej thiab ib qho kev hloov pauv ntau dua los ntawm ntug ingot mus rau qhov chaw. Lub coarse-grained txheej yog nyias, thiab tag nrho cov nplej refinement nyhuv yog muaj zog nyob rau hauv lub ingot.
4.2 Thaum cov ntaub ntawv raw yav tas los refined nrog Al-3Ti-0.15C yog siv, cov nplej refinement nyhuv ntawm Al-5Ti-1B yog txo. Tsis tas li ntawd, nce Al-Ti-B ntxiv dhau ntawm ib qho taw tes tsis sib haum xeeb txhim kho cov nplej kom zoo. Yog li, Al-Ti-B ntxiv yuav tsum txwv tsis pub ntau tshaj 2 kg / t.
4.3 Ingots refined nrog Al-3Ti-0.15C muaj feem ntau ntawm cov nplua, globular equiaxed nplej. Grain loj yog sib xws thoob plaws qhov dav ntawm slab. Ib qho ntxiv ntawm 3-4 kg / t ntawm Al-3Ti-0.15C muaj txiaj ntsig zoo hauv kev ruaj khov ntawm cov khoom zoo.
4.4 Tshwj xeeb tshaj yog, thaum Al-5Ti-1B siv nyob rau hauv 7050 alloy, TiB₂ particles zoo li cais mus rau oxide zaj duab xis nyob rau hauv ingot nto nyob rau hauv ceev ceev txias tej yam kev mob, tsim pawg uas ua rau slag tsim. Thaum lub sij hawm ingot solidification, cov pawg no shrinks sab hauv los ua groove zoo li folds, hloov qhov nro ntawm cov yaj. Qhov no ua rau kom yaj viscosity thiab txo cov fluidity, uas nyob rau hauv lem txhawb kev tawg tsim nyob rau hauv lub hauv paus ntawm cov pwm thiab cov ces kaum ntawm lub dav thiab nqaim lub ntsej muag ntawm lub ingot. Qhov no ua rau muaj kev cuam tshuam loj heev thiab cuam tshuam tsis zoo rau cov ingot tawm los.
4.5 Xav txog kev tsim tus cwj pwm ntawm 7050 alloy, cov qauv nplej ntawm cov khoom zoo sib xws hauv tsev thiab thoob ntiaj teb, thiab qhov zoo ntawm cov khoom ua tiav kawg, Al-3Ti-0.15C yog qhov zoo dua li cov khoom hauv-kab refiner rau casting 7050 alloy-tshwj tsis yog cov xwm txheej tshwj xeeb xav tau lwm yam.
5. Grain Refinement Cwj Pwm ntawm Al-3Ti-0.15C
5.1 Thaum cov nplej refiner ntxiv rau ntawm 720 ° C, cov nplej muaj feem ntau ntawm cov qauv equiaxed nrog qee cov qauv thiab yog qhov loj tshaj plaws.
5.2 Yog hais tias lub yaj yog tuav ntev dhau lawm tom qab ntxiv cov refiner (xws li, dhau 10 feeb), coarse dendritic loj hlob dominates, ua rau coarser nplej.
5.3 Thaum ntxiv cov nplej refiner yog 0.010% rau 0.015%, nplua equiaxed nplej tiav.
5.4 Raws li cov txheej txheem kev lag luam ntawm 7050 alloy, qhov zoo tshaj plaws ntawm cov khoom ua kom zoo yog: qhov kub thiab txias ntawm 720 ° C, lub sij hawm los ntawm kev ntxiv rau qhov kawg solidification tswj nyob rau hauv 20 feeb, thiab refiner npaum li cas ntawm kwv yees li 0.01-0.015% (3-4 kg / t ntawm Al-3Ti-0.15C).
5.5 Txawm hais tias muaj kev hloov pauv hauv qhov loj me, tag nrho lub sij hawm los ntawm kev ntxiv cov nplej refiner tom qab yaj tawm, los ntawm cov kab hauv kab, trough, thiab pwm, mus rau qhov kawg solidification feem ntau yog 15-20 feeb.
5.6 Nyob rau hauv kev lag luam chaw, nce tus nqi ntawm cov nplej refiner tshaj li Ti cov ntsiab lus ntawm 0.01% tsis ua kom zoo dua cov nplej. Hloov chaw, kev sib ntxiv ntau dhau ua rau Ti thiab C enrichment, ua rau muaj feem cuam tshuam ntawm cov khoom siv.
5.7 Kev ntsuam xyuas ntawm cov ntsiab lus sib txawv-degas inlet, degas qhov hluav taws xob, thiab casting trough-pom qhov sib txawv me me ntawm cov nplej loj. Txawm li cas los xij, ntxiv cov refiner ncaj qha rau ntawm qhov casting trough yam tsis muaj filtration ua rau muaj kev pheej hmoo ntawm qhov tsis xws luag thaum kuaj ultrasonic ntawm cov khoom tiav.
5.8 Txhawm rau ua kom cov nplej zoo ib yam thiab tiv thaiv kev sib sau ua ke, cov nplej refiner yuav tsum tau ntxiv rau ntawm qhov nkag ntawm lub tshuab degassing.
Post lub sij hawm: Lub Xya hli ntuj-16-2025
