Thaum lub sij hawm solidification txheej txheem ntawm ib tug casting, feem ntau muaj peb cheeb tsam ntawm nws cross section, uas yog lub cheeb tsam, lub solidification cheeb tsam, thiab cov kua cheeb tsam.
Lub solidification cheeb tsam yog thaj chaw uas "khoom thiab kua coexist" ntawm cov kua zone thiab cov khoom zone. Nws qhov dav yog hu ua solidification zone width. Qhov dav ntawm thaj tsam solidification muaj kev cuam tshuam zoo rau qhov zoo ntawm cov casting. Cov txheej txheem solidification ntawm lub casting yog raws li qhov dav ntawm lub solidification cheeb tsam qhia nyob rau hauv tus ntoo khaub lig seem ntawm lub casting, thiab muab faib mus rau hauv txheej-los ntawm-txheej solidification, paste solidification, thiab intermediate solidification.
Cia peb saib cov yam ntxwv ntawm cov txheej txheem solidification xws li txheej-los-txheej solidification thiab paste solidification.
Txheej-los ntawm-txheej txheej solidification: Thaum qhov dav ntawm lub solidification cheeb tsam yog nqaim heev, nws belongs rau txheej txheej-los ntawm-txheej solidification txoj kev. Nws solidification pem hauv ntej yog nyob rau hauv ncaj qha kev sib cuag nrog cov kua hlau. Cov hlau uas muaj nyob rau hauv cheeb tsam nqaim muaj xws li cov hlau ntshiab (kev lag luam tooj liab, muaj zinc, muaj tin), eutectic alloys (aluminium-silicon alloys, ze-eutectic alloys xws li grey cam khwb cia hlau), thiab alloys nrog ib tug nqaim crystallization ntau yam (xws li. qis carbon steel). , aluminium bronze, tooj dag nrog me me crystallization ntau). Cov rooj plaub hlau saum toj no tag nrho yog cov txheej txheem ntawm txheej txheej txheej.
Thaum cov kua solidifies mus rau hauv ib tug khoom lub xeev thiab shrinks nyob rau hauv ntim, nws yuav tsum tsis tu ncua replenished los ntawm cov kua, thiab cov nyiam ua dispersed shrinkage yog me me, tab sis concentrated shrinkage qhov yog tshuav nyob rau hauv lub kawg solidified ib feem ntawm lub casting. Concentrated shrinkage kab noj hniav yog yooj yim tshem tawm, yog li cov khoom shrinkage zoo. Intergranular kab nrib pleb tshwm sim los ntawm hindered shrinkage yog yooj yim sau nrog molten hlau los kho cov kab nrib pleb, yog li castings muaj me ntsis nyiam kub tawg. Nws kuj muaj peev xwm sau tau zoo dua thaum solidification tshwm sim thaum lub sij hawm txhaws.
Dab tsi yog paste coagulation: Thaum lub coagulation cheeb tsam yog dav heev, nws belongs rau txoj kev paste coagulation. Cov hlau uas muaj nyob rau hauv thaj tsam loj muaj xws li txhuas alloys, magnesium alloys (aluminium-tooj alloys, aluminium-magnesium alloys, magnesium alloys), tooj liab alloys (tin bronze, aluminium bronze, tooj dag nrog qhov dav crystallization kub ntau), hlau-carbon alloys. (high carbon steel, ductile hlau).
Qhov dav ntawm thaj chaw solidification ntawm cov hlau, qhov nyuaj dua rau cov npuas thiab cov khoom siv hauv cov hlau molten kom ntab thiab tshem tawm thaum lub sij hawm casting, thiab nws kuj nyuaj rau noj. Castings yog nquag mus kub cracking. Thaum cov kab nrib pleb tshwm sim ntawm cov muaju, lawv tsis tuaj yeem ntim cov kua hlau los kho lawv. Thaum hom alloy no solidifies thaum lub sij hawm filling txheej txheem, nws muaj peev xwm filling kuj tsis zoo.
Intermediate solidification yog dab tsi: Lub solidification ntawm lub nqaim solidification cheeb tsam thiab dav solidification cheeb tsam yog hu ua intermediate solidification zone. Alloys teej tug mus rau nruab nrab solidification cheeb tsam muaj xws li carbon steel, siab manganese hlau, ib co tshwj xeeb tooj dag thiab dawb cam khwb cia hlau. Nws cov yam ntxwv pub mis, thermal cracking nyiam thiab pwm filling muaj peev xwm nyob nruab nrab ntawm txheej-los-txheej txheej solidification thiab paste solidification txoj kev. Kev tswj ntawm solidification ntawm no hom ntawm casting yog tsuas yog los kho cov txheej txheem tsis, tsim kom muaj ib tug dej siab kub gradient ntawm tus ntoo khaub lig seem ntawm lub casting, txo lub solidification cheeb tsam ntawm lub casting cross section, thiab hloov lub solidification hom los ntawm pasty solidification rau txheej. -by-layer solidification kom tau txais kev tsim nyog castings.
Post lub sij hawm: May-17-2024
