Kev tsis xws luag thiab yuav tiv thaiv lawv li cas?
Feem ntau qhov tsis xws luag hauv qhov nres disc ntau lawm: cua qhov, shrinkage porosity, xuab zeb qhov, thiab lwm yam; Qhov nruab nrab thiab hom graphite hauv cov qauv metallographic tshaj tus qauv, lossis tus qauv carbide kom muaj nuj nqis; Brinell hardness siab dhau ua rau kev ua haujlwm nyuaj lossis tsis sib xws; Cov qauv graphite yog ntxhib, cov khoom siv kho tshuab tsis yog raws li tus qauv, qhov roughness tsis zoo tom qab ua tiav, thiab pom tseeb qhov porosity ntawm qhov casting nto kuj tshwm sim los ntawm lub sijhawm.
1. Kev tsim thiab kev tiv thaiv ntawm lub qhov cua: lub qhov cua yog ib qho ntawm cov tsis xws luag ntawm brake disc castings. Nres disc qhov me me thiab nyias, cua txias thiab ua kom khov nrawm nrawm, thiab muaj peev xwm me ntsis ntawm nag lossis daus qhov thiab qhov cua reactive. Cov roj binder xuab zeb core muaj roj ntau lawm. Yog tias cov pwm ya raws cov ntsiab lus siab, ob yam no feem ntau ua rau cov pores invasive hauv casting. Nws pom tau tias yog tias cov ntsiab lus noo ntawm molding xuab zeb tshaj, qhov porosity seem yuav nce ntau; Nyob rau hauv ib co nyias xuab zeb core castings, choking (choking pores) thiab nto pores (shelling) feem ntau tshwm sim. Thaum siv cov resin coated xuab zeb kub tub ntxhais lub thawv txoj kev, lub qhov hws yog qhov tshwj xeeb tshaj yog vim muaj roj loj; Feem ntau, lub nres nres nrog cov xuab zeb tuab tsis tshua muaj qhov tsis xws luag;
2. Kev tsim ntawm lub qhov cua: cov roj uas tsim los ntawm lub disc xuab zeb core ntawm nres disc casting ntawm qhov kub thiab txias yuav tsum ntws tawm sab nraud los yog sab hauv kab rov tav los ntawm cov tub ntxhais xuab zeb sib txawv raws li ib txwm muaj. Lub disc xuab zeb core ua thinner, cov roj txoj kev yuav nqaim thiab cov ndlwg kuj nce. Nyob rau hauv ib rooj plaub, thaum lub molten hlau sai sai submerged lub disc xuab zeb core, ib tug loj npaum li cas ntawm cov roj yuav tawg; Los yog kub-kub molten hlau tiv tauj nrog dej siab cov ntsiab lus xuab zeb loj (cov xuab zeb sib tov tsis sib haum) ntawm qee qhov chaw, ua rau muaj roj tawg, choking hluav taws thiab ua rau cov pores; Hauv lwm qhov xwm txheej, cov pa hluav taws xob tsim hluav taws xob ua rau cov hlau molten thiab ntab thiab khiav tawm. Thaum cov pwm tsis tuaj yeem tso tawm hauv lub sijhawm, cov pa roj yuav kis mus rau hauv cov roj txheej nruab nrab ntawm cov hlau molten thiab qis dua ntawm cov pwm sab saud, tuav ib feem ntawm qhov chaw nyob rau saum npoo ntawm lub disc. Yog hais tias cov hlau molten yog solidifying, los yog lub viscosity loj thiab poob fluidity, qhov chaw nyob los ntawm cov roj tsis tuaj yeem refilled, yuav tawm ntawm qhov pores. Feem ntau, yog tias cov roj tsim los ntawm cov tub ntxhais tsis tuaj yeem ntab thiab khiav tawm los ntawm cov hlau molten nyob rau lub sijhawm, nws yuav nyob rau saum npoo ntawm lub disc, qee zaum raug raws li ib qho pore, qee zaum raug tom qab txhaj tshuaj blasting kom tshem tawm cov oxide nplai, thiab qee zaum pom tom qab machining, uas yuav ua rau khib nyiab ntawm cov sijhawm ua haujlwm. Thaum tus brake disc core yog tuab, nws yuav siv sij hawm ntev rau cov hlau molten los ntawm cov tub ntxhais disc thiab submerge lub disc core. Ua ntej submerging, cov roj uas tsim los ntawm cov tub ntxhais muaj sij hawm ntau ntws mus rau saum npoo ntawm cov tub ntxhais los ntawm qhov sib txawv ntawm cov xuab zeb, thiab qhov tsis kam ntws tawm sab nraud los yog sab hauv ntawm txoj kab rov tav kuj yog me me. Yog li ntawd, qhov chaw pore defects tsis tshua tsim, tab sis tus kheej cov pores cais kuj tuaj yeem tshwm sim. Uas yog hais tias, muaj ib qho tseem ceeb loj los tsim choking pores los yog nto pores ntawm lub thickness thiab thickness ntawm cov xuab zeb core. Thaum lub thickness ntawm cov xuab zeb core yog tsawg tshaj li qhov tseem ceeb ntawm no, yuav muaj ib tug loj nyiam ntawm pores. Qhov tseem ceeb no nce nrog qhov nce ntawm radial dimension ntawm tus nres disc thiab nrog lub thinning ntawm lub disc core. Kub yog ib qho tseem ceeb cuam tshuam rau porosity. Cov hlau molten nkag mus rau hauv pwm kab noj hniav los ntawm lub puab sprue, bypasses nruab nrab core thaum sau lub disc, thiab raws li opposite lub puab sprue. Vim yog cov txheej txheem ntev, qhov kub thiab txias txo qis dua, thiab cov viscosity nce raws li, lub sijhawm zoo rau cov npuas kom ntab thiab tawm yog luv luv, thiab cov hlau molten yuav solidify ua ntej cov pa tawm tag, yog li qhov pores yooj yim rau tshwm sim. Yog li ntawd, lub sij hawm zoo ntawm npuas ntab thiab tso tawm tuaj yeem ua kom ntev los ntawm kev ua kom cov hlau molten kub ntawm lub disc opposite sab hauv sprue.
