Investment casting ndeyekupfekedza akawanda ma layers e refractory coating pamusoro pe wax mold. Mushure mekuomeswa nekuomeswa, mold yewakisi inonyungudutswa nekudziya kuti pawane goko rine mhango rinoenderana nechimiro chewakisi. Mushure mekubika, inodururwa muNzira yekuwana castings, saka inonziwo kurasika kukanda wax. Nekuenderera mberi kwekuvandudza tekinoroji yekugadzira, maitiro matsva ekuumba wakisi anoramba achionekwa, uye zvakasiyana-siyana zvezvinhu zviripo zvekuumba zviri kuwedzera. Iye zvino nzira yekubvisa mold haichagumiri pakunyunguduka, uye zvinhu zvekuumba hazvigumiri kune wax zvinhu. Plastic molds inogonawo kushandiswa. Nekuti ma castings anowanikwa nenzira iyi ane epamusoro dimensional kurongeka uye yakaderera pamusoro roughness values, inonziwo precision casting.
Chinhu chakakosha cheInvestment castingndeyekuti mold inonyungudika inoraswa inoshandiswa pakugadzira goko. Nekuti hapana chikonzero chekudhirowa mold, iyo goko inosanganisirwa isina nzvimbo yekuparadzanisa, uye goko rakagadzirwa nezvinhu zvinopikisa zvine hunyanzvi hwekuita tembiricha. Investment casting inogona kuburitsa yakaoma-yakaita castings, ine hushoma madziro ukobvu hwe 0.3mm uye dhayamita shoma yegomba rekukanda re 0.5 mm. Dzimwe nguva mukugadzira, zvimwe zvikamu zvinoumbwa nezvikamu zvakati wandei zvinogona kusanganiswa kuita zvakazara nekushandura chimiro uye zvakananga kuumbwa nekukandira kwekudyara. Izvi zvinogona kuchengetedza kugadzirisa maawa emunhu uye kushandiswa kwesimbi zvinhu, uye kugadzira chimiro chekukanda zvikamuzvine musoro.
Huremu hwekukanda kunogadzirwa nekudyara kwekudyara kazhinji hunobva pamakumi emagiramu kusvika kumakirogiramu akati wandei, kana kunyange makumi emakirogiramu. Yakanyanya kurema castings haina kukodzera kukanda mari nekuda kwekuganhurirwa kwekuita kweiyo molding zvinhu uye kuoma mukugadzira goko.
Castings inogadzirwa neinvestment castinghazvina kuganhurirwa nemhando dzealloys, kunyanya kune alloys ayo akaoma kucheka kana kugadzira, izvo zvinogona kuratidza hukuru hwayo. Nekudaro, kugadzirwa kwekudyara kwekudyara zvakare kune zvimwe zvinokanganisa, kunyanya nekuda kwehuwandu hukuru hwematanho, marefu ekugadzira kutenderera, yakaoma tekinoroji maitiro, uye zvinhu zvakawanda zvinokanganisa kunaka kwekukanda, izvo zvinofanirwa kudzorwa zvakanyanya kudzikamisa kugadzirwa.
Kuenzaniswa nedzimwe nzira dzekukanda, chinhu chinoshamisa chekudyara kwekudyara ndiko kushandiswa kwezviumbwa zvinonyungudika kugadzira goko. Imwe yekudyara mold inopedzwa pese panogadzirwa goko. Chinodiwa chinodiwa kuti uwane emhando yepamusoro castings ine yakakwira dimensional kurongeka uye yakaderera pamusoro roughness kukosha ndeyekudyara mold ine yakakwirira dimensional kurongeka uye yakaderera pamusoro roughness values. Naizvozvo, kuita kwechigadzirwa chekugadzira (chinonzi mold material), kunaka kwekuumba (patani inoshandiswa kudzvanya mari) uye maitiro ekuumba anokanganisa zvakananga kunaka kwekukanda mari.
Investment casting molds parizvino inowanzo shandiswa mugoko rakagadzirwa neakawanda refractory zvinhu. Mushure mekunge module yanyudzwa uye yakaputirwa nerefractory coating, chimwaya iyo granular refractory material, wobva waoma nekuomesa, uye dzokorora maitiro aya kakawanda kusvikira refractory material layer yasvika pahukobvu hunodiwa. Nenzira iyi, ganda re-multi-layer shell rinoumbwa pane module, iyo inowanzomira kwenguva yakareba kuti iome uye iomese, uye inogadziriswa kuti iwane ganda rakasiyana-siyana. Mamwe magomba emhando dzakawanda anoda kuzadzwa nejecha, uye mamwe haaite. Mushure mokugocha, vanogona kudururwa zvakananga, iyo inonzi ganda repamusoro-simba.
Hunhu hwegoko rakanangana nehunhu hwekukanda. Zvinoenderana nemamiriro ekushanda kwegomba, zvinodikanwa zvekushanda kwegomba zvinonyanya zvinosanganisira:
1) Iyo ine yakakwirira yakajairika tembiricha simba, inokodzera yakakwirira tembiricha simba uye yakaderera yasara simba.
2) Iine mhepo yakanaka yepermeability (kunyanya yakakwira tembiricha yemhepo permeability) uye thermal conductivity.
3) Iyo mutsara yekuwedzera coefficient idiki, iyo yekuwedzera yekupisa yakaderera uye kuwedzera kwakafanana.
4) Kunyanya kupikisa kukurumidza kutonhora uye kupisa uye kugadzikana kwe thermochemical.
Izvi zvimiro zvegoko zvine hukama zvakanyanya nezvinhu zvinoshandiswa mukugadzira goko uye maitiro ekugadzira goko. Shell zvinhu zvinosanganisira refractory zvinhu, binders, solvents, hardener, surfactants, etc. Pakati pavo, refractory zvinhu uye binder zvakananga kuumba goko, inova huru goko zvinhu. Zvinhu zvinoramba zvichishandiswa mukudyara kwekudyara zvinonyanya silika jecha, corundum uye aluminosilicate refractories (senge refractory ivhu uye aluminium banadium, nezvimwewo). Mukuwedzera, zircon jecha uye magnesia jecha dzimwe nguva inoshandiswa.
Powdered refractory material uye binder zvinogadzirirwa kuita refractory coating, uye iyo granular refractory material inosaswa pane refractory coating kana goko ragadzirwa. Mabhainda anoshandiswa mune refractory coatings anonyanya kusanganisira ethyl silicate hydrolysate, girazi remvura uye silica sol. Iyo pendi yakagadzirwa ne ethyl silicate ine yakanaka yekuvharisa zvivakwa, yakakwira goko kusimba, diki yekupisa deformation, yakakwirira dimensional kurongeka kweiyo yakawanikwa castings, uye yakanaka yepamusoro mhando. Iyo inonyanya kushandiswa kugadzira yakakosha alloy simbi castings uye mamwe castings ane yakakwirira yepamusoro yemhando zvinodiwa. Iyo SiO2 yemukati ye ethyl silicate inogadzirwa kuChina inowanzo 30% kusvika 34% (chikamu chehuwandu), saka inodaidzwa kuti ethyl silicate 32 (32 inomiririra chikamu chepakati cheSiO2 mu ethyl silicate). Ethyl silicate inogona kuita basa rekusunga chete mushure mehydrolysis.
Iyo yekuputira ganda rakagadzirwa negirazi remvura iri nyore kusvibisa uye kutsemuka. Kuenzaniswa ne ethyl silicate, ma castings anogadzirwa ane yakaderera dimensional kurongeka uye yakakwirira pamusoro roughness. Mvura yegirazi binder yakakodzera kugadzirwa kwemadiki akajairwa simbi castings uyenon-ferrous alloy castings. Girazi remvura rekukanda mari yekudyara kazhinji rine modulus ye3.0 ~ 3.4 uye density ye1.27 ~ 1.34 g/cm3.
Silica sol binder is aqueous solution ye silicic acid, inozivikanwawo se silica sol. Mutengo wayo 1/3 ~ 1/2 yakaderera pane iyo ethyl silicate. Hunhu hwekukandira hunogadzirwa nekushandisa silica sol sebhainda hwakakwira kupfuura hwegirazi remvura. Iyo inosungira mumiriri yakagadziridzwa zvakanyanya. Silica sol ine kugadzikana kwakanaka uye inogona kuchengetwa kwenguva yakareba. Izvo hazvitsvage mahardener akakosha pakugadzira magoko. Kusimba kwetembiricha yepamusoro yegoko kuri nani pane iyo ethyl silicate shells, asi silica sol haina kunyorova kwekudyara uye inotora nguva yakareba kuti iome. Iwo makuru maitiro ekugadzira goko anosanganisira moduru degreasing, kukoira uye jecha, kuomesa uye kuomesa, kudhiza uye kugocha.
Nguva yekutumira: Feb-11-2021