Tšepe ea tšepeke sehlopha sa li-alloys tsa tšepe-carbon tse nang le khabone e kholo ho feta 2%.Molemo oa eona o tsoa ho mocheso oa eona o batlang o le tlase oa ho qhibiliha.Likarolo tsa alloy li ama 'mala oa eona ha e robehile: tšepe e tšoeu e na le litšila tsa carbide tse lumellang mapetsong hore a fete ka ho toba, tšepe e bohlooho e na le li-graphite flakes tse khelosang lekhalo le qalang mapetsong a mangata ha thepa e robeha,' me ductile cast iron e na le chitja. graphite "nodules" e thibelang petso ho tsoela pele.

Carbon (C) ho tloha ho 1.8 ho ea ho 4 wt%, le silicon (Si) 1-3 wt%, ke likarolo tse ka sehloohong tsa motsoako oa tšepe ea tšepe.Lisebelisoa tsa tšepe tse nang le khabone e tlase li tsejoa e le tšepe.

Ts'epe ea tšepe e atisa ho ba brittle, ntle le litšepe tsa tšepe tse bonolo.Ka ntlha ea eona e batlang e le tlase e qhibilihisang, metsi a matle, ho lahla, ho sebetsa ka mokhoa o babatsehang, ho hanyetsa ho senyeha le ho apara ho hanyetsa, litšepe tse entsoeng ka tšepe li fetohile lisebelisoa tsa boenjiniere tse nang le mefuta e mengata ea likopo 'me li sebelisoa liphaepheng, mechine le likarolo tsa indasteri ea likoloi, tse kang cylinder. lihlooho, li-cylinder blocks le mekotla ea li-gearbox.E hanela ts'enyo ka oxidation.

Lintho tsa khale tsa tšepe tse entsoeng ka tšepe ke tsa lekholong la bo5 la lilemo BC, 'me li ile tsa sibolloa ke baepolli ba lintho tsa khale sebakeng seo hona joale se bitsoang Jiangsu, Chaena.Tšipe ea tšepe e ne e sebelisoa Chaena ea boholo-holo bakeng sa ntoa, temo le meaho.Lekholong la bo15 la lilemo, tšepe e entsoeng ka tšepe e ile ea sebelisoa bakeng sa likanono Burgundy, Fora, le Engelane nakong ea Nchafatso.Tekanyo ea tšepe e entsoeng ka tšepe e sebelisoang bakeng sa likanono e ne e hloka tlhahiso e kholo.Borokho ba pele ba tšepe bo hahiloe ka 1770s ke Abraham Darby III, 'me bo tsejoa e le The Iron Bridge in Shropshire, England.Ho ile ha boela ha sebelisoa tšepe e entsoeng ka tšepe ha ho hahoa mehaho.

Alloying elements

Thepa ea tšepe ea cast e fetoloa ka ho kenyelletsa likarolo tse fapaneng tsa alloy, kapa li-alloyants.Haufi le carbon, silicon ke motsoako oa bohlokoa ka ho fetisisa hobane o qobella carbon ho tsoa tharollo.Karolo e tlase ea silicon e lumella carbon hore e lule e le tharollo e etsang carbide ea tšepe le tlhahiso ea tšepe e tšoeu.Karolo e phahameng ea silicon e qobella carbon ho tsoa ka tharollo ho etsa graphite le tlhahiso ea tšepe e bohlooho.Lisebelisoa tse ling tsa alloying, manganese, chromium, molybdenum, titanium le vanadium li loantša silicon, li khothalletsa ho boloka carbon, le ho thehoa ha li-carbides tseo.Nickel le koporo li eketsa matla, le machinability, empa u se ke ua fetola palo ea graphite e entsoeng.Khabone ka sebopeho sa graphite e hlahisa tšepe e bonolo, e fokotsa ho honyela, e theola matla le ho fokotsa bongata.Sebabole, haholo-holo se silafatsang ha se le teng, se etsa iron sulfide, e thibelang ho thehoa ha graphite le ho eketsa boima.Bothata ba sebabole ke hore se etsa viscous ea tšepe e qhibilihisitsoeng, e bakang likoli.Ho thibela liphello tsa sebabole, manganese e eketsoa hobane tse peli li theha manganese sulfide ho e-na le iron sulfide.Manganese sulfide e bobebe ho feta ho qhibiliha, kahoo e atisa ho phaphamala ho tsoa ho qhibiliha ho ea ho slag.Palo ea manganese e hlokahalang ho fokotsa sebabole ke 1.7 × sebabole se nang le + 0.3%.Haeba palo e fetang ena ea manganese e eketsoa, ​​​​joale mefuta ea manganese carbide, e eketsang ho thatafala le ho bata, ntle le ka tšepe e bohlooho, moo ho fihlang 1% ea manganese e eketsang matla le letsoalo.

Nickel ke e 'ngoe ea likarolo tse tloaelehileng tsa alloying hobane e hloekisa pearlite le sebopeho sa graphite, e ntlafatsa ho tiea, le ho hlahisa phapang pakeng tsa boima ba likarolo.Chromium e eketsoa ka chelete e nyane ho fokotsa graphite e sa lefelloeng, ho hlahisa serame, le hobane ke carbide stabilizer e matla;nickel hangata e eketsoa hammoho.Tekanyo e nyane ea thini e ka eketsoa e le sebaka sa chromium ea 0.5%.Koporo e kenngoa ka ladle kapa ka sebōping, ka taelo ea 0.5-2.5%, ho fokotsa ho bata, ho hloekisa graphite, le ho eketsa metsi.Molybdenum e eketsoa ka tatellano ea 0.3-1% ho eketsa serame le ho hloekisa sebopeho sa graphite le pearlite;hangata e eketsoa hammoho le nickel, koporo, le chromium ho etsa litšepe tse matla haholo.Titanium e eketsoa joalo ka degasser le deoxidizer, empa hape e eketsa metsi.0.15-0.5% vanadium e eketsoa ho tšepe ea tšepe ho tsitsisa samente, ho eketsa boima, le ho eketsa ho hanyetsa ho apara le mocheso.0.1-0.3% zirconium e thusa ho theha graphite, deoxidize, le ho eketsa metsi.

Ka tšepe e qhibilihang e qhibilihang, bismuth e eketsoa, ​​​​ka tekanyo ea 0.002-0.01%, ho eketsa hore na silicon e ka eketsoa hakae.Ka tšepe e tšoeu, boron e eketsoa ho thusa tlhahiso ea tšepe e bonolo;e boetse e fokotsa phello e hlabang ea bismuth.

Tšepe e bohlooho e entsoeng ka tšepe

Grey cast iron e khetholloa ke microstructure ea eona ea graphite, e etsang hore ho robeha ha thepa ho be le ponahalo ea bohlooho.Ke tšepe e entsoeng ka ho fetisisa e sebelisoang ka ho fetisisa le lisebelisoa tse sebelisoang ka ho fetisisa tse thehiloeng ho boima ba 'mele.Litšepe tse ngata tse entsoeng ka tšepe li na le lik'hemik'hale tsa 2.5-4.0% carbon, 1-3% silicon, le tšepe e setseng.Grey cast iron e na le matla a fokolang a ho tsieleha le ho hanyetsa ho ts'oha ho feta tšepe, empa matla a eona a ho hatella a ka bapisoa le tšepe ea carbon e tlaase le e bohareng.Lintho tsena tsa mechine li laoloa ke boholo le sebōpeho sa li-graphite flakes tse teng ka har'a microstructure 'me li ka khetholloa ho latela tataiso e fanoeng ke ASTM.

Tšepe ea tšepe e tšoeu

Tšepe ea tšepe e tšoeu e bonts'a libaka tse tšoeu tse robehileng ka lebaka la boteng ba tšepe ea carbide e bitsoang cementite.Ka silicon e tlase (e etsang graphitizing) le sekhahla sa ho pholisa ka potlako, k'habone e ka har'a tšepe e tšoeu ea tšepe e tsoa ho qhibiliha joalo ka samente ea metastable phase, Fe.₃C, eseng graphite.Samente e theohang ho tsoa ho qhibiliha e etsa likaroloana tse batlang li le kholo.Ha iron carbide e tsoa, ​​​​e ntša carbon ho tsoa ho qhibiliha ha pele, ho tsamaisa motsoako ho o haufi le eutectic, 'me karolo e setseng ke iron-carbon austenite e tlaase (eo ha ho pholile e ka fetoha martensite).Li-eutectic carbides tsena li kholo haholo hore li ka fana ka molemo oa seo ho thoeng ke ho thatafala ha pula (joalo ka litšepe tse ling, moo lipula tse nyane haholo tsa cementite li ka thibelang [plastic deformation] ka ho sitisa motsamao oa ho kheloha ka matrix a tšepe a hloekileng).Ho e-na le hoo, ba eketsa boima bo bongata ba tšepe e entsoeng ka tšepe ka lebaka la ho thatafala ha bona ho phahameng haholo le karoloana ea bona ea boholo ba molumo, e le hore boima bo bongata bo ka lekanngoa ka molao oa motsoako.Ho sa tsotellehe boemo leha e le bofe, ba fana ka boima ka litšenyehelo tsa ho thatafala.Kaha carbide e etsa karolo e kholo ea thepa, tšepe e tšoeu e ka hlalosoa e le cermet.Tšepe e tšoeu e pshatleha haholo hore e ka sebelisoa likarolong tse ngata tsa meralo, empa ka ho thatafala ho hoholo le ho haneloa ha abrasion le litšenyehelo tse tlase, e sebelisoa lits'ebetsong tse joalo ka bokaholimo ba lipompo tsa slurry, li-shell liner le lithapo tse phahamisang bolo. liloala le litsila tse ikemetseng, libolo le mehele ka har'a pulverisers ea mashala, le meno a bakete ea ho chekoa ea backhoe (le hoja tšepe e entsoeng ka carbon-carbon martensitic e tloaelehile haholo bakeng sa ts'ebeliso ena).

Ho thata ho pholisa li-castings tse teteaneng ka potlako ho tiisa ho qhibiliha joalo ka tšepe e tšoeu.Leha ho le joalo, ho pholisa ka potlako ho ka sebelisoa ho tiisa khetla ea tšepe e tšoeu e entsoeng ka tšepe, ka mor'a moo e setseng e pholile butle ho etsa motheo oa tšepe e bohlooho.Sephetho sa ho lahla, se bitsoang achilled casting, e na le melemo ea sebaka se thata se nang le hare-hare e batlang e le thata.

Li-alloys tsa tšepe tse tšoeu tsa chromium li lumella li-castings tse kholo (mohlala, impeller ea lithane tse 10) hore e be lehlabathe, kaha chromium e fokotsa sekhahla sa ho pholisa se hlokahalang ho hlahisa li-carbide ka botenya bo boholo ba thepa.Chromium e boetse e hlahisa li-carbides tse nang le khanyetso e tsotehang ea abrasion.Li-alloys tsena tse phahameng tsa chromium li amahanngoa le bothata ba tsona bo phahameng ka lebaka la boteng ba chromium carbides.Mofuta o ka sehloohong oa li-carbide tsena ke eutectic kapa ea mantlha M₇C₃carbides, moo "M" e emelang tšepe kapa chromium 'me e ka fapana ho itšetlehile ka motsoako oa motsoako.Li-eutectic carbides li bopeha joalo ka dingata tsa lithupa tse sekoti tsa hexagonal 'me li hola ho ea ka sefofane sa hexagonal basal.Ho thatafala ha li-carbide tsena li ka har'a mefuta ea 1500-1800HV.

Tshepe e tshepehang

Aene e ka belehang e qala e le tšepe e tšoeu e tšeloang mocheso letsatsi kapa a mabeli ka mocheso o ka bang 950 °C (1,740 °F) ebe e pholile ka letsatsi kapa a mabeli.Ka lebaka leo, carbon e ka har'a carbide ea tšepe e fetoha graphite le ferrite hammoho le carbon (austenite).Ts'ebetso e liehang e lumella tsitsipano ea holim'a metsi hore e thehe graphite ka likaroloana tsa spheroidal ho e-na le li-flakes.Ka lebaka la karo-karolelano ea eona e tlase, li-spheroids li batla li le khuts'oane ebile li hole le tse ling, 'me li na le karolo e ka tlase ea sefapano ho fapana le ho phatloha ho hoholo kapa phonon.Li boetse li na le meeli e hlabang, ho fapana le li-flakes, tse fokotsang mathata a khatello ea kelello a fumanoang ka tšepe ea grey cast.Ka kakaretso, thepa ea tšepe ea tšepe e bonolo e tšoana le ea tšepe e bonolo.Ho na le moeli oa hore na karolo e kholo hakae e ka kenngoa ka tšepe e bonolo, kaha e entsoe ka tšepe e tšoeu ea tšepe.

ductile cast iron