Insimbiiyiqembu lama-alloys e-iron-carbon ane-carbon content engaphezu kuka-2%.Ukuba wusizo kwayo kuvela ekuncipheni kwayo okuncibilika okuphansi.Izakhi ze-alloy zithinta umbala wayo lapho iphukile: insimbi emhlophe inokungcola kwe-carbide evumela imifantu ukuthi idlule iqonde, insimbi empunga inama-graphite flakes asusa ukuqhekeka okudlulayo futhi aqalise imifantu emisha eminingi njengoba kuphuka, kanye nensimbi eyi-ductile cast ine-spherical. ama-graphite "nodules" avimba umfantu ukuthi ungaqhubeki phambili.

Ikhabhoni (C) esukela ku-1.8 kuya ku-4 wt%, kanye ne-silicon (Si) 1–3 wt%, izakhi eziyinhloko ezihlanganisa insimbi ekhonjiwe.Ama-aloyi e-ayoni anekhabhoni ephansi aziwa ngokuthi yinsimbi.

I-cast iron ijwayele ukuba brittle, ngaphandle kwezinsimbi ezisansimbi ezithambile.Ngephuzu layo lokuncibilika eliphansi, i-fluidity enhle, i-castability, i-machinability enhle kakhulu, ukumelana nokuguqulwa nokumelana nokugqoka, izinsimbi ezisansimbi seziphenduke izinto zobunjiniyela ezinohlu olubanzi lwezinhlelo zokusebenza futhi zisetshenziselwa amapayipi, imishini kanye nezingxenye zemboni yezimoto, njenge-cylinder. amakhanda, ama-cylinder blocks namakesi e-gearbox.Imelana nokulimala nge-oxidation.

Izinto zobuciko zokuqala ezisansimbi zisukela ekhulwini lesi-5 BC, futhi zatholwa abavubukuli endaweni manje ebizwa ngokuthi iJiangsu eChina.I-cast iron yayisetshenziswa e-China yasendulo ngempi, ezolimo, kanye nezakhiwo.Phakathi nekhulu le-15, insimbi yensimbi yasetshenziswa ukudubula inganono eBurgundy, eFrance, naseNgilandi ngesikhathi seNguquko.Amanani ensimbi ensimbi asetshenziselwa inganono ayedinga ukukhiqizwa okukhulu.Ibhuloho lokuqala elakhiwe ngensimbi lakhiwa ngeminyaka yawo-1770 ngu-Abraham Darby III, futhi laziwa ngokuthi Ibhuloho Lensimbi eShropshire, eNgilandi.I-cast iron nayo yasetshenziswa ekwakhiweni kwezakhiwo.

Izakhi ze-alloying

Izakhiwo ze-cast iron zishintshwa ngokwengeza izakhi ezihlukahlukene ze-alloying, noma ama-alloyants.Eduze kwe-carbon, i-silicon iyi-alloyant ebaluleke kakhulu ngoba iphoqa i-carbon ukuphuma kwisisombululo.Iphesenti eliphansi le-silicon livumela ikhabhoni ukuthi ihlale esixazululweni esenza i-iron carbide kanye nokukhiqizwa kwensimbi emhlophe.Iphesenti eliphezulu le-silicon likhipha ikhabhoni esixazululweni esenza i-graphite kanye nokukhiqizwa kwensimbi empunga.Amanye ama-alloying agents, i-manganese, i-chromium, i-molybdenum, i-titanium kanye ne-vanadium iphikisana ne-silicon, ikhuthaza ukugcinwa kwe-carbon, nokwakheka kwalawo ma-carbides.I-nickel ne-copper kwandisa amandla, kanye nokusebenza kanzima, kodwa akushintshi inani le-graphite elakhiwe.Ikhabhoni esesimweni se-graphite iphumela ekubeni yinsimbi ethambile, inciphisa ukushwabana, yehlise amandla, futhi yehlise ukuminyana.Isibabule, ikakhulukazi ukungcola lapho sikhona, sakha i-iron sulfide, evimbela ukwakheka kwe-graphite futhi yandise ubulukhuni.Inkinga ngesibabule ukuthi yenza i-viscous yensimbi encibilikisiwe, edala ukukhubazeka.Ukuze kunqandwe imiphumela yesibabule, i-manganese iyengezwa ngoba lezi zimbili zakha i-manganese sulfide esikhundleni se-iron sulfide.I-manganese sulfide ilula kunokuncibilika, ngakho-ke ijwayele ukuntanta iphume ekuncibilikeni iye e-slag.Inani le-manganese elidingekayo ukuze kuncishiswe isulfure liyi-1.7 × okuqukethwe kwesulfure + 0.3%.Uma ngaphezu kwaleli nani le-manganese lengezwa, khona-ke amafomu e-manganese carbide, okwandisa ubulukhuni nokubandayo, ngaphandle kwe-iron empunga, lapho kufika ku-1% we-manganese kwandisa amandla nokuqina.

I-Nickel ingenye yezakhi ezivame kakhulu ze-alloying ngoba icwenga ukwakheka kwe-pearlite ne-graphite, ithuthukisa ukuqina, futhi ihlukanise umehluko wobunzima phakathi kobukhulu besigaba.I-Chromium yengezwa ngamanani amancane ukuze kuncishiswe i-graphite yamahhala, ikhiqize ukugodola, futhi ngenxa yokuthi iyi-carbide stabilizer enamandla;i-nickel ivame ukungezwa ngokuhlanganyela.Inani elincane lethayela lingangezwa esikhundleni se-chromium engu-0.5%.I-Copper yengezwa ku-ladle noma esithandweni, ngohlelo luka-0.5-2.5%, ukunciphisa ukubandayo, ukucwenga i-graphite, nokwandisa uketshezi.I-Molybdenum yengezwe ngohlelo lwe-0.3-1% ukuze kwandiswe ukubandayo nokucwenga ukwakheka kwegraphite ne-pearlite;kuvame ukungezwa ngokuhambisana ne-nickel, ithusi, ne-chromium ukuze kwakhiwe ama-ayina anamandla aphezulu.I-Titanium yengezwa njenge-degasser ne-deoxidizer, kodwa futhi yandisa uketshezi.I-0.15-0.5% i-vanadium yengezwa ku-iron cast ukuze kuqiniswe usimende, ukwandisa ubulukhuni, nokwandisa ukumelana nokugqoka nokushisa.I-0.1-0.3% i-zirconium isiza ukwakha i-graphite, i-deoxidize, nokwandisa uketshezi.

Ekuncibilikeni kwensimbi ethambileyo, i-bismuth iyengezwa, esikalini sika-0.002–0.01%, ukuze kwandiswe ukuthi ingakanani i-silicon engangezwa.Ngensimbi emhlophe, i-boron yengezwa ukuze isize ekukhiqizeni insimbi ethambile;iphinde yehlise umphumela wokuqhafaza we-bismuth.

Insimbi empunga

I-Grey cast iron ibonakala nge-graphitic microstructure yayo, eyenza ukuphuka kwento kube nokumpunga.Yinsimbi ekhonjiwe esetshenziswa kakhulu futhi isetshenziswa kabanzi esekelwe esisindweni.Izinsimbi eziningi ezisansimbi zinekhemikhali engu-2.5-4.0% yekhabhoni, i-silicon engu-1-3%, nensimbi esele.Insimbi empunga inamandla amancane okuqina kanye nokumelana nokushaqeka kunensimbi, kodwa amandla ayo acindezelayo aqhathaniswa nensimbi enekhabhoni ephansi naphakathi.Lezi zakhiwo zemishini zilawulwa ubukhulu nokuma kwe-graphite flakes ekhona ku-microstructure futhi ingabonakala ngokuvumelana neziqondiso ezinikezwe i-ASTM.

Insimbi emhlophe

I-iron cast emhlophe ibonisa izindawo ezimhlophe eziphukile ngenxa yokuba khona kwe-iron carbide precipitate ebizwa ngokuthi i-cementite.Ngokuqukethwe kwe-silicon ephansi (i-ejenti ye-graphitizing) kanye nezinga lokupholisa elisheshayo, ikhabhoni ensimbi ewugqinsi emhlophe iphuma ekuncibilikeni njenge-metastable phase cementite, Fe.₃C, esikhundleni se-graphite.I-cementite encibilika ivela njengezinhlayiya ezinkulu uma kuqhathaniswa.Njengoba i-iron carbide iqhuma, ikhipha ikhabhoni ekuncibilikeni kwasekuqaleni, ihambisa ingxube endaweni eseduze ne-eutectic, futhi isigaba esisele yi-iron-carbon austenite ephansi (okuthi ekupholiseni ingase iguquke ibe i-martensite).Lawa ma-eutectic carbides makhulu kakhulu ukuhlinzeka ngenzuzo yalokho okubizwa ngokuthi ukuqina kwemvula (njengakwezinye izinsimbi, lapho imvula kasimende encane ingase ivimbele [ukuguqulwa kwepulasitiki] ngokuvimbela ukunyakaza kokugudluka nge-matrix yensimbi ehlanzekile ye-ferrite).Kunalokho, zandisa ubulukhuni bensimbi ewuquqaba ngenxa nje yokuqina kwazo okuphezulu kakhulu kanye nengxenye yazo yevolumu enkulu, kangangokuthi ukuqina kwenqwaba kungalinganiswa ngomthetho wezingxube.Kunoma yikuphi, banikeza ubulukhuni ngezindleko zokuqina.Njengoba i-carbide yenza ingxenye enkulu yezinto ezibonakalayo, insimbi emhlophe ingahlukaniswa ngokunengqondo njenge-cermet.Insimbi emhlophe ishwabene kakhulu ukuthi ingasetshenziswa ezingxenyeni eziningi zesakhiwo, kodwa ngokuqina okuhle nokungaqhumi kanye nezindleko eziphansi, ithola ukusetshenziswa ezindaweni ezigugile (i-impeller ne-volute) yamaphampu anodaka, ama-shell liners kanye nezinsimbi zokuphakamisa ibhola. izigayo nezigayo zokugaya ezizenzelayo, amabhola namaringi kumshini wokugawula amalahle, namazinyo ebhakede lokumba le-backhoe (nakuba insimbi ye-cast medium-carbon martensitic ivame kakhulu kulolu hlelo lokusebenza).

Kunzima ukupholisa ukulingwa okuwugqinsi ngokushesha ngokwanele ukuze kuqiniswe ukuncibilika njengensimbi esakazwayo emhlophe yonke indlela.Nokho, ukupholisa ngokushesha kungasetshenziswa ukuze kuqiniswe igobolondo lensimbi ewugqinsi emhlophe, ngemva kwalokho insalela iphole kancane ukuze kwakhe umnyombo wensimbi empunga.Ukulingisa okuwumphumela, okubizwa ngokuthi aukusakaza okupholile, inezinzuzo zendawo eqinile enengaphakathi eliqinile.

Ama-alloys ensimbi amhlophe ane-chromium ephezulu avumela ukulingwa okukhulu (isibonelo, i-impeller engamathani angu-10) ukuthi kufakwe isihlabathi, njengoba i-chromium yehlisa izinga lokupholisa elidingekayo ukuze kukhiqizwe ama-carbides ngokuqina okukhulu kwento.I-Chromium iphinde ikhiqize ama-carbides anokumelana nokuhuqwa okuhlaba umxhwele.Lawa ma-alloys ane-chromium ephezulu aveza ubulukhuni bawo obuphakeme ngokuba khona kwe-chromium carbides.Ifomu eliyinhloko lalawa ma-carbide yi-eutectic noma i-primary M₇C₃carbides, lapho okuthi "M" imele insimbi noma i-chromium futhi ingahluka kuye ngokuthi ingxubevange yakhiwe kanjani.I-eutectic carbides yakheka njengenqwaba yezinduku ezine-hexagonal ezingenalutho futhi ikhula iqonde endizeni ye-basal ene-hexagonal.Ukuqina kwalawa ma-carbides kungaphakathi kwebanga le-1500-1800HV.

Insimbi ethambile ethambile

I-ayoni ethambileyo iqala njengokujikijelwa kwensimbi emhlophe bese iphathwa ngokushisa usuku noma ezimbili cishe ku-950 °C (1,740 °F) bese ipholiswa phakathi nosuku noma ezimbili.Ngenxa yalokho, i-carbon ku-iron carbide ishintsha ibe i-graphite ne-ferrite kanye ne-carbon (austenite).Inqubo ehamba kancane ivumela ukungezwani kwendawo ukuthi yakhe i-graphite ibe yizinhlayiya eziyi-spheroidal kunokuba ama-flakes.Ngenxa ye-aspect ratio yawo ephansi, ama-spheroid mafishane uma kuqhathaniswa futhi aqhelelene kwelinye, futhi anesigaba esiphambanayo esingaphansi vis-a-vis a propagation crack noma phonon.Futhi banemingcele ebuthuntu, ngokuphambene nama-flakes, edambisa izinkinga zokugxilisa ingqondo ezitholakala ku-grey cast iron.Ngokuvamile, izakhiwo zensimbi ethambile ethambile zifana nezensimbi ethambile.Kunomkhawulo wokuthi ingxenye enkulu ingaphonswa ngensimbi ethambile, njengoba yenziwa ngensimbi ewugqinsi emhlophe.

I-Ductile cast iron