Simbiiboka re iron-carbon alloys ine kabhoni inodarika 2%.Kubatsira kwayo kunobva mukudziya kwayo kwakadzikira kunyungudika.Iyo alloy constituents inokanganisa ruvara rwayo kana yatsemuka: white cast iron ine carbide tsvina inobvumira mitswe kuti ipfuure yakananga, grey cast iron ine graphite flakes inobvisa mutswe unopfuura uye inotanga kusaverengeka kutsva kwakatsemuka sezvo zvinhu zvinotsemuka, uye ductile cast iron ine spherical. graphite "nodules" iyo inomisa mutswe kuti usaenderere mberi.

Carbon (C) kubva 1.8 kusvika 4 wt%, uye silicon (Si) 1-3 wt%, ndiwo makuru alloying zvinhu zvesimbi yakakandwa.Iron alloys ane yakaderera kabhoni content anozivikanwa sesimbi.

Simbi yakakandwa inoita kunge ine brittle, kunze kwemasimbi anogadzika.Nekunyungudika kwayo kwakadzikira, kunaka kwemvura, kukanda, kugona kwakanakisa, kuramba deformation uye kupfeka kuramba, simbi dzakakandwa dzave chinhu cheinjiniya chine huwandu hwakawanda hwekushandisa uye inoshandiswa mumapombi, michina uye zvikamu zveindasitiri yemotokari, senge silinda. misoro, cylinder blocks uye gearbox makesi.Inoshingirira kukuvadzwa neoxidation.

Zvigadzirwa zvekutanga zvesimbi zvakatanga kusvika muzana ramakore rechi 5 BC, uye zvakawanikwa nevanochera matongo mune yava kunzi Jiangsu kuChina.Cast iron yaishandiswa muChina yekare kuhondo, kurima, uye kuvaka.Mukati mezana ramakore rechi 15, simbi yakakandwa yakashandiswa kuita cannon muBurgundy, France, uye muEngland panguva yeReformation.Huwandu hwesimbi yakakandwa yakashandiswa kugadzira kanoni yaida kugadzirwa kwakakura.Zambuko rekutanga resimbi rakavakwa muma1770s naAbraham Darby III, uye rinozivikanwa seThe Iron Bridge muShropshire, England.Simbi yakakandwa yakashandiswawo pakuvaka zvivakwa.

Alloying zvinhu

Cast iron's zvimiro zvinoshandurwa nekuwedzera akasiyana alloying zvinhu, kana alloyants.Pedyo nekabhoni, silicon ndiyo inonyanya kukosha alloyant nekuti inomanikidza kabhoni kubuda mumhinduro.Iyo yakaderera muzana yesilicon inobvumira kabhoni kuti irambe iri mumhinduro inogadzira iron carbide uye kugadzirwa kwewhite cast iron.Iyo yakakwira muzana yesilicon inomanikidza kabhoni kunze kwemhinduro kugadzira graphite uye kugadzirwa kwegrey cast iron.Mamwe alloying agents, manganese, chromium, molybdenum, titanium uye vanadium inopesana nesilicon, inosimudzira kuchengetwa kwekabhoni, uye kuumbwa kweiyo carbides.Nickel nemhangura zvinowedzera simba, uye machinability, asi usashandura huwandu hwegraphite yakaumbwa.Iyo kabhoni iri muchimiro chegraphite inoguma nesimbi yakapfava, inoderedza kuderera, inoderedza simba, uye inoderedza density.Sulfur, kunyanya inosvibisa kana iripo, inoumba iron sulfide, iyo inodzivirira kuumbwa kwegraphite uye inowedzera kuoma.Dambudziko nesarufa nderekuti inogadzira yakanyungudutswa simbi yakanyungudutswa viscous, izvo zvinokonzeresa kuremara.Kurwisa mhedzisiro yesarufa, manganese inowedzerwa nekuti maviri anoumba manganese sulfide pachinzvimbo chesimbi sulfide.Iyo manganese sulfide yakareruka kupfuura kunyunguduka, saka inowanzoyangarara ichibva mukunyunguduka ichienda kune slag.Huwandu hwemanganese hunodiwa kumisa sarufa ndeye 1.7 × sulfur content + 0.3%.Kana yakawanda kupfuura iyi manganese yakawedzerwa, ipapo manganese carbide mafomu, ayo anowedzera kuoma uye kutonhora, kunze kwesimbi yegrey, uko kusvika ku1% yemanganese inowedzera simba uye kusimba.

Nickel ndechimwe chezvinhu zvakajairika alloying nekuti inonatsa pearlite uye graphite chimiro, inovandudza kuomarara, uye kunyange kunze kwekuomarara misiyano pakati pemakobvu echikamu.Chromium inowedzerwa mune zvidiki kuderedza mahara graphite, kuburitsa kutonhora, uye nekuti ine simba carbide stabilizer;nickel inowanzowedzerwa pamwe chete.Chiyero chidiki cherata chinogona kuwedzerwa sechinzvimbo che 0.5% chromium.Mhangura inowedzerwa muladle kana muchoto, pahurongwa hwe0.5-2.5%, kuderedza kutonhora, kunatsa graphite, uye kuwedzera fluidity.Molybdenum inowedzerwa pakurongeka kwe0.3-1% kuti iwedzere kutonhora uye kunatsa girafu uye pearlite chimiro;inowanzowedzerwa pamwe chete ne nickel, mhangura, uye chromium kuti iite iron yakasimba.Titanium inowedzerwa se degasser uye deoxidizer, asi inowedzera fluidity.0.15-0.5% vanadium inowedzerwa kukanda simbi kuti igadzikane simenti, kuwedzera kuoma, uye kuwedzera kuramba kupfeka uye kupisa.0.1-0.3% zirconium inobatsira kuumba graphite, deoxidize, uye kuwedzera mvura.

Musimbi inonyungudika inonyunguduka, bismuth inowedzerwa, pachiyero che 0.002-0.01%, kuwedzera kuti yakawanda sei silicon inogona kuwedzerwa.Musimbi chena, boron inowedzerwa kubatsira mukugadzirwa kwesimbi inogoneka;zvakare inoderedza coarsening mhedzisiro yebismuth.

Gray cast iron

Grey cast iron inoratidzwa neiyo graphitic microstructure, iyo inokonzera kuputsika kwechigadzirwa kuve nechitarisiko chegrey.Ndiyo inonyanya kushandiswa simbi yakakandwa uye inonyanya kushandiswa yakakandwa zvinhu zvinoenderana nehuremu.Masimbi akawanda anokandwa ane kemikari ye2.5-4.0% kabhoni, 1-3% silicon, uye yakasara iron.Simbi ye grey ine simba shoma uye inodzivirira kuvhunduka kupfuura simbi, asi simba rayo rekumanikidza rinofananidzwa nesimbi yakaderera uye yepakati-kabhoni.Aya ma mechanical properties anodzorwa nehukuru uye chimiro che graphite flakes iripo mu microstructure uye inogona kuonekwa maererano nemirairo inopiwa neASTM.

White cast iron

Simbi yewhite cast inoratidzira machena akatsemuka nekuda kwekuvapo kwesimbi carbide precipitate inonzi cementite.Iine yakaderera silicon yemukati (graphitizing agent) uye nekukurumidza kutonhora mwero, iyo kabhoni iri muchena yakakandwa iron inodonha kubva mukunyunguduka se metastable phase simenti, Fe.₃C, pane graphite.Iyo cementite inodonha kubva mukunyunguduka inoumba sezvimedu zvakakura.Sezvo iyo iron carbide inobuda, inobvisa kabhoni kubva mukunyungudika kwepakutanga, ichifambisa musanganiswa ichienda kune imwe iri padyo neeutectic, uye chikamu chasara ndicho chepasi iron-carbon austenite (iyo pakutonhora inogona kushandura kuita martensite).Aya eutectic carbides akakura zvakanyanya kuti ape rubatsiro rwezvinonzi precipitation harding (sezvinoita mune mamwe masimbi, uko madiki ecementite precipitates anogona kutadzisa [plastic deformation] nekutadzisa kufamba kwekutenderera kuburikidza nesimbi yakachena ferrite matrix).Asi, vanowedzera kuomarara kwesimbi yakakandwa nekuda kwekuomarara kwavo kwakanyanya uye nechikamu chevhoriyamu yakakura, zvekuti kuomarara kwakawanda kunogona kuenzaniswa nemutemo wemisanganiswa.Chero zvazvingava, vanopa kuoma pamutengo wekuoma.Sezvo carbide ichiita chikamu chikuru chezvinyorwa, simbi chena inogona kuverengerwa se cermet.Simbi chena yakanyanya brittle kuti ishandiswe muzvinhu zvakawanda zvezvimiro, asi nekuoma kwakanaka uye kuramba abrasion uye nemutengo wakaderera, inowana kushandiswa mumashandisirwo akadai seaya anopfeka (impeller uye volute) yemapombi ane slurry, shell liners uye masimbi ekusimudza mubhora. zvigayo uye zvigayo zvega zvega zvinogaya, mabhora uye zvindori mumarasha pulverisers, uye mazino ebackhoe's bhaketi rekuchera (kunyangwe cast medium-carbon martensitic simbi inowanzoitika kune iyi application).

Zvakaoma kutonhodza makanda akakora nekukasira kuomesa kunyunguduka sesimbi chena nzira yese.Nekudaro, kutonhora nekukurumidza kunogona kushandiswa kuomesa goko rewhite cast iron, mushure meizvozvo iyo yasara inotonhora zvishoma nezvishoma kuita pakati pegrey cast iron.Kukandira kunoguma, kunonzi achilled casting, ine mabhenefiti enzvimbo yakaoma ine mukati mekati yakaoma.

High-chromium white iron alloys inobvumira kukanda kukuru (semuenzaniso, 10-tonne impeller) kuve jecha rakakandwa, sezvo chromium ichideredza kutonhora kunodiwa kugadzira carbides kuburikidza nehukuru hwezvinhu.Chromium inogadzirawo carbides ine inoshamisa abrasion resistance.Aya ma-high-chromium alloys anoratidza kuoma kwavo kwepamusoro nekuvapo kwechromium carbides.Nzira huru yeiyi carbides ndiyo eutectic kana yekutanga M₇C₃carbides, apo "M" inomiririra iron kana chromium uye inogona kusiyana zvichienderana nekuumbwa kwealloy.Iyo eutectic carbides inoumba semasumbu ehollow hexagonal tsvimbo uye inokura perpendicular kune hexagonal basal ndege.Kuoma kwema carbides aya ari mukati mehuwandu hwe1500-1800HV.

Simbi inokwenenzveka

Simbi inogadzika inotanga sesimbi chena inokandwa iyo inobatwa nekupisa kwezuva rimwe kana maviri panosvika 950 °C (1,740 °F) yozotonhodzwa kwezuva rimwe kana maviri.Nekuda kweizvozvo, iyo kabhoni musimbi carbide inoshandura kuita graphite uye ferrite pamwe nekabhoni (austenite).Iyo inononoka maitiro inobvumira kushushikana kwepamusoro kuumba graphite kuita spheroidal particles pane maflakes.Nekuda kwechiyero chechikamu chepasi, ma spheroids ari mapfupi uye ari kure kubva kune mumwe, uye ane chikamu chepasi chemuchinjikwa vis-a-vis a propagating crack or phonon.Ivo zvakare vane miganhu isina kujeka, kupesana nemaflakes, ayo anorerutsa matambudziko ekugadzirisa kushushikana anowanikwa mugrey cast iron.Kazhinji, zvimiro zvesimbi inokwenenzverwa zvakada kufanana nedzesimbi yakapfava.Pane muganhu wekuti chikamu chakakura sei chinogona kukandwa musimbi inogadzika, sezvainogadzirwa kubva kumucheka chena.

Ductile cast iron