Austenite - yintoni na le nto?

unyango ekutshiseni ngesinyithi - yindlela enamandla ukuphembelela isakhiwo sayo kunye neempawu. Oku kusekelwe ulungiso ze yikristale emkhusaneni njengomsebenzi obushushu somdlalo. Iimeko ezahlukeneyo yentsimbi-carbon ingxubevange kunokuba ferrite langoku, ngeperlite, cementite kunye austenite. Le yokugqibela idlala indima enkulu zonke utshintshwano thermal kwi ngentsimbi.

definition

Steel - an intsila ngentsimbi carbon, apho isiqulatho ikhabhoni ukuya ku 2.14% kwethiyori, kodwa yobuchwepheshe luqulathe esebenzayo mali hayi ngaphezulu kwe-1,3%. Ngako oko, onke amaqela enziwa kuyo phantsi kwempembelelo yangaphandle, nazo wobeko aluminium.

Le mfundiso ubukho babo kwiiyantlukwano 4: umthondo isisombululo eziqinileyo, isisombululo esiluqilima se-ngaphandle, umxube ngomatshini okanye iinkozo ezimbaxa imichiza.

Austenite - into eqinileyo carbon atom granetsentricheskuyu umthondo isisombululo ngendlela cc akhazimlayo emkhusaneni yentsimbi, nezaziwa γ. carbon ingaphezulu yaziswa em- emkhusaneni γ-yentsimbi. imilinganiso yalo ngaphezulu ezo pores phakathi Fe athom, ezichaza limited odlula kuzo "udonga" ngesakhiwo isiseko. Senziwe ngexesha lobushushu iinguqu ferrite kunye ngeperlite ngokwandisa 727˚S ubushushu ngasentla.

Lo mzobo aluminiyamu yentsimbi-carbon

Igrafu ebizwa Isigaba umzobo besinyithi-cementite sakhiwa abantu balinge, kubonisa ngokucacileyo zonke ezahlukeneyo kunokwenzeka of utshintshwano e yodidi kunye ngeentsimbi cast. Amaxabiso ezithile lobushushu banikwa isixa kwekhabhoni ingxubevange zenza ingongoma ebalulekileyo apho kukho utshintsho ebalulekileyo kulwakhiwo kwi zokufudumeza okanye ukupholisa iinkqubo, nabo benza umgca kakhulu.

line GSE equlathe point IZe ₃ Mseb _m, ubonisa inqanaba carbon ukunyibilika kunye nokunyusa izinga ubushushu.

Iimpawu zemfundo

Austenite - isakhiwo ezikhandelwa ngexesha ukufudumeza ngentsimbi. Xa lobushushu kakhulu ukwenza perlite kunye nezinto ferrite ephambili.

zokufudumeza yazo:

1. Uniform, de afikelele ixabiso olifunayo, indawana emfutshane zokupholisa. Kuxhomekeka iimpawu ingxubevange, lo austenite ukuze abunjwe njenge ngokupheleleyo okanye ngokuyinxenye.
2. Ukwanda kade lobushushu, ixesha elide nokugcina inqanaba kuko ubushushu ukwenza austenite enyulu.

Iimpawu umbandela eshushu, kwakunye oko kuya kwenzeka ngenxa yokuba kobubi. Kuxhomekeka kwinqanaba afunyenwe bubushushu. Kubalulekile ukuphepha nobushushu okanye perepal.

Imiba emincinci yombutho kunye Izinto zobumnini

Nganye izigaba, ngokuqhelekileyo aluminiyamu yentsimbi-carbon, bakholisa ukuba ngumnikazi ubume amaqoqo kunye neenkozwana. isakhiwo austenite - ipleyiti ukuba imilo kufutshane inaliti-ezifana nengqondo, icolekile. Xa ichithwe ngokupheleleyo kwekhabhoni iinkozo γ-yentsimbi abe imilo ngaphandle ukukhanya inclusions cementite emnyama.

Yobulukhuni 170-220 HB. conductivity emhlabeni yaye lombane ngaphantsi kunalowo ferrite. iipropati Magnetic azifumaneki.

Ezahlukeneyo kunye nezinga okupholisa ekhokelela kuseko iinguqulelo ezahlukeneyo ngurhulumente "iqhosha lokulayita": martensite, bainite, troostite, sorbitol, perlite. Baye isakhiwo yenaliti-like, kodwa eziziintsali yamasuntswana ezahlukeneyo, ubukhulu okuziinkozo kwisuntswana cementite.

Impembelelo ye austenite okupholisa

ukubola austenite lwenzeka kwi manqaku manye ezibalulekileyo. impumelelo yayo ixhomekeke ezi zinto zilandelayo:

1. Izinga lungapholi. Ichaphazela uhlobo ubumdaka carbon, ukuyilwa okuziinkozo, lokusekwa emincinci sokugqibela kunye neempawu zayo. Kuya kuxhomekeka kokusingqongileyo, esetyenziswa njengesipholisi.
2. Ukufumaneka ingxenye isothermal kwesinye amanqanaba ekonakaleni - uvikivwa ukuya kwinqanaba elithile ubushushu, ubushushu igcinwe esitalini ngexesha elithile, emva koko ukuphola rapid qhutywa, okanye nokuba oko kwenzeka kubanjiswene kunye izixhobo zokufudumeza (oven).

Ngenxa yoko, elahliwe kunye ngokuqhubekayo isothermal benguqu austenite.

Iimpawu zinguquko umlinganiswa. itshathi

C-ezimile igrafu ebonisa imfano kutshintshwe emincinci metal ekuhambeni kwexesha lekhefu kuxhomekeka utshintsho ubushushu - le yenguqu yemizobo austenite. Elona Ukupholisa ngokuqhubekayo. Kukho kuphela izigaba ezithile ngenkani nokugcinwa ubushushu. Le grafu ichaza iimeko isothermal.

Character kunokuba umzimba kunye Diffusionless.

Ngesantya utshintsho eqhelekileyo ukunciphisa ubushushu kwe- austenite iinkozo kwenzeka. Ezi athom zone ukungazinzi thermodynamic uqale ukususa kunye. Abo musani ukuphatha ndzulu emkhusaneni intsimbi, benza inclusions cementite. Bona kwangenelela ne-amasuntswana ezingabamelwane carbon, sikhululwe crystals yayo. Cementite senziwa kwimida beenkozo disintegrating. ziikristale lihlanjululwe kwenza ipleyiti zabo ferrite. isakhiwo saa abunjwe - umxube okuziinkozo, ubukhulu kunye yoxinaniso leyo ixhomekeke wathandwa kwe lungapholi kunye umxholo kwekhabhoni ingxubevange. , Njengoko perlite kunye nezigaba zawo esiphakathi: sorbitol, troostite, bainite.

Nge lobushushu kokunciphisa isantya ebalulekileyo yokubola austenite wenza imvelo diffusive. Complex crystal ubugqwetha olwenzeka ngaphakathi apho bonke athom ngaxeshanye ukuhambisa-moya ngaphandle kokutshintsha indawo. Ukungabikho kwe- kunegalelo ukuvela martensite.

Isiphumo icima ngokobunjani yokubola austenite. martensite

Lukhuni - uhlobo lwe unyango ubushushu, leyo iqulathe ncakasana a ngokukhawuleza zokufudumeza ukuya kumaqondo obushushu aphezulu ngaphezu ingongoma ebalulekileyo kunye IZe ₃ Mseb _m, kulandele lungapholi olukhawulezayo. Ukuba ukuhla lobushushu lwenzeka ngamanzi ngesantya esingaphezulu kwama-200 ° C ngomzuzwana, ngoko into eqinileyo Isigaba acicular benalo igama martensite.

Kuyinto isisombululo supersaturated eqinileyo kwekhabhoni umthondo yentsimbi uhlobo akhazimlayo emkhusaneni ne α. Ngenxa ezinamandla iintshukumo atom egqwethekileyo kwaye yenza efestileni tetragonal ekhonza ukuba lukhuni. Isakhiwo wambumba umntu umthamo omkhulu. Le ziikristale kuphumela zaye lingqongwe moya zixinaniswe iipleyiti nucleate acicular.

Martensite - ixesha elide kwaye kunzima kakhulu (700-750 HB). Senziwe kuphela ngenxa-high speed ucimayo.

Tempering. isakhiwo nokuhanjiswa

Austenite - Ukwakheka lwazo zamntu kuveliswa bainite, troostite, sorbite, kunye perlite. Ukuba Ukupholisa ucimayo kwenzeka ngenxa sesiqhelo ephantsi, ukuguquka wenziwe kwe-, indlela yabo ezichazwe apha ngasentla.

Troost - na perlite, esibonakala nezinga eliphezulu nokusasazeka. Kwamiswa 100 ° C ukuncipha ekufudumaleni mzuzu. Inani elikhulu ezinokutya emihle ferrite kunye cementite isasazwa kulo lonke moya. "Lukhuni" yinqobo imilo cementite ipleyiti kunye troostite evela tempering elandelayo, uye nokuthelekelela granular. Ukuqina - HB 600-650.

Bainite - an kwisigaba esiphakathi, nto leyo ziikristale nangakumbi umxube ophezulu-iintsali ferrite kunye cementite. Ngokutsho iipropati koomatshini nobuchwepheshe obuphantsi martensite, kodwa lidlula troostite. Kwakheka ngaphakathi uluhlu lobushushu apho kwe- akunakwenzeka kunye nomkhosi ucinezelo ze uhambisae isakhiwo crystalline ukuguqukela martensite - ayonelanga.

Sorbitol - iintlobo acicular izigaba erhabaxa pearlitic ngokulinganisela ka-10 ° C yesibini nganye zokupholisa. Iipropati umsebenzi Mechanical ezi oluphakathi phakathi troostite kunye ngeperlite.

Perlite - ezininzi kuThixo ngeenkozwana ferrite kunye cementite, esenokuba granular, okanye imilo ipleyiti. , Njengoko ngenxa yokubola egudileyo austenite kwi nokuphola 1 rate ngomzuzwana.

Beit troostite kunye - libhekisele izakhiwo zicime, ngelixa sorbitol kunye perlite nga iqalise tempering, annealing kunye normalizing iimpawu ezichaza imilo nobukhulu ukutya.

Isiphumo annealing kwi ibole ethile austenite

Phantse zonke iintlobo annealing kuqheleke esekelwe kwi inguqu lwamacala austenite. annealing elipheleleyo part-time isetyenziswa ukuba doevtektoidnyh yodidi. Iinkcukacha itshiswe ngokusondele kwi-oveni ngasentla iingongoma ezibalulekileyo Mseb _{1 ne-AC-3,} ngokulandelelana. Kuba udidi lokuqala iphawulwa ithuba exposure elide, nto leyo eqinisekisa ukuguqulwa epheleleyo: austenite-ferrite-austenite kunye ngeperlite. Elandelwa billets Ukupholisa okucothayo kule eziko. Xa imveliso ukunika umxube omhle ferrite kunye ngeperlite, ngaphandle neengxaki ngaphakathi aqinileyo zeplastiki. annealing Soft kangako umbane olunzulu, utshintsha kuphela isakhiwo perlite, ferrite eshiya zilolo hlobo zazilulo. Ukuzinza ithetha izinga eliphezulu lobushushu ukuhla, nangona kunjalo, iplastiki kunye nesakhiwo ngaphantsi ontlakantlaka ngamashishini. Kuba ingxubevange steel ezinomthamo carbon of ukususela 0.8 ukuya 1.3% xa zipholile kwi ukubola ukuzinza kwenzeka kubo: austenite, ngeperlite, austenite-cementite.

Olunye uhlobo lonyango ubushushu osekelwe phezu utshintshwano kwesakhiwo, kuba homogenisation. Uya kusebenza iindawo ezininzi. Libonisa lungundoqo ekuphumezeni karhulumente yomgrayo austenitic kwiqondo lobushushu 1000-1200˚S nonyamezelo eziko elithile lithatha ixesha ukuya kutsho kwiiyure 15. iinkqubo Isothermal kuqhubeka ukupholisa kade, nto leyo inegalelo ngokulinganiswa izakhiwo yesinyithi.

annealing isothermal

Ngamnye ezi ndlela eziphembelela metal yoququzelelo ukuqonda ithathwa nenguqu isothermal of austenite. Noko ke, ngamnye kubo kuphela kwinqanaba elithile uneempawu. Enyanisweni, utshintsho kwenzeka kunye nokuncipha uthotho ubushushu, isantya olumisela isiphumo.

Enye indlela ngowona usondeleyo iimeko ezifanele - annealing isothermal. kubume bayo liquka zivula nokuqhelana ukuwa epheleleyo zonke izakhiwo kwi austenite. Olupholisa yaqaphela kwizigaba eziliqela, nto leyo inegalelo ukuba kancinci elide ngakumbi nangakumbi thermally izinzile lokubola yayo.

1. Ukuhla ngokukhawuleza lobushushu kwixabiso ngaphantsi kwe-100 ° C ukuya Mseb ₁ point.
2. Forced ukugcinwa ixabiso bhetye (ibekwe iziko) ixesha elide de kugqitywe ukuyilwa a izigaba ferritic-pearlitic.
3. Zokupholisa nisamana emoyeni.

Le ndlela kusebenza yodidi ingxubevange, obubonakala ngokuba yincwadi evuliweyo ubukho austenite intsalela ukwimeko refrigerated.

austenite lentsalela yodidi austenitic

Maxa wambi kuba ukubola kunokwenzeka buso, xa kukho austenite intsalela. Oku kwenzeka meko zilandelayo:

1. Ukupholisa rapid kakhulu xa kusenzeka baphazamiseka epheleleyo. Eli licandelo noshowo bainite okanye martensite.
2. carbon steel High okanye ingxubevange ephantsi, apho iinkqubo zingabi saa zinguquko austenite. Ifuna ukusebenzisa iindlela zonyango ubushushu ezikhethekileyo, ezifana, ngokomzekelo, iqhagamshela okanye isothermal annealing.

Kuba high-- Akukho nkqubo ichazwe yi zinguquko. Alloying steel nge-nickel, manganese, chromium ikhuthaza ukuyilwa austenite njengolwakhiwo yokuqala ethi ayifuni iimpembelelo ezongezelelweyo. yodidi Austenitic luphawulwa ngamandla aphezulu, nokumelana kunye nokumelana nobushushu, ukumelana ubushushu kunye nokumelana neemeko ndlongondlongo ukusebenza nzima.

Austenite - yinto isakhiwo apho akunakwenzeka ngaphandle kusekwe Akukho zivula-lobushushu eliphezulu zentsimbi kunye leyo inxaxheba phantse zonke zayo iindlela zonyango ubushushu ukuphucula iipropati koomatshini kanye processing.