Austenite - Iyini?

ukwelashwa ukushisa ensimbi - is a indlela enamandla ukuthonya isakhiwo yayo kanye nezimpahla. Kusekelwe ukushintshwa eheleni crystal njengoba umsebenzi nezinga lokushisa elizosetshenziswa kule game. Imibandela ezahlukene yensimbi-carbon ingxubevange kungaba samanje ferrite, pearlite, cementite futhi austenite. Lesi sakamuva inendima enkulu kulo lonke kugucuka ezishisayo ku steel.

definition

Steel - i ingxubevange zensimbi carbon, lapho okuqukethwe carbon isesikhathini 2.14% theory, kodwa ubuchwepheshe zihlanganisa esebenzayo isamba ayibi ngaphezu kuka-1.3%. Ngenxa yalokho, bonke izakhiwo akhiwa therein ngaphansi amathonya zangaphandle, futhi yokwahluka Alloys.

Imfundiso kusho ukuba khona kwabo 4 ukuhlukahluka: Ukungena isixazululo eziqinile, isixazululo esiqinile okuhlukile, ingxube mechanical noma ikhemikhali kwakwakhe okusanhlamvu.

Austenite - okuqinile carbon athomu isixazululo granetsentricheskuyu Ukungena endaweni cubic crystal ngehele yensimbi, ukubizwa ngokuthi γ. carbon athomu is busuka umgodi we γ Iron ngehele. Ubukhulu balo idlule labo ikhule ezimbotsheni phakathi Fe athomu, echaza okulinganiselwe odlula kubo ngokusebenzisa 'udonga' lokuphikiswa isakhiwo isizinda. Kwakheka ngesikhathi lokushisa ukuguqulwa of ferrite futhi pearlite ngokwandisa 727˚S ukushisa ngenhla.

Isifanekiso lensimbi carbon Alloys

Igrafu ngokuthi isigaba umdwebo we-iron cementite ezakhiwa zokucwaninga, kuyinto esobala zonke ezahlukeneyo okungenzeka kugucuka e lezinsimbi bese waphonsa izinyawo ngeketanga. amagugu ethile lokushisa banikezwe inani carbon e ingxubevange yakha iphuzu ezibucayi lapho kukhona izinguquko ezibalulekile ezihlelekile Ukushisa noma Ukupholisa ngomoya izinqubo, futhi yakha umugqa ezibucayi.

umugqa GSE equkethe iphuzu futhi IzE ₃ IzE _m, ubonisa izinga carbon solubility ne bandise ukushisa.

Izici zemfundo

Austenite - isakhiwo esenzelwa ngesikhathi steel bafudumale. Lapho izinga lokushisa esibucayi ukwakha Perlite futhi ferrite impahla ebalulekile.

Ukushisa ukuhlukahluka:

1. Uniform, kuze ekufinyeleleni ukubaluleka oyifunayo, ngcaphuno emfushane lwaluyophola. Kuye izici ingxubevange, le austenite kungase zimiswe njengendlela ngokugcwele noma kancane.
2. Ukwanda kancane izinga lokushisa, isikhathi eside nokugcina ezingeni kufinyelelwa ukushisa ukwakha austenite okumsulwa.

Izakhiwo impahla ukufuthelana, kanye ukuthi oluzokwenzeka ngenxa Ukupholisa ngomoya. Okuningi kuxhomeke ezingeni izuzwe ukushisa. Kubalulekile ukugwema okweqile noma perepal.

Microstructure kanye Properties

Ngamunye izigaba, ejwayelekile lensimbi carbon Alloys, bavame ukuba ngumnikazi isakhiwo amaqoqo nokusanhlamvu. austenite isakhiwo - ipuleti kokuba ukuma eduze inaliti-efana nasengqondweni, futhi olungaqinile. Lapho siphela ngokugcwele carbon ku okusanhlamvu γ Iron abe ukuma ngaphandle ukukhanya ebumnyameni cementite inclusions.

Nobulukhuni 170-220 HB. conductivity ezishisayo kagesi kanye ingaphansi kunobukaJohane ferrite. izakhiwo Magnetic azitholakali.

Ukuhluka nokukala ukupholisa kuholela ekwakhekeni izinguqulo ezahlukahlukene "abandayo" isimo: martensite, bainite, troostite, sorbitol, Perlite. Sinenkosi isakhiwo inaliti-efana, kodwa ehlukene kuyizinhlayiyana kuhlakazeka ubukhulu wokusanhlamvu namaqatha kuyizinhlayiyana cementite.

Ithonya ukupholisa austenite

kwamazinyo austenite kwenzeka amaphuzu efanayo ezibucayi. ukusebenza kwawo kuxhomeke kulokho lezi zinto ezilandelayo:

1. Izinga indlu. Ithinta ubunjalo ukungcola carbon, ukwakheka okusanhlamvu, ukwakheka microstructure sokugcina futhi izakhiwo zalo. It kuncike imvelo, esetshenziswa njengendawo kokupholisayo.
2. Ukutholakala isothermal ingxenye omunye izigaba zokuwohloka - lehliselwa lokushisa ezingeni elithile, ukushisa inakekelwa esitebeleni ngesikhathi esithile, ngemva kwalokho Ukupholisa okusheshayo iyaqhubeka, noma ngabe kwenzeka ngokuhlanganyela Ukushisa apharathasi (kuhhavini).

Ngakho, ngilahliwe futhi okuqhubekayo isothermal ukuguqulwa of austenite.

Izici uhlamvu kugucuka. ishadi

C emise igrafu ebonisa ukuthi iphethini yokushintsha we microstructure zensimbi isikhawu kuye ngokuthi lokushisa ushintsho - lokhu austenite ukuguqulwa idayagramu. I Ukupholisa langempela ngokuqhubekayo. Kukhona kuphela izigaba ezithile ngenkani ukushisa nokugcinwa. Igrafu uchaza izimo isothermal.

Uhlamvu kungaba ehlasela umzimba kanye Diffusionless.

Ngezinye ejwayelekile isivinini ushintsho ukunciphisa ukushisa okusheshayo austenite okusanhlamvu kwenzeka. I thermodynamic ama-athomu ukuntengantenga zone aqale ukuhambisa ndawonye. Labo cha angena eheleni yensimbi, yakha inclusions cementite. Basuke elajoyinwa izinhlayiya angomakhelwane carbon, sikhululwe zinhlayiya yayo. kwakhiwa Cementite ngaso imingcele okusanhlamvu uwohloka. zinhlayiya ukuhlanzwa bakha abafanele ipuleti ferrite. kwakhiwa isakhiwo bahlakazeka is - ingxube okusanhlamvu, ubukhulu kanye lokuhlushwa okuyinto incike rapidity of Ukupholisa ngomoya kanye okuqukethwe carbon e ingxubevange. Kwakheka njengoba Perlite futhi izigaba zalo esimaphakathi: sorbitol, troostite, bainite.

Nge ukunciphisa lokushisa nesivinini abalulekile noqhekeko austenite kungaqali imvelo diffusive. Inxanxathela crystal ukuhlanekezela okwenzeka ngaphakathi lapho bonke ama-athomu kanyekanye ukuhambisa ngendiza ngaphandle kokushintsha indawo. Ukuswelakala kokusebenza ngokuhlanganyela okusheshayo kunomthelela ukuvela martensite.

Umthelela eqeda ku austenite noqhekeko izici. martensite

Ukuqina - uhlobo ukwelashwa ukushisa, okuyinto ngokuyisisekelo liqukethe okusheshayo Ukushisa kuze kufinyelele ezingeni lokushisa eliphezulu ngaphezu iphuzu ezibucayi kanye IzE ₃ IzE _m, kulandele Ukupholisa okusheshayo. Uma ukwehla lokushisa senzeka ngamanzi ngesivinini ezingaphezu kuka-200 ° C ngomzuzwana ke okuqinile isigaba acicular kulotshwé igama martensite.

Kuyinto isixazululo supersaturated okuqinile carbon e Ukungena yensimbi uhlobo crystal ngehele nge α. Ngenxa enamandla ukunyakaza ama-athomu siphazamisekile futhi yakha ngehele tetragonal elikhonza imbangela ukuqina. Isakhiwo kwakhiwa has a umthamo emikhulu. Zinhlayiya okuholela abangu iphahlwe indiza onomfutho nucleate acicular amapuleti.

Martensite - eqinile futhi kanzima kakhulu (700-750 HB). Kwakheka kuphela ngenxa ngesivinini eqeda.

Tempering. isakhiwo okusheshayo

Austenite - Ukwakheka kwezitho okungase eyayenziwe ekhiqizwa bainite, troostite, sorbite, futhi Perlite. Uma indlu eqeda kwenzeka ngoba velocities ephansi, ukuguqulwa eyenziwa okusheshayo, indlela yabo kuchaziwe ngenhla.

Troost - kuyinto Perlite, esibonakala by ngezinga eliphezulu ukuhlakazwa. Kwakheka at 100 ° C ukwehla ngesikhathi sokushisa kwemini okwamanje. Inani elikhulu okusanhlamvu esihle ferrite futhi cementite isakazwa phezu kwawo wonke indiza. "Lukhuni" eyinqaba cementite ipuleti ukuma troostite okubangelwa tempering okwalandela, has a ngeso luyimbudumbudu. Ukuqina - HB 600-650.

Bainite - i esigabeni esimaphakathi, esiwumfanekiso zinhlayiya nakakhulu inhlanganisela ephezulu abahlakazekile bakwa ferrite futhi cementite. Ngokwe izakhiwo mechanical nezobuchwepheshe kunabayeni martensite, kodwa idlula troostite. Kwakheka esezingeni lokushisa lapho ukwanda okusheshayo akunakwenzeka kanye kokucindezelwa amandla bese ukuhambisa isakhiwo crystalline ukuguqula martensite - enganele.

Sorbitol - indawo ezihlukahlukene acicular izigaba pearlitic ngesikhathi lwaluyophola ngesilinganiso 10 ° C ngomzuzwana. Mechanical umsebenzi izakhiwo Lesisemkhatsini phakathi troostite futhi pearlite.

Perlite - sebuningini nangangesihlabathi ferrite futhi cementite, okungase luyimbudumbudu, noma ipuleti ukuma. Kwakheka ngenxa noqhekeko abushelelezi austenite at nokuphola izinga 1s ngomzuzwana.

Beit troostite futhi - ibhekisele izakhiwo Ningamcimi, kuyilapho sorbitol futhi Perlite zingase zimiswe futhi tempering, annealing futhi normalizing izici ezichaza ukuma kanye nosayizi okusanhlamvu.

Umthelela annealing phezu ethile noqhekeko austenite

Cishe zonke izinhlobo annealing futhi ukuzinza esekelwe ukuguqulwa okuhambisanayo of austenite. annealing Okugcwele kanye itoho isetshenziswa doevtektoidnyh lezinsimbi. Yekuchumana ngenkathi kushiswa okuthile kuhhavini ngenhla amaphuzu ezibucayi IzE ₁ futhi IzE _3, ngokulandelana. Ukuze uhlobo lokuqala elinesimo ukuchayeka isikhathi eside, okuyinto kuqinisekisa ukuguqulwa okuphelele: austenite-ferrite-austenite futhi pearlite. Kulandele kancane Ukupholisa amalunga esithandweni. Ngesikhathi okukhiphayo ukunikeza ingxube esihle ferrite futhi pearlite, ngaphandle ekucindezelekeni yangaphakathi futhi plastic okuqinile. annealing Soft kancane amandla khudlwana, eshintsha isakhiwo Perlite kuphela, ferrite kokushiya cishe enjalo. Kokulinganisa kusho lelisetulu lokushisa ukwehla, Nokho, plastic nokuncane isakhiwo indawo kwayo kuleyo ndawo yokuhweba. Ukuze steel ingxubevange nge wokuqukethwe carbon kusuka 0.8 kuya 1.3% uma selehlile ku kwamazinyo ukuzinza kwenzeka ngase: austenite, pearlite, austenite-cementite.

Olunye uhlobo ukwelashwa ukushisa ogxile kugucuka kwesakhiwo, kuyinto homogenisation. Kuyinto osebenzayo izingxenye ezinkulu. Litjho ngokuphelele ekufezeni isimo indawo austenitic okushisa 1000-1200˚S nokukhuthazela esithandweni esikhathini kufika emahoreni angu-15. izinqubo Isothermal uqhubeke Ukupholisa kancane, okuyinto enomthelela zokulinganiswa izakhiwo metal.

annealing isothermal

Ngayinye yalezi izindlela ezinomthelela metal for lula ukuqonda uthathwa njengoba ukuguqulwa isothermal ka austenite. Nokho, ngamunye wabo kuphela esikhathini esithile sinezici. Empeleni, izinguquko zenzeka ne ukwehla unganciphi, ijubane okuyinto inquma yi.

Enye indlela esiseduzane izimo ezikahle - annealing isothermal. Ingqikithi Its futhi liqukethe Ukushisa nokuchayeka wokugoqa oluphelele lwazo zonke izakhiwo ku austenite. I Ukupholisa yaqaphela izigaba eziningana, okuyinto enomthelela esitebeleni kancane, isikhathi eside ngokwengeziwe futhi thermally zokuwohloka yayo.

1. I iconsi okusheshayo e lokushisa kunani ngezansi 100 ° C kuya IzE ₁ iphuzu.
2. Ephoqelekile nokugcinwa ukubaluleka izuzwe (ibekwe esithandweni) isikhathi eside kuze kuphelele ekwakhekeni izigaba ferritic-pearlitic.
3. Lwaluyophola namanje emoyeni.

Le ndlela esebenzayo ingxubevange lezinsimbi, izimpawu khona austenite asalile esimweni esiqandisini.

austenite asalayo lezinsimbi austenitic

Ngezinye izikhathi kungenzeka ukuwohloka ngokwengxenye, uma kukhona austenite asalile. Lokhu kungenzeka ezimweni ezilandelayo:

1. Ukupholisa kakhulu okusheshayo lapho ukuwohloka ngokuphelele kwenzeka. Kuyinto ingxenye isakhi bainite noma martensite.
2. High carbon steel noma ingxubevange ongaphakeme, okuyiwona izinqubo nzima bahlakazeka kugucuka austenite. Kudinga ukusebenzisa izindlela ezikhethekile ukwelashwa ukushisa, ezifana, isibonelo, homogenization noma isothermal annealing.

Ukuze high-- Ayikho inqubo ochazwa kugucuka. Alloying steel ne-nickel, manganese, chromium Akhuthaza ukwakheka kwe-austenite njengoba primary isakhiwo esiqinile okungadingi i amathonya ezengeziwe. lezinsimbi Austenitic zinezikhathi namandla high, ukugqwala ukumelana nokushisa ukumelana, ukushisa ukumelana kanye ukumelana nezimo nolaka ukusebenza nzima.

Austenite - isakhiwo lapho akunakwenzeka ngaphandle obumba kungekho ephezulu lokushisa Ukushisa steel futhi okuyinto ehilelekile cishe zonke izindlela zayo ukwelashwa ukushisa ukuthuthukisa izakhiwo mechanical nokucutshungulwa.