Austenite - menene wannan?

Zafi magani daga karfe - shi ne mai iko inji tasiri da tsarin da kaddarorin. Yana dogara ne a kan gyare-gyare na da crystal raga a matsayin aiki na da yawan zafin jiki na game. A daban-daban yanayi a baƙin ƙarfe-carbon gami iya zama ba ferrite, pearlite, cementite da austenite. A karshen taka wata muhimmiyar rawa a cikin dukkan thermal canje a karfe.

definition

Karfe - wani gami da na baƙin ƙarfe, da carbon, cikinsa da carbon abun ciki shi ne har zuwa 2.14% na ka'idar, amma shi ne technologically m hada da a wani adadin ba fiye da 1.3%. Haka kuma, duk da Tsarin cewa an kafa cikinta karkashin waje tsoma, suna kuma bambance-bambancen karatu gami.

Ka'idar shi ne su zama cikin 4 bambancin: shigar azzakari cikin farji m bayani, wani m bayani da wani togiya, wani inji cakuda ko sinadaran fili hatsi.

Austenite - mai ɗamfarar carbon zarra granetsentricheskuyu shigar azzakari cikin farji bayani a cubic crystal raga na baƙin ƙarfe, da ake magana a kai a matsayin γ. carbon zarra ne ya gabatar a cikin kogo na γ-baƙin ƙarfe raga. Its girma wuce wadanda pores tsakanin Fe kwayoyin halitta, wanda ya bayyana da iyaka wucewa da su ta hanyar da "bango" daga cikin tushe tsarin. Kafa a lokacin canji zafin jiki na ferrite da pearlite ta kara zafi 727˚S sama.

A zane na baƙin ƙarfe-carbon gami

Jadawali kira zamani zane na baƙin ƙarfe-cementite gina ta experimentation, ne bayyananne zanga-zanga na dukkan yiwu bambance-bambancen karatu na rikirkida a steels da simintin mari. Specific dabi'u ga wani ba yawan zafin jiki da adadin carbon a cikin gami samar da wata m batu a wanda akwai muhimmanci tsarin canje-canje a cikin dumama ko sanyaya matakai, sun kuma samar da wani m line.

GSE line cewa ya ƙunshi batu da kuma Ac ₃ Ac _m, nuna da matakin na carbon solubility tare da kara zafi matakan.

ilimi Features

Austenite - a tsarin da aka kafa a lokacin karfe dumama. Lokacin da m zazzabi samar perlite kuma ferrite na game kayan.

dumama bambancin:

1. Uniform, har ya kai da ake so darajar, a takaice dai sharhin, an ɗauko sanyaya. Dangane da halaye na gami, da austenite za a iya kafa a matsayin cikakken ko partially.
2. The m Yunƙurin a zazzabi, wata mudda ta rike da cimma matakin zafi ta samar da wata m austenite.

A Properties daga cikin mai tsanani abu, kazalika da abin da zai faru a sakamakon sanyaya. Yawanci ya dangana a kan matakin cimma ta cikin zãfi. Yana da muhimmanci a kauce zafi fiye da kima ko perepal.

Microstructure kuma Properties

Kowace daga cikin manzilõli, hali na baƙin ƙarfe-carbon gami, ayan mallaki tsarin iri-iri da kuma hatsi. austenite tsarin - farantin da ciwon siffar kusa da allura-kamar da tunani, kuma ƙwayoyi. Lokacin da cikakken narkar da carbon a γ-baƙin ƙarfe hatsi da siffar ba tare da wani haske duhu cementite inclusions.

Taurin 170-220 HB. Thermal da kuma lantarki watsin ne m fiye da na ferrite. Magnetic Properties ba su da samuwa.

Bambance-bambancen karatu, kuma sanyaya kudi take kaiwa ga samuwar na daban-daban versions na "sanyi" jiha: martensite, bainite, troostite, sorbitol, perlite. Suna da allura-kamar tsarin, amma daban-daban barbashi watsawa, da hatsi size da cementite barbashi.

Rinjayar sanyaya austenite

austenite lalata faruwa a wannan mawuyacin maki. Ingancinta ya dogara da wadannan dalilai:

1. A kudi na sanyaya. Rinjayar da yanayin da carbon impurities, da samuwar hatsi, samuwar karshe microstructure kuma da kaddarorin. Ya dogara da yanayi, wanda aka yi amfani a matsayin coolant.
2. Availability isothermal bangaren a kan daya daga cikin matakai na lalace - aka saukar zuwa wasu zafin jiki matakin, zafi ne kiyaye barga a lokacin wani lokaci, bayan da m sanyaya aka ci gaba da shi, ko da shi ya auku a tare da wani dumama inji (tanda).

Saboda haka, ya zama ruwan dare da kuma ci gaba da isothermal canji na austenite.

Features hali canje. ginshiƙi

C-dimbin yawa jadawali cewa ya nuna da juna na canji na karfe microstructure a cikin lokaci tazara dangane da yawan zafin jiki canji - wannan austenite canji zane. Da ainihin sanyaya ci gaba. Akwai kawai wasu bulan tilasta zafi riƙewa. A jadawali bayyana isothermal yanayi.

Character iya zama yaxuwa da kuma Diffusionless.

A misali gudun canji rage zafin rana yadawa austenite hatsi ya auku. A thermodynamic rashin zaman lafiya zone atoms fara matsawa tare. Waɗanda suka ba su sarrafa su shiga cikin baƙin ƙarfe raga, samar da cementite inclusions. Sun hadu ne da makwabta barbashi carbon, da warware ta lu'ulu'u. Cementite aka kafa a iyakoki na hatsi disintegrating. Tsarkakakku lu'ulu'u dokoki Game ferrite farantin. Tarwatsa tsarin da aka kafa - cakuda hatsi, da size da kuma maida hankali wanda ya dogara a kan rapidity sanyaya da kuma abun ciki na carbon a cikin gami. Kafa kamar yadda perlite kuma ta tsaka-tsaki bulan: sorbitol, troostite, bainite.

Tare da gagarumin gudun rage zafin jiki austenite bazuwar ya aikata ba diffusive yanayi. Complex crystal murdiya da ke faruwa a cikin abin da duk kwayoyin halitta a lokaci guda matsawa a cikin wani jirgin sama ba tare da canza wuri. A rashin yadawa na taimaka wa fitowan martensite.

A sakamakon quenching a kan austenite bazuwar halaye. martensite

Hardening - wani irin zafi magani, wanda da gaske ya ƙunshi a cikin wani m dumama har zuwa high yanayin zafi sama da m batu da kuma Ac ₃ Ac _m, bi da m sanyaya. Idan karu a zazzabi daukan wuri da ruwa a gudun fiye da 200 ° C da na biyu, sa'an nan mai ɗamfarar acicular lokaci da ciwon martensite sunan.

Yana da wani supersaturated m bayani na carbon a shigar azzakari cikin farji baƙin ƙarfe irin crystal raga tare da α. Saboda na iko ƙungiyoyi kwayoyin halitta aka gurbata da Forms tetragonal raga cewa hidima hanyar hardening. The kafa tsarin yana da wani ya fi girma girma. A sakamakon lu'ulu'u ne da aka daure jirgin matsa nucleate acicular faranti.

Martensite - m da wuya (700-750 HB). Kafa na musamman a sakamakon high-gudun quenching.

Tempering. yadawa tsarin

Austenite - shi ne samuwar wanda za a iya artificially samar bainite, troostite, sorbite, kuma perlite. Idan quenching sanyaya faruwa ga ƙananan velocities, da hira da za'ayi yadawa, su inji aka bayyana a sama.

Troost - shi ne perlite, wanda aka halin a babban mataki na watsawa. Kafa a 100 ° C karu a cikin zãfi na lokacin. A manyan yawan lafiya hatsi da ferrite da cementite ne rarraba bisa dukan jirgin sama. "Ƙẽƙashe" peculiar cementite farantin siffar da troostite sakamakon daga m tempering, yana da wani granular gani. Taurin - HB 600-650.

Bainite - wani tsaka-tsaki lokaci, wanda shi ne wani ma fi lu'ulu'u na high-tarwatsa cakuda ferrite da cementite. Bisa ga inji da fasaha Properties na baya zuwa martensite, amma ya wuce troostite. Ta kafa a cikin zafin jiki iyaka inda yadawa ne ba zai yiwu ba da matsawa karfi kuma matsar da crystalline tsarin ya maida zuwa martensite - kasa.

Sorbitol - da m acicular iri-iri pearlitic bulan a sanyaya kudi na 10 ° C da na biyu. Inji aiki Properties ne tsaka-tsaki tsakanin troostite da pearlite.

Perlite - a jam'i na hatsi na ferrite da cementite, wanda zai iya zama granular, ko farantin siffar. Kafa a sakamakon da m bazuwar na austenite a sanyaya kudi 1s da na biyu.

Beit troostite kuma - koma zuwa wani ice Tsarin, yayin da sorbitol da perlite za a iya kafa da kuma tempering, annealing da kuma maido da siffofin da ayyana siffar da size da hatsi.

Effect na annealing a kan musamman austenite bazuwar

Kusan duk iri annealing da kuma daidaita dogara ne a kan na juna canji na austenite. Cikakken da kuma part-time annealing ake amfani da su doevtektoidnyh steels. Details mai tsanani a tanda sama da m maki AM ₁ da kuma Ac _3, bi da bi. Domin na farko da irin halin da shafe tsawon daukan hotuna lokaci, wadda tabbatar da cikakken hira: austenite-ferrite-austenite da pearlite. Biye da jinkirin sanyaya billets a cikin gagarumar wuta. A fitarwa ba lafiya cakuda ferrite da pearlite, ba tare da ciki gajiyan da kuma roba m. Soft annealing ƙasa da makamashi-m, kawai ya canjãwa tsarin perlite, ferrite barin kusan canzawa. Daidaita yakan haifar da mafi girma kudi na zazzabi ƙi, duk da haka, mafi roba da kuma kasa m tsarin a kanti. Domin karfe gami da carbon abun ciki na daga 0.8 zuwa 1.3% a lokacin da sanyaya a daidaita lalata auku zuwa ga: austenite, pearlite, austenite-cementite.

Wani irin zafi magani wanda dogara ne a kan tsarin canje, shi ne homogenisation. Shi ne m zuwa manyan sassa. Yana yakan haifar da cikakkar cimma m austenitic jihar a yanayin zafi 1000-1200˚S da kuma jimiri a cikin wani gini a wani lokacin har zuwa 15 hours. Isothermal matakai ci gaba da jinkirin sanyaya, wanda na taimaka wa equalization na karfe Tsarin.

isothermal annealing

Kowace daga cikin wadannan hanyoyin da influencing da karfe don gudanarwa da na fahimtar matsayin isothermal canji na austenite. Duk da haka, kowace daga cikinsu ne kawai a wani mataki yana da halaye. A gaskiya, canje-canje faruwa da wani kwari da rage zafi, da gudun wanda kayyade sakamakon.

Daya hanyar da cewa shi ne mafi kusa ga manufa yanayi - isothermal annealing. Its ainihi kuma kunshi a dumama da kuma daukan hotuna da cikakken rushewar duk Tsarin cikin austenite. A sanyaya aka gane a cikin da dama manzilõli, wanda na taimaka wa mai hankali, mafi shafe tsawon kuma mafi thermally barga na ta lalace.

1. A m drop a zafin jiki zuwa wani daraja a kasa 100 ° C zuwa AM ₁ batu.
2. Tilasta riƙewa cimma darajar (sanya shi a cikin wutar makera) na dogon lokaci har ƙarshe na samuwar wani ferritic-pearlitic bulan.
3. Sanyaya a yanzu iska.

A Hanyar ne m ga gami steels, wanda aka halin gaban saura austenite a firiji jihar.

Saura austenite da austenitic steels

Wani lokaci yana yiwuwa m lalata, idan akwai wata saura austenite. Wannan zai iya faruwa a cikin wadannan yanayi:

1. Too m sanyaya idan ya gama fashewa faruwa. Yana da wani tsarin bangaren bainite ko martensite.
2. High carbon karfe ko low gami, ga abin da tafiyar matakai an wuya tarwatsa austenite canje. Yana bukatar yin amfani da musamman zafi magani hanyoyin, kamar, misali, homogenization ko isothermal annealing.

Domin high-- Babu tsari ne aka bayyana da canje. Alloying karfe tare da nickel, manganese, chromium inganta samuwar austenite matsayin farko ɗamfarar jũna wanda ba ya bukatar ƙarin tsoma. Austenitic steels halin high ƙarfi, lalata juriya da kuma zafi juriya, zafi juriya da kuma juriya ga m yanayin aiki da wuya.

Austenite - shi ne da wani tsari wanda yake ba zai yiwu ba ba tare da kafa wani high-zazzabi dumama karfe da kuma wanda aka hannu a kusan dukan zafi magani hanyoyin inganta inji da kuma aiki Properties.