Bakin karfe na Ferritic yana nufin bakin karfe tare da cubic ferrite na tsakiya a matsayin tsarin matrix a babban zafin jiki da zafin jiki na al'ada. Bakin karfe na Ferritic yana da baƙin ƙarfe da chromium a matsayin manyan abubuwa, gabaɗaya baya ƙunshi nickel, wasu kuma sun ƙunshi ƙaramin adadin molybdenum, titanium ko niobium da sauran abubuwa. Yana da kyawawa juriya na iskar shaka, juriya na lalata da juriya mai lalata chloride. Bugu da kari, ferritic bakin karfe kuma yana da halaye na babban thermal watsin, kananan fadada coefficient, mai kyau hadawan abu da iskar shaka juriya, da kuma m danniya lalata juriya. Ana amfani da shi galibi don kera sassan da ke da juriya ga yanayin yanayi, tururin ruwa, ruwa, da lalata acid oxidative. Matsayin wakilai na bakin karfe na ferritic sune: AISI 410 (UNS S41000), AISI 420 (UNS S42000), AISI 430 (UNS S43000) bisa ga ASTM; 1.4006, 1.4021, 1.4016, bisa ga ma'aunin EN ... da dai sauransu.
Ferritic bakin karfe za a iya raba zuwa low chromium, matsakaici chromium da babban chromium bisa ga chromium abun ciki. Dangane da tsaftar karfe, musamman abun ciki na carbon da nitrogen impurities, ana iya raba shi zuwa bakin karfe na ferritic na yau da kullun da ultra-pure ferritic bakin karfe. Bakin karfe na ferritic na yau da kullun yana da rashin lahani na ƙarancin zafin jiki da ƙarancin zafin jiki, ƙima mai ƙima, babban halayen lalata tsakanin granular, da ƙarancin weldability. Duk da cewa irin wannan nau'in karfe an ƙera shi a baya, an taƙaita aikace-aikacensa na masana'antu sosai. Waɗannan ƙarancin baƙin ƙarfe na yau da kullun na ferritic bakin karfe suna da alaƙa da tsabtar ƙarfe, musamman babban abun ciki na abubuwan tsaka-tsaki kamar carbon da nitrogen a cikin ƙarfe. Muddin carbon da nitrogen a cikin karfe sun yi ƙasa sosai, za a iya shawo kan gazawar da ke sama.
Idan aka kwatanta daaustenitic bakin karfe, Ferritic bakin karfe yana da mafi kyau lalata juriya, zafi juriya da processability. Tunda lokacin ferrite ba zai iya narkar da carbon ba, ferrite yana da halaye na kasancewa mai laushi da sauƙin lalacewa. Kamar martensitic bakin karfe, tun da lattice tsarin ne na jiki-tsakiyar cubic tsarin, shi ne paramagnetic, don haka feritic bakin karfe ne Magnetic. Austenitic bakin karfe ba maganadisu ba ne saboda tsarin mai siffar siffar fuska.
Farashin ferritic bakin karfe ba kawai in mun gwada da low kuma barga, amma kuma yana da yawa musamman fasali da kuma abũbuwan amfãni. An tabbatar da cewa ferritic bakin karfe ne mai matukar kyau madadin abu.
Talakawa bakin karfe feritic
Irin waɗannan karafa sun haɗa da ƙananan, matsakaici da babban abun ciki na chromium. Bakin karfe mai ƙarancin chromium ferritic ya ƙunshi kusan 11% zuwa 14% chromium, kamar 00Cr12 da 0Cr13Al a China. American AISI 400, 405, 406MF-2. Irin wannan karfe yana da kyau tauri, roba, sanyi nakasawa da weldability. Domin karfe ya ƙunshi wani adadin chromium da aluminum, yana da kyau juriya na iskar shaka da tsatsa. 405 za a iya amfani da matsayin man fetur tace hasumiya, tanki rufi, tururi ruwa ruwa, high zafin jiki sulfur lalata resistant na'urar, da dai sauransu 400 ga iyali da kuma ofishin kayan, da dai sauransu 409 da ake amfani da mota shaye muffler tsarin na'urorin da sanyi da dumi ruwa bututu. da dai sauransu Matsakaici chromium ferritic bakin karfe, abun ciki na chromium shine 14% zuwa 19%, kamar 1Cr17 da 1Cr17Mo a China. AISI 429, AISI 430, AISI 433, AISI 434, AISI 435, AISI 436, AISI 439 a Amurka. Irin wannan karfe yana da mafi kyawun tsatsa da juriya. Matsakaicin ƙarfin aikin sa ƙarami ne (n≈2), kuma yana da kyakkyawan aikin zane mai zurfi, amma ductility ɗin sa ba shi da kyau. AISI 430 ferritic bakin karfe ana amfani dashi don kayan ado na gine-gine, kayan ado na mota, kayan dafa abinci, masu ƙone gas da sassa na kayan masana'antu na nitric acid, da dai sauransu. AISI 434 ana amfani dashi don kayan ado na waje na motoci da gine-gine. Ana amfani da 439 azaman tiyo don dumama ruwan gas, bututun gawayi da iskar gas, da dai sauransu. Babban chromium ferritic bakin karfe ya ƙunshi 19% zuwa 30% chromium, kamar Cr18Si2 da Cr25 a China, AISI 442, AISI 443 da AISI 446 a cikin United Jihohi. Irin waɗannan ƙarfe suna da juriya mai kyau na iskar shaka. Ana amfani da AISI 442 akai-akai a cikin yanayi, matsakaicin iyakar zafin jiki shine 1035 ° C, kuma matsakaicin zafin jiki don ci gaba da amfani shine 980 ° C. AISI 446 ferritic bakin karfe yana da mafi kyawun juriya na iskar shaka.
High-tsarki ferritic bakin steel
Irin wannan ƙarfe yana ƙunshe da ƙarancin carbon, nitrogen; high chromium, molybdenum, titanium, niobium da sauran abubuwa. Irin su 00Cr17Mo na China, 00Cr18Mo2, 00Cr26Mol, 00Cr30Mo2. Wannan nau'in karfe yana da kyawawan kaddarorin inji (musamman taurin), weldability, juriya na lalata intergranular, juriya lalata, juriya lalata, da kyakkyawan juriya lalata lalata. Alal misali, 18-2 ferritic bakin karfe yana da kyau lalata juriya a cikin nitric acid, acetic acid, NaOH, pitting lalata juriya a cikin 3% NaCl da FeCl3 daidai ko ya wuce 18-8 austenitic bakin karfe, 26CrMo karfe a yawancin kafofin watsa labarai Lalacewar juriya. , musamman a cikin kwayoyin acid, acid oxidizing, da kuma alkalis mai karfi. Yana da kyakkyawan juriya na lalata rami a cikin matsakaicin chloride mai ƙarfi. Babu damuwa lalata fatattaka faruwa a chloride, hydrogen sulfide, wuce kima sulfuric acid da kuma karfi alkali. 30Cr-2Mo yana da juriya mafi girma ga lalata lalata da ɓarnawar ɓarna yayin da yake riƙe juriya na damuwa.
Lalata juriya na ferritic bakin karfe
(1) Lalacewar Uniform.
Chromium shine kashi mafi sauƙi don wucewa. A cikin yanayi na yanayi, baƙin ƙarfe-chromium gami tare da abun ciki na chromium fiye da 12% na iya zama da kansa. A cikin oxidizing matsakaici, da chromium abun ciki za a iya passivated idan ya kasance fiye da 17%. A cikin wasu matsakaici masu lalata, ana iya ƙara babban chromium da molybdenum, nickel, jan ƙarfe da sauran abubuwa don samun juriya mai kyau.
(2) Lalacewar intergranular.
Ferritic bakin karafa, kamar austenitic bakin karfe, fama da intergranular lalata, amma ji da hankali jiyya da zafi magani don kauce wa wannan lalata ne kawai akasin haka. Bakin ƙarfe na Ferritic yana da haɗari ga lalatawar intergranular daga saurin sanyaya sama da 925 ° C, kuma ana iya kawar da jihar (jihar mai hankali) wanda ke da saurin lalatawar ɓarna bayan ɗan gajeren lokaci na zafi a 650-815 ° C. Lalacewar tsaka-tsakin ƙarfe na ƙarfe kuma shine sakamakon raguwar chromium da hazo na carbide ke haifarwa. Sabili da haka, rage abubuwan da ke cikin carbon da nitrogen a cikin ƙarfe da ƙara abubuwa kamar titanium da niobium na iya rage yiwuwar lalata intergranular.
(3) Rufewa da lalatawa.
Chromium da molybdenum sune abubuwan da suka fi dacewa don haɓaka juriya na lalata da ramuka. Yayin da abun ciki na chromium ya karu, abun ciki na chromium a cikin fim din oxide kuma yana ƙaruwa, kuma kwanciyar hankali na sinadarai na fim yana ƙaruwa. Molybdenum yana adsorbed a kan karfe mai aiki a cikin nau'i na MoO4, wanda ke hana rushewar karfe, inganta farfadowa, da kuma hana lalacewar fim din. Saboda haka, babban chromium da molybdenum ferritic bakin karfe yana da kyakkyawan juriya ga pitting da lalata lalata.
(4) Juriya ga damuwa lalata fatattaka.
Saboda halaye na tsarin tsarin, ferritic bakin karfe yana da juriya a cikin matsakaici inda austenitic bakin karfe ke haifar da lalata lalata.
Mechanical Properties na ferritic bakin karfe
Ba za a iya ƙarfafa bakin karfe na Ferritic ta hanyar magani mai zafi ba saboda babu canjin lokaci. Yawanci, ana amfani da shi bayan annealing a 700-800 ° C. Saboda irin wannan atomic girman baƙin ƙarfe da chromium, da m bayani ƙarfafa sakamako ne kananan, yawan amfanin ƙasa ƙarfi da tensile ƙarfi na ferritic bakin karfe ne dan kadan mafi girma fiye da na low carbon karfe, da kuma ductility ne m fiye da na low carbon karfe. .
1) Room zafin jiki brittleness na talakawa feritic bakin karfe.
Bakin karfe na ferritic na yau da kullun yana kula da notches, kuma gaggautsa zafin jiki yana sama da zafin ɗaki ban da ƙarancin ƙarfe mai ƙarancin chromium feritic. Mafi girman abun ciki na chromium, mafi girman raunin sanyi. Wannan karyewar sanyi yana da alaƙa da abubuwa masu tsaka-tsaki kamar carbon da nitrogen a cikin ƙarfe, kuma ƙarfe mai tsafta na ferritic yana da ƙarancin abun ciki na carbon a cikin abubuwan tsaka-tsaki kamar carbon da nitrogen, don haka yana iya samun tauri mai kyau, da gaggarumar juyawa. za a iya saukar da zafin jiki ƙasa da zafin jiki.
2) High zafin jiki embrittlement na talakawa ferritic bakin karfe.
Bakin karfe na ferritic na yau da kullun yana mai zafi zuwa sama da 927°C sannan a sanyaya cikin sauri zuwa zafin jiki, filastik da taurin suna raguwa sosai. Wannan yanayin zafi mai zafi yana da alaƙa da saurin hazo na carbon (nitride) mahadi akan iyakokin hatsi ko ɓarna a zazzabi na 427-927 ° C. Rage abubuwan da ke cikin carbon da nitrogen na ƙarfe (ta amfani da fasaha mai tsafta) na iya haɓaka wannan gaɓoɓin. Bugu da kari, lokacin da aka yi zafi da karfen ferritic sama da 927°C, karfin hatsin za a yi murhu, kuma dattin hatsin zai lalata filastik da taurin karfe.
3) Samuwar σ-lokaci.
Dangane da zane-zane na ƙarfe-chromium, idan aka kiyaye shi a 500-800 ° C, gami da ke ɗauke da 40% -50% chromium zai samar da lokaci guda σ, kuma gami da ke ɗauke da ƙasa da 20% ko fiye da 70% chromium zai samar. tsarin α+σ dual-phase. Samar da σ-lokaci zai rage ductility da taurin karfe. Don haka, kada a yi amfani da bakin karfe na ferritic na dogon lokaci a 500-800 ° C.
4) Rashin ƙarfi a 475 ° C.
Babban chromium (> 15%) ferritic karfe zai kasance da ƙarfi sosai idan aka kiyaye shi a 400-500 ° C. Irin wannan tashin hankali yana ɗaukar ɗan gajeren lokaci fiye da hazo na σ lokaci. Misali, lokacin da 0.080C-0.4Si-16.9Cr ferritic bakin karfe aka ajiye a 450°C na 4 hours, da dakin zafin jiki tasiri taurin ya kusan faduwa zuwa sifili. Matsayin embrittlement yana ƙaruwa tare da haɓaka abun ciki na chromium, amma za'a iya dawo da taurin bayan jiyya sama da 600 ° C. Embrittlement a 475°C sakamakon hazo na chromium-rich alpha period. Irin wannan ƙarfe ya kamata ya guje wa dumama kusa da 475 ° C.
Lokacin aikawa: Mayu-02-2023