Kusanthula kwa Kupanga ndi Kusweka kwa Kupatukana kwa Phosphorus mu Chitsulo Chomangira Kaboni
Pakadali pano, zomwe zimagwiritsidwa ntchito kwambiri pakupanga waya ndi mipiringidzo yachitsulo cha carbon ndi mipiringidzo yachitsulo m'nyumba ndi φ5.5-φ45, ndipo kukula kwake ndi φ6.5-φ30. Pali ngozi zambiri zabwino zomwe zimachitika chifukwa cha kugawanika kwa phosphorous mu zipangizo zazing'ono za waya ndi mipiringidzo. Tiyeni tikambirane za momwe phosphorous imakhudzira kugawanika kwa ming'alu komanso kusanthula kwa mapangidwe a ming'alu kuti mugwiritse ntchito.
Kuonjezera phosphorous ku chitsulo kungatseke chigawo cha austenite mu chithunzi cha gawo la iron-carbon. Chifukwa chake, mtunda pakati pa solidus ndi liquidus uyenera kukulitsidwa. Chitsulo chokhala ndi phosphorous chikaziziridwa kuchokera ku madzi kupita ku cholimba, chiyenera kudutsa kutentha kwakukulu. Kufalikira kwa phosphorous mu chitsulo kumakhala pang'onopang'ono. Pakadali pano, chitsulo chosungunuka chokhala ndi phosphorous yambiri (malo otsika osungunuka) chimadzazidwa m'mipata pakati pa dendrites yoyamba yolimba, motero kupanga kusiyana kwa phosphorous.
Mu njira yozizira kapena yotulutsa zinthu zozizira, zinthu zosweka nthawi zambiri zimawoneka. Kuyang'ana ndi kusanthula kwa metallographic kwa zinthu zosweka kumasonyeza kuti ferrite ndi pearlite zimagawidwa m'magulu, ndipo mzere wa chitsulo choyera ukhoza kuwoneka bwino mu matrix. Mu ferrite, pali zinthu zosakanikirana za imvi sulfide pa matrix iyi ya ferrite yofanana ndi band. Kapangidwe kameneka kopangidwa ndi band komwe kamayambitsidwa ndi kugawanika kwa sulfure phosphide kamatchedwa "mzere wa mizimu". Izi zili choncho chifukwa malo okhala ndi phosphorous m'derali omwe ali ndi phosphorous yambiri amawoneka oyera komanso owala. Chifukwa cha kuchuluka kwa phosphorous m'lamba woyera ndi wowala, kuchuluka kwa carbon mu lamba woyera ndi wowala wolemera ndi phosphorous kumachepa kapena kuchuluka kwa carbon kumakhala kochepa kwambiri. Mwanjira imeneyi, makristalo a columnar a continuous casting slab amakula pakati panthawi yopitira patsogolo yopangira lamba wolemera ndi phosphorous. . Pamene billet yakhazikika, austenite dendrites amayamba kutuluka kuchokera ku chitsulo chosungunuka. Phosphorus ndi sulfure zomwe zili mu dendrites izi zachepa, koma chitsulo chosungunuka cholimba chimakhala ndi zinthu zambiri zodetsa phosphorous ndi sulfure, zomwe zimauma pakati pa dendrite axis, chifukwa cha kuchuluka kwa phosphorous ndi sulfure, sulfure imapanga sulfide, ndipo phosphorous idzasungunuka mu matrix. Sizosavuta kufalitsa ndipo zimakhala ndi mphamvu yotulutsa kaboni. Mpweya sungasungunuke mkati, kotero kuzungulira yankho la phosphorous solid (Mbali za gulu loyera la ferrite) zimakhala ndi kuchuluka kwa kaboni. Gawo la kaboni mbali zonse ziwiri za lamba wa ferrite, ndiko kuti, mbali zonse ziwiri za dera lolemera phosphorous, motsatana amapanga lamba wopapatiza, wozungulira wa pearlite wofanana ndi lamba woyera wa ferrite, ndi minofu yoyandikana nayo yosiyana. Pamene billet ikatenthedwa ndikukanikizidwa, mipata idzatambasukira motsatira njira yoyendetsera. Ndi chifukwa chakuti gulu la ferrite lili ndi phosphorous yambiri, ndiko kuti, kusiyana kwakukulu kwa phosphorous kumabweretsa kupangidwa kwa kapangidwe ka gulu lalikulu komanso lowala la ferrite, ndi chitsulo chodziwikiratu Pali mizere yopepuka ya sulfide mu gulu lalikulu komanso lowala la thupi la chinthucho. Gulu la ferrite lolemera ndi phosphorous ili lokhala ndi mizere yayitali ya sulfide ndilo lomwe nthawi zambiri timatcha gulu la "mzere wa mizimu" (onani Chithunzi 1-2).
Chithunzi 1 Waya wa mzimu mu chitsulo cha kaboni SWRCH35K 200X
Chithunzi 2 Waya wa mzimu mu chitsulo chopanda kaboni Q235 500X
Ngati chitsulo chikutenthedwa, bola ngati pali kugawanika kwa phosphorous mu billet, sizingatheke kupeza kapangidwe ka microstructure kofanana. Komanso, chifukwa cha kugawanika kwakukulu kwa phosphorous, kapangidwe ka "waya wa mzimu" kapangidwa, komwe kadzachepetsa mphamvu zamakina a zinthuzo.
Kugawikana kwa phosphorous mu chitsulo cha kaboni n'kofala, koma mlingo wake ndi wosiyana. Pamene phosphorous yagawikana kwambiri (kapangidwe ka "mzere wa mzimu" kamawonekera), izi zimabweretsa zotsatirapo zoyipa kwambiri pa chitsulo. Mwachionekere, kugawikana kwakukulu kwa phosphorous ndiko chifukwa cha kusweka kwa zinthu panthawi yozizira. Chifukwa chakuti tirigu wosiyanasiyana mu chitsulocho uli ndi phosphorous yosiyana, zinthuzo zimakhala ndi mphamvu ndi kuuma kosiyana; kumbali ina, zimapangitsanso kuti zinthuzo zipange kupsinjika kwamkati, zomwe zimapangitsa kuti zinthuzo zikhale zosavuta kusweka mkati. Mu zinthu zomwe zili ndi kapangidwe ka "waya wa mzimu", ndi kuchepa kwa kuuma, mphamvu, kutalika pambuyo pa kusweka ndi kuchepa kwa malo, makamaka kuchepetsa kulimba kwa mphamvu, zomwe zingayambitse kufooka kozizira kwa zinthuzo, kotero kuchuluka kwa phosphorous ndi kapangidwe ka chitsulo zimakhala ndi ubale wapafupi kwambiri.
Kuzindikira kwa Metallographic Mu minofu ya "mzere wa mizimu" pakati pa munda wowonera, pali ma sulfide ambiri opepuka a imvi. Zosakaniza zopanda chitsulo mu chitsulo chomangidwa zimapezeka makamaka mu mawonekedwe a ma oxides ndi ma sulfide. Malinga ndi GB/T10561-2005 "Standard Grading Chart Microscopic Inspection Method for the Content of Non-metallic Inclusions in Steel", zosakaniza za Mtundu B zimasungunuka panthawiyi. Mlingo wazinthu umafika 2.5 ndi kupitirira apo. Monga tonse tikudziwira, zosakaniza zopanda chitsulo ndi magwero omwe angayambitse ming'alu. Kukhalapo kwawo kudzawononga kwambiri kupitiriza ndi kuphatikizika kwa kapangidwe ka chitsulo, ndikuchepetsa kwambiri mphamvu ya chitsulo pakati pa granular. Kuchokera pa izi, zimaganiziridwa kuti kukhalapo kwa ma sulfide mu "mzere wa mizimu" wa kapangidwe ka mkati mwa chitsulo ndi malo omwe angayambitse ming'alu. Chifukwa chake, ming'alu yozizira komanso mankhwala otentha oletsa ming'alu m'malo ambiri opangira zomangira zimayambitsidwa ndi kuchuluka kwa ma sulfide owonda a imvi. Kuoneka kwa zolukidwa zoipa zotere kumawononga kupitiriza kwa zinthu zachitsulo ndikuwonjezera chiopsezo cha kutentha. "Ulusi wa mizimu" sungachotsedwe mwa kusintha zinthu kukhala zachibadwa, ndi zina zotero, ndipo zinthu zodetsa ziyenera kulamulidwa mosamala kuyambira pakusungunula kapena zinthu zopangira zisanalowe mufakitale.
Zinthu zopanda chitsulo zimagawidwa m'magulu a alumina (mtundu A) silicate (mtundu C) ndi oxide wozungulira (mtundu D) malinga ndi kapangidwe kake ndi kufooka kwake. Kukhalapo kwawo kumadula kupitiriza kwa chitsulocho, ndipo mabowo kapena ming'alu imapangidwa pambuyo pochotsa. N'zosavuta kupanga gwero la ming'alu panthawi yozizira komanso kuyambitsa kupsinjika panthawi yotenthetsera, zomwe zimapangitsa kuti ming'alu izitha. Chifukwa chake, zinthu zopanda chitsulo ziyenera kulamulidwa mosamala. Miyezo ya chitsulo cha GB/T700-2006 "Carbon Structural Steel" ndi GB/T699-2016 "High-quality Carbon Structural Steel" sizimafotokoza momveka bwino zofunikira pazinthu zopanda chitsulo. Pazigawo zofunika, mizere yolimba komanso yopyapyala ya A, B, ndi C nthawi zambiri siipitirira 1.5, ndipo mizere yolimba komanso yopyapyala ya D ndi D siipitirira 2.
Nthawi yotumizira: Okutobala-21-2021
