Udindo wa zinthu zomwe zimagwiritsidwa ntchito kwambiri mu chitsulo chotuwira
1.Carbon ndi silicon: Mpweya ndi silicon ndi zinthu zomwe zimalimbikitsa kwambiri graphitization. Mpweya wofananawo ukhoza kugwiritsidwa ntchito kuwonetsa zotsatira zake pamapangidwe a metallographic ndi makina achitsulo chotuwa. Kuchulukitsa kofanana ndi mpweya kumapangitsa kuti ma graphite flakes akhale okulirapo, kuchulukirachulukira, komanso kuchepa kwa mphamvu ndi kuuma. M'malo mwake, kuchepetsa mpweya wofanana akhoza kuchepetsa chiwerengero cha graphite, kuyenga graphite, ndi kuonjezera chiwerengero cha pulayimale austenite dendrites, potero kuwongolera mawotchi zimatha chitsulo imvi kuponyedwa. Komabe, kuchepetsa kufanana kwa kaboni kumabweretsa kuchepa kwa ntchito yoponya.
2.Manganese: Manganese palokha ndi chinthu chomwe chimakhazikika pama carbides ndikulepheretsa graphitization. Imakhala ndi mphamvu yokhazikika ndikuyenga pearlite mu chitsulo chotuwira. Pakati pa Mn = 0.5% mpaka 1.0%, kuwonjezera kuchuluka kwa manganese kumathandizira kukulitsa mphamvu ndi kuuma.
3.Phosphorus: Pamene phosphorous yomwe ili mu iron iron iposa 0.02%, intergranular phosphorous eutectic ikhoza kuchitika. Kusungunuka kwa phosphorous mu austenite ndi kochepa kwambiri. Chitsulo chachitsulo chikamalimba, phosphorous amakhalabe m'madzimo. Pamene solidification ya eutectic yatsala pang'ono kutha, gawo lotsala lamadzimadzi pakati pa magulu a eutectic lili pafupi ndi gawo la ternary eutectic (Fe-2%, C-7%, P). Gawo lamadzimadzili limalimba pafupifupi 955 ℃. Chitsulo chachitsulo chikalimba, molybdenum, chromium, tungsten ndi vanadium zonse zimagawika m'gawo lamadzimadzi lokhala ndi phosphorous, zomwe zimachulukitsa kuchuluka kwa phosphorous eutectic. Pamene phosphorous zili mu chitsulo chotayidwa ndi mkulu, kuwonjezera pa zotsatira zoipa za phosphorous eutectic palokha, izo kuchepetsa alloying zinthu zili mu masanjidwewo zitsulo, potero kufooketsa mphamvu ya zinthu alloying. Madzi a phosphorous eutectic ndi mushy kuzungulira gulu la eutectic lomwe limalimba ndikukula, ndipo ndizovuta kuwonjezeredwa panthawi yolimba, ndipo kuponyera kumakhala ndi chizolowezi chochepa.
4.Sulfur: Imachepetsa kusungunuka kwachitsulo chosungunuka ndikuwonjezera chizolowezi cha castings kung'ambika kutentha. Ndi chinthu chovulaza mu castings. Choncho, anthu ambiri amaganiza kuti m'munsi sulfure zili bwino. Ndipotu, pamene sulfure ali ndi ≤0.05%, chitsulo chamtundu woterechi sichigwira ntchito pa inoculant wamba yomwe timagwiritsa ntchito. Chifukwa chake ndi chakuti inoculation imawola mofulumira kwambiri, ndipo mawanga oyera nthawi zambiri amawonekera mu castings.
5.Copper: Copper ndiye chinthu chomwe chimaphatikizidwa kwambiri popanga chitsulo chotuwira. Chifukwa chachikulu ndichakuti mkuwa umasungunuka kwambiri (1083 ℃), ndiosavuta kusungunuka, komanso umakhala ndi ma alloying abwino. Mphamvu ya graphitization yamkuwa ndi pafupifupi 1/5 ya silicon, kotero imatha kuchepetsa chizolowezi chachitsulo chokhala ndi choyera. Panthawi imodzimodziyo, mkuwa ukhozanso kuchepetsa kutentha kwakukulu kwa kusintha kwa austenite. Choncho, mkuwa akhoza kulimbikitsa mapangidwe pearlite, kuonjezera zili pearlite, ndi kuyenga pearlite ndi kulimbikitsa pearlite ndi ferrite mmenemo, potero kuwonjezera kuuma ndi mphamvu ya chitsulo choponyedwa. Komabe, kuchuluka kwa mkuwa kumakhala bwinoko. Kuchuluka koyenera kwa mkuwa wowonjezera ndi 0.2% mpaka 0.4%. Powonjezera mkuwa wambiri, kuwonjezera tini ndi chromium nthawi yomweyo kumawononga ntchito yodula. Zidzapangitsa kuti mapangidwe ambiri a sorbite apangidwe mu dongosolo la matrix.
6.Chromium: Mphamvu ya alloying ya chromium ndi yolimba kwambiri, makamaka chifukwa chowonjezera cha chromium chimawonjezera chizolowezi chachitsulo chosungunuka kuti chikhale ndi choyera choyera, ndipo kuponyera kumakhala kosavuta kuchepa, zomwe zimapangitsa kuti ziwonongeke. Chifukwa chake, kuchuluka kwa chromium kuyenera kuwongoleredwa. Kumbali imodzi, tikuyembekeza kuti chitsulo chosungunuka chimakhala ndi chromium yowonjezera mphamvu ndi kuuma kwa kuponyera; Kumbali inayi, chromium imayendetsedwa mosamalitsa pamalire apansi kuti ateteze kuponyera kuti asachepetse ndikupangitsa kuchuluka kwa zinyalala. Zomwe zachitika kale zimatsimikizira kuti chromium yomwe ili muchitsulo chosungunula choyambirira ikadutsa 0.35%, imakhala ndi zotsatira zoyipa pakuponya.
7. Molybdenum: Molybdenum ndi chinthu chokhazikika chomwe chimapangika ndi pearlite yolimba. Ikhoza kuyeretsa graphite. Pamene ωMo<0.8%, molybdenum imatha kuyeretsa pearlite ndi kulimbikitsa ferrite mu pearlite, potero kumapangitsanso mphamvu ndi kuuma kwachitsulo chachitsulo.
Zinthu zingapo mu chitsulo chotuwira ziyenera kuzindikirika
1.Kuwonjezera kutenthedwa kapena kukulitsa nthawi yogwira kungapangitse kuti ma cores omwe alipo omwe ali osungunuka awonongeke kapena kuchepetsa mphamvu zawo, kuchepetsa chiwerengero cha mbewu za austenite.
2.Titanium imakhala ndi zotsatira zoyenga austenite yoyamba mu chitsulo chotuwa. Chifukwa titanium carbides, nitrides, ndi carbonitrides amatha kukhala maziko a austenite nucleation. Titaniyamu imatha kukulitsa phata la austenite ndikuyenga mbewu za austenite. Kumbali ina, Ti mukakhala chitsulo chosungunula, S mu chitsulocho amachitira ndi Ti m'malo mwa Mn kupanga tinthu tating'ono ta TiS. Pakatikati pa graphite ya TiS siyothandiza ngati ya MnS. Choncho, mapangidwe eutectic graphite pachimake akuchedwa, potero kuwonjezera mpweya nthawi ya pulayimale austenite. Vanadium, chromium, aluminiyamu, ndi zirconium ndizofanana ndi titaniyamu chifukwa ndizosavuta kupanga ma carbides, nitrides, ndi carbonitrides, ndipo zimatha kukhala ma austenite cores.
3.Pali kusiyana kwakukulu kwa zotsatira za katemera wosiyanasiyana pa chiwerengero cha magulu a eutectic, omwe amakonzedwa motere: CaSi>ZrFeSi>75FeSi>BaSi>SrFeSi. FeSi yomwe ili ndi Sr kapena Ti imakhala ndi mphamvu zochepa pamagulu a eutectic. Timinoculati tokhala ndi maiko osowa timakhala ndi zotsatira zabwino kwambiri, ndipo zotsatira zake zimakhala zofunikira kwambiri zikaphatikizidwa ndi Al ndi N. Ferrosilicon yomwe ili ndi Al ndi Bi imatha kukulitsa kwambiri magulu a eutectic.
4. Njere za graphite-austenite two-phase symbiotic kukula kopangidwa ndi ma graphite nuclei monga pakati amatchedwa masango a eutectic. Submicroscopic graphite aggregates, otsalira unmelted graphite particles, pulayimale graphite flake nthambi, mkulu kusungunuka mfundo mankhwala ndi inclusions mpweya amene ali mu chitsulo chosungunula ndipo akhoza kukhala pakati pa eutectic graphite ndi mitima ya masango eutectic. Popeza eutectic nucleus ndiye poyambira kukula kwa eutectic cluster, kuchuluka kwa magulu a eutectic kumawonetsa kuchuluka kwa ma cores omwe amatha kukula kukhala graphite mu eutectic iron liquid. Zomwe zimakhudza kuchuluka kwa magulu a eutectic ndi kuphatikiza mankhwala, chitsulo chosungunuka komanso kuzizira.
Kuchuluka kwa kaboni ndi silicon muzomwe zimapangidwira zimakhala ndi mphamvu yofunikira. Kuyandikira kwa mpweya wofanana ndi kapangidwe ka eutectic, m'pamenenso pali magulu a eutectic. S ndi chinthu china chofunikira chomwe chimakhudza masango a eutectic achitsulo chotuwa. Kutsika kwa sulfure sikungathandize kuonjezera masango a eutectic, chifukwa sulfide muchitsulo chosungunuka ndi chinthu chofunika kwambiri pakatikati pa graphite. Kuphatikiza apo, sulfure imatha kuchepetsa mphamvu yolumikizirana pakati pa phata lambiri ndi kusungunula, kuti ma cores ambiri ayambike. Pamene W (S) ili pansi pa 0.03%, chiwerengero cha magulu a eutectic chimachepetsedwa kwambiri, ndipo zotsatira za inoculation zimachepetsedwa.
Pamene gawo lalikulu la Mn lili mkati mwa 2%, kuchuluka kwa Mn kumawonjezeka, ndipo kuchuluka kwamagulu a eutectic kumawonjezeka motere. Nb ndiyosavuta kupanga mankhwala a carbon ndi nitrogen muchitsulo chosungunuka, chomwe chimakhala ngati maziko a graphite kuonjezera masango a eutectic. Ti ndi V amachepetsa chiwerengero cha magulu a eutectic chifukwa vanadium imachepetsa mpweya wa carbon; titaniyamu imagwira mosavuta S mu MnS ndi MgS kupanga titanium sulfide, ndipo mphamvu yake ya nucleation siyothandiza monga MnS ndi MgS. N mu chitsulo chosungunuka kumawonjezera chiwerengero cha masango a eutectic. Pamene N zili zochepa kuposa 350 x10-6, sizodziwikiratu. Pambuyo pamtengo wina, kutentha kwakukulu kumawonjezeka, motero kumawonjezera chiwerengero cha magulu a eutectic. Oxygen muchitsulo chosungunula chimapanga mosavuta mitundu yosiyanasiyana ya oxide inclusions monga ma cores, kotero kuti mpweya ukuwonjezeka, chiwerengero cha magulu a eutectic chimawonjezeka. Kuphatikiza pakupanga kwamankhwala, chikhalidwe cha eutectic melt ndichofunikira kwambiri. Kusunga kutentha kwakukulu ndi kutenthedwa kwa nthawi yaitali kumapangitsa kuti chiyambi choyambirira chizimiririka kapena kuchepa, kuchepetsa chiwerengero cha magulu a eutectic, ndikuwonjezera m'mimba mwake. Kuchiza kwa inoculation kumatha kusintha kwambiri chikhalidwe chapakati ndikuwonjezera kuchuluka kwamagulu a eutectic. Kuzizira kumakhala ndi zotsatira zoonekeratu pa chiwerengero cha magulu a eutectic. Kuzizira kofulumira, m'pamenenso pali magulu a eutectic.
5.Kuchuluka kwa magulu a eutectic kumasonyeza mwachindunji makulidwe a mbewu za eutectic. Nthawi zambiri, njere zabwino zimatha kusintha zitsulo. Pansi pa zomwe zimapangidwira mankhwala ndi mtundu wa graphite, kuchuluka kwa masango a eutectic kumawonjezeka, mphamvu zamakokedwe zimawonjezeka, chifukwa mapepala a graphite m'magulu a eutectic amakhala abwino kwambiri pamene chiwerengero cha magulu a eutectic chikuwonjezeka, chomwe chimawonjezera mphamvu. Komabe, pakuwonjezeka kwa silicon, chiwerengero cha magulu a eutectic chimawonjezeka kwambiri, koma mphamvu imachepa m'malo mwake; mphamvu ya chitsulo chosungunuka imawonjezeka ndi kutentha kwapamwamba kwambiri (mpaka 1500 ℃), koma panthawiyi, chiwerengero cha magulu a eutectic chimachepa kwambiri. Ubale pakati pa lamulo la kusintha kwa chiwerengero cha magulu a eutectic omwe amayamba chifukwa cha chithandizo cha nthawi yaitali cha inoculation ndi kuwonjezeka kwa mphamvu sikumakhala ndi chikhalidwe chomwecho. Mphamvu yomwe imapezeka ndi chithandizo cha inoculation ndi FeSi yomwe ili ndi Si ndi Ba ndi yapamwamba kuposa yomwe imapezeka ndi CaSi, koma chiwerengero cha magulu a eutectic a chitsulo choponyedwa ndi chochepa kwambiri kuposa cha CaSi. Ndi kuchuluka kwa magulu a eutectic, chizolowezi cha shrinkage chachitsulo chimawonjezeka. Pofuna kupewa kupanga shrinkage m'magawo ang'onoang'ono, chiwerengero cha magulu a eutectic chiyenera kuyendetsedwa pansi pa 300 ~ 400 / cm2.
6. Kuwonjezera zinthu za alloy (Cr, Mn, Mo, Mg, Ti, Ce, Sb) zomwe zimalimbikitsa supercooling mu graphitized inoculants akhoza kusintha mlingo wa supercooling wa chitsulo chosungunuka, kuyeretsa mbewu, kuwonjezera kuchuluka kwa austenite ndikulimbikitsa mapangidwe a pearlite. The anawonjezera pamwamba yogwira zinthu (Te, Bi, 5b) akhoza adsorbed pamwamba pa phata graphite kuchepetsa kukula kwa graphite ndi kuchepetsa graphite kukula, kuti akwaniritse cholinga kukonzanso mabuku mawotchi katundu, kuwongolera kufanana, ndi kuonjezera malamulo a bungwe. Mfundo imeneyi yakhala ikugwiritsidwa ntchito popanga chitsulo chochuluka cha carbon cast (monga ma brake parts).
Nthawi yotumiza: Jun-05-2024
