Anafunsa 30 akalozera
Njira yothetsera:
1. Kuzimitsa kwamadzi kumodzi -- kuzirala mu sing'anga yozimitsira, madzi amodzi omwe amazimitsa kupsinjika kwa microstructure ndi kupsinjika kwa kutentha kumakhala kwakukulu, kuziziritsa kusinthika kumakhala kwakukulu.
2. Kuzimitsa kwamadzi kawiri - cholinga: kuzizira mofulumira pakati pa 650 ℃ ~ Ms, kotero kuti V> Vc, itakhazikika pang'onopang'ono pansi pa Ms kuti muchepetse kupsinjika kwa minofu. Carbon steel: madzi pamaso pa oil.Alloy steel: mafuta pamaso pa mpweya.
3. Fractional quenching - chogwirira ntchito chimachotsedwa ndikukhala pa kutentha kwina kuti kutentha kwa mkati ndi kunja kwa workpiece kukhale kofanana, ndiyeno njira yoziziritsira mpweya.Fractional quenching ndi kusintha kwa M gawo mu kuzizira kwa mpweya, ndipo kupsinjika kwamkati kumakhala kochepa.
4. Isothermal quenching - imatanthawuza kusinthika kwa bainite kumapezeka m'dera la kutentha kwa bainite isothermal, ndi kuchepa kwapakati mkati ndi kusinthika kochepa. zotheka kupewa kuzimitsa deformation ndi akulimbana.
Chemical meteorological deposition makamaka njira ya CVD.Zimene sing'anga munali ❖ kuyanika zinthu zakuthupi ndi vaporized pa kutentha m'munsi, ndiyeno anatumiza mu mkulu-kutentha anachita chipinda kukhudzana workpiece pamwamba kubala mkulu-kutentha mankhwala anachita.Aloyi kapena zitsulo ndi zinthu zake zimatenthedwa ndikuyikidwa pamwamba pa workpiece kuti apange zokutira.
Makhalidwe akuluakulu a njira ya CVD:
1. Itha kuyikapo mitundu yosiyanasiyana ya crystalline kapena amorphous inorganic film.
2. Kuyera kwakukulu ndi mphamvu zomangirira zamagulu.
3. Wothina sedimentary wosanjikiza ndi ma pores ochepa.
4. Kufanana kwabwino, zida zosavuta ndi ndondomeko.
5. High anachita kutentha.
Ntchito: Kukonzekera mitundu yosiyanasiyana ya mafilimu pamwamba pa zinthu monga chitsulo ndi zitsulo, aloyi zolimba, zitsulo zosakhala ndi chitsulo komanso zopanda zitsulo, makamaka filimu ya insulator, semiconductor film, conductor ndi superconductor film ndi filimu yotsutsa corrosion.
Physical and meteorological deposition: njira yomwe zinthu za mpweya zimayikidwa mwachindunji pa workpiece pamwamba pa mafilimu olimba, otchedwa PVD method. Pali njira zitatu zofunika, zomwe ndi, vacuum evaporation, sputtering ndi ion plating. Ntchito: kuvala zokutira zosagwira, kutentha ❖ kuyanika kosagwira ntchito, ❖ kuyanika kwa dzimbiri, kupaka mafuta, kuyanika kogwira ntchito kokongoletsa.
Tizilombo tating'onoting'ono: mawonekedwe amizere omwe amawonedwa pansi pa maikulosikopu ya ma elekitironi, omwe amadziwika kuti magulu otopa kapena kutopa.
Macroscopic: nthawi zambiri, imakhala ndi mawonekedwe a fracture yophulika popanda macroscopic mapindikidwe owoneka ndi maso.Kutopa komwe kumaphwanyidwa kumakhala ndi malo opangira ming'alu, kufalikira kwa ming'alu ndi zone yomaliza yosweka. Malo oyambira kutopa amakhala ocheperapo, nthawi zina kalilole owala, malo ofikira ming'alu ndi gombe kapena chipolopolo, zina mwazomwe zimayambitsa kutopa ndi malo osagwirizana ndi ofanana. arcs pakati pa bwalo.The microscopic morphology ya zone yosweka fracture zimatsimikiziridwa ndi khalidwe katundu mode ndi kukula kwa zinthu, ndipo akhoza kukhala dimple kapena quasi-dissociation, dissociation intergranular fracture kapena mawonekedwe osakanikirana.
1 .cracking: Kutentha kwa kutentha ndipamwamba kwambiri ndipo kutentha sikuli kofanana;Kusankhidwa kolakwika kwa kuzimitsa sing'anga ndi kutentha;Kutentha si nthawi yake komanso yosakwanira;Zinthu zimakhala ndi zovuta kwambiri, kugawanika kwa zigawo, zolakwika ndi kuphatikizika kwambiri;Zigawo sizili bwino. zopangidwa.
2. Kulimba kwapamadzi kosagwirizana: kapangidwe kake kopanda nzeru; Kutentha kosagwirizana; Kuzizira kosagwirizana; Kusakhazikika kwazinthu (zomangamanga zomangika, decarbonization pang'ono.
3. Kusungunula pamwamba: kapangidwe ka inductor n'kopanda nzeru; Zigawo zimakhala ndi ngodya zakuthwa, mabowo, zoipa, ndi zina zotero; Kutentha nthawi yayitali kwambiri, ndipo malo ogwirira ntchito ali ndi ming'alu.
Tengani W18Cr4V mwachitsanzo, chifukwa chiyani kuli bwino kuposa wamba kupsa mtima mawotchi katundu?
Poyerekeza ndi chitsulo chothamanga kwambiri, ma carbides a M2C amawotcha kwambiri, ndipo M2C, V4C ndi Fe3C carbides ali ndi kufalikira kwakukulu komanso kufanana bwino, ndipo pafupifupi 5% mpaka 7% bainite ilipo, yomwe ndi chinthu chofunika kwambiri cha microstructure cha kutentha kwapamwamba kwambiri. chitsulo ntchito bwino kuposa wamba kupsya mtima mkulu liwiro chitsulo.
Pali endothermic mpweya, kukapanda kudontha mpweya, molunjika thupi mpweya, ena controllable mpweya (nayitrogeni makina mpweya, ammonia kuwola mpweya, exothermic atmosphere).
1. Endothermic atmosphere ndi mpweya waiwisi wosakanizidwa ndi mpweya mu gawo linalake, kupyolera mu chothandizira kutentha kwakukulu, zomwe zimapangidwira makamaka zomwe zimakhala ndi CO, H2, N2 ndi kufufuza CO2, O2 ndi H2O mlengalenga, chifukwa momwe zimayamwa kutentha, zomwe zimatchedwa Endothermic atmosphere kapena RX gas. Amagwiritsidwa ntchito popangira carburizing ndi carbonitriding.
2. M'mlengalenga, methanol imalozedwera mu ng'anjo kuti iphwanyike, ndipo chonyamulira chokhala ndi CO ndi H2 chimapangidwa, ndiyeno wolemera amawonjezedwa kuti apange carburizing; Kutsika kwa carbonitriding, chitetezo kutentha kuzimitsa kowala, ndi zina zotero.
3. The infiltration wothandizila monga gasi ndi mpweya kusakaniza mu gawo lina mwachindunji mu ng'anjo, pa kutentha 900 ℃ anachita mwachindunji kwaiye carburizing atmosphere.Amonia kuwola mpweya ntchito nitriding chonyamulira mpweya, chitsulo kapena sanali chitsulo kutentha otsika kutentha. Kutentha chitetezo mpweya.Nayitrogeni - zochokera mpweya mkulu mpweya zitsulo kapena kukhala ndi zitsulo chitetezo zotsatira zabwino.Exothermic mpweya ntchito yowala kutentha mankhwala otsika mpweya zitsulo, mkuwa kapena decarburization annealing wa malleable kuponyedwa chitsulo.
Cholinga: Zabwino zamawotchi ndi kupotoza kwakung'ono kwa chitsulo cha ductile kumatha kupezedwa ndi kuzimitsa kwa isothermal m'malo osinthika a bainite pambuyo pa austenitizing.Kutentha kwa isothermal: 260 ~ 300 ℃ bainite kapangidwe;
Carburizing: makamaka pamwamba pa workpiece mu ndondomeko ya maatomu a carbon, pamwamba tempering martensite, otsalira A ndi carbide, cholinga chapakati ndi kukonza pamwamba mpweya zili, ndi kuuma mkulu ndi mkulu kuvala kukana, pakati ali A mphamvu zina ndi kulimba kwakukulu, kotero kuti imakhudzidwa kwambiri ndi kukangana, chitsulo chochepa cha carbon monga 20CrMnTi, gear ndi piston piston zomwe zimagwiritsidwa ntchito nthawi zambiri.
Nitriding: pamwamba pa kulowa maatomu nayitrogeni, ndi pamwamba kuuma, kuvala kukana kutopa mphamvu ndi kukana dzimbiri ndi matenthedwe kuuma kusintha, pamwamba ndi nitride, mtima wa tempering sorbsite, mpweya nitriding, madzi nitriding, ambiri ntchito 38CrMoAlA. , 18CrNiW.
Carbonitriding: carbonitriding ndi kutentha kochepa, liwiro lachangu, mapindikidwe ang'onoang'ono a part.The pamwamba microstructure ndi yabwino singano tempered martensite + granular carbon ndi nayitrogeni pawiri Fe3 (C, N) + yotsalira pang'ono austenite. compressive mphamvu, ndipo ali ndi dzimbiri resistance.Nthawi zambiri ntchito katundu magiya sing'anga opangidwa ndi otsika ndi sing'anga mpweya aloyi zitsulo.
Nitrocarburizing: ndondomeko ya nitrocarburizing imathamanga kwambiri, kuuma kwapansi kumatsika pang'ono kuposa nitriding, koma kukana kutopa ndikwabwino, kumagwiritsidwa ntchito makamaka popanga nkhungu zokhala ndi mphamvu yaying'ono, kukana kwamphamvu kwambiri, kuchepa kwa kutopa ndi kusinthika kwazing'ono. monga carbon structural chitsulo, aloyi structural chitsulo, aloyi chida chitsulo, imvi kuponyedwa chitsulo, nodular kuponyedwa chitsulo ndi ufa zitsulo, akhoza nitrocarburized
1. Zamakono zamakono.
2. Njirayi ndi yodalirika, yololera komanso yotheka.
3. Chuma cha ndondomekoyi.
4. Chitetezo cha ndondomeko.
5. Yesani kugwiritsa ntchito zida zogwirira ntchito ndi makina apamwamba komanso njira zodzipangira okha.
1. Kugwirizana pakati pa teknoloji yozizira ndi yotentha yotentha kuyenera kuganiziridwa bwino, ndipo ndondomeko ya chithandizo cha kutentha iyenera kukhala yomveka.
2. Landirani teknoloji yatsopano momwe mungathere, fotokozani mwachidule ndondomeko ya kutentha kwa kutentha, fupikitsani nthawi yopangira.Pansi pa chikhalidwe chowonetsetsa zofunikira ndi machitidwe a magawo, yesetsani kupanga njira zosiyanasiyana kapena njira zamakono pamodzi ndi wina ndi mzake.
3. Nthawi zina pofuna kupititsa patsogolo khalidwe la mankhwala ndikutalikitsa moyo wautumiki wa workpiece, m'pofunika kuwonjezera njira yochizira kutentha.
1. Mtunda wolumikizana pakati pa inductor ndi workpiece uyenera kukhala pafupi kwambiri.
2. Chogwirira ntchito chotenthedwa ndi khoma lakunja la koyilo chiyenera kuyendetsedwa ndi maginito otuluka.
3. Mapangidwe a sensa ya workpiece yokhala ndi ngodya zakuthwa kuti apewe zotsatira zakuthwa.
4. Chochitika chotsutsana ndi mizere ya maginito chiyenera kupewedwa.
5. Sensor kapangidwe ayenera kuyesa kukumana workpiece akhoza kutembenukira pamene usavutike mtima.
1. Sankhani zinthu molingana ndi momwe zimagwirira ntchito magawo, kuphatikiza mtundu wa katundu ndi kukula, chilengedwe ndi njira zazikulu zolephera;
2. Poganizira kapangidwe, mawonekedwe, kukula ndi zinthu zina za zigawo, zinthu ndi hardability wabwino akhoza kukonzedwa ndi kuzimitsa mafuta kapena madzi sungunuka quenching sing'anga kuti zosavuta kuzimitsa kupotoza ndi akulimbana;
3. Kumvetsetsa kapangidwe ndi katundu wa zipangizo pambuyo mankhwala kutentha.Makalasi ena achitsulo opangidwira njira zosiyanasiyana zochizira kutentha adzakhala ndi mapangidwe abwinoko ndi katundu pambuyo pa chithandizo;
4. Pazifukwa zowonetsetsa kuti ntchito ndi moyo wa ziwalo zikugwira ntchito, njira zothandizira kutentha ziyenera kukhala zosavuta momwe zingathere, makamaka zipangizo zomwe zingathe kupulumutsidwa.
1. Ntchito yoponya.
2. Pressure Machining ntchito.
3. Machining ntchito.
4. Kuwotcherera ntchito.
5. Ntchito yochizira kutentha.
Kuwola, kutsatsa, kufalikira masitepe atatu.Kugwiritsa ntchito njira yowongolera magawo, chithandizo cholowera pawiri, kufalikira kwa kutentha kwambiri, kugwiritsa ntchito zida zatsopano kuti zipititse patsogolo kufalikira, kulowetsedwa kwamankhwala, kulowetsedwa kwathupi; Pewani makutidwe ndi okosijeni a workpiece, omwe amathandizira kufalikira, kotero kuti njira zitatu zogwirizana bwino, kuchepetsa workpiece pamwamba kupanga mpweya wakuda ndondomeko, kufulumizitsa ndondomeko ya carburizing, kuonetsetsa kuti kusintha wosanjikiza ndi otakata ndi wofatsa khalidwe kulowerera wosanjikiza; Kuchokera pamwamba mpaka pakati, dongosolo ndi hypereutectoid, eutectoid, hyperhypoeutectoid, primordial hypoeutectoid.
Mtundu wamavalidwe:
Kuvala kumamatira, kuvala kwa abrasive, kuvala kwa dzimbiri, kutopa kukhudzana.
Njira zopewera:
Pazovala zomatira, kusankha koyenera kwa zinthu zolimbana ndi mikangano; Kugwiritsa ntchito chithandizo chapamwamba kuti muchepetse kugundana kapena kulimbitsa kulimba kwapang'onopang'ono; Chepetsani kupsinjika kwa kukhudzana; Chepetsani roughness. Pakuvala kwa abrasive, kuwonjezera pa kuchepetsa kuthamanga kwa kukhudzana ndi kutsetsereka kwamtunda pamapangidwe ya mafuta kusefera chipangizo kuchotsa abrasive, komanso kusankha wololera wa mkulu kuuma zipangizo; Kulimba pamwamba pa mikangano awiri zipangizo anali bwino ndi pamwamba kutentha mankhwala ndi pamwamba ntchito hardning. Zida zolimbana ndi dzimbiri; Chitetezo cha electrochemical; Kupsinjika kwa kupsinjika kwamphamvu kumatha kuchepetsedwa pamene corrosion inhibitor ikuwonjezedwa. Kuchepetsa kupsinjika kwa nkhawa; Sankhani zinthu zomwe sizimamva kupsinjika kwa dzimbiri; Sinthani sing'anga. chiyero cha zinthu, kuchepetsa kuphatikizika; Kupititsa patsogolo mphamvu pachimake ndi kuuma kwa mbali; Kuchepetsa roughness pamwamba mbali; Kupititsa patsogolo mamasukidwe akayendedwe a mafuta mafuta kuchepetsa mphero kanthu.
Amapangidwa ndi ferrite yayikulu (yofanana) komanso dera la carbon A.
Kubwerera kwa mpira wamba: onjezani kuuma, sinthani makina, chepetsani kusokoneza kusokoneza.
Isothermal mpira regression: amagwiritsidwa ntchito pazitsulo zapamwamba za carbon, alloy tool steels.
Mpira wozungulira kumbuyo: wogwiritsidwa ntchito ngati chitsulo cha carbon, alloy tool.
1. Chifukwa cha chitsulo chochepa cha hypoeutectoid zitsulo, mawonekedwe oyambirira P + F, ngati kutentha kozimitsa kumakhala kotsika kuposa Ac3, padzakhala wosasungunuka F, ndipo padzakhala mfundo yofewa pambuyo pozimitsidwa.Kwa chitsulo cha eutectoid, ngati kutentha ndi okwera kwambiri, ochuluka kwambiri K 'kusungunuka, kuonjezera kuchuluka kwa pepala M, kosavuta kuyambitsa mapindikidwe ndi kusweka, kuonjezera kuchuluka kwa A', kwambiri K 'kusungunuka, ndi kuchepetsa kukana kwachitsulo.
2. Kutentha kwa chitsulo cha eutectoid ndipamwamba kwambiri, chizolowezi cha okosijeni ndi decarbonization chimawonjezeka, kotero kuti mawonekedwe a pamwamba a zitsulo sali ofanana, mlingo wa Ms ndi wosiyana, zomwe zimapangitsa kuti azimitsidwa.
3. Kusankha kutentha kozimitsa Ac1 + (30-50 ℃) kumatha kusunga K wosasunthika kuti muchepetse kukana kwa mavalidwe, kuchepetsa mpweya wa matrix, ndikuwonjezera kulimba kwa pulasitiki ndi kulimba kwachitsulo.
Kutentha kwa yunifolomu kwa ε ndi M3C kumapangitsa kuti mpweya wa M2C ndi MC ukhale wofanana kwambiri ndi kutentha kwachiwiri, zomwe zimalimbikitsa kusintha kwa ena otsalira austenite kukhala bainite ndikuwongolera mphamvu ndi kulimba.
ZL104: aluminiyamu yachitsulo, MB2: aloyi ya magnesium yowonongeka, ZM3: magnesium, TA4: α titanium alloy, H68: brass, QSN4-3: tin brass, QBe2: beryllium brass, TB2: β titanium alloy.
Kulimba kwa ng'anjo ndi chizindikiro cha katundu chomwe chimasonyeza kuthekera kwa chinthu kukana kuthyoka.
Makhalidwe osinthika a gawo la chitsulo chotuwa poyerekeza ndi chitsulo:
1) Chitsulo chachitsulo ndi fe-C-Si ternary alloy, ndipo kusinthika kwa eutectoid kumachitika pamtunda waukulu wa kutentha, komwe kuli ferrite + austenite + graphite;
2) Njira ya graphitization ya chitsulo choponyedwa ndi yosavuta kuchita, ndipo matrix a ferrite, matrix a pearlite ndi matrix a ferrite + pearlite achitsulo choponyedwa amapezedwa poyang'anira ndondomekoyi;
3) Mpweya wa kaboni wa A ndi zinthu zosinthira zitha kusinthidwa ndikuwongoleredwa mu A osiyanasiyana polamulira kutentha kwa austenitizing kutentha, kutchinjiriza ndi kuzirala;
4) Poyerekeza ndi chitsulo, mtunda wa ma atomu a carbon ndi wautali;
5) Kutentha chithandizo chachitsulo chosasunthika sichingasinthe mawonekedwe ndi kugawa kwa graphite, koma kungasinthe gulu lamagulu ndi katundu.
Njira yopangira: mapangidwe a kristalo wa kristalo, kukula kwa njere A, kusungunuka kwa simenti yotsalira, homogenization ya A; Zinthu: kutentha kutentha, nthawi yogwira, kuthamanga kwachangu, kapangidwe kachitsulo, kapangidwe koyambirira.
Njira: njira yoyendetsera kagawo kakang'ono, chithandizo cholowetsera pawiri, kutentha kwapamwamba, kugwiritsa ntchito zipangizo zatsopano kuti zifulumizitse kufalikira, kulowetsa mankhwala, kulowetsa thupi.
Njira yosinthira kutentha: kutengera kutentha kwa conduction, kutengera kutentha kwa convection, kutengera kutentha kwa ma radiation (ng'anjo ya vacuum pamwamba pa 700 ℃ ndikutengera kutentha kwa radiation).
Gulu lakuda limatanthawuza mawanga akuda, malamba akuda ndi ukonde wakuda. Pofuna kupewa kuoneka kwa minofu yakuda, nayitrogeni yomwe ili mugawo lopindika sayenera kukhala yokwanira, nthawi zambiri kuposa 0.5% imakhala ndi minofu yakuda yamawanga; okhutira mu permeable wosanjikiza sayenera kukhala otsika kwambiri, apo ayi n'zosavuta kupanga tortenite network.Kuti ziletsa tortenite maukonde, Kuwonjezera kuchuluka kwa ammonia ayenera kukhala zolimbitsa.Ngati ammonia ali ochuluka kwambiri ndipo mame a mpweya wa ng'anjo achepa, minofu yakuda idzawonekera.
Pofuna kuletsa maonekedwe a tortenite maukonde, quenching Kutentha kutentha akhoza moyenerera anakweza kapena sing'anga yozizira ndi mphamvu kuzirala amphamvu angagwiritsidwe ntchito.Pamene kuya kwa minofu yakuda ndi zosakwana 0.02mm, kuwombera peening ntchito kuthetsa izo.
Njira yowotchera: Kutentha koyambira kuzima kuli ndi njira ziwiri zozimitsira nthawi yomweyo kutentha ndi kusuntha kutentha kosalekeza, kutengera momwe zida ziliri komanso mtundu wa magawo. zambiri kuposa 1.5 kW/cm2.Zatali kutsinde mbali, tubular mkati dzenje kuzimitsira mbali, pakati modulus zida ndi mano lonse, Mzere mbali kutengera kuzimitsidwa mosalekeza; zida Large utenga limodzi dzino mosalekeza kuzimitsa.
Zoyezera magawo:
1. Kutentha kwapang'onopang'ono: Chifukwa cha kuthamanga kwachangu kwa kutentha, kutentha kozimitsa ndi 30-50 ℃ kuposa chithandizo cha kutentha kwanthawi zonse kuti kusintha kwa minofu kukhale kodzaza;
2. Kutentha nthawi: malinga ndi zofunikira zaumisiri, zipangizo, mawonekedwe, kukula, mafupipafupi omwe alipo, mphamvu zenizeni ndi zina.
Njira yozimitsa yozizira ndi sing'anga yozimitsa: Njira yozimitsa yozimitsa yozimitsa nthawi zambiri imagwiritsa ntchito kuziziritsa kwautsi ndi kuziziritsa kowononga.
Kutentha kuyenera kukhala pa nthawi yake, mutatha kuzimitsa mbali mkati mwa 4h kutentha.Njira zodziwika bwino ndizodziletsa, kutentha kwa ng'anjo ndi kutenthetsa.
Cholinga chake ndi kupanga ntchito yamagetsi apamwamba komanso apakatikati pamagetsi amtundu wa resonant, kuti zida zizisewera bwino kwambiri.
1. Sinthani magawo amagetsi otenthetsera kutentha kwambiri. Pansi pa 7-8kV otsika voteji katundu, sinthani kugwirizana ndi ndemanga malo a handwheel kuti chiŵerengero cha chipata panopa ndi anode panopa 1: 5-1:10, ndiyeno onjezani voteji ya anode ku voteji yautumiki, sinthaninso magawo amagetsi, kuti voteji yanjira isinthe pamtengo wofunikira, machesi abwino kwambiri.
2. Sinthani magawo magetsi wapakatikati pafupipafupi Kutentha, sankhani yoyenera quenching thiransifoma motembenukira chiŵerengero ndi capacitance malinga ndi kukula kwa mbali, mawonekedwe aumitsa zone kutalika ndi dongosolo inductor, kuti ntchito mu dziko resonance.
Madzi, madzi amchere, madzi amchere, mafuta opangira makina, saltpeter, mowa wa polyvinyl, yankho la trinitrate, wothira madzi osungunuka, mafuta ozizimitsa apadera, etc.
1. Mphamvu ya mpweya wa carbon: ndi kuchuluka kwa carbon mu zitsulo za hypoeutectoid, kukhazikika kwa A kumawonjezeka ndipo C curve imayenda bwino; wokhotakhota wa C amasuntha kumanja.
2. Mphamvu ya ma alloying element: Kupatula Co, zinthu zonse zachitsulo zomwe zili munjira yolimba zimasuntha momwemo C curve.
Kutentha kwa 3.Kutentha ndi nthawi yogwira: Kutentha kwa A kumakhala kotalika, nthawi yayitali yogwira, carbide imasungunuka kwambiri, njere ya A imakhala yochuluka, ndipo piritsi la C limasunthira kumanja.
4. Chikoka cha minofu yapachiyambi: Kuchepa kwa minofu yapachiyambi ndikosavuta, kumakhala kosavuta kupeza yunifolomu A, kotero kuti CURVE ya C imayenda bwino ndipo Ms amasunthira pansi.
5. Chikoka cha kupsinjika ndi kupsyinjika kumapangitsa C curve kusuntha kumanzere.
Nthawi yotumiza: Sep-15-2021
- Ena: Kodi chitsulo chosapanga dzimbiri ndi chiyani?
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