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Passivation imakhalabe gawo lofunikira pakukulitsa kukana kwa dzimbiri kwa magawo ndi magulu opangidwa ndi chitsulo chosapanga dzimbiri.Izi zingapangitse kusiyana pakati pa kuchita bwino ndi kulephera msanga.Kuyenda molakwika kungayambitse dzimbiri.
Passivation ndi njira yopangira zinthu zomwe zimakulitsa kukana kwa dzimbiri kwa ma aloyi achitsulo chosapanga dzimbiri pomwe chopangiracho chimapangidwa.Uku sikutsitsa kapena kujambula.
Palibe mgwirizano pa njira yeniyeni yomwe passivation imagwira ntchito.Koma amadziwika motsimikiza kuti pali zoteteza okusayidi filimu padziko passivated zosapanga dzimbiri zitsulo.Filimu yosaonekayi akuti ndi yowonda kwambiri, yokhuthala yosakwana 0.0000001 inchi, yomwe ili pafupifupi 1/100,000th kukhuthala kwa tsitsi la munthu!
Chigawo choyera, chopangidwa mwatsopano, chopukutidwa, kapena chosapanga dzimbiri chidzipezera filimu ya okusayidiyi chifukwa chokumana ndi mpweya wa mumlengalenga.Pamikhalidwe yabwino, wosanjikiza woteteza wa oxide umakwirira mbali zonse za gawolo.
M'zochita, komabe, zonyansa monga dothi la fakitale kapena tinthu tachitsulo kuchokera ku zida zodulira zimatha kufika pamtunda wazitsulo zosapanga dzimbiri panthawi yokonza.Ngati sichichotsedwa, matupi akunjawa angachepetse mphamvu ya filimu yoteteza yoyambirira.
Pamakina, zida zachitsulo zaulere zimatha kuchotsedwa pachidacho ndikusamutsira pamwamba pazitsulo zosapanga dzimbiri.Nthawi zina, dzimbiri laling'ono limatha kuwonekera pagawolo.M'malo mwake, izi ndizowonongeka kwa chitsulo chachitsulo, osati chitsulo choyambira.Nthawi zina ming'alu yochokera kuzitsulo zomata kuchokera ku zida zodulira kapena zowonongeka zimatha kuwononga gawolo.
Momwemonso, tinthu tating'ono tating'ono tazitsulo tachitsulo tomwe timatha kumamatira pamwamba pa gawolo.Ngakhale kuti chitsulocho chikhoza kuwoneka chonyezimira potsirizira pake, pambuyo pa kukhudzana ndi mpweya, tinthu tating'ono tosaoneka tachitsulo chaulere timayambitsa dzimbiri pamwamba.
Ma sulfide owonekera angakhalenso vuto.Amapangidwa powonjezera sulfure ku chitsulo chosapanga dzimbiri kuti apititse patsogolo machinability.Sulfides amawonjezera mphamvu ya aloyi kupanga tchipisi pa Machining, amene angathe kuchotsedwa kwathunthu ku chida kudula.Ngati mbali zake sizinadulidwe bwino, ma sulfide amatha kukhala poyambira kuwononga zinthu zamakampani.
Muzochitika zonsezi, passivation imafunika kuti muwonjezere kukana kwachilengedwe kwa chitsulo chosapanga dzimbiri.Imachotsa zonyansa zapamtunda monga tinthu tachitsulo ndi tinthu tachitsulo mu zida zodulira zomwe zimatha kupanga dzimbiri kapena kukhala poyambira kuwonongeka.Passivation imachotsanso ma sulfide omwe amapezeka pamtunda wazitsulo zosapanga dzimbiri zosapanga dzimbiri.
Njira yamagulu awiri imapereka kukana kwa dzimbiri kwabwino: 1. Kuyeretsa, njira yayikulu, koma nthawi zina kunyalanyazidwa 2. Kusamba kwa asidi kapena passivation.
Kuyeretsa kuyenera kukhala kofunikira nthawi zonse.Pamwamba payenera kutsukidwa bwino ndi mafuta, zoziziritsa kukhosi kapena zinyalala zina kuti zitsimikizike kuti dzimbiri sizingawonongeke.Machining zinyalala kapena dothi la fakitale akhoza kupukuta pang'onopang'ono mbaliyo.Zochotsera zamalonda kapena zotsukira zitha kugwiritsidwa ntchito kuchotsa mafuta opangira mafuta kapena zoziziritsa kukhosi.Zinthu zakunja monga ma thermal oxides angafunike kuchotsedwa ndi njira monga kugaya kapena pickling.
Nthawi zina wogwiritsa ntchito makina amatha kulumpha kuyeretsa koyambirira, molakwika akukhulupirira kuti kuyeretsa ndi kusuntha kudzachitika nthawi imodzi, kungomiza gawo lopaka mafuta mu bafa la asidi.Sizidzachitika.Mosiyana ndi zimenezi, mafuta oipitsidwa amakumana ndi asidi kupanga thovu la mpweya.Izi thovu kusonkhanitsa pa workpiece pamwamba ndi kusokoneza passivation.
Choyipa kwambiri, kuipitsidwa kwa njira zotsatsira, zomwe nthawi zina zimakhala ndi ma chloride ambiri, zimatha kuyambitsa "kung'anima".Mosiyana ndi kupanga filimu ya oxide yomwe mukufuna yokhala ndi malo owala, oyera, osachita dzimbiri, kung'anima kungapangitse kuti pamwamba pakhale mdima wandiweyani kapena wakuda—kuwonongeka kwapamwamba komwe kumapangitsa kuti mpweya ukhale wabwino.
Zigawo zachitsulo zosapanga dzimbiri za Martensitic [maginito, osachita dzimbiri pang'ono, zopatsa mphamvu mpaka pafupifupi 280,000 psi (1930 MPa)] zimazimitsidwa pakutentha kwambiri kenako kutenthedwa kuti zipereke kuuma komwe kumafunidwa ndi makina amakina.Ma aloyi owumitsidwa ndi mpweya (omwe ali ndi mphamvu zabwinoko komanso kukana dzimbiri kuposa magiredi a martensitic) amatha kuthandizidwa, opangidwa pang'ono, okalamba ndi kutentha pang'ono, kenako kutha.
Pachifukwa ichi, gawolo liyenera kutsukidwa bwino ndi degreaser kapena zotsukira musanatenthe kutentha kuti muchotse zizindikiro zilizonse zamadzimadzi.Kupanda kutero, choziziritsa chotsalira pambalicho chingayambitse makutidwe ndi okosijeni kwambiri.Matendawa amatha kuyambitsa mano pazigawo zing'onozing'ono pambuyo pochotsa ndi asidi kapena njira zotupa.Ngati choziziritsa chisiyidwa pazigawo zolimba zonyezimira, monga ng'anjo ya vacuum kapena m'malo oteteza, kuphulika kwa pamwamba kumatha kuchitika, zomwe zimapangitsa kuti zisawonongeke.
Mukatsuka bwino, zitsulo zosapanga dzimbiri zimatha kumizidwa mumtsuko wa acidic acid.Njira iliyonse mwa njira zitatuzi ingagwiritsidwe ntchito - passivation ndi nitric acid, passivation ndi nitric acid ndi sodium dichromate, ndi passivation ndi citric acid.Njira yogwiritsira ntchito imadalira mtundu wazitsulo zosapanga dzimbiri komanso njira zovomerezeka zovomerezeka.
Magiredi a nickel chromium osamva dzimbiri amatha kupitsidwa ndi 20% (v/v) nitric acid osambira (Chithunzi 1).Monga momwe tawonetsera patebulo, zitsulo zosapanga dzimbiri zosagonjetsedwa zocheperachepera zimatha kupitsidwanso powonjezera sodium dichromate mumadzi osambira a nitric acid kuti yankho likhale lowonjezera oxidizing ndikutha kupanga filimu yodutsa pamwamba pazitsulo.Njira ina yosinthira nitric acid ndi sodium chromate ndikuwonjezera kuchuluka kwa nitric acid mpaka 50% ndi voliyumu.Kuphatikizika kwa sodium dichromate komanso kuchuluka kwa nitric acid kumachepetsa mwayi wa kung'anima kosafunika.
Njira yopititsira patsogolo zitsulo zosapanga dzimbiri zosapanga dzimbiri (zomwe zikuwonetsedwanso mkuyu. 1) ndizosiyana pang'ono ndi magiredi osapanga zitsulo zosapanga dzimbiri.Ichi ndi chifukwa pa passivation mu nitric asidi kusamba ena kapena onse machinable sulfidi munali sulfides amachotsedwa, kupanga tosaoneka inhomogeneities padziko workpiece.
Ngakhale kutsuka m'madzi komwe kumakhala kothandiza kumatha kusiya asidi otsalira m'ma discontinuities awa atadutsa.Chidulo ichi chidzaukira pamwamba pa gawolo ngati sichinasinthidwe kapena kuchotsedwa.
Pofuna kupititsa patsogolo zitsulo zosapanga dzimbiri zosapanga dzimbiri, Carpenter wapanga njira ya AAA (Alkaline-Acid-Alkaline), yomwe imalepheretsa asidi otsalira.Njira yodutsayi imatha kutha pasanathe maola awiri.Nayi ndondomeko ya sitepe ndi sitepe:
Mukathira mafuta, zilowerereni mbali mu 5% sodium hydroxide solution pa 160°F mpaka 180°F (71°C mpaka 82°C) kwa mphindi 30.Kenako muzimutsuka mbalizo bwinobwino m’madzi.Kenako mizani gawolo kwa mphindi 30 mu 20% (v/v) nitric acid solution yomwe ili ndi 3 oz/gal (22 g/l) sodium dichromate pa 120°F mpaka 140°F (49°C) mpaka 60°C.) Mukachotsa mbaliyo mu kusamba, muzimutsuka ndi madzi, ndiyeno muyimitse mu sodium hydroxide solution kwa mphindi 30.Tsukani gawolo kachiwiri ndi madzi ndikuwumitsa, kukwaniritsa njira ya AAA.
Citric acid passivation ikukula kwambiri ndi opanga omwe akufuna kupewa kugwiritsa ntchito mineral acids kapena mayankho omwe ali ndi sodium dichromate, komanso mavuto otaya ndi kuwonjezereka kwachitetezo chokhudzana ndi kugwiritsidwa ntchito kwawo.Citric acid imatengedwa kuti ndi yochezeka m'mbali zonse.
Ngakhale citric acid passivation imapereka zabwino zachilengedwe, masitolo omwe achita bwino ndi inorganic acid passivation ndipo alibe nkhawa zachitetezo angafune kupitilirabe.Ngati ogwiritsa ntchitowa ali ndi sitolo yoyera, zipangizozi zili bwino komanso zoyera, zoziziritsa kuzizira zimakhala zopanda ma deposits a fakitale, ndipo ndondomekoyi ikupanga zotsatira zabwino, sipangakhale kufunikira kwenikweni kwa kusintha.
Citric acid bath passivation yapezeka kuti ndi yothandiza pazitsulo zambiri zosapanga dzimbiri, kuphatikizapo magulu angapo amtundu wazitsulo zosapanga dzimbiri, monga momwe tawonetsera pa Chithunzi 2. Kuti zikhale zosavuta, Chithunzi 2. 1 ikuphatikizapo njira yachikhalidwe ya passivation ndi nitric acid.Dziwani kuti mitundu yakale ya nitric acid imawonetsedwa ngati maperesenti ndi voliyumu, pomwe milingo yatsopano ya citric acid imawonetsedwa ngati maperesenti ndi misa.Ndikofunika kuzindikira kuti pochita izi, kusamala mosamala nthawi yonyowa, kutentha kwa kusamba, ndi kuika maganizo ndikofunikira kuti tipewe "kuwomba" komwe tafotokoza pamwambapa.
Passivation imasiyanasiyana kutengera zomwe zili mu chromium komanso mawonekedwe amtundu uliwonse.Zindikirani mizati ya Njira 1 kapena Njira 2. Monga momwe zasonyezedwera mu Chithunzi 3, Njira 1 ili ndi masitepe ocheperapo kuposa Njira 2.
Mayesero a labotale awonetsa kuti njira ya citric acid passivation ndiyosavuta "kuwira" kuposa njira ya nitric acid.Zomwe zimapangitsa kuti izi zichitike ndi kutentha kwambiri m'madzi osambira, nthawi yayitali yonyowa, komanso kusamba.Zogulitsa za citric acid zomwe zili ndi corrosion inhibitors ndi zina zowonjezera monga zonyowetsa zilipo malonda ndipo akuti amachepetsa kutengeka kwa "flash corrosion".
Chisankho chomaliza cha njira yopititsira patsogolo chidzadalira njira zovomerezeka zokhazikitsidwa ndi kasitomala.Onani ASTM A967 kuti mumve zambiri.Itha kupezeka pa www.astm.org.
Mayesero nthawi zambiri ikuchitika kuwunika pamwamba mbali passivated.Funso loyenera kuyankhidwa ndilakuti "Kodi passivation imachotsa chitsulo chaulere ndikukulitsa kukana kwa dzimbiri kwa ma alloys kuti azidula okha?"
Ndikofunika kuti njira yoyesera igwirizane ndi kalasi yomwe ikuwunikiridwa.Mayeso omwe ali okhwima kwambiri sangadutse zida zabwino kwambiri, pomwe mayeso omwe ali ofooka amadutsa magawo osakwanira.
PH ndi zosavuta kupanga 400 zitsulo zosapanga dzimbiri zimawunikidwa bwino m'chipinda chokhoza kusunga chinyezi cha 100% (chitsanzo chonyowa) kwa maola 24 pa 95 ° F (35 ° C).Chigawo chamtanda nthawi zambiri chimakhala chovuta kwambiri, makamaka pamakalasi aulere.Chifukwa chimodzi cha izi ndikuti sulfide imakokedwa munjira yamakina kudutsa pamwamba apa.
Malo ovuta amayenera kuyimitsidwa m'mwamba, koma pamakona a madigiri 15 mpaka 20 kuchokera kumtunda, kuti chinyezi chiwonongeke.Zinthu zomwe sizingapangike bwino sizichita dzimbiri, ngakhale kuti mawanga ang'onoang'ono angawonekere.
Magiredi achitsulo osapanga dzimbiri a Austenitic amathanso kuyesedwa ndi kuyezetsa chinyezi.Pachiyeso ichi, madontho a madzi ayenera kukhala pamwamba pa chitsanzo, kusonyeza chitsulo chaulere ndi kukhalapo kwa dzimbiri lililonse.
Njira zophatikizira zazitsulo zosapanga dzimbiri zomwe zimagwiritsidwa ntchito nthawi zambiri komanso pamanja mu citric kapena nitric acid solution zimafunikira njira zosiyanasiyana.Pa mkuyu.3 pansipa imapereka mwatsatanetsatane pakusankhidwa kwa njira.
(a) Sinthani pH ndi sodium hydroxide.(b) Onani mkuyu.3 (c) Na2Cr2O7 ndi 3 oz/gal (22 g/L) sodium dichromate mu 20% nitric acid.Njira ina yosakanikirana ndi 50% nitric acid popanda sodium dichromate.
Njira yofulumira ndiyo kugwiritsa ntchito ASTM A380, Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems.Mayesowa akuphatikizapo kupukuta gawolo ndi yankho la mkuwa la sulfate/sulfuric acid, kulisunga lonyowa kwa mphindi zisanu ndi chimodzi, ndikuyang'ana plating yamkuwa.Kapenanso, gawolo likhoza kumizidwa mu yankho kwa mphindi 6.Ngati chitsulo chasungunuka, plating yamkuwa imachitika.Mayesowa sagwira ntchito pamalo opangira chakudya.Komanso, sayenera kugwiritsidwa ntchito pazitsulo 400 za martensitic kapena zitsulo zotsika za chromium ferritic chifukwa zotsatira zabodza zikhoza kuchitika.
M'mbiri, 5% yoyezetsa mchere pa 95 ° F (35 ° C) idagwiritsidwanso ntchito kuwunika zitsanzo zomwe sizinachitike.Mayesowa ndi okhwima kwambiri kwa mbewu zina ndipo nthawi zambiri safunikira kutsimikizira mphamvu ya kulima.
Pewani kugwiritsa ntchito ma chloride ochulukirapo, omwe angayambitse kuyaka kowopsa.Gwiritsani ntchito madzi apamwamba okha okhala ndi magawo 50 pa miliyoni (ppm) kloride ngati kuli kotheka.Madzi apampopi nthawi zambiri amakhala okwanira, ndipo nthawi zina amatha kupirira magawo mazana angapo pa miliyoni imodzi ya kloridi.
Ndikofunikira m'malo kusamba nthawi zonse kuti asataye passivation angathe, zomwe zingachititse kugunda mphezi ndi kuwonongeka kwa mbali.Kusamba kuyenera kusungidwa pa kutentha koyenera, chifukwa kutentha kosalamulirika kungayambitse dzimbiri m'dera lanu.
Ndikofunikira kutsatira ndondomeko yeniyeni yosinthira yankho panthawi yakupanga kwakukulu kuti muchepetse kuipitsidwa.Chitsanzo chowongolera chinagwiritsidwa ntchito kuyesa mphamvu ya kusamba.Ngati chitsanzocho chawukiridwa, ndi nthawi yoti musinthe bafa.
Chonde dziwani kuti makina ena amangotulutsa zitsulo zosapanga dzimbiri;gwiritsani ntchito choziziritsa kukhosi chofananacho podula zitsulo zosapanga dzimbiri kusiya zitsulo zina zonse.
Zigawo za DO rack zimapangidwa padera kuti zipewe kukhudzana ndi zitsulo.Izi ndizofunikira kwambiri pamakina aulere achitsulo chosapanga dzimbiri, chifukwa njira zosavuta zoyendera komanso zowotcha zimafunikira kufalitsa dzimbiri la sulfide ndikuletsa kupanga matumba a asidi.
Osadutsa magawo achitsulo osapanga dzimbiri kapena nitrided.Kukaniza dzimbiri mbali ankachitira motere akhoza kuchepetsedwa moti akhoza kuonongeka mu passivation kusamba.
Osagwiritsa ntchito zida zachitsulo zokhala ndi chitsulo m'malo ogwirira ntchito omwe sali oyera kwenikweni.Zitsulo zachitsulo zitha kupewedwa pogwiritsa ntchito zida za carbide kapena ceramic.
Dziwani kuti dzimbiri zitha kuchitika posamba ngati gawolo silinatenthedwe bwino.Magiredi a Martensitic okhala ndi kaboni wambiri ndi chromium ayenera kuumitsa kuti asawonongeke.
Passivation nthawi zambiri ikuchitika pambuyo tempering wotsatira pa kutentha kusunga kukana dzimbiri.
Musanyalanyaze kuchuluka kwa nitric acid mu kusamba kwa passivation.Kufufuza kwakanthawi kuyenera kupangidwa pogwiritsa ntchito njira yosavuta yosinthira zilembo za Carpenter.Osagwiritsa ntchito chitsulo chosapanga dzimbiri chimodzi panthawi imodzi.Izi zimalepheretsa chisokonezo chokwera mtengo komanso zimalepheretsa machitidwe a galvanic.
Za Olemba: Terry A. DeBold ndi Stainless Steel Alloys R&D Specialist ndipo James W. Martin ndi Bar Metallurgy Specialist ku Carpenter Technology Corp.(Kuwerenga, Pennsylvania).
Mtengo wake ndi chiyani?Ndikufuna malo ochuluka bwanji?Kodi ndizovuta zotani zomwe ndingakumane nazo?Kodi njira yophunzirira ndiyokwera bwanji?Kodi anodizing ndi chiyani kwenikweni?Pansipa pali mayankho a mafunso oyambirira a ambuye okhudza anodizing mkati.
Kupeza zotsatira zosasinthasintha, zapamwamba kuchokera ku njira yopera yopanda malo kumafuna kumvetsetsa koyambira.Mavuto ambiri ogwiritsira ntchito okhudzana ndi kugaya kopanda malo amabwera chifukwa cha kusamvetsetsa zofunikira.Nkhaniyi ikufotokoza chifukwa chake njira yopanda nzeru imagwira ntchito komanso momwe mungagwiritsire ntchito bwino pamisonkhano yanu.