Wava nechokwadi chekuti zvikamu zvakagadzirwa nenzira chaiyo.Iye zvino, iva nechokwadi chokuti watora matanho ekudzivirira zvikamu izvi mumamiriro ezvinhu anotarisirwa nevatengi vako.#basic
Passivation inoramba iri danho rakakosha mukuwedzera kusimba kwekurara kwesimbi isina michina yezvikamu uye maassemblies.Inogona kuita mutsauko pakati pekuita kunogutsa uye kutadza nguva isati yakwana.Kuitwa zvisina kunaka, passivation inogona kukonzera ngura.
Passivation inzira yemashure-yekugadzira iyo inowedzera iyo inherent corrosion resistance ye-stainless simbi alloys inobudisa workpiece.Haisi kurapa kwekudzikisa, uye haisi yekuputira pendi.
Hapana kubvumirana kwakawanda pamusoro pemaitiro chaiwo ekuti passivation inoshanda sei.Asi ndeyechokwadi kuti pane inodzivirira oxide firimu pamusoro pe passivated Stainless steel.Iri firimu risingaoneki rinofungidzirwa kuva rakatetepa zvakanyanya, risingasviki 0.0000001 inch gobvu, inenge 1/100,000th ukubvu hwebvudzi remunhu!
Yakachena, ichangobva kugadzirwa, yakakwenenzverwa kana pickled Stainless simbi chikamu chichangoerekana chawana iyi oxide firimu nekuda kwekusangana kwayo nemhepo oksijeni.Pasi pemamiriro akanaka, iyi inodzivirira oxide layer inovhara zvachose nzvimbo dzese dzechikamu.
Mukuita, zvisinei, zvinosvibisa zvakadai semarara ezvitoro kana zvidimbu zvesimbi kubva pakucheka zvishandiso zvinogona kuendesa kune pamusoro pezvikamu zvesimbi zvisina tsvina panguva yekugadzira.Kana isina kubviswa, miviri iyi yekunze inogona kuderedza kushanda kwefirimu yekudzivirira yepakutanga.
Panguva yekugadzira, kutsvaga huwandu hwesimbi yakasununguka hunogona kupera kubva pachigadziro uye kuendesa kumusoro kwesimbi isina tsvina workpiece.Mune dzimwe nguva, tsvina yakaonda yehutu inogona kuoneka pane chikamu.Izvi chaizvoizvo kuora kwesimbi nechishandiso, kwete chesimbi yepasi.Pane imwe nguva, mitsetse yesimbi yakavharidzirwa kubva kumidziyo yekucheka kana kuparara kwezvigadzirwa zvayo zvinogona kukonzera kukoromoka.
Saizvozvowo, zvimedu zviduku zvevhu rekutengesa ferrous zvinogona kunamatira kumusoro kwechikamu chacho.Kunyange zvazvo simbi inogona kuonekwa ichipenya mumamiriro emuchina, mushure mekusangana nemhepo, zvimedu zvisingaoneki zvesimbi yakasununguka zvinogona kukonzera kupisa kwepamusoro.
Masulfide akafumurwa anogonawo kuva dambudziko.Vanobva pakuwedzera sarufa kune simbi isina tsvina kuti vavandudze machinability.Sulfidis inowedzera kukwanisa kwealloy kuumba machipisi panguva yekugadzira, iyo inogona kuderedzwa zvachose kubva pachigadziro chekucheka.Kunze kwekunge zvikamu zvakanyatsopedzwa, sulfides inogona kuva nzvimbo yekutanga yekuora kwepamusoro pane zvigadzirwa zvakagadzirwa.
Muzviitiko zvose zviri zviviri, passivation inodiwa kuti iwedzere kupikisa kwepanyama kwesimbi isina tsvina.Inobvisa tsvina yepasi, yakadai se ferrous shop dirt particles uye iron particles mukucheka maturusi, izvo zvinogona kuita ngura kana kuva nzvimbo yekutanga ye corrosion.Passivation inobvisawo sulfides yakazaruka pamusoro pesimbi isina tsvina isina kusununguka.
Nzira ine-matanho maviri inopa yakanyanya kunaka kusaora: 1. Kuchenesa, nzira yakakosha asi dzimwe nguva isingatarisirwi; 2. Acid kugeza kana passivation kurapwa.
Kuchenesa kunofanira kugara kuchinyanya kukosha.Panzvimbo panofanira kunyatsocheneswa girizi, inotonhodza kana mamwe madhaka emuchitoro kuitira kuti arambe akagwinya.Machining marara kana imwe tsvina yemuchitoro inogona kucheneswa kubva pachikamu chacho.Madhigirii ekutengesa kana macleaner anogona kushandiswa kubvisa maprocess oils kana anotonhodza.Nzvimbo dzekunze dzakadai senge thermal oxides dzinobviswa kana mapicking oxides.
Dzimwe nguva mushandisi wemuchina anogona kusvetuka kucheneswa kwekutanga, achikanganisa achifunga kuti kuchenesa uye kufambisa zvichaitika panguva imwe chete nekungonyika chikamu chakazara girizi muasidhi yekugezera. Izvo hazvizoitike. Sezvineiwo, girisi yakasvibiswa inopindirana neasidhi kuita mabubbles emhepo. Aya mabhuru anoungana panzvimbo yebasa uye anovhiringidza kufamba.
Kuita kuti zvinhu zvinyanye kushata, kusvibiswa kwezvigadziriso, izvo dzimwe nguva zvine huwandu hwakanyanya hwekloridhi, zvinogona kukonzera "kupenya." Kusiyana nekuwana iyo yaunoda firimu reoxide ine inopenya, yakachena, isingaite ngura, flash etching inogona kuguma neyakadzimirwa zvakanyanya kana kusviba - kushata kwechiso uko kufambisa kwakagadzirirwa kukwirisa.
Zvikamu zvakagadzirwa kubva martensitic Stainless simbi [magineti, zvine mwero inoshingirira mukuora, goho simba rinosvika 280 ksi (1930 MPa)] dzakaomeswa patembiricha yakakwira uye zvino kudzikamiswa kuti ive nechokwadi chekuoma kwaidiwa uye michina zvinhu. Kunaya kwakaomarara alloys, ane simba riri nani uye corrosion inogadziriswa mativi, maratensitic inogadziriswa simbi inogadziriswa, simbi inogadziriswa simbi inogadziriswa. vachembera pakudzikira tembiricha, vozopedza.
Muchiitiko ichi, chikamu chacho chinofanira kunyatsocheneswa ne degreaser kana kuchenesa kubvisa chero maitiro ekucheka kwemvura kusati kwaitwa kupisa.Kana zvisina kudaro, mvura yekucheka yakasara pane chikamu inogona kukonzera oxidation yakawandisa.Ichi chiitiko chinogona kuita kuti zvikamu zvisinganyanyi kunyunguduka mushure mokunge chikero chabviswa neasidhi kana abrasive nzira.Kana kucheka kwemvura kunobvumirwa kuramba kune zvikamu zvinopenya zvakaomeswa, zvakadai semhepo inodzivirira, furna , mhepo inodzivirira inogona kuitika mumhepo yefurna, furna , mhepo inodzivirira. zvichiita kuti pave nekurasikirwa kwekusagadzikana.
Mushure mekunyatsocheneswa, simbi isina tsvina inogona kunyudzwa mu passivating acid bath.Chero nzira nhatu dzinogona kushandiswa - nitric acid passivation, nitric acid ine sodium dichromate passivation, uye citric acid passivation.Ndeipi nzira yekushandisa inoenderana negiredhi resimbi isina tsvina uye yakatarwa yekubvuma maitiro.
Mamwe magiredhi asingadziviriki echrome-nickel anogona kupfuudzwa mu20% (v/v) nitric acid bath (Figure 1) .Sezvinoratidzwa patafura, simbi isina simbi isingadziviriri inogona kupfuudzwa nekuwedzera sodium dichromate kune nitric acid bath, zvichiita kuti mhinduro yacho iwedzere oxidizing uye inokwanisa kuumba a passive . kuwedzera huwandu hwe nitric acid kusvika ku50% nehuwandu.Zvose kuwedzera kwe sodium dichromate uye yakakwirira ye nitric acid inoderedza mukana wekutsvaga kusingadiwi.
Maitiro ekupfuura emahara-machining masimbi asina tsvina (zvakare anoratidzwa muMufananidzo 1) akati siyanei neaya asiri emahara-machining simbi isina magiredhi.Izvi imhaka yekuti panguva yekupfuura mune yakajairika nitric acid yekugezera, mamwe kana ese esarufa ane machinable giredhi sulfide anobviswa, achigadzira microscopic discontinuities chikamu mumichina.
Kunyange kushambadza kwemvura kunowanzoshanda kunogona kusiya yakasara acid mune izvi discontinuities mushure me passivation.This asidhi ichabva yarwisa pamusoro pechikamu kunze kwekunge isina neutralized kana kubviswa.
Kuti ibudirire passivate nyore machinable Stainless simbi, Carpenter akagadzira AAA (Alkali-Acid-Alkali) muitiro, iyo neutralizes residual acid.Iyi passivation nzira inogona kupedzwa isingasviki maawa 2. Heino nhanho-nhanho maitiro:
Mushure mekudzikisa, simbisai zvikamu mu 5% sodium hydroxide solution pa 160 ° F kusvika 180 ° F (71 ° C kusvika 82 ° C) kwemaminitsi 30. Zvadaro simbura zvikamu zvakakwana mumvura. Zvadaro, inyura chikamu kwemaminitsi makumi matatu mu 20% (v / v) nitric acid / solution ye nitric / gal ine 2 dich sodium / gal ine 2 dich sodium solution 120°F kusvika 140°F (49°C) kusvika 60°C). Mushure mokubvisa chikamu kubva mubhati, chisuke nemvura uye wochiisa mu sodium hydroxide solution kune imwe maminitsi 30. Geza chikamu zvakare nemvura uye wooma, kuzadzisa nzira yeAAA.
Citric acid passivation inowedzera kufarirwa nevagadziri vanoshuva kudzivisa kushandiswa kwemaminerari acids kana zvigadziriso zvine sodium dichromate, pamwe chete nenyaya dzekurasa uye kunyanya kunetseka kwekuchengeteka kunobatanidza nekushandiswa kwavo.Citric acid inoonekwa seyakanaka zvakatipoteredza munzira dzose.
Kunyange zvazvo citric acid passivation ichipa zvinoyevedza zvakatinakira zvakatipoteredza, zvitoro zvakave nebudiriro neinorganic acid passivation uye vasina zvinetswa zvekuchengetedza vangada kuramba vari kosi.Kana vashandisi ava vaine shopu yakachena, inochengetedzwa uye yakachena michina, inotonhorera isina ferrous shop fouling, uye maitiro anoburitsa mhedzisiro yakanaka, panogona kunge pasina kudikanwa kwechokwadi kwekuchinja.
Passivation mubhati ye citric acid yakawanikwa ichibatsira kune yakakura yakawanda yesimbi isina tsvina, kusanganisira makirasi akawanda ega ega ega ega, sezvinoratidzwa mumufananidzo 2. Kuti zvive nyore, iyo tsika ye nitric acid passivation nzira muMufananidzo 1 inosanganiswa.Cherechedza kuti yekare nitric acid formulations inoratidzwa muhuwandu hwezana, nepo itsva citric acid concentrations inoratidzwa mukuenzanisa kwemaitiro ekuenzanisa, iyo inotevedzwa inotaridzirwa muhuwandu hwekuenzanisa, iyo inoshandiswa pakuyera kurema kwezvikamu izvi. nguva, tembiricha yekugeza uye kutarisisa kwakakosha kuti udzivise "kupenya" kwakatsanangurwa kare.
Mishonga yepassivation inosiyana zvichienderana nemukati mechromium uye machining maitiro egiredhi rega rega.Cherechedza makoramu anonongedza process 1 kana process 2.Sezvinoratidzwa muFigure 3, process 1 inosanganisira nhanho shoma pane 2.
Kuongororwa kwe laboratory kwakaratidza kuti citric acid passivation process inonyanya ku "flashing" kupfuura iyo nitric acid process.Zvikonzero zvinokonzera kurwisa uku zvinosanganisira kupisa kwakanyanya kwekugezera, nguva yakareba yakanyorova, uye kusvibiswa kwebhati.Citric acid zvigadzirwa zvine corrosion inhibitors uye zvimwe zvinowedzera zvakadai semvura inonyorova inotengeswa uye inonzi inoderedza "flash corrobility".
Sarudzo yekupedzisira yenzira yekufambisa ichaenderana nemaitiro ekugamuchirwa anotarwa nemutengi.Ona ASTM A967 yeruzivo.Inogona kuwanikwa pawww.astm.org.
Maedzo anowanzoitwa kuti atarise pamusoro pezvikamu zvisina kuvharwa. Mubvunzo wekupindura ndewekuti, "Ko kufambisa kunobvisa simbi yemahara uye kunowedzera kusadzivirirwa nekuora kwemagiredhi emahara?"
Zvakakosha kuti nzira yekuedza ienderane negiredhi riri kuongororwa.Miedzo yakanyanya kuomesesa ichakundikana zvakakwana zvinhu zvakanaka, ukuwo bvunzo dzakanyanya kusununguka dzichapfuura zvisingagutsi.
400 series precipitation kuomesa uye mahara-machining Stainless steels zvinonyanya kuongororwa mu cabinet inokwanisa kuchengetedza 100% humidity (wet samples) kwemaawa makumi maviri nemana pa95 ° F (35 ° C) .Chikamu chemuchinjikwa chinowanzova chinonyanya kuoma pamusoro, kunyanya kune mahara-kucheka magiredhi.Chimwe chikonzero cheizvi ndechokuti iyi sulfide inogadziriswa mumuchina uyu.
Nzvimbo dzakaomarara dzinofanira kuiswa kumusoro, asi pa15 kusvika 20 madhigirii kubva pakatwasuka kuitira kuti mwando urasikike.Iyo yakavharwa zvakanaka haingaite ngura, kunyangwe ichigona kuratidza kutsvuka kudiki.
Austenitic Stainless steel mamakisi anogonawo kuongororwa nekunyorova kuyedzwa.Kana yakaedzwa, madonhwe emvura anofanirwa kunge aripo pamusoro peiyo sampuli, achiratidza simbi yemahara nekuvapo chero ngura.
Maitiro ekupfuura anowanzo shandiswa akasununguka-kucheka uye asingasununguke-akasununguka-akatema simbi isina tsvina mu citric kana nitric acid mhinduro inoda maitiro akasiyana.
(a) Gadzirisa pH ine sodium hydroxide.(b) Ona Mufananidzo 3 (c) Na2Cr2O7 inomiririra 3 oz/gallon (22 g/l) sodium dichromate mu20% nitric acid. Imwe nzira yemusanganiswa uyu i50% nitric acid isina sodium dichromate.
Nzira yekukurumidza ndeye kushandisa mhinduro muASTM A380, "Yakajairwa Kudzidzira Kuchenesa, Kudzikisa, uye Passivation yeStainless Simbi Zvikamu, Equipment, uye Systems." Muedzo uyu une kupukuta chikamu nemhangura sulfate / sulfuric acid mhinduro, ichiichengeta yakanyorova kwemaminetsi matanhatu uye kutarisa kune imwe nzira yekunyudzwa yemhangura muchikamu chemhangura. maminitsi.Kana simbi yakanyunguduka, mhangura yemhangura inoitika.Muedzo uyu haufanire kushandiswa panzvimbo yezvikamu zvekugadzira zvokudya.Uyewo, haifaniri kushandiswa 400 series martensitic kana low chromium ferritic steels semigumisiro yenhema inogona kuitika.
Kubva kare, 5% yesalt spray test pa 95°F (35°C) yakashandiswawo kuongorora masamples asina kunyorwa.Muedzo uyu wakaomarara kune mamwe magiredhi uye kazhinji haudiwi kuratidza kuti kupasa kunoshanda.
Dzivisa kushandisa ma chlorides akawandisa, anogona kukonzera kukuvadza kweflash.Kana zvichibvira, shandisa mvura yemhando yepamusoro chete ine zvikamu zvisingasviki makumi mashanu pamiriyoni (ppm) chloride.Mvura yepombi inowanzokwana uye inogona kushivirira kusvika kumazana akati wandei ppm chloride mune dzimwe nguva.
Zvakakosha kutsiva bhati nguva dzose kuti udzivise kurasikirwa kwepassivation inogona kutungamirira ku flashover uye zvikamu zvakakanganisika.Kugezera kunofanira kuchengetedzwa pahutano hwakakodzera, sezvo kupisa kwemhepo kunogona kukonzera kuparara kwenzvimbo.
Zvakakosha kuchengetedza yakanyatsogadzirisa sarudzo yekushandura purogiramu panguva yekugadzirwa kwepamusoro kunomhanya kuderedza mukana wekusvibiswa.Sampu yekudzora yakashandiswa kuedza kushanda kwebhati.Kana muenzaniso uchirwiswa, inguva yekutsiva bhati.
Ndapota tsanangurai kuti mimwe michina inogadzira simbi isina tsvina chete; shandisa chitonhodzo chimwechete chaunoda kucheka simbi isina tsvina, kusasanganisa mamwe simbi dzese.
DO rack parts inobatwa mumwe nomumwe kudzivirira simbi-to-metal contact.Izvi zvinonyanya kukosha kune mahara machining Stainless simbi, sezvo kusununguka-kuyerera passivation uye flushing mhinduro zvinodiwa kuparadzira corrosion zvigadzirwa mu sulfides uye kudzivisa kuumbwa kweasidhi homwe.
Rega passivate carburized kana nitrided Stainless simbi parts.The ngura kuramba kwezvikamu saka kurapwa anogona kuderedzwa kusvika apo vaizorwiswa passivation kugeza.
Usashandise ferrous zvishandiso munzvimbo yewekishopu isina kunyanya kuchena.Steel grit inogona kudziviswa nekushandisa carbide kana ceramic zvishandiso.
Usakanganwa kuti ngura inogona kuitika mubhati yepassivation kana chikamu chisina kupisa chakabatwa zvakanaka.High carbon, high chromium martensitic grade inofanira kuomeswa nekuda kwekusagadzikana.
Passivation inowanzoitwa mushure mekuzopisa kunotevera uchishandisa tembiricha inochengetedza corrosion resistance.
Usaregeredza nitric acid concentration mu passivation bath.Periodic checks inofanira kuitwa uchishandisa simple titration process inopiwa naCarpenter.Usapfure zvinopfuura imwe stainless simbi panguva.Izvi zvinodzivirira kuvhiringika kunodhura uye kudzivirira galvanic reactions.
Nezvevanyori: Terry A. DeBold inyanzvi yesimbi isina tsvina yekutsvaga nekusimudzira uye James W. Martin ibar metallurgist paCarpenter Technology Corp. (Kuverenga, PA).
Munyika iri kuramba ichiomesera mapeji epamusoro, zviyero zviri nyore “kushata” zvichiri kubatsira. Ngatitarisei kuti sei kuyerwa kwepamusoro kwakakosha uye kuti kungatariswe sei pauriri hwechitoro nezviyero zvemhando yepamusoro zvinotakurika.
Une chokwadi here kuti une yakanakisa yekuisa pakuita uku? Tarisa chip, kunyanya kana isina kutarisirwa. Mamiriro eChip anogona kukuudza zvakawanda.