Uqinisekisile ukuba amalungu enziwe ngokweenkcukacha.Ngoku qiniseka ukuba uthatha amanyathelo okukhusela ezi ndawo kwindawo elindelwe ngabathengi bakho.#isiseko
I-passivation ihlala ilinyathelo elibalulekileyo ekwandiseni ukuxhathisa kwe-corrosion yamacandelo kunye neendibano ezenziwe ngoomatshini kwintsimbi engenasici.Oku kunokwenza umahluko phakathi kwentsebenzo eyanelisayo kunye nokusilela kwangaphambi kwexesha.I-passivation engafanelekanga inokubangela umhlwa.
I-passivation yindlela yokwenziwa emva kokwenza ukunyusa ukuxhathisa kwe-corrosion yendalo ye-alloys yensimbi engenasici apho i-workpiece yenziwe khona.Oku akukokwehla okanye ukupeyinta.
Akukho mvumelwano malunga nendlela echanekileyo esebenza ngayo i-passivation.Kodwa iyaziwa ngokuqinisekileyo ukuba kukho ifilimu ekhuselayo ye-oxide ebusweni bensimbi engenasici.Lo mboniso bhanyabhanya ungabonakaliyo kuthiwa ubhityile kakhulu, ungaphantsi kwe-0.0000001 intshi ubukhulu, obumalunga ne-1/100,000 yobukhulu beenwele zomntu!
Indawo ecocekileyo, esandula ukwenziwa ngoomatshini, ipolishiweyo, okanye intsimbi engatyiwayo ecoliweyo iya kufumana ngokuzenzekelayo le filimu yeoxide ngenxa yokuvezwa komoya womoya.Ngaphantsi kweemeko ezifanelekileyo, lo maleko we-oxide okhuselayo ugubungela ngokupheleleyo yonke imiphezulu yenxalenye.
Ekusebenzeni, nangona kunjalo, ukungcola okufana nokungcola kwefektri okanye iinqununu zentsimbi ezivela kwizixhobo zokusika zingafumana phezu kwendawo yensimbi engenasici ngexesha lokucubungula.Ukuba ayisuswanga, le mibutho yangaphandle inokunciphisa ukusebenza kwefilimu yokuqala yokukhusela.
Ngethuba lokucoca, iintambo zentsimbi zamahhala zingasuswa kwisixhobo kwaye zidluliselwe kumphezulu wentsimbi yensimbi engenasici.Kwezinye iimeko, inxalenye encinci yomhlwa inokuvela.Enyanisweni, oku kukugqwala kwesixhobo sensimbi, kungekhona isiseko sesinyithi.Ngamanye amaxesha ukuqhekeka kwiinqununu zetsimbi ezifakwe kwizixhobo zokusika okanye iimveliso zabo zokubola zinokuphazamisa inxalenye ngokwayo.
Ngokufanayo, iincinci ezincinci ze-ferrous metallurgical dilt zinokubambelela kumphezulu wenxalenye.Nangona isinyithi sinokubonakala sikhazimulayo kwimeko yaso egqityiweyo, emva kokuvezwa emoyeni, iincinci ezingabonakaliyo zentsimbi yamahhala zingabangela i-rust surface.
Iisulfides eziveziweyo nazo zinokuba yingxaki.Zenziwa ngokongeza isulfure kwinsimbi engenasici ukuze kuphuculwe ukusebenziseka.I-sulfides yandisa amandla e-alloy ukwenza ii-chips ngexesha lokucoca, ezinokususwa ngokupheleleyo kwisixhobo sokusika.Ukuba iindawo azigqithiswanga ngokufanelekileyo, iisulfides zinokuba yindawo yokuqala yokubola komphezulu weemveliso zemizi-mveliso.
Kuzo zombini iimeko, i-passivation iyadingeka ukunyusa ukuxhathisa kwemvelo ye-corrosion yensimbi engenasici.Isusa ukungcola okungaphezulu njengamaqhekeza ensimbi kunye neentsimbi zentsimbi kwizixhobo zokusika ezinokuthi zenze i-rust okanye zibe yindawo yokuqala yokubola.I-Passivation iphinda isuse i-sulphides efunyenwe kumphezulu we-alloys yensimbi engenasici evulekileyo.
Inkqubo yamanyathelo amabini inika ukuchasana kwe-corrosion engcono kakhulu: 1. Ukucoca, inkqubo ephambili, kodwa ngamanye amaxesha ingahoywa 2. Ibhafu ye-Acid okanye i-passivation.
Ukucoca kufuneka kuhlale kuyinto ephambili.Umphezulu kufuneka ucocwe ngokucokisekileyo kwigrisi, into yokupholisa okanye obunye ubumdaka ukuqinisekisa ukuxhathisa kokudleka kakuhle.I-debris ye-Machining okanye enye inkunkuma yefektri inokusulwa ngobunono kwindawo.Iidegreaser zorhwebo okanye izicoci zingasetyenziselwa ukususa i-oyile yenkqubo okanye izinto zokupholisa.Izinto zangaphandle ezifana ne-thermal oxides zingadinga ukususwa ngeendlela ezifana nokusila okanye ukukha.
Ngamanye amaxesha umqhubi womatshini unokutsiba ukucoca okusisiseko, ngempazamo ekholelwa ukuba ukucocwa kunye nokunyanzeliswa kuya kwenzeka ngexesha elinye, ngokuntywiliselwa nje inxalenye eneoli kwibhafu ye-asidi.Ayinakwenzeka.Ngokuchaseneyo, igrisi engcolisekileyo idibana neasidi yenze amaqamza omoya.La maqamza aqokelela kwindawo yokusebenza kwaye aphazamise i-passivation.
Okubi nangakumbi, ukungcoliseka kwezisombululo zokudlula, ezithi ngamanye amaxesha ziqulathe ukuxinana okuphezulu kwekloridi, kunokubangela "iflash".Ngokwahlukileyo ekuveliseni ifilimu efunwayo yeoksidi enomgangatho ocwebezelayo, ococekileyo, onganyangekiyo ku-corrosion, ukufakwa kwe-flash kunokubangela ukuba umphezulu ube bukhali okanye ube mnyama—ukonakala kumphezulu olungiselelwe ukuba ugqitywe.
Amalungu entsimbi ye-Martensitic [umazibuthe, enganyangekiyo ku-corrosion, amandla emveliso ukuya kuthi ga kwi-280 lamawaka e-psi (1930 MPa)] acinywa kumaqondo obushushu aphezulu aze athotywe ukuze abonelele ngobulukhuni obufunwayo kunye neempawu zoomatshini.I-alloys eqinisiweyo yemvula (enamandla angcono kunye nokumelana nomhlwa kunamabanga e-martensitic) inokunyangwa isisombululo, ifakwe ngoomatshini, iguge kumaqondo aphantsi, kwaye igqitywe.
Kule meko, inxalenye kufuneka ihlambuluke ngokucokisekileyo kunye ne-degreaser okanye i-cleaner ngaphambi kokuba unyango lobushushu lisuse nayiphi na impawu yokusika amanzi.Ngaphandle koko, ukupholisa okushiyekileyo kwindawo kunokubangela i-oxidation egqithisileyo.Le meko inokubangela ukuba izibonda zenzeke kumalungu amancinane emva kokuncipha ngeasidi okanye iindlela zokurhawuzelela.Ukuba isisipholisi sishiywe kwiindawo eziqinileyo ezimenyezelayo, njengakwiziko lokufunxa okanye kwindawo ekhuselayo, i-carburization yomphezulu inokwenzeka, ekhokelela ekuphulukaneni nokumelana nomhlwa.
Emva kokucoca ngokucokisekileyo, iinxalenye zetsimbi ezingenasici zinokuntywiliselwa kwindawo yokuhlambela iasidi.Naziphi na iindlela ezintathu zingasetyenziswa - i-passivation kunye ne-nitric acid, i-passivation kunye ne-nitric acid kunye ne-sodium dichromate, kunye ne-passivation kunye ne-citric acid.Yiyiphi indlela yokusetyenziswa ixhomekeke kwibakala lensimbi engenasici kunye neendlela ezichaziweyo zokwamkelwa.
Amanqanaba e-nickel e-chromium anganyangekiyo ngakumbi kunokugqithiswa kwi-20% (v/v) yokuhlambela i-nitric acid (Umfanekiso 1).Njengoko kubonisiwe kwitheyibhile, iintsimbi ezingenasici ezingenakunyanzeliswa ziyakwazi ukugqithiswa ngokudibanisa i-sodium dichromate kwindawo yokuhlambela ye-nitric acid ukwenza isisombululo sibe ne-oxidizing kwaye sikwazi ukwenza ifilimu edlulayo kwi-metal surface.Enye inketho yokutshintsha i-nitric acid kunye ne-sodium chromate kukunyusa ukuxinwa kwe-nitric acid ukuya kwi-50% ngomthamo.Komibini ukongezwa kwe-sodium dichromate kunye noxinzelelo oluphezulu lwe-nitric acid kunciphisa ukubakho kwesibane esingafunwayo.
Inkqubo yokugqithisa i-machinable steels stainless (kwakhona iboniswe kwi-Fig. 1) ihluke kancinane kwindlela yokwenza amabakala ensimbi engenasici.Oku kungenxa yokuba ngexesha lokugqitha kwibhafu ye-nitric acid, ezinye okanye zonke iisulfide ezinesulfure ezinobuqili ziyasuswa, zenze i-microscopic inhomogeneities kumphezulu womsebenzi.
Nokuba ukuhlamba amanzi okuqhelekileyo kunokushiya i-asidi eshiyekileyo kwezi zinto zingaqhubekiyo emva kokudlula.Le asidi iya kuhlasela umphezulu wenxalenye ukuba ayithathwanga okanye isuswe.
Ukuphumelela ngokufanelekileyo kwensimbi engenasici kumatshini, uMchweli uye waphuhlisa inkqubo ye-AAA (i-Alkaline-Acid-Alkaline), eyenza i-asidi eseleyo.Le ndlela yokudlula ingagqitywa ngaphantsi kweeyure ezi-2.Nantsi inkqubo yenyathelo ngenyathelo:
Emva kokunciphisa, gcoba iinxalenye kwi-5% yesisombululo se-sodium hydroxide kwi-160 ° F ukuya kwi-180 ° F (71 ° C ukuya kwi-82 ° C) imizuzu engama-30.Emva koko uhlambulule iindawo ngokucokisekileyo emanzini.Emva koko ucwilise inxalenye yemizuzu ye-30 kwi-20% (v / v) isisombululo se-nitric acid equkethe i-3 oz / gal (22 g / l) i-sodium dichromate kwi-120 ° F ukuya kwi-140 ° F (49 ° C) ukuya kwi-60 ° C.) Emva kokususa inxalenye ekuhlambeni, yihlambulule ngamanzi, uze uyifake kwisisombululo se-sodium hydroxide imizuzu engama-30.Hlanza inxalenye kwakhona ngamanzi kwaye uyomile, ugqibezela indlela ye-AAA.
I-Citric acid passivation iya ithandwa kakhulu ngabavelisi abafuna ukuphepha ukusetyenziswa kwee-acids zamaminerali okanye izisombululo eziqukethe i-sodium dichromate, kunye neengxaki zokulahla kunye nokunyuka kweenkxalabo zokhuseleko ezinxulumene nokusetyenziswa kwazo.I-citric acid ithathwa njengobungane bendalo kuzo zonke iinkalo.
Ngelixa i-citric acid passivation ibonelela ngezibonelelo ezithandekayo zokusingqongileyo, iivenkile eziye zaphumelela nge-inorganic acid passivation kwaye azinaxhala lokhuseleko zinokufuna ukuhlala ekhosi.Ukuba aba basebenzisi banevenkile ecocekileyo, izixhobo zikwimeko entle kwaye zicocekile, i-coolant ayinayo idiphozithi yeferrous yefektri, kwaye inkqubo ivelisa iziphumo ezilungileyo, akunakubakho mfuneko yokwenyani yotshintsho.
I-Citric acid bath passivation ifunyenwe ibe luncedo kuluhlu olubanzi lweentsimbi ezingenasici, kubandakanywa amabakala amaninzi ensimbi engenasici, njengoko kuboniswe kuMzobo 2. Ukuze kube lula, i-Figure 2. I-1 ibandakanya indlela yendabuko yokugqithisa nge-nitric acid.Qaphela ukuba ukwakhiwa kweasidi ye-nitric endala ichazwa njengeepesenti ngomthamo, ngelixa ugxininiso olutsha lwe-citric acid lubonakaliswa ngokweepesenti ngobunzima.Kubalulekile ukuba uqaphele ukuba xa usenza ezi nkqubo, ulungelelwaniso olucokisekileyo lwexesha lokucwina, ubushushu bokuhlamba, kunye nokugxininiswa kubaluleke kakhulu ukuphepha "ukukhanya" okuchazwe ngasentla.
Ukugqithiswa kuyahluka ngokuxhomekeke kumxholo wechromium kunye neempawu zokusetyenzwa kweentlobo ezahlukeneyo.Qaphela iikholamu zeNkqubo 1 okanye iNkqubo 2. Njengoko kubonisiwe kuMfanekiso 3, Inkqubo 1 inamanyathelo ambalwa kuneNkqubo yesi-2.
Uvavanyo lwebhubhoratri lubonise ukuba inkqubo ye-citric acid passivation iyakwazi "ukubilisa" kunenkqubo ye-nitric acid.Izinto ezinegalelo kolu hlaselo ziquka ubushushu obuphezulu bebhafu, ixesha elide lokufunxa, kunye nokungcoliseka kwebhafu.Iimveliso ezisekelwe kwi-citric acid equkethe i-corrosion inhibitors kunye nezinye izongezo ezifana nee-agent zokumanzisa zifumaneka ngokurhweba kwaye zichazwe ukunciphisa "i-flash corrosion".
Ukhetho lokugqibela lwendlela yokudlulisa luya kuxhomekeka kwiikhrayitheriya zokwamkelwa ezibekwe ngumthengi.Jonga i-ASTM A967 ngeenkcukacha.Inokufumaneka ku-www.astm.org.
Uvavanyo luhlala luqhutyelwa ukuvavanya umphezulu weendawo ezigqithisiweyo.Umbuzo omele uphendulwe ngulo "Ngaba i-passivation isusa intsimbi yasimahla kwaye yandise ukuxhathisa ukubola kweealloyi zokusika ngokuzenzekelayo?"
Kubalulekile ukuba indlela yovavanyo ihambelane neklasi evandlakanywayo.Uvavanyo olungqongqo kakhulu aluyi kudlula izinto ezilungileyo ngokupheleleyo, ngelixa iimvavanyo ezibuthathaka kakhulu ziya kudlula iindawo ezingonelisiyo.
I-PH kunye ne-easy-machining ye-400 series steels stainless ihlolwe kakuhle kwigumbi elikwazi ukugcina i-100% yomswakama (isampuli emanzi) kwiiyure ezingama-24 kwi-95 ° F (35 ° C).Icandelo lomnqamlezo lidla ngokuba ngowona mhlaba ubaluleke kakhulu, ngakumbi kumabakala okusika asimahla.Esinye isizathu soku kukuba isulfide itsalwa kwicala lomatshini kulo mphezulu.
Imiphezulu ebalulekileyo kufuneka ibekwe phezulu, kodwa kwi-angle ye-15 ukuya kwi-20 degrees ukusuka kwinqanaba, ukuvumela ukulahleka komswakama.Izinto ezifakwe ngokufanelekileyo aziyi kuhlwa, nangona amabala amancinci anokuthi avele kuyo.
I-Austenitic stainless steel grade zingavavanywa ngovavanyo lokufuma.Kulo vavanyo, amaconsi amanzi kufuneka abe khona phezu kwendawo yomzekelo, ebonisa isinyithi samahhala ngokubakho kwanoma yimuphi umhlwa.
Iinkqubo zokugqithiswa kwezixhobo eziqhelekileyo ezizenzekelayo kunye nezandla ezingenasici kwi-citric okanye i-nitric acid solutions zifuna iinkqubo ezahlukeneyo.Kwikhiwane.3 ngezantsi inika iinkcukacha ngokhetho lwenkqubo.
(a) Lungisa i-pH kunye ne-sodium hydroxide.(b) Bona umkhiwane.I-3 (c) i-Na2Cr2O7 yi-3 oz / gal (22 g / L) i-sodium dichromate kwi-20% ye-nitric acid.Enye indlela kulo mxube yi-50% ye-nitric acid ngaphandle kwe-sodium dichromate.
Indlela ekhawulezayo kukusebenzisa i-ASTM A380, uMzikelo oMgangatho wokuCoca, ukuCandwa, kunye nokuPasa iiNdawo zeNtsimbi eStainless, izixhobo kunye neeNkqubo.Uvavanyo lubandakanya ukusula inxalenye ngesisombululo se-copper sulfate / sulfuric acid, ukuyigcina imanzi imizuzu engama-6, kunye nokujonga i-plating yethusi.Ngaphandle koko, inxalenye inokuntywiliselwa kwisisombululo semizuzu emi-6.Ukuba intsimbi inyibilika, i-copper plating iyenzeka.Olu vavanyo alusebenzi kwiindawo zokulungisa ukutya.Kwakhona, akufanele isetyenziswe kwiintsimbi ze-400 ze-martensitic okanye i-chromium ephantsi ye-ferritic steels njengoko iziphumo zobuxoki zinokuthi zenzeke.
Ngokwembali, i-5% yovavanyo lwesitshizi setyuwa ku-95°F (35°C) nayo isetyenziselwe ukuvavanya iisampulu ezigqithisiweyo.Olu vavanyo lungqongqo kakhulu kwezinye iicultivars kwaye alufuneki ngokubanzi ukuqinisekisa ukusebenza ngempumelelo kwe-passivation.
Kuphephe ukusebenzisa iikloridi ezigqithisileyo, ezinokubangela ukugqabhuka okuyingozi.Sebenzisa kuphela amanzi akumgangatho ophezulu anamalungu angaphantsi kwama-50 kwisigidi (ppm) chloride nanini na kunokwenzeka.Amanzi etephu adla ngokwanela, kwaye kwezinye iimeko anokumelana namakhulu aliqela eenxalenye kwisigidi sekloridi.
Kubalulekile ukubuyisela indawo yokuhlambela rhoqo ukuze ungalahlekelwa amandla okudlula, oko kunokukhokelela ekubetheni kombane kunye nomonakalo kwiindawo.Ibhafu kufuneka igcinwe kwiqondo lokushisa elifanelekileyo, njengoko amaqondo okushisa angalawulwayo angabangela ukubola kwendawo.
Kubalulekile ukulandela ishedyuli echanekileyo yokutshintsha isisombululo ngexesha lemveliso enkulu yokunciphisa ungcoliseko olunokwenzeka.Isampuli yokulawula yayisetyenziselwa ukuvavanya ukusebenza kakuhle kwebhafu.Ukuba lo mzekelo uhlaselwe, lixesha lokubuyisela ibhafu.
Nceda uqaphele ukuba abanye oomatshini bavelisa kuphela isinyithi esingenasici;sebenzisa into yokupholisa efanayo ekhethwayo ukusika intsimbi engatyiwayo ngaphandle kwazo zonke ezinye iintsimbi.
Amalungu e-rack ye-DO afakwe ngokwahlukileyo ukuphepha isinyithi ukuya kwintsimbi.Oku kubaluleke kakhulu kwi-machining yamahhala yensimbi engenasici, njengoko i-passivation ehamba lula kunye nezisombululo zokugungxulwa zifunekayo ukusabalalisa iimveliso ze-sulfide corrosion kunye nokuthintela ukubunjwa kweepokotho ze-asidi.
Musa ukudlula i-carburized okanye i-nitrided steel stainless parts.Ukuxhatshazwa kwe-corrosion kwamacandelo aphathwa ngolu hlobo kunokuncitshiswa kangangokuba angonakaliswa kwindawo yokuhlamba i-passivation.
Musa ukusebenzisa izixhobo zetsimbi yeentsimbi kwiimeko zokusebenzela ezingacocekanga ngokukodwa.Iitshiphu zetsimbi zinokuphetshwa ngokusebenzisa i-carbide okanye izixhobo ze-ceramic.
Qaphela ukuba i-corrosion ingenzeka kwi-bath passivation ukuba inxalenye ayizange iphathwe ngokufanelekileyo ubushushu.Amabanga e-Martensitic anekhabhoni ephezulu kunye nomxholo wechromium kufuneka enziwe lukhuni ukuxhathisa ukubola.
I-passivation idla ngokuqhutywa emva kobushushu obulandelayo kumaqondo obushushu agcina ukuxhathisa ukubola.
Musa ukunyathela ukuxinwa kwe-asidi ye-nitric kwindawo yokuhlamba i-passivation.Ukuhlolwa rhoqo kufuneka kwenziwe kusetyenziswa inkqubo elula yokubhalwa kwetitration ecetyiswe nguMchweli.Sukudlula ngaphezu kwentsimbi enye ngexesha.Oku kuthintela ukudideka okunexabiso elikhulu kwaye kuthintele ukusabela kwegalvanic.
Malunga nababhali: UTerry A. DeBold yiNgcali ye-Stainless Steel Alloys R&D kunye noJames W. Martin yiNgcali ye-Bar Metallurgy kwi-Carpenter Technology Corp.(Ukufunda, ePennsylvania).
Yimalini?Ingakanani indawo endiyidingayo?Yiyiphi imiba yendalo endiza kujamelana nayo?Limnqake kangakanani igophe lokufunda?Yintoni kanye i-anodizing?Ngezantsi kukho iimpendulo kwimibuzo yokuqala yeenkosi malunga ne-anodizing yangaphakathi.
Ukufumana iziphumo ezihambelanayo, ezikumgangatho ophezulu ukusuka kwinkqubo yokugaya engenaziko kufuna ukuqonda okusisiseko.Uninzi lweengxaki zesicelo ezinxulumene nokusila okungenaziko zivela ngenxa yokungaqondi kakuhle izinto ezisisiseko.Eli nqaku lichaza ukuba kutheni inkqubo engenangqondo isebenza kunye nendlela yokuyisebenzisa ngokufanelekileyo kwiworkshop yakho.