Pitting corrosion perforation tsis ua hauj lwm yog hais txog cov ntsiab lus me me ntawm cov yeeb yaj kiab tsis zoo nyob rau sab hauv thiab sab nrauv ntawm 316 stainless hlau cua sov tubs raug ntxias los ntawm cov tshuaj chloride ions, sulfides thiab cov khoom siv khawb. Electrochemical anodic dissolution tshwm sim zoo dua ntawm cov haujlwm tsis zoo no los tsim cov pits me me cais tawm. Lub occluded microenvironment nyob rau hauv pits tsis tu ncua concentrates corrosive ions thiab txo pH tus nqi, accelerating pit qhov tob expansion raws phab ntsa thickness kev taw qhia. Nws thiaj li, cov yeeb nkab phab ntsa yog nkag mus rau hauv cov pinhole to, thaum feem ntau ntawm cov kav dej saum npoo tseem tuav tsis zoo los tiv thaiv -corrosion passivation zaj duab xis. Qhov kev txhim kho hauv cheeb tsam no muaj qhov zais cia muaj zog thiab ntws tawm sai sai, uas yog ib qho ntawm cov kev ua haujlwm tsis zoo tshaj plaws ntawm cov kav dej cua sov stainless hlau hauv halogen- muaj cov xov xwm ua haujlwm.
1. Passive Film Breakdown thiab Pitting Development Mechanism
Ua kom tiav chromium-nplua nuj oxide passive zaj duab xis ua rau cov hlau tsis muaj steel tiv thaiv corrosion tsis zoo nyob rau hauv nruab nrab thiab tsis muaj zog corrosive ib puag ncig. Chloride ions muaj zog permeability thiab adsorption muaj peev xwm, uas tuaj yeem hloov cov pa atoms ntawm cov zaj duab xis passive thiab rhuav tshem cov txheej txheem tiv thaiv ntawm cov teeb meem hauv zos. Cov hlau matrix raug nyob rau hauv lub qhov taub ua hauj lwm raws li lub anode rau tas mus li dissolution, thiab sab nrauv passivation cheeb tsam ua raws li lub cathode ua kom tiav cov galvanic cell cov tshuaj tiv thaiv. Cov khoom corrosion sib sau ua ke hauv lub qhov ncauj kom kaw qhov qhib me me, ua rau thaj chaw kaw nrog cov tshuaj chloride siab thiab muaj zog acidity. Qhov no tus kheej -catalytic corrosion system ua kom tob rau hauv lub qhov tsis nthuav dav qhov corrosion sab nraud, ua rau los ntawm - phab ntsa perforation nrog tsuas yog ib qho me me qhov taw tes ntawm sab nrauv. Tsis zoo li cov phab ntsa thinning corrosion, pitting puas concentrates ntawm discrete me me ntsiab lus nrog tsis tshua muaj neeg nkag mus efficiency.
2. Tej yam hauj lwm ua rau Pitting Corrosion puas
Sab hauv phab ntsa hauv qab ntawm cov kav dej kab rov tav qhov twg cov sediment thiab chloride ntsev deposits khaws cia ntev;
Scratched thiab mechanically abraded txoj hauj lwm tsim thaum lub sij hawm thauj mus los, hoisting thiab installation;
Weld nto pores, slag inclusions thiab tsis sib xws oxide nplai thaj tsam nrog tsis muaj zog passive zaj duab xis stability;
Cov ceg tuag thiab cov kav dej tsis tu ncua uas tsis yog - ncig nruab nrab thiab txuas ntxiv ion ntxiv;
Sab nrauv phab ntsa rwb thaiv tsev puas qhov chaw uas cov dej nag thiab cov condensate sib sau ua ke tsim ib cheeb tsam corrosive ib puag ncig.
3. Core Inducing Factors Accelerating Pitting Failure
Cov txheej txheem nruab nrab muaj cov tshuaj chloride, bromide thiab lwm yam halogen ions yam tsis muaj kev pom thiab kev kho kom huv;
Cov yeeb nkab sab hauv phab ntsa tsis yog pickled thiab passivated tom qab fabrication, tsis muaj ib tug ntom khoom tiv thaiv zaj duab xis;
Khoom impurities nyob rau hauv nruab nrab khawb cov yeeb nkab phab ntsa nto thiab tsim thawj qhov chaw rau pitting pib;
Ntev - lub sij hawm kaw standby yam tsis muaj qhov nruab nrab qhov khoob ua rau corrosive Cheebtsam los nag thiab ua raws li cov yeeb nkab phab ntsa;
Qhov kub thiab txias hauv zos ua kom nrawm ion tsiv teb tsaws thiab electrochemical tshuaj tiv thaiv tus nqi kom luv perforation voj voog.
4. Tag nrho -Txuas Kev Tiv Thaiv thiab Tswj Kev Ntsuas Kev Ntsuas
① Txhim kho qhov pom tseeb thiab cov khoom siv nruab nrab softening ntawm qhov system pem hauv ntej kawg
Tshem tawm halogen ions thiab khoom impurities kom tshem tawm pitting inducing qhov chaw hauv paus.
② Siv ib qho kev xaiv, passivation thiab nto polishing rau cov kav dej tiav tom qab vuam thiab kev teeb tsa
Tsim kom muaj ib qho zoo sib xws thiab ruaj khov los tiv thaiv -pitting passive zaj duab xis ntawm cov hlau nto.
③ Optimize pipeline gradient layout thiab teem caij tsis tu ncua thiab cov ntsiab lus ntws
Tsis txhob stagnation nruab nrab thiab ntsev deposition nyob rau hauv qis -dej thiab dig muag yeeb nkab txoj hauj lwm.
④ Standardize hoisting thiab kev tsim kho cov txheej txheem los tiv thaiv cov khoom sib tsoo thiab nto khawb puas
Txo cov neeg kho tshuab tsis xws luag uas yooj yim induce pitting nucleation.
⑤ Ua kom pom cov thickness tsis tu ncua thiab kev saib xyuas cov kua dej rau cov yeeb nkab tseem ceeb
Tshawb nrhiav pitting pits thaum ntxov ua ntej nkag mus rau qhov tshwm sim.
5. Kev Tiv Thaiv Cov Teeb Meem Sib piv
表格
| Kev Kho Mob & Kev Ua Haujlwm Hom | Pitting Perforation Risk | Daim ntawv thov tswv yim |
|---|---|---|
| Unfiltered siab -chloride nruab nrab + tsis muaj ncej-weld passivation + ntev- lub sij hawm nruab nrab tuav | Pinhole leakage tshwm sim nyob rau hauv nruab nrab - lub sij hawm pipeline lag luam | Ntxiv nruab nrab purification ntaus ntawv thiab ua tag nrho pickling passivation renovation |
| Nruab nrab impurity interception + standardized passivation kev kho mob + periodic blowdown txij nkawm | Ua tau zoo inhibit qhov kev puas tsuaj ntawm zaj duab xis thiab nws tus kheej -catalytic qhov loj hlob | Txuj kev tiv thaiv -pitting kev tsim tshwj xeeb rau 316 stainless hlau cua sov txheej txheem kav |
| Nto super-kev kho mob passivation + online ion concentration xyuas + txhua xyoo phased array flaw nrhiav pom | Tsis tshua muaj siab zais txaus ntshai ntawm kev cia li pinhole to thiab cov cuab yeej kaw | Cov tswv yim nyiam rau kev lag luam tshuaj corrosive nruab nrab cua sov pipeline ntev -cov haujlwm ua haujlwm |
Xaus
Pitting corrosion ntawm 316 stainless hlau cua sov raj pib los ntawm lub zos tawg ntawm lub nto passivation zaj duab xis nyob rau hauv halogen ion yaig, tsim ib tug kaw tus kheej -accelerating corrosion cell uas nkag mus rau hauv cov yeeb nkab phab ntsa los tsim pinholes. Cov kev tiv thaiv tseem ceeb suav nrog kev ua kom huv hauv nruab nrab los txo cov corrosive Cheebtsam, ua kom tiav cov pickling thiab passivation los txhawb cov yeeb yaj kiab tiv thaiv, ua kom zoo dua cov raj xa dej kom tsis txhob muaj qhov nruab nrab deposition, tsis txhob ntog txhua yam puas tsuaj thiab ua raws li kev tshuaj ntsuam xyuas thiab kev tu lub tshuab. Tag nrho- txheej txheem kev tswj kom zoo ntawm kev ua cov kav dej, nruab nrab pretreatment thiab kev saib xyuas kev ua haujlwm txhua hnub tuaj yeem tshem tawm sai sai thiab kev cuam tshuam ntawm kev tsim khoom los ntawm pitting perforation ntawm stainless hlau cua sov raj.
