1. C70600 flanges yog tus qauv rau cov kav dej hiav txwv. Dab tsi yog cov txheej txheem tshwj xeeb uas 10% Nickel cov ntsiab lus hloov pauv tus cwj pwm corrosion ntawm tooj liab kom nws tiv taus kev cuam tshuam rau hauv siab -ceev seawater?
Qhov sib ntxiv ntawm 10% Nickel induces ib tug transformative kev hloov nyob rau hauv lub xwm thiab tenacity ntawm lub alloy tiv thaiv nto zaj duab xis.
Pure Copper's Vulnerability: Copper cia siab rau Cu₂O (cuprous oxide) txheej, uas, thaum tiv thaiv hauv cov dej nyob ntsiag to, yog mos thiab tuaj yeem ua rau cov neeg kho tshuab scoured los ntawm siab - nrawm, dej turbulent uas muaj xuab zeb lossis cua npuas. Qhov no ua rau muaj kev tawm tsam sai.
C70600 Mechanism: A Superior Passive Film
Cov npib tsib xee hloov cov oxide txheej hauv ob txoj hauv kev tseem ceeb:
Enhanced Cation Selectivity: Nickel txhawb kev tsim cov txheej txheem nyuaj, nyias, thiab ua raws cov txheej txheem feem ntau yog tsim los ntawm Cu₂O, tab sis ua kom nplua nuj nrog nickel oxide (NiO) ntawm cov hlau -oxide interface. Cov npib tsib xee - nplua nuj sub- txheej no muaj kev tiv thaiv zoo heev thiab ua haujlwm zoo tshaj plaws.
Kev hloov kho zaj duab xis thiab tus kheej- Kho: Qhov tseem ceeb tshaj, npib tsib xee ua kom cov yeeb yaj kiab muaj peev xwm ua rau tus kheej - kho. Thaum muaj kev puas tsuaj me me (piv txwv li, los ntawm cov xuab zeb particle), lub xub ntiag ntawm nickel catalyzes sai sai re-passivation ntawm qhov chaw raug. Cov yeeb yaj kiab hloov kho yuav luag tam sim ntawd, tiv thaiv cov kab mob hauv zos los ntawm kev nthuav tawm mus rau hauv lub qhov los yog zawj.
Qhov no muaj zog thiab nws tus kheej- zaj duab xis kho yog vim li cas C70600 flanges tuaj yeem tiv taus dej hiav txwv tshaj li ntawm 4 m / s, ua rau lawv zoo tagnrho rau cov twj tso kua mis, cov dej tua hluav taws, thiab lwm yam siab - cov ntawv thov ntws qhov twg tooj liab lossis Admiralty tooj dag yuav sai sai.
2. Nyob rau hauv ib tug complex seawater pipework los ua ke, flanges ua los ntawm C70600 yuav txuas mus rau cov kav dej ntawm tib alloy. Txawm li cas los xij, lawv kuj tseem tuaj yeem raug bolted rau li qub lossis cov cuab yeej ua los ntawm cov khoom sib txawv xws li Super Duplex Stainless Steel. Dab tsi yog qhov kev pheej hmoo ntawm galvanic corrosion nyob rau hauv qhov xwm txheej no, thiab ob qho kev tsim qauv tshwj xeeb raug coj los txo nws?
Qhov kev pheej hmoo tseem ceeb yog C70600 yuav ua raws li cov anode hauv ob peb galvanic, ua rau nws nrawm dua corrosion.
Galvanic Series: Hauv dej hiav txwv, qhov muaj peev xwm corrosion ntawm cov hlau yog qhov ruaj khov. Super Duplex Stainless Steel (piv txwv li, UNS S32750) yog qhov zoo heev (cathodic) vim nws cov yeeb yaj kiab tsis muaj zog. C70600, thaum corrosion-tiv taus, tsis tshua muaj suab npe (anodic). Thaum cov hluav taws xob txuas nrog hauv cov electrolyte (seawater), electrons ntws los ntawm C70600 (anode) mus rau Super Duplex (cathode), ua rau C70600 corrode.
Kev ntsuas txo qis:
Kev cais hluav taws xob (Dielectric Isolation): Qhov no yog txoj hauv kev zoo tshaj plaws. Insulating Gasket Cov Khoom Siv yog ntsia nruab nrab ntawm cov flanges. Cov khoom siv no suav nrog cov khoom siv uas tsis yog-cov khoom siv hluav taws xob (piv txwv li, PTFE, roj hmab-lined) thiab lub tes tsho thiab cov ntxhua khaub ncaws uas cais cov bolts ntawm ib lub flange, yog li rhuav tshem cov hluav taws xob txuas ntxiv ntawm lub voj voog. Qhov no tiv thaiv cov galvanic tam sim no los ntawm ntws.
Kev Tiv Thaiv Cathodic: Rau cov kab ke uas kev sib cais tsis zoo, tag nrho cov kab ke tuaj yeem tiv thaiv los ntawm kev ua kom nws lub cathode. Qhov no yog ua tiav los ntawm kev txuas nws mus rau ntau cov khoom siv anodic (ib qho kev txi anode), xws li zinc lossis aluminium anodes bolted rau cov kav dej. Kev tiv thaiv tam sim no los ntawm anode suppresses corrosion ntawm C70600, zoo ua rau nws cathodic txheeb ze rau anode.
Siv ob qho tib si kev sib cais thiab kev tiv thaiv txheej ntawm C70600 flange ntsej muag muab lub zog, ntau yam - txheej tiv thaiv galvanic corrosion.
3. Kev vam meej vuam ntawm C70600 flange mus rau C70600 yeeb nkab yog qhov tseem ceeb rau kev ncaj ncees. Dab tsi yog qhov tseem ceeb tshaj plaws ntawm cov hlau muab tub lim uas yuav tsum tau siv, thiab dab tsi tshwj xeeb microstructure nyob rau hauv cov hlau weld no txhawb kom tiv thaiv kev nyiam corrosion?
Cov yam ntxwv tseem ceeb tshaj plaws yog tias cov hlau muab tub lim yuav tsum dhau - alloyed nrog cov nitride muaj zog dua li tooj liab.
Qhov teeb meem: Weld Hlau Preferential Corrosion
Standard C70600 muab tub lim hlau (piv txwv li, ERCuNi) muaj ib qho zoo sib xws rau lub hauv paus hlau. Thaum lub sij hawm vuam, cov cua kub hnyav tuaj yeem ua rau cov npib tsib xee thiab hlau hauv cov hlau welding kom oxidize, ua rau nws depleted me ntsis hauv cov ntsiab lus tseem ceeb. Qhov tseem ceeb tshaj, yog tias cov hlau weld solidifies nrog cov qauv cored, cov cheeb tsam interdendritic tuaj yeem ua kom muaj tooj liab. Hauv dej hiav txwv, qhov micro- sib cais no tuaj yeem teeb tsa micro-galvanic hlwb, ua rau tooj liab- nplua nuj thaj chaw anodic thiab ua rau xaiv kev tawm tsam ntawm cov hlaws dai.
Kev daws: Niobium-Stabilized Filler Hlau
Tus qauv thiab raug muab tub lim hlau rau vuam C70600 yog ERCuNi (raws li AWS A5.7), uas feem ntau muaj qhov sib ntxiv ntawm 1.0-2.0% Niobium (Nb).
Niobium lub luag haujlwm: Niobium yog ib qho muaj zog nitride thiab carbide qub. Nws muaj kev sib raug zoo ntau dua rau nitrogen (ib qho impurity) dua li tooj liab lossis npib tsib xee. Los ntawm kev tsim cov niobium nitrides / carbides ruaj khov, nws tiv thaiv kev tsim cov tooj liab nitrides, uas yog corrosive.
Ua rau Microstructure: Lub niobium txhawb nqa qhov zoo dua, ntau homogeneous raws li - nrum microstructure hauv cov hlau vuam los ntawm kev txo kev sib cais. Qhov no tsim ib tug ntau electrochemically uniform nto, tshem tawm cov anodic txoj kev uas ua rau nyiam weld corrosion.
Kev siv cov niobium kom raug- hloov kho cov hlau tsis yog- sib tham tau los tsim ib qho kev sib txuas uas nws cov corrosion kuj sib xws ntawm C70600 puag hlau.
4. Rau qhov loj - txoj kab uas hla, siab - siab seawater system ntawm FPSO (Floating Production Storage and Offloading nkoj), C70600 flange yuav yog qhov loj thiab kim forging. Cov cuab yeej tseem ceeb dab tsi, dhau ntawm kev tiv thaiv corrosion, ua pov thawj tias nws siv ntau dua tus nqi qis dua, coated carbon steel flange nyob rau hauv no dynamic, hnyav- ib puag ncig rhiab heev?
Cov cuab yeej tseem ceeb ua kom pom tseeb yog qhov ua tau zoo dua rau Biofouling.
FPSO yog ib lub sijhawm ntev - cov cuab yeej cuab tam nyob rau hauv ib qho chaw rau xyoo, tsim ib qho chaw zoo meej rau cov kab mob hauv hiav txwv (barnacles, mussels, algae, tubeworms) kom colonize submerged structures -ib txoj kev hu ua biofouling.
Coated Carbon Steel Flange:
Lub txheej yog ib qho kev thaiv ib ntus. Thaum puas lawm (los ntawm kev cuam tshuam, puas, lossis UV degradation), cov hlau hauv qab yog raug.
Biofouling yuav nkag mus rau txheej txheej thiab cov hlau raug. Cov kab mob ' metabolic kev ua ub no thiab lub cev muaj nyob ntawm fouling tsim corrosive, oxygen-depleted microenvironment nyob rau hauv fouling, accelerating localized corrosion.
Qhov nce rub thiab hnyav los ntawm hnyav fouling yog qhov tseem ceeb rau kev ua haujlwm.
Yuav tsum tau nquag, kim, thiab muaj kev phom sij hauv - kev tshuaj xyuas dej thiab ntxuav.
C70600 Flange:
Copper ions maj mam leach los ntawm cov hlau nto hauv dej hiav txwv. Cov ions no yog cov tshuaj lom rau cov kab mob larval thiab spores ntawm feem ntau cov kab mob marine fouling.
Qhov no tsim ib cheeb tsam "anti-fouling" nyob ib ncig ntawm lub flange, tiv thaiv kev sib haum xeeb thiab kev loj hlob ntawm macro-fouling. Qhov saum npoo tej zaum yuav tsim ib qho sliming microfilm, tab sis nws yuav tsis txhawb nqa tawv fouling.
Qhov no muab kev saib xyuas -dawb, kev daws teeb meem tas mus li uas tshem tawm cov nqi, kev pheej hmoo, thiab lub sijhawm poob qis uas cuam tshuam nrog kev tswj fuling ntawm qhov tseem ceeb ntawm cov dej hiav txwv nkag los yog tso tawm.
Rau FPSO, qhov chaw qhuav - docking rau kev txij nkawm yog ib qho kev tshwm sim ntau - lab daus las, lub neej biofouling tsis kam ntawm C70600 muab kev lag luam thiab kev ua haujlwm tsis zoo.
5. Thaum lub sij hawm kev teeb tsa ntawm C70600 flange, kev xaiv gasket yog qhov tseem ceeb. Vim li cas ho tsis yog-absorbent, tsis yog-cov ntaub ntawv gasket zoo li cov khoom siv hluav taws xob zoo li PTFE lossis roj hmab- hom kab nyiam dua li compressed uas tsis yog-asbestos (CNAF) gaskets rau lub sijhawm ntev - kev pabcuam dej hiav txwv?
Kev xaiv gasket yog tsav los ntawm kev xav tau los tiv thaiv Crevice Corrosion thiab Galvanic Corrosion.
Crevice Corrosion Risk:
CNAF Gaskets: Cov no yog cellulose-raws li thiab nqus tau. Lawv tuaj yeem wick dej hiav txwv rau hauv lawv cov qauv fibrous, tsim kom muaj kev pheej hmoo, ntim cov electrolyte hauv flange crevice. Cov dej hiav txwv stagnation nyob rau hauv qhov crevice tuaj yeem ua deoxygenated thiab acidic, muaj peev xwm nyuaj rau cov yeeb yaj kiab tiv thaiv ntawm C70600 thiab pib crevice corrosion dhau sijhawm.
PTFE/Rubber-Ntaus Gaskets: Cov ntaub ntawv no tsis yog-absorbent thiab chemically inert. Lawv tsis khaws cov dej noo, zoo sealing lub ntsej muag flange thiab tiv thaiv kev tsim ntawm ib puag ncig, corrosive crevice.
Galvanic Corrosion Risk:
Yog hais tias lub flange txuas nrog cov khoom sib txawv (xws li, lub titanium valve lossis steel twj), siv cov khoom siv hluav taws xob yuav tsim kom muaj kev ncaj qha hluav taws xob, exacerbating galvanic corrosion raws li tau tham ua ntej.
PTFE thiab roj hmab yog cov khoom siv hluav taws xob zoo heev. Thaum siv los ua ib feem ntawm cov khoom siv insulating gasket, lawv rhuav tshem cov hluav taws xob hluav taws xob ntawm ob lub flanges, muab kev tiv thaiv tseem ceeb tiv thaiv galvanic nres.
Yog li ntawd, thaum CNAF gaskets haum rau ntau yam kev pab cuam, rau qhov tseem ceeb, mus tas li, thiab corrosive ib puag ncig ntawm lub seawater system, lub inert thiab tsis yog -conductive xwm ntawm PTFE los yog roj hmab-lined gaskets muab ib tug deb npaum li cas txhim khu kev qha thiab ruaj lub foob, kom lub sij hawm ntev - kev ncaj ncees ntawm C70600 flang.
