Thaum xaiv cov khoom siv hlau rau kev siv dej hiav txwv, cov kws tsim khoom thiab cov kws tshaj lij yuav tau ntsib cov lus nug classic:Koj yuav tsum xaiv li cas ntawm titanium thiab stainless hlau?
Cov lus teb tsis yog ncaj nraim.
Cov dej hiav txwv yog cov khoom siv electrolyte uas muaj cov tshuaj chloride ions, nrog cov tshuaj chloride concentration ntawm kwv yees li 19,000 ppm-ntau dua li cov dej tsis qab, qhov twg cov tshuaj chloride feem ntau qis dua. Cov dej hiav txwv tseem muaj cov pa oxygen yaj, tshem tawm cov khib nyiab, cov kab mob, thiab cov organic teeb meem. Ua ke, cov khoom no tuaj yeem ua rau pitting corrosion, crevice corrosion, thiab stress corrosion cracking (SCC), uamkev xaiv aterial rau cov khoom siv dej hiav txwv tseem ceeb tshwj xeeb.
Qhov cuam tshuam ntawm corrosion mus dhau qhov kev puas tsuaj saum npoo. Rau cov chaw tsim hluav taws xob hauv ntug dej hiav txwv thiab dej hiav txwv desalination systems, corrosion- ntsig txog kev saib xyuas thiab cov khoom siv downtime tuaj yeem cuam tshuam rau cov nqi khiav lag luam. Yog li ntawd, kev xaiv cov khoom yuav tsum tsis txhob ua raws li tus nqi pib yuav khoom xwb. Kev pabcuam lub neej, kev saib xyuas yuav tsum tau ua, thiab ntev - lub sijhawm ua haujlwm kev ntseeg siab kuj yuav tsum tau xav txog.
Titanium thiab stainless hlau yog ob qho tib si dav siv corrosion-cov ntaub ntawv engineering, tab sis lawv tsis tuaj yeem raug kho raws li ob pawg khoom ruaj khov. "Stainless steel" suav nrog ntau qib, xws li 304, 316L, duplex stainless hlau, thiab S31254 (254 SMO), thiab lawv cov kev ua haujlwm hauv dej hiav txwv tuaj yeem sib txawv. Titanium kuj yog tsev neeg ntawm cov ntaub ntawv, nrog rau cov qib sib txawv tsim los rau cov kev pabcuam sib txawv.
Kev nkag siab txog kev txhim kho corrosion ntawm ob tsev neeg cov khoom siv no tuaj yeem pab koj ntsuas lawv cov kev tiv thaiv corrosion, nqi, thiab kev cia siab rau lub neej hauv kev siv dej hiav txwv.
Vim li cas Seawater thiaj li Corrosive rau hlau?
Seawater yog ib puag ncig corrosive complex. Ntau yam tuaj yeem cuam tshuam rau kev ua haujlwm corrosion ntawm titanium thiab stainless hlau hauv marine thiab seawater systems.
Chloride concentration:
Cov dej hiav txwv muaj kwv yees li 19,000 ppm chloride. Cov tshuaj chloride ntau tuaj yeem ua rau muaj kev pheej hmoo ntawm pitting thiab crevice corrosion, tshwj xeeb tshaj yog rau cov hlau uas cia siab rau cov yeeb yaj kiab tsis zoo rau kev tiv thaiv corrosion.
Kub:
Kev kub siab dua feem ntau ua rau cov tshuaj electrochemical thiab cov txheej txheem corrosion. Raws li dej hiav txwv kub nce, tus cwj pwm corrosion ntawm cov khoom tuaj yeem hloov pauv loj.
Oxygen Muaj:
Cov pa oxygen dissolved tuaj yeem cuam tshuam rau kev ruaj ntseg thiab kev coj tus cwj pwm ntawm cov yeeb yaj kiab passive thiab tuaj yeem ua rau muaj qhov sib txawv ntawm cov khoom siv hluav taws xob hauv zos.
Seawater Flow Velocity:
Kev khiav nrawm dua tuaj yeem ua rau muaj kev yaig ntau dua -kev pheej hmoo corrosion, tshwj xeeb tshaj yog nyob ib ncig ntawm lub luj tshib, li qub, thiab lwm qhov chaw uas muaj kev cuam tshuam hauv zos.
Dej hiav txwv Stagnant:
Tsawg- qhov chaw ntws los yog nyob ruaj khov tuaj yeem tsim qhov sib txawv ntawm cov pa oxygen thiab cov tshuaj lom neeg hauv zos, ua rau muaj kev pheej hmoo ntawm pitting thiab crevice corrosion.
Crevices thiab Deposits:
Flanges, gaskets, fastener kev sib txuas, thiab tso nyiaj tuaj yeem tsim cov cheeb tsam corrosive. Cov cheeb tsam no yog qhov tseem ceeb tshwj xeeb tshaj yog thaum ntsuas cov hlau tsis muaj corrosion kuj hauv dej hiav txwv.
Marine Biofouling:
Cov yeeb yaj kiab microbial thiab cov khoom siv roj ntsha tuaj yeem ua rau muaj kev cuam tshuam hauv cheeb tsam hauv qee qhov xwm txheej.
Galvanic Corrosion:
Thaum cov hlau tsis sib xws tau ncaj qha lossis tsis ncaj qha rau hauv cov dej hiav txwv conductive, lawv qhov sib txawv ntawm electrochemical muaj peev xwm tsim tau ob peb galvanic thiab ua kom corrosion ntawm cov hlau ntau dua.
Vim li no, kev ntsuam xyuas cov khoom siv rau kev pabcuam dej hiav txwv yuav tsum muaj ntau dua li kev sib piv cov nominal corrosion kuj ntawm ob hlau.
Titanium vs Stainless hlau: Corrosion Resistance nyob rau hauv Seawater
Ib qho ntawm qhov sib txawv tseem ceeb tshaj plaws ntawm titanium thiab stainless hlau hauv dej hiav txwv yog tus cwj pwm ntawm lawv cov yeeb yaj kiab passive.
Titanium Passive Zaj duab xis
Titanium's corrosion resistance los ntawm nyias titanium dioxide (TiO₂) passive zaj duab xis uas ib txwm ua rau nws nto. Txawm hais tias zaj duab xis tsuas yog ob peb nanometers tuab, nws yog qhov ruaj khov thiab muaj tshuaj tiv thaiv.
Thaum puas lawm, zaj duab xis passive tuaj yeem hloov kho sai sai thaum muaj dej thiab oxygen, txuas ntxiv tiv thaiv cov hlau hauv qab.
Qhov kev coj cwj pwm ruaj khov no yog ib qho laj thawj tseem ceebtitanium muaj zoo heev corrosion kuj nyob rau hauv ntuj seawater.
Stainless hlau Passive Zaj duab xis
Stainless hlau cia siab rau chromium -nplua nuj oxide passive zaj duab xis los tiv thaiv corrosion. Thaum cov zaj duab xis passive tseem nyob ruaj khov, stainless hlau tuaj yeem muab kev tiv thaiv corrosion zoo heev.
Txawm li cas los xij, hauv cov tshuaj chloride- muaj cov dej hiav txwv, chloride ions tuaj yeem txhawb kev ua haujlwm hauv cheeb tsam ntawm lub xeev passive, tshwj xeeb tshaj yog nyob rau hauv crevices thiab hauv qab deposits. Qhov no ua rau muaj kev pheej hmoo ntawm pitting thiab crevice corrosion.
Cov seawater kev ua tau zoo ntawm cov hlau tsis muaj steel yog li ntawd nyob ntawm cov qib tshwj xeeb . 316L thiab siab dua- cov qib alloy xws li S31254 (254 SMO) tuaj yeem muaj qhov sib txawv corrosion kuj.
Los ntawm kev sib piv, titanium tuav cov zaj duab xis uas ruaj khov heev thiab muaj kev tiv thaiv zoo heev rau pitting, crevice corrosion, thiab kev nyuaj siab corrosion cracking (SCC) hauv dej hiav txwv ntuj thiab ntau qhov chaw siab -chloride.
Qhov no ua rau titanium tshwj xeeb tshaj yog txaus nyiam rau lub sijhawm ntev - kev pabcuam dej hiav txwv thiab cov ntawv thov uas kev ntseeg siab yog qhov tseem ceeb.
Stainless hlau ua haujlwm li cas hauv Seawater?
Stainless hlau yog "tsev neeg," tsis yog ib qho khoom siv. Cov qib stainless hlau sib txawv tuaj yeem muaj ntau qib sib txawv ntawm corrosion kuj nyob rau hauv marine thiab seawater ib puag ncig.
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Stainless hlau hom |
Hom Qib |
Kwv yees li. PREN |
Seawater Suitability |
|
General -lub hom phiaj stainless hlau |
304 |
~18 |
Haum rau cov dej tshiab thiab qhov chaw me me; feem ntau tsis pom zoo rau ntev -lub sij hawm raug dej hiav txwv ncaj qha |
|
Marine- qib stainless hlau |
316 / 316L |
~24–26 |
Muaj 2-3% molybdenum thiab siv dav hauv kev siv dej hiav txwv; haum rau qee qhov kev tswj xyuas los yog cov dej hiav txwv me me, tab sis qhov chaw corrosion tseem muaj kev txhawj xeeb |
|
Duplex stainless hlau |
2205 (S32205) |
~33–35 |
Kev ua tau zoo dua li 316L hauv ntau qhov chaw chloride thiab tuaj yeem siv rau hauv cov dej hiav txwv tsim nyog |
|
Super austenitic stainless hlau |
254 PAB (S31254) |
~42–45 |
Zoo heev localized corrosion kuj; tuaj yeem txiav txim siab rau qhov xav tau chloride ib puag ncig, tab sis crevices thiab stagnant seawater tseem tuaj yeem tsim kev pheej hmoo corrosion |
|
Super duplex stainless hlau |
2507 (S32750) |
~40–43 |
Combines siab zog nrog siab tsis kam mus rau localized corrosion |
PREN yog dab tsi?
PREN (Pitting Resistance Equivalent Number) feem ntau yog siv los ua ib qho piv txwv ntawm kev tiv thaiv rau thaj tsam pitting corrosion:
PREN=%Cr + 3.3 × %Mo + 16 × %N
Feem ntau, PREN siab dua qhia tias muaj kev tiv thaiv ntau dua rau thaj tsam pitting corrosion.
Txawm li cas los xij, PREN yuav tsum tau siv los ua qhov ntsuas qhov sib piv es tsis yog ib qho kev tsim nyog rau kev pabcuam dej hiav txwv. Kev ua tau zoo tiag tiag kuj nyob ntawm qhov kub, chloride concentration, oxygen muaj, qhov chaw nyob, ntws, crevice geometry, vuam, thiab lwm yam tsim.
Lub ntsiab lus tseem ceeb yog tias 316L tsuas yog ib tus tswv cuab ntawm tsev neeg stainless hlau. Nws yog ib qho ntawm cov qib stainless hlau feem ntau suav hais tias yog rau kev siv dej hiav txwv, tab sis nws tsis sawv cev rau kev ua tau zoo ntawm txhua yam stainless hlau.
Yog tias koj ua haujlwm nyob rau hauv ntug dej hiav txwv lossis dej ntsev, tsis txhob xaiv cov qib stainless hlau raws li PREN ib leeg. Cov qib siab dua -PREN qib xws li super duplex stainless hlau tuaj yeem muab kev tiv thaiv zoo dua rau hauv cheeb tsam corrosion, tab sis cov kev pabcuam tiag tiag thiab kev tsim qauv tseem yuav tsum tau soj ntsuam.
Txheej txheem cej luam ntawm Titanium kev ua tau zoo hauv Seawater
Tsis zoo li feem ntau cov hlau tsis muaj steel, titanium tuav lub xeev ruaj khov heev hauv dej hiav txwv; yog li ntawd, nws qhov ntev - lub sij hawm tsis zoo corrosion feem ntau yog tsawg heev. Ntau qib titanium tau raug alloyed kom haum rau qhov tshwj xeeb corrosive ib puag ncig thiab tsim cov cai.
Qib 2 Titanium(Kev lag luam Pure Titanium): Kev xaiv thawj zaug rau Standard Seawater Environments
- Seawater corrosion tus nqi: <0.0001-0.0005 mm / xyoo
- Critical crevice corrosion kub: 82 degree
- Tsis muaj pitting lossis crevice corrosion pom nyob rau hauv ntuj seawater
- Ceev: 4.51 g / cm³ (kwv yees li 56% ntawm stainless hlau)
- Haum rau: seawater piping, heat exchangers, condensers, thiab desalination khoom
Qib 7 thiab 12: Kev xaiv rau ntau qhov kev thov ua haujlwm
Thaum cov txheej txheem dej hiav txwv cuam tshuam nrog qhov kub siab dua, crevices, deposits, lossis complex chemical ib puag ncig, titanium qib nrog txhim kho corrosion kuj yuav raug txiav txim siab raws li cov kev ua haujlwm tshwj xeeb.
- Qib 7: Kev lag luam ntshiab titanium nrog me me ntxiv ntawm palladium; Feem ntau yog siv los txhim kho corrosion kuj nyob rau hauv tej yam aggressive corrosive xov xwm.
- Qib 12: Corrosion resistance nyob rau hauv ib puag ncig tshwj xeeb yog txhim kho los ntawm kev sib ntxiv ntawm molybdenum thiab npib tsib xee, muab qhov zoo nyob rau hauv siab - kub lossis nyuaj corrosive tej yam kev mob.
Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias Qib 7 thiab 12 tsis yog "kev hloov kho tshiab" ntawm Qib 2 rau kev siv dej hiav txwv dav dav. Kev xaiv cov ntaub ntawv tseem yuav tsum tau ua raws li qhov ntsuas kub, dej hiav txwv ntws nrawm, qhov sib txawv ntawm qhov sib txawv, cov kab mob, thiab cov tshuaj muaj pes tsawg leeg.
Qhov no qhia txog qhov sib txawv tseem ceeb thaum muab piv rau titanium nrog cov hlau tsis muaj steel: Qib 2 nws tus kheej muab cov npoo zoo ntawm kev tiv thaiv corrosion nyob rau hauv ntau qhov chaw dej hiav txwv, whereas stainless hlau xaiv yuav tsum xaiv ntawm cov qib tshwj xeeb xws li 316L, 2205, 254 SMO, thiab 2507.
Titanium vs Stainless hlau rau Seawater Daim ntaub ntawv: Cov ntaub ntawv xaiv
Cov lus hauv qab no muab qhov pib dav dav rau kev sib piv titanium thiab stainless hlau hauv cov dej hiav txwv sib txawv.
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Cov xwm txheej ua haujlwm |
Khoom siv pom zoo |
Qhov Zoo Tshaj Plaws |
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Kub<15°C, clean flowing seawater, no significant crevices, service life <10 years |
316L |
Tus nqi pib qis dua thiab muaj peev xwm ua tau raws li qhov tsim nyog |
|
Kub 15-50 degree, huv seawater, txwv crevices |
2205/254 SMO |
Qhov zoo tshaj plaws hauv cheeb tsam corrosion kuj tshaj 316L, nrog rau cov nqi pib qis dua titanium |
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Ntev -lub sij hawm raug dej hiav txwv ncaj qha, nrog kev ntseeg siab thiab kev ua haujlwm ntev |
Qib 2 titanium |
Kev tiv thaiv corrosion zoo heev thiab tsis tshua muaj corrosion- ntsig txog kev saib xyuas |
|
Kub kub, complex crevices, los yog ntau aggressive corrosion tej yam kev mob |
Qib 7 / Qib 12 lossis lwm yam siab dua - cov ntaub ntawv alloy |
Muab kev tiv thaiv corrosion ntxiv thaum xav tau |
Puas yog Titanium zoo dua stainless hlau rau Seawater?
Thaum seawater corrosion kuj thiab ntev -lub sij hawm kev cia siab yog tseem ceeb tshaj li cov khoom pib nqi,Qib 2 titanium tuaj yeem yog lwm txoj hauv kev txaus nyiam.
Stainless hlau yog ntau tsev neeg ntawm cov ntaub ntawv -los ntawm 304 thiab 316L mus rau duplex thiab super austenitic stainless hlau- nrog rau ntau yam corrosion kuj.
316L yog ib qho ntawm cov ntsiab lus pib tshaj plaws rau kev siv dej hiav txwv, tab sis nws qhov tsim nyog rau cov dej hiav txwv yog nyob ntawm qhov kub thiab txias, dej ntws, crevice geometry, thiab lwm yam. Txawm tias siab - qib kev ua tau zoo xws li 254 SMO tuaj yeem ntsib kev pheej hmoo corrosion hauv cov crevices thiab dej hiav txwv stagnation.
Titanium muaj qhov tshwj xeeb siab corrosion kuj nyob rau hauv seawater piv nrog ntau cov pa engineering hlau. Txawm hais tias nws cov khoom siv thawj zaug yog siab dua li ntawm 316L, nws cov nqi qis heev, lub neej ua haujlwm ntev, thiab tsis tshua muaj corrosion- ntsig txog kev saib xyuas yuav ua rau nws muaj txiaj ntsig zoo thaum tag nrho cov nqi ntawm lub neej raug txiav txim siab.
Zecheng Hlau tshwj xeeb hauv kev tsim cov khoom titanium. Yog tias koj tsis paub meej tias qib twg titanium lossis cov khoom tsim nyog rau koj daim ntawv thov, thov hu rau peb pab neeg ntawminfo@zctitanium.com.