1. Lub hauv paus metallurgy ntawm peb qib no txawv heev. Dab tsi yog qhov sib txawv ntawm cov khoom lag luam ntshiab (CP) qib zoo li Qib 2, alpha-beta alloy zoo li Qib 5, thiab qib "palladium- txhim kho" qib zoo li Qib 7, thiab qhov no qhia ncaj qha rau lawv daim ntawv thov thawj zaug li cas?
Qhov tseem ceeb sib txawv yog nyob rau hauv lawv cov tshuaj muaj pes tsawg leeg thiab ua rau microstructure, uas dictates lawv txhua yam thiab corrosion zog.
Qib 2 (CP Titanium): Qhov no yog ib qho -theem (alpha) alloy. Nws cov microstructure muaj tag nrho ntawm hexagonal ze -packed (HCP) siv lead ua qauv. Nws yog qhov tseem ceeb unalloyed titanium (99.2% min) ntxiv dag zog los ntawm interstitial hais xws li oxygen. Qhov no muab nws zoo heev ductility, formability, thiab weldability tab sis nruab nrab lub zog.
Daim ntawv thov tseem ceeb: Lub workhorse rau corrosion-cov cuab yeej tiv taus hauv cov khoom siv tsis yog- cov ntaub ntawv siv lub zog tseem ceeb: cov txheej txheem tshuaj piping, kub exchangers, thiab marine Cheebtsam uas nws zoo heev tshuav nyiaj li cas ntawm cov khoom thiab cov nqi yog zoo tagnrho.
Qib 5 (Ti-6Al-4V): Qhov no yog alpha-beta alloy. Nws cov microstructure yog sib xyaw ntawm HCP alpha theem thiab lub cev-centered cubic (BCC) beta theem, enabled los ntawm ntxiv ntawm 6% Aluminium (alpha stabilizer) thiab 4% Vanadium (beta stabilizer). Qhov no ob-theem qauv, uas tuaj yeem ntxiv dag zog los ntawm kev kho cua sov (kev laus), ua rau nws muaj zog heev.
Daim Ntawv Thov Tseem Ceeb: Cov khoom siv dav hlau dav dav dav dav dav dav dav dav thiab siab - cov khoom siv kho mob muaj zog (hauv qib ELI). Siv rau cov khoom siv dav hlau, cov khoom siv dav hlau dav hlau, thiab cov khoom siv phais mob tseem ceeb uas lub zog - rau - qhov hnyav piv yog qhov tseem ceeb.
Qib 7 (Ti-0.15Pd): Qhov no yog "palladium- txhim kho" qhov txawv ntawm Qib 2. Nws muaj tib theem alpha microstructure thiab txhua yam khoom raws li Qib 2 tab sis nrog me me, tseem ceeb ntxiv ntawm 0.12-0.25% Palladium.
Daim Ntawv Thov Tseem Ceeb: Ib tus kws tshaj lij rau kev ua tshuaj nyob rau hauv qhov hnyav tshaj plaws txo cov kua qaub ib puag ncig uas Qib 2 yuav ua tsis tiav, xws li kub, tsis yog -oxidizing hydrochloric thiab sulfuric acid.
2. Rau ib qho chaw ua tshuaj piping system, tag nrho peb qib yuav raug txiav txim siab. Hauv ib qho me me oxidizing lossis chloride- ib puag ncig nplua nuj xws li dej hiav txwv sov, qhov ua tau zoo ntawm Qib 2 thiab 7 zoo ib yam. Raws li qhov tshwj xeeb, cov tshuaj lom neeg mob hnyav puas yog Qib 7 yog qhov kev xaiv tsis meej, thiab dab tsi yog lub tshuab electrochemical tom qab nws qhov zoo tshaj?
Qib 7 dhau los ua qhov kev xaiv tsis sib xws hauv qhov tsis yog -oxidizing, txo cov kua qaub ib puag ncig, tshwj xeeb yog kub, dilute hydrochloric acid (HCl) thiab sulfuric acid (H₂SO₄).
Qhov teeb meem rau Qib 2: Hauv kev txo cov kua qaub, cov tshuaj tiv thaiv TiO₂ passive zaj duab xis ntawm titanium tsis ruaj khov thiab tawg. Cov hlau nkag mus rau hauv lub xeev "active", ua rau siab, zoo corrosion kuj. Qib 2 muaj me ntsis kom tsis muaj kev tawm tsam hauv qhov xwm txheej no.
Qib 7 Kev daws: Cathodic Modification (Anodic Depolarization)
Qhov me me ntawm Palladium, cov hlau zoo, yog tus yuam sij. Nws precipitates zoo, discrete hais thoob plaws hauv titanium matrix.
Hauv kev txo cov kua qaub, titanium puag hlau pib corrode (ua raws li anode).
Cov palladium hais, ua cathodic heev, ua raws li qhov chaw zoo rau txo cov hydrogen ions.
Qhov kev mob siab rau hauv zos cathodic no ua rau lub zog hluav taws xob muaj peev xwm ntawm tag nrho titanium nto nyob rau hauv qhov zoo (zoo) kev coj.
Qhov kev hloov pauv no muaj peev xwm txaus rau polarize qhov chaw mus rau thaj chaw ruaj khov "passive" qhov chaw tiv thaiv TiO₂ zaj duab xis tuaj yeem tsim thiab khaws cia.
Hauv cov ntsiab lus, cov palladium particles ua raws li tsim- nyob rau hauv cov catalysts uas yuam cov titanium passivate nws tus kheej, txo tus nqi corrosion los ntawm kev txiav txim siab piv rau Qib 2. Rau cov txheej txheem kwj uas yog, los yog yuav ua tau, txo, Qib 7 muab ib qho tseem ceeb kev nyab xeeb margin.
3. Lub chaw tsim khoom yuav tsum tsim kom muaj ntau qhov siab - lub zog fasteners los ntawm titanium bar. Vim li cas Qib 5 yuav raug xaiv dhau Qib 2, thiab cov txheej txheem thermal ua haujlwm tshwj xeeb yog siv rau qhov bartom qabcov fasteners yog machined kom ua tiav lawv lub zog siab?
Qib 5 yog xaiv rau ib qho laj thawj: nws lub peev xwm los nag lossis daus hardening, uas tso cai rau nws ua kom muaj zog tensile tshaj 1000 MPa (145 ksi), deb tshaj qhov muaj peev xwm ntawm Qib 2 (~ 345 MPa).
Txheej Txheem: Kev Kho Mob thiab Kev Laus (STA)
Cov fasteners tsis machined los ntawm pre{0}}hardened bar. Hloov chaw, ib qho tshwj xeeb thermal ua raws li nram no:
Machining: Cov fasteners yog machined los ntawm Qib 5 bar muab nyob rau hauv lub annealed (mos) mob. Lub xeev no yog cov ductile thiab yooj yim rau tshuab kom meej qhov ntev, nrog rau cov xov nyuaj.
Kev Kho Kev Kho Mob: Cov machined fasteners yog rhuab mus rau qhov kub siab (~ 955-970℃/ 1750-1800℃F) kom yaj cov alloying ntsiab rau hauv ib homogeneous khoom tov, ces sai quenched. Lawv tam sim no nyob rau hauv ib tug kuj mos mos, metastable xeev.
Kev laus (Precipitation Hardening): Qhov no yog qhov tseem ceeb, tsis yog - kauj ruam sib thamtom qabtshuab. Cov fasteners yog reheated rau qhov kub thiab txias (~ 480-595℃/ 900-1100℃F) thiab tuav rau ob peb teev. Qhov no ua rau cov nag lossis daus ntawm nplua, dispersed hais ntawm theem nrab alpha theem hauv microstructure. Cov particles xauv qhov txav txav txav, ua kom cov txiaj ntsig thiab lub zog tensile mus rau lawv qhov kawg, kev ua haujlwm siab.
Kev sim tshuab threads rau hauv lub hnub nyoog tag nrho -qib qib 5 bar yuav nyuaj heev thiab yuav rhuav tshem cov cuab yeej txiav. Cov txheej txheem "machine soft, then age{3}}harden" process is fundamental to manufacturing complex, high-strength components.
4. Thaum vuam cov qauv siv Qib 2, Qib 5, thiab Qib 7, qhov kev pheej hmoo ntawm embrittlement yog ib qho kev txhawj xeeb thoob ntiaj teb, tab sis lub hauv paus ua rau txawv. Dab tsi yog lub hauv paus embrittlement mechanism rau Qib 2/7 piv rau Qib 5 thaum lub sij hawm vuam, thiab dab tsi yog qhov tseem ceeb tshaj plaws kev tswj hwm rau txhua tus los tiv thaiv nws?
Thaum qhov kev cuam tshuam sib txawv, lub hauv paus embrittlement mechanism rau tag nrho cov titanium alloys thaum vuam yog Interstitial Contamination los ntawm atmospheric gases.
Qib 2 & 7: Qhov kev pheej hmoo tseem ceeb yog kis los ntawm Oxygen thiab Nitrogen. Cov ntsiab lus no dissolve interstitially nyob rau hauv HCP lattice, ua rau ib tug heev nce nyob rau hauv hardness thiab ib tug loj heev poob ntawm ductility thiab toughness nyob rau hauv lub weld thiab tshav kub-Tshwj xeeb cheeb tsam (HAZ).
Qib 5: Nws muaj kev cuam tshuam rau cov pa oxygen thiab nitrogen khaws ib yam nkaus, tab sis nws ntsib qhov kev pheej hmoo ntxiv, tshwj xeeb: kev tsim cov theem nkig hu ua "Alpha Case." Thaum kub vuam kub, titanium reacts nrog oxygen los ua ib qho nyuaj, nkig txheej txheej ntawm oxygen -stabilized alpha theem. Cov txheej no tuaj yeem yog qhov chaw pib rau cov kab nrib pleb.
Ib qho Kev Tswj Xyuas Txheej Txheem Tseem Ceeb Tshaj Plaws: Ultra-High-Purity Inert Gas Shielding.
Qhov no tsis yog - sib tham tau thiab nruj dua li cov hlau tsis muaj steel. Cov txheej txheem yuav tsum muaj xws li:
Primary Shielding: High-purity argon (>99.995%) los ntawm vuam teeb.
Trailing Shield: Ib qho txuas txuas ntxiv uas txuas ntxiv rau daim pam kub, khov kho cov hlaws hlaws thiab HAZ nrog argon kom txog thaum nws txias qis dua ~ 400℃(750℃F).
Back Purging: Rau ib qho kev sib koom ua ke, lub hauv paus sabyuav tsumtiv thaiv nrog qhov sib npaug ntawm qhov chaw ntshiab argon kom tiv thaiv oxidation ntawm backside weld.
Kev vam meej titanium weld ntawm ib qho ntawm cov qib no yuav ci ntsa iab, silvery, thiab discoloration -dawb. Txhua lub straw, xiav, grey, lossis xim dawb qhia tias muaj kab mob thiab embrittlement.
5. Nyob rau hauv lub neej- voj voog kev soj ntsuam tus nqi rau cov dej hiav txwv sab nrauv, muab piv rau Qib 2 titanium bar rau 316L stainless hlau bar, tus nqi pib ntawm titanium yog siab dua. Peb qhov tseem ceeb ntev npaum li cas -lub sij hawm ua tau zoo ua tau zoo rau kev xaiv qib 2 titanium, ua rau nws xaiv kev lag luam ntau dua rau lub neej ntawm lub platform?
Qhov kev ncaj ncees rau Qib 2 titanium nyob rau hauv nws Cov Nqi Tag Nrho Cov Tswv Cuab (TCO), uas tau tsav los ntawm kev ntseeg siab tsis sib xws thiab xoom txij nkawm.
Kev tiv thaiv rau chloride-Induced Corrosion: Qhov no yog qhov tseem ceeb tshaj plaws.
316L Stainless Hlau: Nws muaj qhov cuam tshuam rau thaj chaw pitting thiab crevice corrosion nyob rau hauv sov, stagnant seawater. Qhov tseem ceeb tshaj, nws yog qhov yooj yim rau Chloride Stress Corrosion Cracking (Cl-SCC), nkig, kev puas tsuaj loj.
Qib 2 Titanium: Nws muaj kev tiv thaiv zoo rau ob qho tib si pitting thiab Cl-SCC hauv dej hiav txwv, tsis hais qhov kub thiab txias los yog chloride concentration. Qhov no tshem tawm qhov tsis ua haujlwm tseem ceeb rau cov khoom siv sab nrauv.
Erosion-Kev tiv thaiv corrosion: Seawater, tshwj xeeb tshaj yog nrog cov xuab zeb, yog abrasive.
316L: tuaj yeem raug kev puas tsuaj los ntawm kev yaig- corrosion, qhov twg cov yeeb yaj kiab tiv thaiv raug scoured thiab corrosion nrawm.
Qib 2: Nws tenacious, nws tus kheej- kho TiO₂ oxide zaj duab xis muab kev tiv thaiv zoo rau siab -ceev, abrasive seawater, ua rau nws zoo tagnrho rau lub twj tso kua mis impellers, li qub, thiab cov kav dej.
Kev tshem tawm ntawm kev tu thiab tsis tau npaj tseg:
Ib qho 316L tivthaiv yuav xav tau kev tshuaj xyuas, hloov, lossis kev tiv thaiv cathodic, ua rau cov nqi kho mob sab nrauv thiab kev tsim khoom raug kaw.
Qib 2 titanium tivthaiv, los ntawm qhov sib piv, feem ntau yog "haum{1}}thiab-tsis nco qab" kev daws teeb meem. Nws lub neej kev pabcuam tuaj yeem phim 20-30 xyoo lub neej ntawm lub platform nws tus kheej tsis muaj kev saib xyuas.
Tus nqi pib siab dua ntawm Qib 2 titanium bar yog kev pov hwm txoj cai tiv thaiv tus nqi qis tshaj ntawm kev ua tsis tiav, kev saib xyuas, thiab kev tsim khoom ploj hauv qhov chaw tsis tuaj yeem nkag mus rau sab nraud.
