1. Qhov tshwj xeeb metallurgical muaj pes tsawg leeg ntawm Hastelloy B yog dab tsi, thiab qhov no txhais tau li cas rau nws cov kev ua tau zoo hauv cov corrosive heev, tsis yog - oxidizing ib puag ncig?
Hastelloy B (UNS N10001) yog npib tsib xee-molybdenum alloy tshwj xeeb tsim los rau kev pabcuam hauv kev txo qis thiab halogen acid ib puag ncig. Nws cov nominal muaj pes tsawg leeg yog ~ 68% Nickel thiab ~ 28% Molybdenum, nrog me me ntxiv ntawm hlau, chromium, thiab cobalt. Qhov no chemistry yog txhob txwm sib npaug kom ua tau zoo qhov twg ntau lwm cov hlau tsis ua haujlwm, tab sis nrog cov kev txwv tshwj xeeb thiab tseem ceeb.
Lub luag haujlwm ntawm Molybdenum: Cov ntsiab lus siab molybdenum tshwj xeeb yog cov alloy lub ntsiab lus. Molybdenum imparts zoo heev tiv thaiv corrosion los ntawm non-oxidizing acids. Qhov no suav nrog hydrochloric acid (HCl) ntawm txhua qhov siab thiab qhov kub thiab txias mus txog qhov kub thiab txias, nrog rau sulfuric, phosphoric, thiab acetic acids nyob rau hauv kev txo qis (tsis tshua muaj oxygen yaj lossis oxidizing ntsev).
Lub luag hauj lwm ntawm Nickel: Lub siab nickel matrix muab lub ntsej muag ruaj khov, lub ntsej muag -centered cubic (FCC) qauv uas yog inherently resistant rau chloride-induced stress corrosion cracking (SCC). Nws kuj muab kev zoo ductility thiab fabricability.
Kev txwv tseem ceeb - Chromium Cov ntsiab lus: Hastelloy B muaj chromium tsawg (feem ntau 1.0% max). Chromium yog qhov tseem ceeb rau kev tsim kev tiv thaiv oxide nplai hauv oxidizing ib puag ncig. Yog li ntawd, Hastelloy B muaj qhov tsis zoo rau oxidizing media, xws li nitric acid, ferric (Fe³⁺) lossis cupric (Cu²⁺) ntsev, thiab ib puag ncig uas muaj cov tshuaj dawb los yog oxygen. Kev raug rau cov no tuaj yeem ua rau muaj kev puas tsuaj sai sai.
Qhov no ua rau Hastelloy B tshwj xeeb alloy. Nws yog cov khoom ntawm kev xaiv rau kev tuav kub, concentrated hydrochloric acid, tab sis nws yuav tsum tau qhia meej meej tias cov txheej txheem kwj tseem txo qis thiab tsis muaj kab oxidants.
2. Rau cov ntawv thov kev lag luam tshwj xeeb dab tsi yog tuab -walled Hastelloy B yeeb nkab tshwj xeeb yuav tsum tau, thiab vim li cas phab ntsa thickness yog qhov tseem ceeb ntawm kev tsim qauv?
Hastelloy B tuab- cov yeeb nkab phab ntsa yog teev rau siab - siab, siab - cov txheej txheem kub hauv kev lag luam uas cov thawj corrodent yog ib qho tsis yog - oxidizing acid, tshwj xeeb tshaj yog hydrochloric acid.
Cov ntawv thov tseem ceeb suav nrog:
Hydrochloric Acid (HCl) Qhuav thiab tuav: Qhov no yog daim ntawv thov quintessential. Thick-walled B yeeb nkab yog siv rau reactor effluent kab, kua qaub hloov kab, thiab preheaters nyob rau hauv cov txheej txheem xws li cov Hargreaves los yog KCl ntsev -sulfuric acid txoj kev rau HCl synthesis, qhov kub thiab txias yog qhov tseem ceeb.
Organic Chemical Processing: Nyob rau hauv cov txheej txheem xws li alkylation, isomerization, thiab acetic acid ntau lawm, qhov twg aggressive txo acids thiab catalysts (xws li, AlCl₃, HF nyob rau hauv ib co systems) muaj nyob rau hauv siab kub thiab siab.
Pharmaceutical & Fine Chemical Synthesis: Rau qhov tseem ceeb ntawm cov reactor them kab, cov kab hloov mus, thiab cov kab distillation tuav halide-muaj cov intermediates nyob rau hauv kev txo qis heev.
Vim li cas Thick -Walled Design yog qhov tseem ceeb:
Kev Tiv Thaiv Kev Ruaj Ntseg: Cov txheej txheem cuam tshuam nrog cov kua qaub tsis hloov pauv zoo li HCl ntawm qhov kub thiab txias ua rau muaj qhov tseem ceeb hauv siab. Lub phab ntsa tuab muab qhov tsim nyog txhua yam lub zog rau kev nyab xeeb.
Corrosion Allowance: Thaum Hastelloy B muaj tus nqi qis dav dav hauv nws qhov kev pab cuam, qhov kev tiv thaiv corrosion yog tus qauv kev coj ua. Kev qhia tshwj xeeb phab ntsa tuab (xws li, teem caij 160, XXS, lossis kev cai hnyav-phab ntsa) ua kom cov yeeb nkab tuav nws txoj kev siab ncaj ntawm nws lub neej kev pab cuam tsim (feem ntau 20+ xyoo), txawm tias muaj tsawg heev, kwv yees hlau poob.
Kev tiv thaiv kev puas tsuaj: Thick - cov yeeb nkab phab ntsa tiv taus ntau dua rau kev cuam tshuam sab nraud, kev puas tsuaj, thiab tuav kev puas tsuaj thaum lub sij hawm nruab thiab tu.
3. Dab tsi yog qhov tseem ceeb ntawm kev tsim thiab kev sib tw vuam cuam tshuam nrog Hastelloy B yeeb nkab, thiab cov txheej txheem dab tsi yog qhov tseem ceeb los tswj nws txoj kev tiv thaiv corrosion?
Fabricating thiab vuam Hastelloy B nthuav tawm cov kev cov nyom sib txawv vim nws cov ntsiab lus molybdenum siab thiab tshwj xeeb rhiab heev.
Fabrication Challenges:
Ua hauj lwm Hardening: Cov alloy ua hauj lwm- hardens sai heev thaum lub sij hawm txias forming, dabtsi yog khoov, los yog machining. Qhov no yuav tsum tau muaj zog ntau dua, tuaj yeem ua rau cov cuab yeej hnav, thiab xav tau qhov nruab nrab annealing rau hnyav deformation los kho cov ductility.
Machining: Nws yog gummy thiab abrasive. Nthuav, zoo- cov cuab yeej carbide nrog siab - lub siab txias yog qhov yuav tsum tau ua. Kev qeeb qeeb thiab hnyav, sib npaug pub yog siv los txiav hauv qab ua haujlwm- tawv tawv.
Vuam – Qhov Kev Sib Tw Tseem Ceeb Tshaj Plaws: Vuam Hastelloy B xav tau kev saib xyuas hnyav los tiv thaiv kev tsim ntawm qis- melting-point, molybdenum- nplua nuj eutectic theem nyob rau hauv tshav kub- cuam tshuam cheeb tsam (HAZ). Cov theem no tuaj yeem ua rau weld centerline lossis HAZ tawg.
Cov txheej txheem vuam tseem ceeb:
Txheej Txheem: Gas Tungsten Arc Vuam (GTAW/TIG) tsuas yog cov txheej txheem pom zoo rau kev pabcuam tseem ceeb, muab kev tswj xyuas zoo tshaj plaws ntawm cov khoom siv hluav taws xob thiab vuam pas dej purity.
Filler Hlau: Yuav tsum siv Hastelloy B muab cov hlau sib xws (ERNiMo-7 lossis sib npaug). Kev siv cov muab tub lim tsis sib haum tuaj yeem tsim cov galvanic hlwb thiab hnyav hauv cheeb tsam corrosion.
Ultra-Cov Cuab Yeej Hluav Taws Xob: Qhov no yog qhov tseem ceeb. Siv qhov tsawg tshaj plaws ua tau amperage, ceev ceev mus txawv tebchaws, thiab tsis txhob weaving. Lub hom phiaj yog kom txo qis lub sij hawm cov hlau siv nyob rau hauv qhov kub thiab txias qhov twg cov theem detrimental tsim.
Interpass Temperature Control: Tswj qhov kub siab tshaj plaws ntawm kev sib tshuam, feem ntau qis li 200℃F (93 degree). Siv qhov kub thiab txias- qhia cov ntawv nplaum los saib xyuas.
Kev huv huv tsis huv: Txhua qhov chaw yuav tsum tsis muaj roj, roj, pleev xim, thiab cov cim cim. Cov kab mob xws li sulfur, phosphorus, lossis txhuas tuaj yeem ua rau kub tawg.
Tom qab- Weld Heat Treatment (PWHT): Ib qho kev daws teeb meem tag nrho (feem ntau yog 2150℃F / 1177℃) ua raws li qhov txias txias (dej quench) feem ntau teev rau tuab -walled welds. Qhov no re-dissols tej teeb meem theem nrab uas tej zaum yuav tau tsim thiab restores zoo corrosion kuj nyob rau hauv weldment.
4. Dab tsi yog cov hom kev txhim kho corrosion tseem ceeb rau Hastelloy B yeeb nkab yog siv tsis raug lossis raug tshem tawm ntawm -cov xwm txheej tshwj xeeb, thiab lawv tuaj yeem tiv thaiv li cas?
Hastelloy B qhov kev ua tau zoo yog nqaim. Deviation los ntawm nws lub hom phiaj txo ib puag ncig ua rau tsis ua hauj lwm sai.
Hom Kev Ua Haujlwm Tseem Ceeb:
Kev nrawm nrawm nrawm hauv Oxidizing cov xwm txheej: Feem ntau thiab tsis ua haujlwm hnyav. Kev taw qhia ntawm huab cua (oxygen), nitric acid, chlorine, los yog oxidizing hlau ions (Fe³⁺, Cu²⁺) yuav rhuav tshem cov molybdenum tiv thaiv- nplua nuj zaj duab xis, ua rau muaj kev puas tsuaj loj rau kev sib tsoo. Cov yeeb nkab tuab - cov yeeb nkab phab ntsa tuaj yeem raug txo kom xau hauv ib hnub lossis teev.
Localized Attack ntawm Weldments: Kev vuam tsis raug, raws li tau piav qhia saum toj no, tuaj yeem tsim cov cheeb tsam hauv HAZ lossis vuam hlau uas muaj thermally rhiab heev thiab ua anodic rau niam txiv hlau. Qhov no ua rau muaj riam phom loj heev -kab tawm los yog qhov tshwj xeeb weld corrosion, ua rau cov xau ntawm seams.
Stress Corrosion Cracking (SCC): Txawm hais tias muaj zog heev rau cov tshuaj chloride-SCC, Hastelloy B tuaj yeem raug rau SCC thaum muaj cov hydroxides (caustics) ntawm qhov kub siab hauv qab tensile stress.
Cov tswv yim tiv thaiv:
Rigorous Process Control: Siv kev soj ntsuam tas li kom ntseeg tau tias cov txheej txheem kwj tseem txo qis. Siv cov pa oxygen scavengers yog tias xav tau. Txhim kho tsis ua haujlwm- muaj kev nyab xeeb los tiv thaiv kev sib tsoo ntawm oxidants.
Kev Qhia Kom Zoo & Tsim: Tsis txhob siv Hastelloy B kiag li yog tias muaj kev tsis ntseeg txog oxidant muaj. Xav txog ntau yam alloy zoo li Hastelloy B-2 (qis-hlau, qis-silicon version nrog zoo thermal stability) los yog Hastelloy C-276 rau cov kwj uas muaj peev xwm oxidizing upsets.
Tsim nyog Vuam & PWHT: Siv cov txheej txheem vuam nruj nruj thiab yuav tsum tau PWHT rau txhua qhov siab- khaws cov welds ntawm tuab- cov yeeb nkab phab ntsa.
Kev soj ntsuam tsis tu ncua: Ua raws li qhov tsis yog{0}}kev kuaj kev puas tsuaj (NDT), suav nrog ultrasonic thickness (UT) ntsuas ntawm lub sijhawm tsis tu ncua los saib xyuas qhov kev xav tau ntawm corrosion.
5. Yuav ua li cas cov hlau niaj hnub Hastelloy B-2 (UNS N10665) txhim kho raws li tus qub Hastelloy B, thiab thaum twg B-2 yuav tsum tau teev nyob rau B rau tuab-walled piping systems?
Hastelloy B-2 tau tsim tshwj xeeb los daws qhov tsis muaj zog hlau loj ntawm tus qub Hastelloy B alloy.
Teeb meem nrog Hastelloy B: Nws muaj pes tsawg leeg suav nrog cov txiaj ntsig zoo ntawm cov hlau, chromium, thiab silicon. Thaum raug kub hnyiab ntawm 1200℃F - 1600℃F (650℃- 870 degree)-uas tuaj yeem tshwm sim thaum vuam, txo kev ntxhov siab, lossis hauv siab -kev pabcuam kub-cov ntsiab lus no txhawb nqa nag lossis daus ntawm intermetallic theem (feem ntau yog cov nplej ₄. Qhov no thermal rhiab heev txo corrosion kuj thiab ductility nyob rau hauv lub HAZ, ua rau cov welded los ua ke yog heev yooj yim mus ua hauj lwm.
B-2 Kev daws: Hastelloy B-2 yog ib qho qis- hlau, qis- silicon, thiab qis-carbon version. Los ntawm kev txo cov ntsiab lus no, nws ua tiav qhov tshwj xeeb thermal stability. Nws yog ntau resistant rau kev tsim ntawm detrimental theem nrab thaum lub sij hawm vuam thiab high-temperature raug.
Kev Taw Qhia Xaiv:
Qhia meej Hastelloy B-2 rau txhua qhov kev tsim kho tshiab thiab cov haujlwm tseem ceeb ntawm kev rov ua dua tshiab. Nws yog lub niaj hnub, superior successor rau yuav luag txhua daim ntawv thov uas yuav tsum tau Ni-Mo corrosion kuj. Nws txhim kho weldability thiab raws li -welded corrosion kuj txo qis fabrication kev pheej hmoo thiab kev saib xyuas mus sij hawm ntev.
Tus thawj Hastelloy B feem ntau suav tias yog siv tsis tau rau cov kav dej tshiab, siab -kev ncaj ncees. Kev siv nws yuav raug txwv rau kev saib xyuas cov nroj tsuag qub uas txuam nrog cov khoom uas twb muaj lawm, lossis hauv cov ntawv thov qhov kub thiab txiaslavkom nyob twj ywm tsawg heev thiab cov khoom tsis welded. Rau ib qho tuab -walled, welded siab piping, Hastelloy B-2 (los yog B-3, ib tug ntxiv optimized version) yog unequivocally raug kev xaiv.
