1. UNS N10665 yog teev rau ib puag ncig ntawm kub, concentrated hydrochloric acid (HCl). Dab tsi tshwj xeeb cov cuab yeej ua rau nws tshwj xeeb tsim nyog rau cov kev pabcuam no, thiab dab tsi yog qhov kev puas tsuaj, tsis yog - kev txwv tsis pub sib tham uas tswj hwm nws tag nrho cov ntawv thov kev xav?
UNS N10665 (B-2) muaj ib qho lus, lub zog tsis sib xws uas tseem yog lub hauv paus ntawm nws qhov muaj qhov tsis zoo.
Kev tsim nyog tshwj xeeb: Tsis muaj qhov sib piv hauv cov ntshiab txo cov kua qaub.
Cov khoom xyaw: ~ 28% Molybdenum, ~ 1% Chromium, sib npaug Nickel.
Mechanism: Cov ntsiab lus molybdenum siab heev muab kev tiv thaiv zoo rau tsis yog -oxidizing, txo cov kua qaub xws li hydrochloric (HCl), sulfuric (H₂SO₄ nyob rau hauv qhov txo qis), thiab phosphoric (H₃PO₄). Nyob rau hauv tag nrho tsis muaj oxidizing tus neeg sawv cev, nws tsim ib tug ruaj khov, tiv thaiv nto zaj duab xis.
Kev puas tsuaj loj, Tsis yog -Ngotiable Limitation: Zero Tolerance for Oxidizing Conditions.
Tib cov ntsiab lus tsis tshua muaj chromium uas tso cai rau nws kom ua tau zoo hauv kev txo cov kua qaub ua rau nws lub peev xwm ua kom passivate. Kev taw qhia txog cov kab mob (ppm qib) ntawm oxidizing hom ua rau tus nqi corrosion nce los ntawm kev txiav txim ntawm qhov loj, ua rau tsis ua hauj lwm sai.
Oxidizing Contaminants: Ferric ions (Fe³⁺), Cupric ions (Cu²⁺), Dissolved oxygen (air), Nitric acid, Dawb chlorine, Hydrogen peroxide.
Daim ntawv thov Philosophy: B-2 tsuas yog siv tau rau hauv kev tswj hwm nruj, qhov chaw ntshiab txo qis. Nws siv txoj cai tsis suav nrog oxidizers los ntawm cov txheej txheem tsim, khoom noj khoom haus, cov txheej txheem ntxuav, thiab inerting kev coj ua. Ib qho lapse tuaj yeem rhuav tshem lub cuab tam.
2. Welding UNS N10665 phaj yog suav tias yog ib qho kev pheej hmoo siab ntawm kev tsim khoom. Dab tsi yog qhov tshwj xeeb metallurgical tshwm sim uas tshwm sim hauv tshav kub- thaj chaw cuam tshuam (HAZ), thiab dab tsi yog qhov kev lees paub nkaus xwb -weld kho cua sov los sim txo nws?
Vuam B-2 yog nws lub pob taws Achilles, vim nws qhov rhiab heev rau cov nag lossis daus ntawm intermetallic.
Metallurgical Phenomenon: μ-Phase thiab P-Phase Precipitation.
Thaum lub HAZ yog cua sov rau hauv thaj tsam ntawm 1200℃F txog 1600℃F (650℃txog 870 degree) thaum lub sij hawm vuam, brittle, molybdenum- nplua nuj intermetallic theem (μ-theem thiab P-theem) sai sai precipitate ntawm grain ciam teb.
Qhov tshwm sim:
Severe Embrittlement: HAZ ua nkig thiab ua rau tawg.
Poob ntawm Corrosion Resistance: Cov theem no yog anodic rau lub matrix, ua rau HAZ muaj kev cuam tshuam rau "riam-kab nres"-ib txoj kab nqaim ntawm qhov hnyav intergranular corrosion nyob ib sab ntawm lub vuam.
Tsuas Muaj Kev Txom Nyem: Tag Nrho Cov Tshuaj Anneal & Rapid Quench.
Txheej txheem: Tag nrho cov welded los ua ke yuav tsum tau rhuab mus rau 2050℃F - 2100℃F (1120℃- 1150 degree), tuav, ua raws li los ntawm ib tug tam sim ntawd quench dej.
Lub hom phiaj: Dissolves cov theem teeb meem.
Cov ntsiab lus tseem ceeb: Lub quench ceev yog yuav tsum tau. Kev ua kom txias qeeb (txawm tias cua txias) tso cai rau cov khoom siv rov qab los ntawm qhov kub thiab txias, ua rau rov- nag lossis daus.
Kev Muaj Peev Xwm Muaj Peev Xwm: Qhov no yog qhov tseem ceeb, raug nqi ntau rau kev tsim cov phaj loj, feem ntau txwv lawv mus kav -tsim cov nkoj thiab ua kev kho qhov chaw yuav luag tsis yooj yim sua. Qhov teeb meem ntawm kev tsim khoom no yog thawj tus tsav tsheb rau kev tsim kho kom ruaj khov Hastelloy B-3 (UNS N10675).
3. Nyob rau hauv cov ntsiab lus ntawm kev lag luam niaj hnub no, dab tsi yog qhov laj thawj tsim nyog rau kev yuav cov phaj tshiab UNS N10665, thiab qhov kev tiv thaiv zoo li cas yuav tsum muaj rau qhov kev yuav khoom zoo li no?
Kev yuav cov phaj B-2 tshiab niaj hnub no yog qhov tsis txaus ntseeg uas yuav tsum muaj kev pom zoo tshwj xeeb thiab kev tiv thaiv nruj.
Muaj peev xwm Justifications (tsis tshua muaj nqaim):
Hloov tshiab-hauv-Kind for Legacy Systems: Thaum kho B-2 lub nkoj uas twb muaj lawm hauv lub cev nrog lub sijhawm ntev, cov ntaub ntawv keeb kwm ntawm kev ua haujlwm tsis muaj oxidizer, thiab qhov twg hloov mus rau B-3 qhia txog kev txhawj xeeb txog kev tsis paub galvanic lossis kev sib raug zoo.
Heev heev, Cov Ntaub Ntawv Purity Requirement: Rau qee yam ultra- siab- purity hluav taws xob cov txheej txheem tshuaj lom neeg uas qhov tshwj xeeb impurity profile ntawm B-2 (vs. B-3's tungsten) yog qhov tseeb. Qhov no tsis tshua muaj.
Kev Tiv Thaiv Kev Muag Khoom Tsis Txaus (yog tias ua tiav):
Melt Practice Certification: Demand VIM + ESR (Electro-Slag Remelting). ESR yog qhov tseem ceeb rau B-2 kom ua tiav cov tshuaj homogeneity uas yuav tsum tau ua kom txo qis nws qhov kev xav ntawm micro-segregation thiab theem tsim. Tsis lees paub cov khoom siv yam tsis muaj ntawv pov thawj no.
Kev kho cua sov Validation: MTR yuav tsum tau ntawv pov thawj "Kev daws teeb meem Annealed thiab Dej Quenched" nrog cov ntaub ntawv ntsuas kub / sijhawm. Thov cov kab kos hluav taws xob.
Chemistry Verification: Paub meej tias Chromium tsawg heev (<1.0%) and Carbon (<0.005%). The presence of Tungsten (W) would indicate it is actually B-3.
Fabricator Tsim Nyog: Siv tsuas yog fabricators nrog ua qauv qhia, paub tseeb kev vam meej vuam thiab cua sov- kho B-2. Xav tau lawv WPS/PQR thiab qhov project keeb kwm.
Kev Tshawb Fawb Kev Ua Haujlwm: Yuav tsum tau kuaj xyuas corrosion ntawm cov khoom siv vuam coupons hauv qhov chaw pabcuam (xws li, boiling HCl) raws li ib qho xwm txheej rau kev them nyiaj zaum kawg thiab tso tawm.
4. Rau ib tug engineer lub luag hauj lwm rau kev tswj kev laus infrastructure tsim nrog UNS N10665 phaj, dab tsi yog qhov tseem ceeb soj ntsuam foci thiab hloov kev npaj ua?
Tswj B-2 cov cuab tam yog ib qho kev tawm dag zog hauv kev tswj hwm kev pheej hmoo thiab kev npaj rau nws cov nyiaj laus uas tsis tuaj yeem zam.
Ntsiab tshuaj ntsuam xyuas:
Weld HAZ Examination: Use Liquid Penetrant Testing (PT) and Ultrasonic Testing (UT) to look for cracks. Perform hardness surveys across welds; a spike (>250 HB) qhia tias muaj kev puas tsuaj rau theem nag lossis daus.
Ultrasonic Thickness (UT) Daim Ntawv Qhia: Tsom ntsoov rau thaj chaw nyob ze ntawm cov welds, nozzles, thiab qhov twg oxidizing cov kab mob tuaj yeem nkag mus (xws li, ze ntawm qhov cua, twj tso kua mis). Saib rau qhov qhia tias qhov chaw nyias nyias ntawm riam- kab lossis pitting nres.
Txheej Txheem Kev Ntsuas Dej: Tsis tu ncua kuaj rau cov kab mob oxidizing (Fe³⁺, Cu²⁺, yaj O₂). Lawv lub xub ntiag yog kev hem thawj ncaj qha.
Hloov Kev Npaj Ua Haujlwm (Lub Sijhawm Npaj Rau B-3 lossis C-2000):
Cov ntaub ntawv pov thawj ntawm Active Corrosion: UT qhia tau hais tias nrawm los yog qhov chaw hauv phab ntsa poob.
Txhua Tus Txheej Txheem Hloov: Kev hloov kho uas tuaj yeem qhia oxidizers lossis nce qhov kub thiab txias.
Qhov tshwm sim tsis ua tiav: Txhua qhov xau lossis yuav tsum tau kho.
Kev poob ntawm Fabrication Expertise: Thaum muaj peev xwm ua kom zoo vuam / kub kho B-2 tsis muaj nyob hauv zos lawm.
Npaj loj Turnaround: Lub qhov rais zoo tshaj plaws los ua qhov kev hloov pauv nrog tsawg kawg ntxiv sijhawm poob.
5. Thaum ua qhov kev soj ntsuam tsis ua hauj lwm ntawm UNS N10665 phaj corroded, dab tsi tshwj xeeb analytical cov txheej txheem tuaj yeem paub qhov txawv ntawm qhov tsis ua hauj lwm vim kev tsim tsis raug (welding/PWHT) thiab tsis ua hauj lwm vim nyob rau hauv - kev pab cuam oxidizing paug?
Ib qho kev tshawb nrhiav forensic yog xav tau los muab cov hauv paus ntsiab lus, uas hais txog kev kho kom raug.
Txhawm rau txheeb xyuas qhov tsis tsim nyog Fabrication Failure:
Metallography ntawm HAZ: Ua piv txwv los ntawm qhov chaw corroded nyob ib sab ntawm lub vuam. Etch thiab tshuaj xyuas nyob rau hauv lub microscope. Kev sib txuas txuas ntxiv ntawm theem nrab ntawm cov ciam teb nplej yog cov pov thawj tseeb ntawm kev nkag siab los ntawm cov vuam tsis zoo / PWHT.
Microhardness Traverse: Lub ncov ntse hauv hardness hauv HAZ cuam tshuam nrog theem nag lossis daus.
SEM/EDS Kev Ntsuam Xyuas: Muaj peev xwm txheeb xyuas cov chemistry ntawm cov theem precipitated (siab hauv Mo, tejzaum nws Cr), lees tias lawv yog μ lossis P-theem.
Txhawm rau txheeb xyuas Oxidizing Contamination Failure:
Kev Ntsuas Nyiaj Txiag: Siv X-ray Diffraction (XRD) thiab Zog Dispersive X-Ray Spectroscopy (EDS) ntawm cov khoom siv corrosion los yog deposits. Cov qib siab hlau (Fe) lossis tooj liab (Cu) qhia tias muaj cov kab mob sib kis.
Corrosion Morphology: Oxidizing attack feem ntau ua rau hnyav, undercut general corrosion los yog loj, qhib pits, es tsis zoo, intergranular riam-kab txuam nrog fabrication teeb meem.
Txheej Txheem Keeb Kwm Kev Ntsuam Xyuas: Txheeb xyuas qhov chaw tsis ua haujlwm nrog cov xwm txheej: kev tu tsis ntev los no nrog cov dej aerated, lub twj tso kua mis tsis ua haujlwm, lossis ib pawg ntawm cov khoom noj tsis huv.
Hauv kev xaus, UNS N10665 (Hastelloy B-2) phaj yog cov khoom tshwj xeeb ntawm yav dhau los. Nws lub luag haujlwm hauv kev tsim qauv tshiab yog zoo li ploj mus, hloov los ntawm qhov muaj zog dua thiab fabricable B-3. Rau cov nroj tsuag uas twb muaj lawm, lub tswv yim yuav tsum yog: kev soj ntsuam ceev faj, kev tswj cov txheej txheem impeccable, thiab kev npaj peev nyiaj txiag rau nws txoj kev hloov pauv nrog kev zam txim ntau dua. Nws sawv cev rau lub luag haujlwm tseem ceeb ntawm kev ua haujlwm.
