1. Hastelloy B-2 feem ntau tau piav qhia tias muaj "kev tiv thaiv zoo rau txo cov kua qaub." Dab tsi tshwj xeeb cov tshuaj ib puag ncig txhais tau hais tias qhov no, thiab nyob rau hauv cov xwm txheej twg yuav B-2 yeeb nkab yuav tsum tau ua kom muaj kev sib npaug ntau dua li Hastelloy C-276?
Hastelloy B-2's muaj pes tsawg leeg (kwv yees . 65% Ni, 28% Mo, 2% Fe, qis Cr) yog ib qho kev qhia tshwj xeeb. Nws dominance yog nyob rau hauv ib puag ncig uas kub, concentrated, thiab profoundly txo.
Defining "Reduction Acid" Ib puag ncig:
Cov no yog cov kua qaub uas nyiam txais cov khoom siv hluav taws xob, feem ntau muaj peev xwm oxidation tsawg. B-2 ua tau zoo hauv:
Hydrochloric Acid (HCl): Nyob rau hauv tag nrho cov concentrations thiab kub, nrog rau lub boiling point. Nov yog nws daim ntawv thov kos npe.
Sulfuric Acid (H₂SO₄): tshwj xeeb tshaj yog nyob rau hauv nruab nrab mus rau siab concentrations (40-85%) ntawm qhov kub thiab txias, nyob rau hauv txo tej yam kev mob.
Phosphoric Acid (H₃PO₄): Hauv cov kab mob, ntub - cov kua qaub uas muaj fluorides thiab chlorides.
Acetic, Formic, thiab lwm yam Organic Acids: Tshwj xeeb ntawm qhov kub thiab txias.
Hydrogen Chloride (HCl) Gas: Hauv cov ntawv qhuav lossis ntub dej.
Yuav tsum xaiv tshaj C-276 (Ni-Cr-Mo):
Qhov sib txawv tseem ceeb yog chromium. C-276 muaj ~ 16% Cr, uas ua rau nws zoo heev tiv thaiv oxidizing xov xwm tab sis ua rau nws yooj yim nyob rau hauv ib puag ncig ntshiab txo.
Scenario 1: Ntshiab, Kub HCl. Nyob rau hauv boiling hydrochloric acid ntawm ib tug concentration, C-276 yuav corrode ntawm tus nqi siab dua B-2. B-2 yeeb nkab yog yuav tsum tau rau reactor hlab ntsha, distillation kab, thiab hloov kab nyob rau hauv HCl ntau lawm, pickling, thiab organic chloride synthesis.
Scenario 2: Severe Sulfuric Acid Service. In concentrated, hot sulfuric acid (>70% ntawm qhov kub siab) nyob rau hauv qhov muaj zog txo qis, B-2 cov ntsiab lus chromium tsawg tiv thaiv kev tsim cov teeb meem Cr-nplua nuj theem uas tuaj yeem tawm tsam.
Scenario 3: Ua tiav Tsis Muaj Oxidizers. Yog tias cov txheej txheem kwj tau lees paub tias tsis muaj cov kab mob oxidizing (piv txwv li, tsis muaj Fe³⁺, Cu²⁺ ions, tsis muaj oxygen yaj, tsis muaj chlorine), B-2 muab cov txiaj ntsig zoo tshaj plaws thiab txhim khu kev qha. Lub sijhawm oxidizers tau qhia, B-2 dhau los ua qhov tsis zoo.
Txoj cai ntawm tus ntiv tes xoo: Xaiv Hastelloy B-2 seamless yeeb nkab thaum ib puag ncig yog aggressively txo, chloride-nplua nuj, thiab tsis muaj oxidizing hom. Xaiv C-276 thaum ib puag ncig sib xyaw (ob qho tib si oxidizing thiab txo qis) los yog muaj cov oxidizers uas tsis paub / sib txawv.
2. Ib qho tsis muaj zog loj ntawm Hastelloy B-2 yog nws qhov ua rau muaj kev tawm tsam sai hauv oxidizing ib puag ncig. Dab tsi tshwj xeeb cov kab mob lossis cov txheej txheem ntxhov siab yuav ua rau muaj kev puas tsuaj loj hauv B-2 piping system, thiab qhov kev pheej hmoo no txo qis hauv kev tsim cov nroj tsuag li cas?
Qhov tsis zoo ntawm B-2 rau oxidizing tej yam kev mob yog nws lub pob taws Achilles. Kev ua tsis tiav tuaj yeem nrawm thiab hnyav.
Kev puas tsuaj Oxidizing Contaminants:
Ferric (Fe³⁺) thiab Cupric (Cu²⁺) Ions: Cov kab mob sib kis los ntawm cov dej ntws tawm ntawm cov hlau los yog tooj liab alloys. Txawm tias ppm qib tuaj yeem nce tus nqi corrosion los ntawm kev txiav txim siab hauv HCl kev pabcuam.
Dissolved Oxygen (O₂) / Cua Ingress: Los ntawm cov twj tso kua mis tawm, qhib qhov cua, lossis thaum lub sijhawm kaw.
Dawb Halogens: Chlorine (Cl₂), bromine (Br₂).
Nitric Acid (HNO₃) los yog Nitrates: Kev sib tsoo los yog nqa mus.
Peroxides thiab lwm yam muaj zog oxidizers.
Mitigation Strategies in Plant Design:
Kev Tswjhwm nruj nruj & Kev soj ntsuam: Kev soj ntsuam tas li ntawm cov txheej txheem kwj rau redox peev xwm (ORP) thiab cov ntsiab lus tshwj xeeb ion (Fe³⁺).
Kev sib xyaw cov ntaub ntawv: xyuas kom txhua yam khoom siv hluav taws xob (valve, twj tso kua mis, cov hlab ntsha) uas sib cuag cov txheej txheem dej ua ntej B-2 yeeb nkab kuj yog ua los ntawm cov khoom siv sib xws (xws li, B-2, tantalum, graphite) los tiv thaiv cov khoom siv corrosion.
Zoo Inerting: Khaws ib daim pam ntawm inert gas (nitrogen) ntawm lub tank headspaces thiab thaum lub sij hawm kaw kom tsis txhob muaj huab cua.
Fail-Safe Design: Siv ob chav thaiv thiab los ntshav li qub thiab mob siab rau, sau cov kav dej kom tiv thaiv kev hla kev sib tsoo -kev sib txuas nrog cov kwj oxidizing.
Kev cob qhia tus neeg ua haujlwm: Ua kom pom tseeb qhov siab tshaj plaws ntawm B-2 rau oxidizers hauv cov txheej txheem ua haujlwm.
Alternative Material Zoning: Nyob rau hauv seem ntawm cov nroj tsuag qhov twg oxidizing upsets yog ua tau (xws li, ib tug pub kwj uas yuav txawv), qhia kom meej lub zog ntau Hastelloy B-3 (UNS N10675), uas tau me ntsis txhim kho thermal stability thiab ductility, los yog C-276.
3. Hastelloy B-2 yog feem ntau ua rau muaj kev cuam tshuam ntawm intermetallic theem yog tias kho tsis raug cua sov. Dab tsi yog qhov yuav tsum tau ua tom qab kev kho cua sov rau B-2 seamless yeeb nkab, thiab yuav ua li cas yog tias cov kauj ruam no raug rho tawm lossis ua tsis raug?
Qhov no yog qhov tseem ceeb tshaj plaws ntawm kev tsim nrog B-2. Cov hlau yuav tsum tau khaws cia rau hauv ib zaug ib zaug -theem, solid-solution condition.
Qhov teeb meem: P-Phase thiab Mu-Phase Precipitation.
Thaum B-2 tuav hauv qhov kub ntawm 1200 ° F txog 1600 ° F (650 ° txog 870 ° F), nkig, molybdenum- nplua nuj intermetallic theem (P-theem thiab μ-theem) precipitate ntawm grain ciam teb. Qhov no tshwm sim nyob rau hauv thaj chaw uas muaj kev kub ntxhov (HAZ) thaum lub sij hawm vuam los yog thaum lub sij hawm qeeb txias los ntawm qhov kub siab.
Qhov tshwm sim ntawm kev tsis pom zoo / Kev kho tsis raug:
Kev poob loj ntawm Ductility & Toughness: Cov khoom ua nkig, feem ntau tawg spontaneously thaum txias los yog nyob rau hauv me ntsis kev ntxhov siab.
Kev puas tsuaj loj ntawm Corrosion Resistance: Cov theem no yog anodic rau lub matrix thiab nyiam tshaj tawm tsam hauv kev pabcuam, ua rau kom nrawm, intergranular corrosion thiab tsis ua haujlwm. Qhov no feem ntau hu ua "riam-line attack" nyob ib sab ntawm welds.
Yuav Tsum Tau Tshaj Tawm -Kev kho cua sov Fabrication:
Tib txoj hauv kev los ua kom yaj cov theem teeb meem no thiab rov ua kom cov khoom muaj txiaj ntsig yog Kev daws teeb meem tag nrho.
Kub: Kub sib npaug mus rau 2050℃F - 2100℃F (1120℃- 1150℃).
Soak Sijhawm: Lub sijhawm txaus ntawm qhov kub (feem ntau 30-60 mins ib nti ntawm tuab).
Txias: RAPID QUENCH hauv dej. Qhov no tsis yog -negotiable. Kev ua kom txias qeeb (cua txias) tso cai rau cov khoom dhau los ntawm qhov ntsuas kub tsis zoo, ua rau cov nag lossis daus rov ua dua - daim ntawv.
Rau Seamless Yeeb Nkab: Lub zeb- muab cov yeeb nkab yuav twb nyob rau hauv cov tshuaj -annealed thiab quenched mob. Ib qho kev sib txuas tom ntej los yog kub sib sau (khoov) yuav tsum tau ua kom tag nrho lub rooj sib txoos tau txais cov tshuaj no ntxiv dua. Kev kho cua sov hauv tshav kub ntawm cov yeeb nkab loj loj yog qhov kev sib tw loj logistical, feem ntau dictating khw fabrication ntawm complex sib dhos.
4. Rau lub tshuab hluav taws xob hydrochloric (HCl) distillation ua haujlwm nyob ze - kub kub, qhov tsim, kev tsim, thiab kev soj ntsuam tshwj xeeb rau Hastelloy B-2 seamless piping voj yog dab tsi?
Qhov no sawv cev rau daim ntawv thov tseem ceeb rau B-2 yeeb nkab, xav tau qib siab tshaj plaws ntawm kev qhuab qhia engineering.
Tsim:
Velocity: Tswj cov dej nrawm kom txo qis kev yaig -corrosion. Siv cov yeeb nkab dav dav.
Thermal Expansion: Tus account rau kev nthuav dav ntawm qhov kub siab; siv cov khoom tsim kom zoo expansion loops lossis bellows.
Kev txhawb nqa: Siv cov khoom siv insulated, padded kev txhawb nqa kom tsis txhob muaj cov crevices thiab chloride concentration.
Fabrication:
Vuam: Siv autogenous GTAW (tsis muaj muab tub lim) qhov haum- zoo meej. Yog tias xav tau, siv ERNiMo-7 (AWS A5.14). Khaws cov khoom siv hluav taws xob tsawg heev.
Kev huv huv: Kev huv huv heev kom tsis txhob muaj cov pa roj carbon lossis silicon paug, uas tuaj yeem txo qhov kev tiv thaiv corrosion.
Ncej - Weld Heat Treatment (PWHT): Raws li saum toj no, kev daws teeb meem tag nrho thiab dej quench ntawm tag nrho cov welded spool yog qhov yuav tsum tau ua. Qhov no feem ntau txhais tau tias fabricating nyob rau hauv ib lub khw nrog ib tug loj, ntsug quench rauv.
Kev tshuaj xyuas:
100% Radiography (RT): Ntawm tag nrho cov welds los xyuas kom meej tag nrho kev nkag mus thiab tsis muaj qhov tsis xws luag uas yuav pib corrosion.
Liquid Penetrant Testing (PT): Nyob rau txhua qhov chaw weld.
Hardness Survey: Hla welds thiab HAZ. Ib qho tseem ceeb nyob rau hauv hardness qhia tau hais tias tej zaum yuav detrimental theem tsim, signaling ib tug ua tsis tau tejyam kev kho cua sov.
Corrosion Test Daim Coupon: Qhov kev sim tseeb. Daim coupon suav nrog cov vuam yuav tsum tau ua raws li ASTM G28 Txoj Kev A- hom kev xeem lossis, zoo dua, kev sim hauv cov kua qaub hydrochloric. Tus nqi corrosion ntawm weld / HAZ yuav tsum phim lub hauv paus hlau.
5. Dab tsi yog cov ntaub ntawv pov thawj tseem ceeb thiab kev xeem yuav tsum tau ua raws li ASTM B626 rau Hastelloy B-2 seamless yeeb nkab, thiab yog vim li cas melt kev xyaum tshwj xeeb yog qhov tseem ceeb rau cov hlau no?
ASTM B626 yog tus qauv rau seamless UNS N10665 yeeb nkab thiab raj. Daim ntawv pov thawj yuav tsum mus dhau chemistry.
Daim Ntawv Pov Thawj Tseem Ceeb:
Chemistry: Tag nrho cov kev tshuaj ntsuam xyuas qhov siab Mo (~ 28%), qis Fe (~ 2%), thiab tseem ceeb, Chromium tsawg heev (<1.0%) and low Carbon (<0.01%).
Mechanical Properties: Tensile, tawm los, elongation.
Hydrostatic Test lossis NDE: Txhua lub yeeb nkab yuav tsum raug kuaj los yog tshuaj xyuas los ntawm tsis yog -txoj kev puas tsuaj.
Daim ntawv pov thawj kho cua sov: Yuav tsum qhia meej meej tias "Kev daws teeb meem Annealed thiab Dej Quenched."
Qhov tseem ceeb tseem ceeb ntawm Kev Ua Txhaum Cai:
Hastelloy B-2's susceptibility to intermetallic phase formation is exacerbated by micro-segregation of molybdenum thaum lub sij hawm solidification.
Kev xyaum tsis zoo: Kev sib xyaw ua ke tuaj yeem ua rau tsis yog- cov khoom sib faib ntawm molybdenum, tsim cov cheeb tsam hauv cheeb tsam uas nplua nuj nyob hauv Mo uas yog supersaturated thiab nquag ua rau cov theem teeb meem.
Yuav tsum tau xyaum: Advanced Melting Techniques yog yuav tsum tau.
Vacuum Induction Melting (VIM) ua raws li Electro-Slag Remelting (ESR) lossis Vacuum Arc Remelting (VAR).
ESR tshwj xeeb tshaj yog nyiam rau B-2 vim nws muab tshuaj lom neeg tshwj xeeb thiab cov qauv sib xyaw ua ke, txo qis kev sib cais thiab kev pheej hmoo ntawm theem nag lossis daus.
Procurement Spec: Daim ntawv xaj yuav tsum hais tias: "Cov khoom yuav tsum tau muab ob npaug rau yaj: VIM + ESR (los yog VAR). Daim Ntawv Tshaj Qhia Mill Test yuav tsum tau lees paub qhov kev xyaum ua yaj. Cov yeeb nkab los ntawm qhov tsis paub los yog ib qho - cov khoom tawg yog qhov tsis txaus ntseeg rau kev pabcuam tseem ceeb.
Hauv cov ntsiab lus, Hastelloy B-2 seamless yeeb nkab yog tus kws tshaj lij cov cuab yeej-unbeatable nyob rau hauv nws cov niche tab sis xav tau cov kws tshaj lij. Nws txoj kev ua tiav zoo yog nyob ntawm: 1) Cov ntawv thov raug (ntshiab txo cov kua qaub), 2) Flawless fabrication nrog yuav tsum tau cov tshuaj annealing, thiab 3) Kev yuav khoom nrog cov ntawv pov thawj, homogeneous yaj pedigree.
