1. Dab tsi yog qhov sib txawv ntawm Incoloy 800, 800H, 800HT, thiab Incoloy 825, thiab cov kev sib txawv no txhais li cas rau lawv cov thawj daim ntawv thov sectors hauv cov roj & roj thiab tshuaj ua lag luam?
Txawm hais tias txhua yam yog npib tsib xee-hlau-chromium alloys, lawv cov kev sib xyaw tshwj xeeb thiab cov txiaj ntsig ua rau lub hom phiaj sib txawv ib puag ncig kev pabcuam.
Incoloy 800 series yog tsim los rau siab -kub lub zog thiab oxidation kuj. Nws cov ntsiab lus tseem ceeb yog kwv yees li 32.5% Ni, 21% Cr, thiab sib npaug Fe, nrog kev tswj xyuas ntxiv ntawm titanium thiab txhuas.
Incoloy 800: Lub hauv paus qib nrog cov ntsiab lus carbon.
Incoloy 800H: Tus "H" sawv rau qhov kub thiab txias. Nws muaj cov ntsiab lus ntawm cov pa roj carbon ntau dua (0.05-0.10%) thiab tau muab tshem tawm los ua cov qauv ntawm cov nplej ntxhib, muab lub zog zoo tshaj plaws ntawm qhov kub siab tshaj 540 ° C (1000 ° F).
Incoloy 800HT: Zoo ib yam li 800H tab sis nrog kev tswj nruj dua ntawm txhuas thiab titanium (Al + Ti ≥ 0.85%) kom zoo dua siab dua - qhov kub thiab txias thiab lub zog.
Cov ntawv thov tseem ceeb (800H / HT): Lawv lub niche yog nyob rau hauv siab -kub, corrosive txheej txheem ib puag ncig. Hauv cov roj & roj, qhov no suav nrog cov raj pyrolysis, cov raj cua sov, thiab cov raj radiant nyob rau hauv ethylene cracking furnaces, uas lawv tiv taus kub ntawm 850 ° C mus rau 1100 ° C hauv carburizing thiab oxidizing cua. Hauv kev ua tshuaj lom neeg, lawv tau siv rau hauv chav methane hloov kho cov rooj sib txoos, cov nroj tsuag hydrogen, thiab cov khib nyiab incineration.
Incoloy 825, nyob rau hauv sib piv, yog optimized rau tshwj xeeb aqueous corrosion kuj, tshwj xeeb tshaj yog tiv thaiv kom txhob acids. Nws muaj pes tsawg leeg (kwv yees . 42% Ni, 21.5% Cr, 3% Mo, 2.2% Cu, balanced Fe) yog qhov sib txawv. Cov ntsiab lus siab nickel muab kev tiv thaiv rau cov tshuaj chloride-ion stress-corrosion cracking (SCC). Molybdenum confers kuj rau pitting thiab crevice corrosion nyob rau hauv chloride ib puag ncig, thaum tooj liab txhim khu kev tiv thaiv rau sulfuric thiab phosphoric acids.
Cov ntawv thov tseem ceeb (825): Nws lub npe yog txhoj puab heev, ntub dej, thiab feem ntau qis dua -kub chemistry. Hauv cov roj & roj, nws yog ib qho tseem ceeb rau cov tubing downhole, cov khoom siv qaub, thiab cov txheej txheem kav dej uas muaj cov chlorides, H₂S, thiab CO₂. Hauv kev ua tshuaj, nws yog tus qauv rau sulfuric thiab phosphoric acid pickling systems, seawater txias piping, nuclear roj reprocessing, thiab offshore dej ntsev piping. Daim ntawv seamless yeeb nkab yog qhov tseem ceeb rau siab - siab, qhov kev pabcuam tseem ceeb uas qhov kev ncaj ncees ntawm cov welded tubing tuaj yeem yog lub luag haujlwm.
2. Vim li cas cov txheej txheem tsim khoom "seamless" tshwj xeeb yog qhov tseem ceeb rau Incoloy 800/825 cov kav dej uas tsim los rau siab -siab, siab - kub, lossis kev pabcuam corrosive?
Cov txheej txheem seamless, qhov twg cov yeeb nkab yog extruded los yog pierced los ntawm ib tug khoom billet, tsis yog -negotiable rau thov daim ntaub ntawv vim peb core zoo tshaj welded (seamed) yeeb nkab:
Homogeneous Structure & Superior Integrity: Cov yeeb nkab tsis muaj seamless muaj qhov sib txuas ua ke, cov qauv zoo ib yam nyob ib puag ncig nws tag nrho ib puag ncig. Qhov no tshem tawm qhov tsis muaj zog ntawm qhov ntev ntawm lub vuam seam, uas yog qhov chaw muaj peev xwm rau:
Corrosion Initiation: Weld zones tuaj yeem muaj qhov sib txawv me me hauv microstructure (kub- thaj chaw cuam tshuam) uas muaj kev cuam tshuam ntau dua rau pitting, crevice corrosion, lossis kev ntxhov siab corrosion tawg hauv kev tawm tsam hnyav xws li chlorides lossis ntub H₂S.
Flaws: Txawm hais tias muaj kev vam meej, welds tuaj yeem muaj qhov sib txuam, porosity, lossis tsis tiav fusion, uas yog cov kev ntxhov siab thiab cov ntsiab lus pib rau kev ua tsis tiav nyob rau hauv lub voj voog siab ( qaug zog) los yog nkag ntawm qhov kub thiab txias.
Enhanced Pressure Containment: Qhov tsis muaj weld seam txhais tau hais tias cov yeeb nkab muaj cov khoom siv zoo ib yam thoob plaws. Qhov no tso cai rau kom muaj kev ruaj ntseg ntau dua thiab txhim khu kev qha ua haujlwm hauv siab -siab tshuab xws li downhole tubing, hydraulic kab, lossis siab -siab kub exchanger tubing. Phab ntsa thickness kuj zoo ib yam.
Txhim kho siab -Kev Ua Haujlwm Kub: Rau cov qib zoo li 800H / HT siv rau hauv cov txheej txheem nkag, ib qho zoo li qub, tswj microstructure yog qhov tseem ceeb. Cov txheej txheem seamless, ua raws li kev daws teeb meem zoo thiab (rau 800H / HT) nplej-coarsening tshav kub kho, ua kom paub tseeb thiab pom kev nkag siab zoo- tawg lub zog. Lub weld seam tuaj yeem yog thaj tsam ntawm cov nplej zoo lossis hloov cov qauv precipitate, ua rau ua tsis tiav ntxov nyob rau lub sijhawm ntev - kev ntxhov siab ntawm qhov kub thiab txias.
Nyob rau hauv qhov tseeb, seamless yeeb nkab yog xaiv rau cov kev pab cuam tseem ceeb tshaj plaws uas tsis ua hauj lwm tsis yog ib qho kev xaiv, ua pov thawj nws cov nqi siab dua piv rau welded lwm txoj kev.
3. Dab tsi yog qhov tseem ceeb corrosion mechanisms uas Incoloy 825 seamless yeeb nkab yog tsim tshwj xeeb rau kev sib ntaus sib tua, thiab nws muaj pes tsawg leeg nyob li cas?
Incoloy 825 yog ntau yam "tshuaj tua rog" tsim los tswj cov dej cawv ntawm cov neeg ua haujlwm corrosive. Nws muaj pes tsawg leeg yog cov lus teb ncaj qha rau cov kev ua tsis tiav tshwj xeeb:
Chloride-Induced Stress Corrosion Cracking (Cl-SCC): Qhov no yog ib qho tsis ua hauj lwm ntawm cov khoom uas ib txwm muaj nyob rau hauv tensile stress nyob rau hauv muaj chlorides thiab oxygen. Cov ntsiab lus npib tsib xee siab (≥42%) yog thawj qhov kev tiv thaiv, ua rau cov hlau tsis muaj zog rau Cl-SCC rau txhua lub hom phiaj siv tau hauv feem ntau cov txheej txheem. Qhov no yog qhov tseem ceeb rau kev ua kom dej hiav txwv txias, kev siv sab nrauv, thiab ntsev- muaj cov txheej txheem ntws.
Pitting thiab Crevice Corrosion: Localized nres nyob rau hauv stagnant chloride tov los yog nyob rau hauv deposits / gaskets. Qhov sib ntxiv ntawm 3% Molybdenum ua rau kom cov alloy qhov tseem ceeb pitting kub (CPT) thiab tsis kam mus rau crevice corrosion, ua rau nws haum rau dej brackish, seawater, thiab chloride - cov txheej txheem dej cawv.
Txo cov kua qaub (Sulfuric, Phosphoric): Ua rau sulfuric acid yog lub zog tseem ceeb. Kev sib xyaw ntawm npib tsib xee thiab tooj liab muab kev tiv thaiv zoo heev rau dilute sulfuric acid thiab zoo tiv thaiv phosphoric acid. Qhov no ua rau 825 zoo tagnrho rau cov kua qaub pickling kab, kua qaub mine kua, thiab phosphate chiv ua khoom siv.
Oxidizing Environments & Polythionic Acid SCC: Lub 21.5% Chromium tsim ib qho ruaj khov, tiv thaiv chromium oxide (Cr₂O₃) cov zaj duab xis passive, muab kev tiv thaiv rau nitric acid, nitrates, thiab oxidizing ntsev. Cov qib chromium no tseem tso cai rau cov alloy kom ruaj khov tiv thaiv polythionic acid kev nyuaj siab corrosion cracking (PASCC) thaum lub sij hawm kaw hauv refinery / petrochemical kev pab cuam los ntawm cov txheej txheem passivation kom raug.
Sulfidic thiab qaub Corrosion: Hauv cov roj & roj ib puag ncig uas muaj H₂S (kev pabcuam qaub), cov hlau nplaum siab nickel thiab chromium cov ntsiab lus muab kev tiv thaiv zoo rau sulfide scaling thiab cracking, tshwj xeeb tshaj yog thaum kub thiab chloride qib kuj nce siab.
4. Hauv kev tsim khoom, dab tsi yog qhov tseem ceeb rau kev vuam thiab tom qab-weld heat treatment (PWHT) ntawm Incoloy 800/825 seamless piping systems?
Kev tsim khoom tsis raug tuaj yeem ua rau muaj kev cuam tshuam tsis zoo hauv lub cev thiab siab - qhov kub thiab txias ntawm cov alloys hwm zoo.
Welding Considerations:
Filler Hlau Xaiv: Sib piv lossis tshaj - cov hlau muab tub lim yuav tsum tau siv.
Incoloy 800/800H/800HT: Feem ntau welded nrog Inconel 82 (ERNiCr-3) los yog Incoloy 800HT muab tub lim (ERNiFeCr-1). Cov fillers no phim lub hauv paus hlau lub siab kub lub zog thiab oxidation kuj.
Incoloy 825: Welded nrog INCO-Weld 825/INCO-Filler 825 (ERNiCrMo-3). Siv cov khoom siv stainless hlau (xws li 309) yuav tsim qhov qis-molybdenum, tawg-rhiab vuam tsis tuaj yeem tiv taus pitting.
Txheej Txheem & Cov Txheej Txheem: Cov txheej txheem cua sov qis xws li Gas Tungsten Arc Vuam (GTAW / TIG) yog qhov zoo dua rau cov hauv paus thiab kub dhau los tswj kev tiv thaiv corrosion. Shielded Hlau Arc (SMAW / Stick) tuaj yeem siv rau sau thiab hau. Kev tu kom huv kom tshem tawm cov roj, roj, thiab cov kab mob sulfur / lead yog qhov tseem ceeb. Cov txheej txheem "butter thiab weld" feem ntau yog siv rau cov pob qij txha sib txawv rau cov hlau.
Tshaj tawm -Weld Heat Treatment (PWHT):
Incoloy 800H / HT: PWHT feem ntau xav tau rau kev pabcuam siab tshaj 540 ° C (1000 ° F). Tus qauv yog ib qho kev daws teeb meem ntawm 1100-1175 ° C (2012-2147 ° F) tom qab txias txias (dej quenching). Qhov no redissoles chromium carbides uas precipitate nyob rau hauv lub weld HAZ, restores ductility, thiab rau 800H / HT, tso cai rau kev txhim kho cov tsim nyog coarse grain qauv.Kev ntxhov siab ntawm qhov kub qis (piv txwv li, 850 ° C) tsis pom zooraws li nws tuaj yeem ua rau rhiab heev.
Incoloy 825: PWHT feem ntau tsis tas yuav tsum tau lossis pom zoo rau cov kev pabcuam corrosion txheem. Cov hlau yog siv rau hauv cov tshuaj -annealed mob. Yog tias PWHT pom tau tias tsim nyog rau kev ntxhov siab tom qab kev tsim kho hnyav, nws yuav tsum yog qhov kev daws teeb meem tag nrho (900-925 ° C ua raws li nrawm nrawm) kom tsis txhob hnov qab txog qhov tseem ceeb ntawm 425-870 ° C ntau qhov teeb meem chromium carbides thiab intermetallic theem tsim, rhuav tshem corrosion kuj.
5. Thaum qhia txog Incoloy 800H/HT los yog 825 seamless yeeb nkab rau ib qhov project, dab tsi yog qhov tseem ceeb ntawm ASTM / ASME cov khoom thiab cov qauv ntsuas uas yuav tsum tau hais los xyuas kom meej qhov zoo thiab kev nyab xeeb-rau- lub hom phiaj?
Precise standardization yog qhov tseem ceeb rau kev ntseeg tau. Cov hauv qab no yog cov qauv tseem ceeb:
Rau Incoloy 800/800H / 800HT Seamless Yeeb Nkab:
Khoom siv tus qauv: ASTM B407 / ASME SB407 - Txuj Specification rau Nickel-Iron-Chromium Alloy Seamless Yeeb thiab Tube. Cov qauv no suav nrog cov tshuaj muaj pes tsawg leeg, cov khoom siv kho tshuab, thiab cov kev xav tau dav dav.
Qib sib txawv: Tus lej UNS tshwj xeeb yuav tsum raug hu tawm:
Incoloy 800: UNS N08800
Incoloy 800H: UNS N08810 (nrog carbon ≥0.05%, Al + Ti ≥0.85%)
Incoloy 800HT: UNS N08811 (nrog carbon ≥0.05%, Al + Ti ≥0.85%)
Test Standards:
ASTM A999 / ASME SA999: Cov kev cai dav dav rau cov yeeb nkab steel hlau. Feem ntau tau thov rau cov kev xav tau ntxiv xws li kev sim hydrostatic, tsis yog -kev kuaj hluav taws xob puas tsuaj (NDE), thiab ntawv pov thawj.
Hydrostatic Test: Raws li ASTM B407, feem ntau kuaj rau lub siab ntsuas los ntawm tus qauv qauv.
Tsis yog-Kev kuaj kev puas tsuaj (NDE): ASTM E213 (Ultrasonic Testing) los yog ASTM E709 (Magnetic Particle Testing -} rau cov ntaub ntawv ferromagnetic, tsawg dua rau cov no) tej zaum yuav raug teev rau qhov tsis zoo.
Grain Size Check for 800H/HT: ASTM E112 yog siv los txheeb xyuas qhov ntxhib lis loj (feem ntau ASTM Tsis yog. 5 lossis coarser) xav tau rau kev pom kev nkag siab zoo.
Rau Incoloy 825 Seamless Yeeb Nkab:
Khoom siv tus qauv: ASTM B423 / ASME SB423 - Txuj Specification rau Nickel-Iron-Chromium-Molybdenum-Copper Alloy (UNS N08825) Seamless Yeeb Nkab thiab Tube.
Test Standards:
ASTM A999 / ASME SA999 rov siv rau cov kav dej dav dav.
Corrosion Testing (yog tias tau teev): Txawm tias tsis yog ib qho yuav tsum tau ua raws li qhov yuav tsum tau ua, kev ntsuam xyuas kev sib xyaw ua ke ntawm ASTM G28 Txoj Kev A (rau kev kuaj xyuas chromium depletion) tuaj yeem raug teev rau cov kev pabcuam tseem ceeb kom ntseeg tau tias cov khoom nyob rau hauv cov kev daws teeb meem zoo -annealed, non{2}}sensitized mob.
Hydrostatic thiab NDE: Cov kev cai zoo ib yam li saum toj no, nrog UT yog thawj NDE txoj kev.
Rau txhua qhov haujlwm, siv tau ASME B31.3 Txheej Txheem Piping Code tswj kev tsim, tsim, tshuaj xyuas, thiab kuaj cov kav dej nruab, xa mus rau cov qauv khoom siv.
