1. Q: Dab tsi yog cov tshuaj muaj pes tsawg leeg ntawm Incoloy 825 (UNS N08825), thiab ua li cas txhua lub ntsiab lus alloying pab rau nws cov kev ua tau zoo hauv cov kua qaub thiab cov khoom noj khoom haus?
A:Incoloy 825 (UNS N08825) yog npib tsib xee- hlau-chromium alloy nrog tswj kev ntxiv ntawm molybdenum, tooj liab, thiab titanium. Nws cov nominal muaj pes tsawg leeg yog 38.0-46.0% npib tsib xee, 19.5-23.5% chromium, 22.0% hlau yam tsawg kawg nkaus, 2.5-3.5% molybdenum, 1.5-3.0% tooj liab, thiab 0.6-1.2% titanium, nrog carbon txwv rau 0.05%. Txhua lub hauv paus ua haujlwm rau lub hom phiaj tshwj xeeb hauv kev pabcuam acid.
Nickel(38–46%) muab lub hauv paus rau kev tiv thaiv chloride-ion stress-corrosion cracking (SCC), hom tsis ua hauj lwm tseem ceeb hauv cov cuab yeej siv tshuaj chlorides thiab acids. Cov ntsiab lus siab nickel tseem ruaj khov rau cov qauv austenitic, kom ntseeg tau tias ductility thiab fabricability.
Chromium(19.5–23.5%) confers tiv thaiv oxidizing tshuaj xws li nitric acid, nitrates, thiab oxidizing ntsev. Hauv kev ua haujlwm pickling qhov twg cov kua qaub sib xyaw (nitric-hydrofluoric) tau siv, chromium ua rau cov hlau tiv thaiv oxidizing tivthaiv ntawm cov kua qaub sib tov.
Molybdenum(2.5–3.5%) thiabtooj liab(1.5–3.0%) ua hauj lwm sib koom ua ke los muab kev tiv thaiv zoo rau kev txo qis ib puag ncig, tshwj xeeb yog sulfuric thiab phosphoric acids. Tooj liab yog tshwj xeeb tshaj yog zoo tiv thaiv sulfuric acid, thaum molybdenum txhim khu kev tiv thaiv rau pitting thiab crevice corrosion-localized nres mechanisms sai sai nkag mus rau hauv cov yeeb nkab phab ntsa nyob rau hauv stagnation los yog tsawg- ntws.
Titanium(0.6–1.2%) ua haujlwm ruaj khov. Los ntawm kev kho cua sov kom tsim nyog, titanium sib xyaw nrog cov pa roj carbon monoxide los tsim cov titanium carbide, tiv thaiv chromium carbide nag lossis daus ntawm cov ciam teb. Qhov kev ruaj khov no tshem tawm qhov cuam tshuam rau intergranular corrosion (sensitization), uas yog qhov tseem ceeb tshwj xeeb rau cov yeeb nkab thiab cov raj hauv cov kua qaub.
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2. Q: Dab tsi ASTM specifications tswj Incoloy 825 seamless yeeb nkab thiab raj rau cov txheej txheem tshuaj, thiab cov specifications txawv li cas?
A:Incoloy 825 seamless yeeb nkab thiab raj tau them los ntawm ntau yam ASTM specifications, txhua qhov hais txog cov khoom tshwj xeeb thiab cov kev pabcuam. Kev nkag siab txog cov kev sib txawv no yog qhov tseem ceeb rau kev xaiv cov khoom tsim nyog hauv cov kua qaub thiab cov khoom siv pickling.
ASTM B 163tswj hwm "Seamless Nickel thiab Nickel Alloy Condenser thiab Thaum tshav kub kub-Exchanger Tubes." Qhov kev qhia tshwj xeeb no siv tshwj xeeb rau cov tubing siv hauv cov ntawv thov hloov hluav taws xob, xws li cov khoom siv hluav taws xob, cov condensers, thiab cov evaporators hauv cov nroj tsuag acid. Nws imposes stringent dimensional tolerances thiab nondestructive xeem yuav tsum tau (feem ntau eddy tam sim no los yog ultrasonic) kom ntseeg tau lub raj kev ncaj ncees rau siab pab.
ASTM B 423 3npog "Nickel-Iron-Chromium-Molybdenum-Copper Alloy (UNS N08825 thiab N08221) Seamless Yeeb Nkab thiab Tube." Qhov no yog cov ntsiab lus tseem ceeb rau kev dav dav - lub hom phiaj seamless yeeb nkab thiab raj hauv kev siv tshuaj lom neeg. Nws hais txog cov khoom lag luam xws li cov twj ntsuas me me mus rau qhov loj - txoj kab uas hla txoj kab kav thiab suav nrog cov kev xav tau rau cov tshuaj muaj pes tsawg leeg, tensile zog, thiab kev kho cua sov.
ASTM B 424 2siv rau phaj, ntawv, thiab sawb, thaumASTM B425, ASTM B425npog cov khoom bar thiab pas nrig. Rau fabricated Cheebtsam xws li flanges thiab fittings,ASTM B564, 1yog qhov tseem ceeb specification rau forgings.
Hauv kev tsim cov kua qaub thiab cov chaw khaws khoom, cov khoom siv hluav taws xob feem ntau tau teev tseg rau ASTM B163, thaum sib txuas cov kav dej raws li ASTM B423. Ob qho kev qhia tshwj xeeb xav tau cov khoom siv los muab hauv cov kev daws teeb meem -annealed mob (stabilize annealed ntawm kwv yees li 940-980 degree) kom ntseeg tau tias qhov siab tshaj corrosion kuj thiab zoo ductility rau fabrication.
3. Q: Vim li cas Incoloy 825 yog cov khoom siv zoo tshaj plaws rau kev pabcuam sulfuric thiab phosphoric acid, thiab qhov zoo ntawm kev tiv thaiv corrosion nws puas muaj ntau dua stainless hlau?
A:Incoloy 825 muaj kev tiv thaiv tshwj xeeb rau ob qho tib si txo thiab oxidizing acids, ua rau nws tshwj xeeb tsim nyog rau cov kua qaub ntau lawm thiab khaws cov ntawv thov uas tsis muaj steel hlau tsis ua hauj lwm ntxov. Nws cov superiority yog feem ntau hais nyob rau hauv sulfuric acid (H₂SO₄) thiab phosphoric acid (H₃PO₄) ib puag ncig.
Kev Pabcuam Sulfuric Acid:Incoloy 825 nthuav tawm qhov ua tau zoo nyob thoob plaws ntau yam ntawm sulfuric acid concentrations thiab kub. Cov tooj liab thiab molybdenum ntxiv muab kev tiv thaiv tiv thaiv qhov txo qis ntawm dilute sulfuric acid, thaum chromium ua kom tsis muaj zog ntawm ntau dua qhov twg oxidizing tej yam kev mob yeej. Los ntawm qhov sib txawv, austenitic stainless hlau zoo li 304L thiab 316L raug kev kub ntxhov ceev hauv sulfuric acid, tshwj xeeb tshaj yog nyob rau qhov kub siab. Piv txwv li, nyob rau hauv 10-50% H₂SO₄ ntawm qhov kub txog li 150℃F (65 degree), Incoloy 825 tswj cov nqi corrosion qis dua 0.1 mm / xyoo, whereas 316L tuaj yeem muaj cov nqi siab tshaj 1.0 mm / xyoo.
Phosphoric Acid Service:Hauv kev tsim cov ntub dej - txheej txheem phosphoric acid (siv hauv kev tsim cov chiv), cov kua qaub muaj cov impurities hnyav xws li fluorides, chlorides, thiab silica. Incoloy 825 resists ob qho tag nrho corrosion thiab localized nres nyob rau hauv qhov chaw no, whereas txheem stainless steels raug kev txom nyem ceev pitting thiab crevice corrosion. Cov hlau yog dav siv rau phosphoric acid evaporators, tshav kub exchangers, thiab piping systems
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Kev ntxhov siab -Corrosion Cracking (SCC) Resistance:Ib qho txiaj ntsig tseem ceeb tshaj plaws ntawm Incoloy 825 tshaj cov hlau tsis muaj steel yog nws cov tshuaj tiv thaiv chloride -induced SCC. Austenitic stainless hlau muaj qhov cuam tshuam rau SCC thaum raug chlorides ntawm qhov kub siab tshaj 140℃F (60 degree). Incoloy 825, nrog nws cov ntsiab lus siab nickel (38-46%), yog qhov zoo tshaj plaws tiv thaiv cov tshuaj chloride SCC, ua rau nws cov khoom xaiv rau cov ntawv thov uas muaj chlorides nrog cov kua qaub.
Pitting thiab Crevice Corrosion:Cov ntsiab lus molybdenum (2.5-3.5%) muab Incoloy 825 nrog superior tsis kam rau pitting thiab crevice corrosion piv rau 316L stainless hlau. Qhov no yog qhov tseem ceeb tshwj xeeb tshaj yog nyob rau hauv kev ua haujlwm pickling qhov chaw nyob ruaj khov lossis crevices hauv qab gaskets thiab flanges tuaj yeem ua rau muaj kev tawm tsam hauv zos.
4. Q: Dab tsi yog qhov kev txiav txim siab tseem ceeb rau kev vuam Incoloy 825 yeeb nkab thiab raj hauv cov khoom siv kua qaub, thiab cov hlau muab tub lim tau pom zoo li cas?
A:Vuam Incoloy 825 yuav tsum muaj cov txheej txheem tshwj xeeb los tswj cov alloy qhov kev tiv thaiv corrosion thiab txhua yam kev ncaj ncees. Lub alloy nthuav tawm zoo weldability nrog txhua txoj kev fusion welding, tab sis ob peb yam tseem ceeb yuav tsum tau hais txog.
Ua ntej- Weld Cleaning:Cov kab mob saum npoo av-tshwj xeeb yog sulfur, lead, thiab roj- tuaj yeem ua rau kub tawg thaum vuam. Ua ntej vuam, cov yeeb nkab lossis cov yeeb nkab yuav tsum tau degreased kom huv si siv acetone los yog lwm yam kuab tshuaj haum. Kev sib tsoo cov log siv rau ntawm cov hlau tsis muaj steel yuav tsum tsis txhob siv rau ntawm Incoloy 825, vim tias kev sib tsoo tuaj yeem ua rau cov impurities.
Thaum tshav kub kub input Control:Incoloy 825 muaj qis thermal conductivity thiab thermal expansion ntau dua austenitic stainless hlau. Yuav kom txo qis distortion thiab residual stresses, welding txheej txheem yuav tsum tau qhia:
Cov cua kub nkag hauv qab 1.0 kJ / mm (kwv yees li 25 kJ / hauv)
Interpass kub hauv qab 100℃(210℃F)
Stringer hlaws txheej txheem (tsis txhob weaving)
Kev siv rov qab -purge gas (argon) rau hauv paus hla los tiv thaiv oxidation ntawm sab hauv
Pom zoo Filler hlau:Ntau qhov kev xaiv hlau muaj rau vuam Incoloy 825:
ERNiFeCr-1 (AWS A5.14): Qhov no yog cov hlau muab tub lim rau Incoloy 825, tseem hu ua INCOLOY® 65 muab tub lim hlau. Nws muab corrosion kuj sib npaug rau lub hauv paus hlau thiab yog haum rau TIG (GTAW) thiab MIG (GMAW) vuam.
INCOLOY® 135 vuam electrodes: Rau phau ntawv hlau arc vuam (MMA / SMAW), cov electrodes muab cov khoom tsim nyog thiab cov khoom siv kho tshuab.
Lwm txoj kev muab tub lim hlau xws li ER383 (27.31.4.LCu) tuaj yeem siv rau cov ntawv thov tshwj xeeb, tab sis kev sib xyaw muab tub lim feem ntau nyiam rau qhov siab tshaj plaws corrosion kuj.
Tshaj tawm -Weld Heat Treatment (PWHT):Hauv cov ntawv thov feem ntau, Incoloy 825 tuaj yeem siv tau raws li -welded mob yam tsis muaj kev tshaj tawm -weld heat treatment. Txawm li cas los xij, rau kev pabcuam hauv ib puag ncig muaj corrosive heev los yog qhov chaw seem muaj kev txhawj xeeb, kev daws teeb meem annealing ntawm 930-980℃tom qab dej quenching yuav raug ua kom rov qab siab tshaj corrosion kuj thiab tshem tawm ib qho rhiab heev hauv tshav kub- cuam tshuam cheeb tsam.
Kev Tsim Nyog:Cov txheej txheem vuam rau Incoloy 825 hauv kev pabcuam acid tseem ceeb yuav tsum tsim nyog raws li ASME Tshooj IX lossis cov lej siv tau, suav nrog kev kuaj tshuab thiab kev kuaj corrosion los xyuas kom meej tias cov welded sib koom ua tau raws li cov qauv kev ua haujlwm.
5. Q: Hauv cov khoom tshwj xeeb hauv cov kua qaub thiab cov chaw pickling yog Incoloy 825 cov yeeb nkab thiab cov raj feem ntau ua haujlwm, thiab cov kev pabcuam twg ua rau nws xaiv?
A:Incoloy 825 yeeb nkab thiab raj tau teev tseg rau ntau yam khoom siv hauv kev tsim cov kua qaub thiab kev ua haujlwm pickling, tshwj xeeb tshaj yog qhov kev pab cuam tshaj li lub peev xwm ntawm cov khoom siv tsis tshua kim stainless hlau.
Pickling kev ua haujlwm:Hauv cov chaw ua cov hlau, cov kab pickling siv cov kua qaub sib xyaw (feem ntau sulfuric acid ua raws li nitric -hydrofluoric acid sib tov) kom tshem tawm cov nplai ntawm cov khoom hlau. Incoloy 825 feem ntau siv rau:
Pickling tank rhaub(steam or electric immersion coils)
Pickling tanks thiab tank linings
Cua sov coils, pob tawb, thiab chainssiv los raus cov khoom steel
Recirculation piping thiab twj tso kua mistuav cov kua qaub kub
Lub alloy tiv taus qhov hnyav heev ntawm cov kua qaub sib tov thaum tswj kev ua haujlwm ntawm kev ua haujlwm kub txog 550℃(1022℃F) luv luv - lub sij hawm raug.
Kev tsim tawm sulfuric acid:Hauv cov nroj tsuag tsim sulfuric acid los ntawm kev sib cuag, Incoloy 825 yog siv rau:
Thaum tshav kub kub exchangers(ob lub plhaub-thiab- raj thiab phaj hom) rau cov kua qaub txias thiab cua sov cov kev pab cuam
Acid distribution pipingtuav kub concentrated H₂SO₄
Ductwork thiab scrubbersnyob rau hauv sulfur rov qab units
Phosphoric Acid Production:ntub- txheej txheem phosphoric acid cov nroj tsuag siv Incoloy 825 rau:
Evaporators thiab concentratorsqhov twg phosphoric acid yog concentrated nyob rau hauv lub tshuab nqus tsev
Fork tubes thiab heat exchanger tubesnyob rau hauv cov tshuaj tiv thaiv thiab concentration
Scrubbers thiab kav dejtuav cov kua qaub slurry uas muaj gypsum thiab lwm yam khib nyiab
Lwm Cov Khoom Siv Tshuaj Txheej Txheem:Tshaj li acid ntau lawm, Incoloy 825 pom daim ntawv thov hauv:
Kev tswj cov pa phem: Flue gas desulfurization (FGD) units hauv fais fab nroj tsuag
Roj thiab roj ntau lawm: Downhole tubing thiab nto piping rau qaub roj (H₂S/CO₂) kev pab cuam
Nuclear roj reprocessing: Cov cuab yeej tuav siv roj yaj (sulfuric thiab nitric acid sib tov)
Radioactive pov tseg: Cia thiab ua cov nkoj
Kev Ncaj Ncees rau Kev Xaiv:Qhov kev txiav txim siab los qhia Incoloy 825 tshaj lwm txoj hauv kev xws li 316L stainless hlau, duplex stainless hlau, lossis siab dua - alloyed npib tsib xee alloys xws li C-276 feem ntau yog raws li lub neej- kev txheeb xyuas tus nqi. Thaum Incoloy 825 nqa tus nqi pib ntau dua li cov hlau tsis muaj steel (feem ntau yog 2-4 npaug ntawm tus nqi ntawm 316L), nws qhov kev tiv thaiv corrosion zoo dua txhais tau tias lub neej ua haujlwm ntev dua, txo txij nkawm downtime, thiab tshem tawm cov kev pheej hmoo ua tsis tiav ntxov ntxov. Piv nrog rau Alloy C-276, Incoloy 825 muaj cov kev daws teeb meem zoo tshaj plaws rau cov ntawv thov uas tsis tas yuav muaj kev tiv thaiv corrosion ntawm C-276.
