1. Inconel 600 yog nto moo tiv thaiv rau chloride kev ntxhov siab corrosion (cl- scc). Dab tsi yog cov metallurgical lub hauv paus rau qhov no tiv taus cov yeeb nkab uas nyiam tshaj plaws rau cov nroj tsuag cua sov ua kom muaj dej txias?
Chloride kev ntxhov siab yog qhov tsis ua hauj lwm hom rau cov hlau tsis ua hauj lwm zoo li 304 thiab 316 nyob rau ib puag ncig muaj chlorides, tensile muaj kev ntxhov siab, thiab nce qhov kub. Inconel 600 kev tiv thaiv kab mob ntawm nws cov khoom siv tseem ceeb.
Metallurgical lub hauv paus: Tus yuam sij yog nws cov ntsiab lus npib tsib xee (~ 72% min.). SCC hauv Austenitic stainless hlau yog ib intergranular crushation protomenon. Nickel, uas muaj kev phom sij rau cov Austenic theem, cov lus qhia txog cov alters cov altrochemical teb rau chlorides. Nws nce lub zog tsim nyog rau cov kab nrib pleb mus pib thiab propagate raws cov ciaj ciam av. Thaum tsis muaj kev tiv thaiv tag nrho cov kev mob siab, rau cov kev siv cua txias (piv txwv li cov kev siv hluav taws xob hauv qab no 200 degree)
Vim li cas cov yeeb nkab seamless rau cov pa hluav taws xob ua kom sov? Cov tub rog sib hloov cua sov yog nyias -}} pa tawm rau sab hauv thiab sab nraud kev caij tsheb kauj vab, thiab kev co thermling, thiab kev co. Tus txheej txheem seamlessting yog qhov tseem ceeb ntawm no rau peb yam:
Homogeneous qauv: lub raj uas tsis muaj dab tsi muaj cov khaub ncaws hnav, homogeneous grages nyob ib ncig ntawm nws ib ncig, kom muaj zog sib xws thiab corrosion tsis kam. Qhov no tseem ceeb heev rau nrog lub plhaub ntawm lub plhaub - thiab- tube.
Kev tshem tawm weld tsis xws luag: lub raj welditudinally muaj lub cev tsis muaj zog tshaj plaws {} {{1}- bein cuam tshuam thaj chaw (Haz). Thaj chaw no tuaj yeem ua rau muaj kev tawm tsam lossis ua raws li kev pib ua rau nkees tawg hauv kev ua haujlwm tshee. Lub raj uas tsis quav dhau me nyuam tshem tawm txoj kev pheej hmoo no.
Superior nto tag nrho: sab hauv ntawm lub raj seamless yog ib txwm smoother tshaj li ntawm welded thiab kos raj. Qhov no minimizes fouling, txhim kho kev hloov kho cua sov, thiab txo cov chaw rau kev xaiv qhov kev pib.
Yog li ntawd, incon 600 seamless hlab yog tus qauv kev hloov pauv hluav taws xob tseem ceeb hauv kev ua kom cua txias thiab tshuaj txias qhov twg muaj cov chlorides, yog siv.
2. Hauv kev siv hluav taws xob nuclear, tshwj xeeb hauv cov tshuab hluav taws xob dej reactors (pwrs), inconel 600 Seamel tubing tau siv dav tab sis ntsib cov kev sib tw tseem ceeb. Dab tsi yog thawj lub chaw ua hauj lwm ua haujlwm, thiab qhov chaw lag luam li cas?
Lo lus nug no tseem ceeb rau tshooj tseem ceeb hauv keeb kwm cov ntaub ntawv keeb kwm. Inconel 600 tau siv ntau yam rau cov roj hluav taws xob tubing hauv cov ntawv sau vim nws lub zog siab thiab dav corrosion tsis kam. Txawm li cas los xij, ib qho kev ua tsis tiav tshwj xeeb thaum: thawj cov dej kev ntxhov siab corrosion (PWSCC).
The PWSCC Mechanism: PWSCC is a form of intergranular cracking that occurs in the high-purity, high-temperature (typically >300 degree) dej ib puag ncig hauv reactor. Rau inconel 600, nws tau pom tias lub alloy lub micy microstructure ntawm cov ciaj ciam tau raug kis tau. Kev sib xyaw ua ke ntawm cov khoom seem siab tshaj plaws (los ntawm raj nthuav dav rau hauv lub raj {{{} coj mus rau qhov pib thiab kev hais tawm ntawm kev sib tsoo. Qhov no yog qeeb tab sis kev tsis meejfless uas tsis muaj lub raj ncaj ncees thiab ua rau muaj kev nyab xeeb thiab ua haujlwm hnyav.
Kev Lag Luam Teb thiab Evolution: Lub Lag Luam nyob qhov no los ntawm ob -} pronged mus ze:
Cov khoom hloov: ntev {{-}} ecloy awno} Cov chav tsim khoom tshiab thiab hloov chav nyob tam sim no tshwj xeeb siv Inconel 690 Seamless tubing.
Mitigation rau cov nroj tsuag uas twb muaj lawm: rau kev ua haujlwm reactors nrog inconel 600 tubing, dav thiab txo tus nqi tswj cov tswv yim tau siv. Cov no suav nrog:
* Ua kom zoo dua nyob rau hauv - Txoj Kev Pab Cuam: ectures eddy tam sim no kev sim (ect) thaum lub sij hawm saib xyuas me ntsis ntawm kev tawg.
* Tube plugging thiab khaub ncaws: Yog kuaj pom, cov leeg cuam tshuam yog txhaws (coj tawm ntawm cov kev pabcuam) lossis kho los ntawm cov tes tsho, uas yog tom qab ntawd welded nyob rau hauv qhov chaw.
Cov keeb kwm no nkag mus rau qhov tseem ceeb ntawm kev ntsuas ntev ntawm ntev}}} lub sij hawm ntsuas thiab solunlification ntawm high secomium zoo li 690 rau cov kev pab cuam tseem ceeb tshaj plaws.
3. Rau siab {-} sov daim ntawv thov zoo li cov kev ua kom zoo 600 ua piv txwv rau nws qhov kev txwv tsis pub tshaj?
Thaum ob qho tib si yog nickel - chromium alloys, inconel 601 tau raug tsim kho kom zoo dua rau kev hloov pauv mus rau oppe- kub oxidizing ib puag ncig.
Kev sib piv ua tau: Inconel 600 muaj cov oxidation zoo tsis kam txog 1100 degree. Txawm li cas los xij, nws cov nplai tiv thaiv yog feem ntau chromium oxide (cr₂o₃). Ntawm qhov kub tshaj 1100 degree, cov nplai no tuaj yeem dhau los ua cov neeg caij tsheb kauj vab thiab tsis tshua muaj kev tiv thaiv, tawm ntawm cov hlau tawg), ua rau cov hlau tawg ntxiv rau kev tawm tsam ntxiv.
Qhov kev txwv txiav thiab 601 qhov zoo: Cov qhov sib txawv tseem ceeb yog cov ntsiab lus txhuas txhuas.
Inconel 600 muaj tsuas yog cov nqi ntawm txhuas.
Inconel 601 muaj ib qho tseem ceeb ntawm ntawm ~ 1.4% Aluminium.
Cov txhuas no oxidizes los ua ib qho ruaj khov, txuas ntxiv, thiab qeeb {{{{}} loj zuj zus txheej (al₂o₃) hauv qab txheej chromia. Lub alumina txheej no tau deb tiv taus spalling thiab muab kev tiv thaiv zoo dua li ntawm 1250 degree.
Yog li no, rau cov qauv tshiab uas muaj kev cuam tshuam radiant roades, rauv muffles, lossis kub kho fixidizing thiab cua sov kev xaiv, tsis muaj kev xaiv zoo dua thiab nyiam. Inconel 600 tseem haum rau qhov hnyav dua, txuas ntxiv siab dua {{}} kub kev pab cuam uas cycling yog tsawg.
4. Los ntawm cov kev txiav txim siab ntawm cov khoom siv ntawm cov khoom siv
Kev tsim kom haum yog qhov tseem ceeb los tiv thaiv kev ua tsis muaj zog uas cuam tshuam rau aleroy cov tshuaj corrosion.
Vuam txiav txim siab:
Xaiv cov chaw xaiv hlau: Qhov kev xaiv feem ntau yog qhov sib xyaw ua ke muab tub lim, xws li Ernicr - 3 (Aws A5.14). Rau cov ntawv thov yuav tsum tau ua kom zoo rau kev sib tw corrosive lossis los tiv thaiv ductility tooliling zoo li ernicrmo-3 (inconel 625) yuav siv tau.
Kev nyiam huv: Raws li nrog txhua tus nickel alloys, txog kev huv yog qhov tseem ceeb heev. Cov tsis huv xws li leej faj, txhuas, thiab phosphorous tuaj yeem ua rau kub tawg. Txhua thaj chaw yuav tsum muaj roj, roj, thiab pleev xim.
Cov tswv yim tshav kub tswj: Siv cov kev tshav kub tsawg thiab cov hlua khi cov hlua khi kom txo qis cais thiab qoob loo kev loj hlob hauv qhov kub {}}} bead cuam tshuam thaj chaw (Haz). Sib txuam kub yuav tsum ua tib zoo tswj (feem ntau khaws cia hauv qab 150 degree).
Rov qab ntxuav tawm: Thaum vuam cov yeeb nkab, siv cov roj av (arter)
Kev kho cua sov (daws annealing): Tom qab vuam los yog txias ua haujlwm, kev daws analing kev kho cua sov feem ntau ua yeeb yam. Qhov no cuam tshuam nrog cov kev sib txoos rau 1050-1150 degree, tuav rau lub sijhawm txaus (piv txwv li, 1 teev toj ib nti ntawm dej quenching. Tus txheej txheem no:
Dissolves ib qho chromium carbides uas tej zaum yuav tau siv nag thaum lub taub, kho kom haum tag nrho corrosion.
Rov qab cuam tshuam cov kev nyuaj siab ntawm vuam thiab kev sib sau, uas yog qhov tseem ceeb rau kev tiv thaiv kev ntxhov siab corrosion.
Recrystallizes micructory, rov kho dua tshiab.
5. Hauv kev siv aqueous selosous, sab nraud ntawm chloride scc, puas tau hais txog cov yeeb nkab scc, thiab nws cov kev txwv piv rau cov khoom siv ntau ntxiv?
Dhau li nws cov kevcai tiv thaiv rau chloride SCC, Inconel 600 yog qhov tseem ceeb hauv ntau lwm qhov chaw corrosive vim nws cov ntsiab lus nickel siab.
Cov txiaj ntsig zoo hauv aquous corrosion:
Caustic dej qab zib (sodium hydroxide): inconel 600 tau ua kom zoo heev rau cov kev daws teeb meem yooj yim, ua rau cov khoom siv evaporator thiab cov cuab yeej siv hauv kev lag luam caustic. Nws yog resrant hla ntau ntau yam kev xav thiab kub.
Dej thiab chav: nws ua kom pom zoo zoo rau cov dej siab siab thiab cov chav purity nyob rau hauv nws cov teeb meem pwscc tau nkag siab).
Cov organic thiab inorganic acids: nws muaj kev ua tau zoo hauv ntau qhov tsis {{}} oxidizing cov kua kub ntawm qhov kub thiab txias thiab ntau dua.
Txwv thiab cov muaj alloys zoo heev:
vs. inconel 625 thiab c-}}}}}}}}}}}}: inconel 600 muaj kev tsis zoo rau cov kua qaub zoo li hydrochloric thiab sulfuric. Alloys muaj Molybdenum, xws li Innonel 625 (9% MO) thiab haastelloy C-276 (16% MO), yog qhov loj dua rau cov chaw ib puag ncig no. Lawv tseem muab ntau qhov zoo dua tsis kam mus pitting thiab crevice corrosion hauv chloride-muaj cov kev daws teeb meem.
vs. inconel 690: Raws li tau tham txog, rau txhua daim ntawv thov uas muaj kev xaiv siab dua vim nws qhov kev tiv thaiv kom muaj PWSCC.
Hauv cov ntsiab lus, Inconel 600 seamless yeeb nyob tseem ceeb nyob rau hauv chloride ib puag ncig muab kev sib txuam ntawm cov khoom siv tau muab kev ua tau zoo thiab tus nqi.
