1. Dab tsi yog qhov tseem ceeb ntawm cov khoom siv hlau thiab cov khoom sib txawv ntawm Inconel 625, Inconel 718, thiab cov khoom lag luam ntshiab N6 npib tsib xee, thiab cov no ua li cas rau lawv cov ntawv thov?
Peb cov ntaub ntawv no sawv cev rau cov pawg sib txawv hauv cov tsev neeg nickel alloy, txhua tus tsim los rau ib lub hnab ntawv tshwj xeeb.
Inconel 625 (UNS N06625): Qhov no yog ib qho khoom siv - kev daws teeb meem, npib tsib xee-chromium- molybdenum alloy nrog qhov tseem ceeb niobium ntxiv. Nws lub zog tseem ceeb yog los ntawm cov nyhuv stiffening ntawm molybdenum thiab niobium atoms nyob rau hauv cov nickel-charting lattice, ntxiv txhim kho los ntawm theem nrab carbide thiab gamma ob npaug - nag lossis daus thaum ua haujlwm. Nws lub npe nrov tshaj plaws yog nws qhov tshwj xeeb, dav -spectrum corrosion kuj, suav nrog kev ua haujlwm zoo rau pitting, crevice corrosion, thiab kev ntxhov siab{10}}corrosion tawg nyob rau hauv ib puag ncig chloride. Nws kuj muaj oxidation zoo heev txog li 1800℃F (980 degree). Cov ntawv thov raug: Cov khoom siv tshuaj lom neeg hauv cov hlab ntsha, cov khoom siv hauv hiav txwv, cov khoom siv dej hiav txwv kub, cov tshuab hluav taws xob desulfurization, thiab aerospace ducting qhov twg corrosion yog thawj qhov kev txhawj xeeb.
Inconel 718 (UNS N07718): Qhov no yog nag lossis daus -nickel hardenable-chromium alloy uas muaj ntau ntawm niobium, molybdenum, titanium, thiab txhuas. Nws lub zog txawv tshaj plaw yog muab los ntawm ob - theem kev kho cua sov (kev laus) uas ua rau lub cev sib xyaw ua ke - theem tetragonal theem (gamma ob npaug -prime, Ni3Nb). Qhov no muab nws lub zog siab tshaj plaws ntawm peb, tshwj xeeb tshaj yog thaum kub txog li 1300℃F (700 degree). Thaum nws muaj kev tiv thaiv corrosion zoo, nws lub ntsiab xaiv tsav tsheb yog siab tensile thiab creep{13}} tawg lub zog. Daim ntawv thov: Gas turbine engine discs, hniav, ncej, thiab fasteners; siab-cov khoom siv lub taub hau siab; foob pob hluav taws motor casings; thiab ib qho kev ua haujlwm siab - kev ntxhov siab ntawm cov qauv ntawm qhov kub siab.
N6 Nickel (UNS N02200/201, ~ 99.0% Ni min): Qhov no yog kev lag luam ntshiab, wrought nickel. Nws cov khoom yog siab ductility, zoo heev thermal thiab hluav taws xob conductivity, thiab superior magnetic zog. Nws qhov zoo tshaj plaws yog qhov ua tau zoo rau corrosion los ntawm caustic alkalis thiab txo cov tshuaj. Txawm li cas los xij, nws muaj lub zog tsis tshua muaj zog piv rau Inconel alloys thiab tsis zoo rau oxidizing acids. Qhov sib txawv tseem ceeb ntawm Nickel 200 (N02200) thiab Nickel 201 (N02201) yog cov ntsiab lus carbon; 201's ultra- carbon qis tso cai rau kev pabcuam siab tshaj 600℃F (315 degree) yam tsis muaj graphitization embrittlement. Cov ntawv thov: Caustic soda cov cuab yeej tsim khoom, cov khoom siv ua khoom noj, cov khoom siv hluav taws xob, thiab cov khoom siv tshuaj lom neeg ua rau thaj chaw tshwj xeeb.
Hauv cov ntsiab lus: Xaiv N6 rau cov tshuaj dawb huv (tshwj xeeb tshaj yog rau caustics). Xaiv Inconel 625 rau qhov zoo tshaj plaws - nyob ib ncig ntawm corrosion kuj nyob rau hauv complex ib puag ncig uas siab zog yog theem nrab. Xaiv Inconel 718 thaum siab tshaj plaws - qhov kub thiab txias tsis kam yog qhov tseem ceeb tshaj plaws.
2. Hauv cov ntsiab lus ntawm kev tsim cov phaj thiab cov ntawv, vim li cas Inconel 718 suav tias yog qhov nyuaj rau vuam ntau dua li Inconel 625, thiab cov txheej txheem tshwj xeeb twg raug yuam?
Qhov kev sib tw vuam nrog Inconel 718 ncaj qha los ntawm nws cov nag lossis daus - hardening metallurgy. Qhov ntxiv dag zog rau gamma ob - theem tseem ceeb yog qhov nkag siab zoo rau cov voj voog thermal, ua rau cov vuam thiab cua sov- thaj chaw cuam tshuam (HAZ) muaj qhov tsis xws luag yog tias tsis tswj xyuas zoo.
Cov kev sib tw tseem ceeb:
Tshaj tawm - Weld Strain Age Cracking (SAC): Qhov no yog qhov teeb meem tseem ceeb tshaj plaws. Thaum txias tom qab vuam, residual tensile stresses tsim. Lub HAZ, rhuab mus rau qhov kub thiab txias ntau yam (800-1200℃F / 427-649 degree), tuaj yeem muaj hnub nyoog hnyav. Qhov no muaj zog ntxiv, ua ke nrog cov kev ntxhov siab seem, tuaj yeem ua rau kev sib tsoo hauv HAZ-ib qho tshwm sim hu ua strain age cracking.
Liquation Cracking: Kev sib cais ntawm qis- melting- cov ntsiab lus (xws li boron) rau cov ciam teb tuaj yeem ua rau microfissuring nyob rau hauv ib feem ntawm cov melted cheeb tsam nyob ib sab ntawm lub weld.
Kev poob ntawm cov khoom: Cov khoom siv hluav taws xob tsis tswj tau tuaj yeem ua rau dhau - kev laus lossis kev tawg ntawm cov dej khov ua kom muaj zog hauv HAZ, tsim kom muaj thaj chaw tsis muaj zog.
Cov txheej txheem vuam txoj cai (Qhov Zoo Tshaj Plaws):
Kev Xaiv Cov Txheej Txheem: Gas Tungsten Arc Vuam (GTAW/TIG) yog qhov zoo dua rau nws qhov kev tswj xyuas kom sov. Gas Hlau Arc Vuam (GMAW/MIG) tuaj yeem siv nrog kev hloov pauv hloov pauv.
Filler Hlau: Siv cov khoom siv hlau sib txuam (ERNiFeCr-2) lossis tawg -cov khoom ua kom tsis muaj zog (xws li ERNiCrMo-3 / Inconel 625 muab tub lim). Lub 625 muab tub lim yog feem ntau xaiv rau nws superior weld hlau ductility thiab tsis kam mus rau tom qab-weld cracking nyob rau hauv heev constrained pob qij txha.
Low Heat Input: Siv qhov tsawg kawg nkaus amperage tsim nyog, nrog rau kev ceev ceev.
Kev Tsim Kho: Siv dav groove cov ces kaum kom txo qis thiab tso cai rau cov hlaws dai uas txo qis kev ntxhov siab.
Interpass Kub: Tswj nruj, feem ntau qis dua 200℃F (93 degree).
Tom qab- Kev Kho Hniav Kub Kub (PWHT): Ib qho kev daws teeb meem tag nrho ntawm kev kho mob thiab kev laus (SA + Hnub Nyoog) yuav luag ib txwm xav tau rau cov khoom tseem ceeb los kho cov khoom zoo li qub thiab txo kev ntxhov siab. Direct aging (DA) tom qab vuam yog ua tau rau qee qhov kev siv tsis tshua muaj txiaj ntsig tab sis yuav tsum muaj cov txheej txheem tsim nyog.
Hauv qhov sib piv, Inconel 625, ua tau zoo - kev daws teeb meem, yog suav tias yog qhov feem ntau weldable ntawm siab -kev ua tau zoo nickel alloys. Nws muaj zog heev rau kev tshaj tawm -weld cracking, thiab nws cov hlau weld khaws cov khoom zoo heev corrosion. Lub hom phiaj tseem ceeb rau vuam 625 yog tswj xyuas cov cua kub tsis tshua muaj zog los tiv thaiv corrosion thiab tiv thaiv theem ob los nag.
3. Rau cov dej hiav txwv -txias phaj kub exchanger tuav ob qho tib si chlorinated dej thiab qaub (H₂S- muaj) cov txheej txheem kwj, cov khoom siv dab tsi -Inconel 625 lossis 718-yog qhov kev xaiv raug, thiab vim li cas?
Inconel 625 yog qhov tseeb tiag thiab tus qauv xaiv rau qhov kev pabcuam no. Kev xaiv yog tsav los ntawm ib puag ncig corrosion, tsis yog txhua yam muaj zog.
Chlorinated Seawater: Qhov chaw no yog qhov kev sim hnyav rau pitting thiab crevice corrosion. Inconel 625, nrog nws ~ 9% Molybdenum thiab ~ 3.5% Niobium cov ntsiab lus, muaj Pitting Resistance Equivalent Number (PREN) zoo tshaj 40, ua rau nws muaj zog heev rau kev tawm tsam hauv zos. Nws kuj tseem muaj kev tiv thaiv zoo rau chloride-induced stress corrosion cracking (SCC).
Sour Service (H₂S): Ob lub alloys tau teev tseg raws li tau txais hauv NACE MR0175 / ISO 15156 rau sulfide stress cracking (SSC) tsis kam. Txawm li cas los xij, Inconel 625 qhov zoo tshaj plaws kev tiv thaiv corrosion muab qhov kev nyab xeeb loj dua tiv thaiv kev sib tw thiab pitting, uas tuaj yeem ua raws li qhov chaw pib rau SSC nyob rau hauv kev ntxhov siab tensile. Nws cov weldments, thaum ua nrog cov muab tub lim, kuj tseem khaws tau zoo heev.
Vim li cas ho tsis Inconel 718? Thaum 718 muaj txaus SCC / SSC tsis kam, nws cov ntsiab lus molybdenum (~ 3%) yog qhov qis dua, muab nws qis dua PREN thiab ua rau nws muaj kev cuam tshuam rau pitting thiab crevice corrosion nyob rau hauv stagnant, chlorinated tej yam kev mob. Tsis tas li ntawd, qhov kev ntxhov siab ntau dhau los ntawm vuam 718 (txawm tias tom qab PWHT) ua rau muaj kev pheej hmoo ntawm ib puag ncig kev pab cuam tawg nyob rau hauv xws li ib tug nruj, ua ke ib puag ncig. Lub zog tensile loj ntawm 718 tsuas yog tsis xav tau- thiab muaj feem cuam tshuam los ntawm corrosion-initi standpoint- nyob rau hauv ib qho zoo li qub lossis ib nrab -static heat exchanger phaj daim ntawv thov.
Cov neeg kho tshuab xav tau ntawm cov khoom siv hluav taws xob sib txawv yog rau kev ntim siab thiab rigidity, tsis yog ultra- siab tensile zog. Inconel 625 phaj muab ntau tshaj qhov muaj zog txaus (cov txiaj ntsig zoo zog ~ 60 ksi nyob rau hauv cov xwm txheej annealed) thaum muab kev tiv thaiv ntau dua tiv thaiv cov txheej txheem corrosion tshwj xeeb tam sim no.
4. Lub thermal expansion yam ntxwv ntawm kev lag luam ntshiab N6 npib tsib xee phaj cuam tshuam nws txoj kev siv hauv clad lossis bi-cov ntawv siv hlau, tshwj xeeb tshaj yog thaum sib txuas nrog hlau?
Lub coefficient ntawm thermal expansion (CTE) yog ib qho tseem ceeb tsim qauv rau clad daim hlau thiab cov qauv bimetallic. Kev lag luam ntshiab npib tsib xee (N6) muaj CTE qis dua li cov pa roj carbon steel tshaj qhov kub ntawm qhov dav.
Nickel (N02200): ~ 13.3 µm / m·℃(70-212℃F)
Carbon Steel (A516 Gr. 70): ~ 14.5 µm/m·℃(70-212℃F)
Qhov kev tsis sib haum xeeb hauv CTE muaj qhov cuam tshuam loj:
Thaum lub sij hawm Fabrication (Cladding / Vuam): Qhov sib txawv ntawm qhov sib txawv thaum txias los ntawm qhov vuam los yog tawg -cladding kub ua rau muaj kev ntxhov siab tseem ceeb ntawm cov khoom sib txuas. Cov nickel txheej yog sab laug nyob rau hauv seem nro, thaum lub steel substrate nyob rau hauv compression. Qhov no yuav tsum tau ua tib zoo tswj kom tsis txhob delamination lossis distortion.
Hauv Kev Pabcuam: Thaum lub sijhawm ua haujlwm cua sov thiab cua txias, cov hlau yuav sim nthuav thiab cog lus ntau dua li cov nickel cladding. Qhov kev sib txawv cyclic no tuaj yeem ua rau:
Kev qaug zog ntawm qhov Interface: Muaj peev xwm ua rau kev pib tawg thiab kev vam meej tsis ua hauj lwm nyob rau hauv lub caij ntuj sov hnyav.
Warping / bowing ntawm tag nrho cov phaj yog tias clad tsuas yog nyob rau ntawm ib sab.
Ntxiv Stress ntawm Welds ntawm junctions nrog rau lwm yam.
Mitigation Strategies:
Intermediate "Buffer" Cladding: Qee lub sij hawm, txheej nyias ntawm cov khoom siv nrog CTE nruab nrab (xws li Inconel 625 lossis cov hlau tshwj xeeb) raug siv ua ntej rau cov hlau ua ntej cov nickel cladding, tsim kom muaj kev hloov pauv ntau dua.
Kev ntxhov siab-Kev kho cua sov: Tom qab-cladding thermal kho tuaj yeem txo cov kev ntxhov siab uas seem, txawm tias nws yuav tsum tau ua kom qis dua qhov kub ntawm cov hlau substrate.
Tsim Kev Pabcuam: Cov kws ua haujlwm yuav tsum suav rau qhov tsis sib haum xeeb no hauv kev txheeb xyuas qhov kawg (FEA), tso cai rau kev hloov pauv hauv kev txhawb nqa thiab kev sib txuas kom haum rau qhov sib txawv txav yam tsis muaj kev cuam tshuam rau daim ntawv cog lus lossis cov qauv.
5. Los ntawm tag nrho cov nqi ntawm lub neej kev xav, thaum twg qhov kev piav qhia tus nqi kim dua Inconel 625 phaj ua kev lag luam ncaj ncees dhau tus qauv 316L lossis duplex 2205 stainless hlau phaj?
Qhov kev ncaj ncees rau Inconel 625 tsis tshua muaj raws li cov khoom siv thawj zaug (nws tuaj yeem yog 5-10x kim dua 316L). Hloov chaw, nws yog ua raws li Kev Tshawb Fawb Txog Kev Ua Neej Nyob (LCCA) uas muaj feem cuam tshuam txog kev ntseeg siab, kev saib xyuas, thiab kev poob qis.
Qhia rau Inconel 625 tshaj 316L / Duplex 2205 thaum:
Qhov Ib puag ncig dhau ntawm Alloy qhov txwv: Thaum cov tshuaj chloride concentration, kub, thiab pH sib xyaw ua ke los thawb ib puag ncig dhau qhov tseem ceeb pitting kub (CPT) los yog qhov tseem ceeb crevice kub (CCT) ntawm 316L los yog 2205. Ib qho pitting tsis ua hauj lwm tuaj yeem rhuav tshem lub nkoj lossis cov khoom sib hloov.
Qhov laj thawj ntawm kev ua tsis tiav yog qhov kev puas tsuaj loj: Hauv cov chaw sab nraud, cov khoom siv dej hiav txwv sib sib zog nqus, lossis cov txheej txheem tshuaj lom neeg tsis tu ncua uas cov dej xau ua rau poob ntau, muaj kev nyab xeeb, lossis kev puas tsuaj ib puag ncig. Tus nqi ntawm ib qho kev kaw ib leeg tuaj yeem ua rau cov khoom siv tau zoo.
Txhawm rau tshem tawm qhov teeb meem Kev Kho Mob Ntev: Yog tias 316L tivthaiv yuav tsum tau tshuaj xyuas ntau zaus, kho qhov vuam, lossis hloov pauv txhua 2-3 xyoos, hloov kho mus rau 625 rau 20+ xyoo kev pabcuam lub neej yam tsis muaj kev cuam tshuam muaj kev txuag nyiaj ntau.
Rau Nyias- Phab ntsa, Siab- Kev Tsim Kho Siab: Inconel 625 lub zog siab dua (kwv yees . 2x lub zog tawm los ntawm annealed 316L) tuaj yeem tso cai rau cov phaj nyias nyias. Qhov no tuaj yeem txo qhov hnyav (tseem ceeb rau sab saum toj ntawm ntug dej hiav txwv), nce kev them nyiaj, thiab qee zaum cuam tshuam cov nqi ntawm cov khoom siv los ntawm kev txuag cov ntaub ntawv thiab yooj yim fabrication ntawm cov qauv sib dua.
Nyob rau hauv Complex, Unpredictable, los yog "phem tshaj plaws-Case" tshuaj kwj: qhov twg cov txheej txheem chemistry yuav txawv los yog chim siab tej yam kev mob yuav ua kom paub cov oxidants npaj txhij txog (Fe³⁺, Cu²⁺) los yog cov kab mob, 625 lub dav, pov thawj kuj muab ib tug invaluable kev nyab xeeb margin uas qis alloys lav tsis tau.
Hauv qhov tseem ceeb, kev sib npaug ntawm kev lag luam hloov pauv los ntawm kev siv peev nyiaj (CAPEX) mus rau kev siv nyiaj lag luam (OPEX). Qhov siab dua pib CAPEX rau Inconel 625 yog qhov tsim nyog los ntawm OPEX qis dua los ntawm ze rau - xoom txij nkawm, tshem tawm lub sijhawm poob qis, thiab lub neej muaj txiaj ntsig ntev heev.
