Incoloy 825 (UNS N08825) Cov.thiab 316L stainless hlau (UNS S31603) feem ntau muab piv vim tias ob qho tib si tiv thaiv corrosion thiab ob qho tib si zoo li "lub ci iab alloy" rau ib tus tsis yog - tus kws tshaj lij. Qhov tseeb lawv zaum hauv tsev neeg cov khoom sib txawv. 316L yog austenitic stainless hlau nrog txog 10-14% npib tsib xee; Incoloy 825 yog npib tsib xee- hlau-chromium alloy nrog 38-46% npib tsib xee ntxiv rau txhob txwm tshaj tawm tooj liab, molybdenum, thiab titanium ntxiv. Qhov sib txawv ntawm cov ntsiab lus npib tsib xee tsis yog qhov nthuav dav - nws txiav txim siab seb cov hlau puas muaj roj qaub, sulfuric acid, thiab cov chlorides kub, los yog ntsiag to tawg.
Cov kab hauv qab: thaum cov kev pabcuam muaj cov roj qaub (H2S), sulfuric lossis phosphoric acid, lossis cov tshuaj chlorides siab tshaj li 60 degree, Incoloy 825 yog qhov kev xaiv zoo engineering thiab 316L tsis tsim nyog . 316L tseem yog cov neeg ua haujlwm pheej yig rau cov dej huv, dej ua haujlwm me me, thiab huab cua raug. Xaiv los ntawm ib puag ncig, tsis yog los ntawm tus nqi: 316L qhov twg corrosion yog me me, 825 qhov twg nws yog nruj los yog qaub.
Dab tsi ua rau Ob Qhov Alloys Qhov txawv txav?
|
Element |
Incoloy 825 N08825 |
316L (S31603) |
Vim Li Cas Nws Tseem Ceeb |
|
Nickel (Ni) |
38-46% |
10-14% |
825: chloride SCC tiv thaiv kab mob; 316l :ua |
|
Chromium (Cr) |
19.5-23.5% |
16-18% |
Ob leeg: oxidizing -acid + passive zaj duab xis |
|
Hlau (Fe) |
Ntau dua lossis sib npaug li 22% (sib npaug) |
~ 65% (sib npaug) |
825 pheej yig dua li tag nrho Ni- puag |
|
Molybdenum (hli) |
2.5-3.5% |
2-3% |
Pitting / crevice kuj |
|
Copper (Cu) |
1.5-3.0% |
- (tsis muaj) |
825 nkaus xwb: txo -acid passivation |
|
Titanium (Ti) |
0.6-1.2% |
- (tsis muaj) |
825 nkaus xwb: weld-stabilized, tsis muaj rhiab heev |
|
Cov pa roj carbon (C) |
Tsawg dua lossis sib npaug li 0.05% |
Tsawg dua lossis sib npaug li 0.03% |
Ob leeg qis; 316l qis |
|
PREN (ntev) |
~31 |
~24-25 |
825 ~ 25% zoo pitting kuj |
[Source] ASTM B424 / B423 (Incoloy 825) thiab A240 / A312 (316L); PREN=%Cr + 3.3×%Mo (+16×%N). Cov txiaj ntsig los ntawm Cov Hlau Tshwj Xeeb- tsev neeg thiab cov ntaub ntawv xa khoom (Globo, Womic, jnalloy, SuperStainlessAlloys).
Xav txog 316L zoo li lub qhov dej- ua cov hlau uas xeb maj mam; xav txog Incoloy 825 raws li npib tsib xee- nplua nuj alloy uas nquag tawm tsam cov kua qaub thiab yuav tsis tawg nyob rau hauv chloride kev nyuaj siab. Cov tooj liab nyob rau hauv 825 ua zoo li lub hauv paus catalyst uas thawb lub nto mus rau hauv lub xeev "passive" (tiv thaiv) nyob rau hauv sulfuric acid; cov npib tsib xee siab ua kom cov tshuaj chloride los ntawm kev ua rau muaj kev puas tsuaj loj uas rhuav tshem 316L hauv kub, ntsev, lossis qaub.
Lawv Cov Cuab Yeej Cuab Yeej Sib Piv Li Cas?
|
Property (ntxiv) |
Incoloy 825 N08825 |
316L (S31603) |
Yeej |
|
Tensile zog (min) |
Ntau dua lossis sib npaug rau 585 MPa (85 ksi) |
Ntau dua lossis sib npaug li 485 MPa |
825 |
|
Yield zog 0.2% (min) |
Ntau dua lossis sib npaug rau 240 MPa (35 ksi) |
Ntau dua lossis sib npaug li 170 MPa |
825 |
|
Elongation (min) |
Ntau dua lossis sib npaug li 30% |
Ntau dua lossis sib npaug li 40% |
316L |
|
Hardness (max) |
Tsawg dua lossis sib npaug li 200 HB / Tsawg dua lossis sib npaug li 35 HRC |
Tsawg dua lossis sib npaug rau 217 HB |
Sib piv |
|
Qhov ntom |
8.14 g / cm³ |
8.00 g / cm³ |
316L (lub teeb) |
|
Max kev pabcuam txuas ntxiv |
~ 540 degree |
~ 425 degree |
825 ({1}} degree) |
[Tau qhov twg los] ASTM B424 / B423 thiab A240 / A312 yam khoom yam tsawg kawg nkaus; kev pabcuam- ntsuas kub ntawm cov khoom siv alloy cov ntaub ntawv (Globo, Sasa, SuperStainlessAlloys).
Sour Service (NACE MR0175 / ISO 15156): Ib qho Tsim Nyog, Ib Tsis Yog
Yog - qhov no yog txoj kab faib kom meej tshaj plaws. Incoloy 825 yog cov ntaub ntawv pom zoo raws li NACE MR0175 / ISO 15156 rau H2S-muaj cov kev pabcuam (qaub), muab rau hauv cov tshuaj-annealed mob ntawm qhov siab tshaj plaws hardness ntawm 35 HRC. Nws cov ntsiab lus siab nickel ua rau nws zoo tiv thaiv sulfide stress cracking (SSC) thiab tiv taus hydrogen-induced cracking. 316L stainless tsis tau txais kev pom zoo rau kev pabcuam qaub thiab yog qhov yooj yim rau kev ntxhov siab chloride-corrosion cracking, yog li qhia txog 316L qhov twg H2S cov ntaub ntawv tsis ua haujlwm.
Qhov kev tsim nyog txhais li cas hauv kev xyaum:
- 825 yuav tsum tau xa cov tshuaj -annealed (tsis txias- ua hauj lwm) rau qaub dej; hardness raug txheeb xyuas Tsawg dua lossis sib npaug li 35 HRC.
- Txias-ua haujlwm 825 yam tsis tau rov ua dua-tsis tso cai rau kev pabcuam qaub - kev ua haujlwm txias ua rau muaj kev nyuaj siab thiab SCC kev pheej hmoo.
- Mill Test Reports yuav tsum siv NACE MR0175 / ISO 15156 nrog tag nrho cov cua sov-rau- khoom traceability.
- 316L tsis muaj qhov tsim nyog thiab yuav tsum raug cais tawm ntawm qaub thiab siab -chloride ib puag ncig.
Kev ceeb toom tshwj xeeb: ob peb qhov chaw hais txog 22 HRC txwv rau 825 hauv kev pabcuam qaub. Kev tswj hwm ISO 15156-3 tus nqi rau UNS N08825 yog 35 HRC (kev daws teeb meem). Ib txwm lees paub qhov tseeb ntawm ib puag ncig kev txwv (H2S ib nrab siab, tshuaj chloride, qhov kub thiab txias, cov ntsiab lus sulfur) tiv thaiv cov lus qauv tam sim no rau koj lub hnab ntawv.
Ib puag ncig acid: sulfuric, phosphoric, thiab hydrochloric
Txiav txim siab. Incoloy 825 tau tsim tshwj xeeb rau sulfuric thiab phosphoric acid. Nws cov tooj liab ntxiv passivates saum npoo hauv kev txo cov kua qaub, muab cov nqi corrosion roughly 50x qis dua 316L hauv 50% sulfuric acid ntawm 60℃. 316L raug kev kub ntxhov dav dav tshaj li 40-50℃ntawm nruab nrab acid concentrations - raws nraim lub luag haujlwm uas 825 tau teev tseg.
|
Ib puag ncig |
Incoloy 825 (mm / xyoo) |
316L (mm / xyoo) |
Nyeem- tawm |
|
50% H2SO4 ntawm 60 degree |
~0.05 |
~2.5 |
825-50x zoo |
|
10% H2SO4 ntawm 60 degree |
<0.1 |
3-5 |
825 zoo heev |
|
20% HCl ntawm 25 degree |
~0.15 |
~1.5 |
825-10x zoo |
|
85% H3PO4 ntawm 85 degree |
~0.1 |
~1.2 |
825 zog |
|
Boiling MgCl2 (SCC xeem) |
Resistant (tsis muaj cracking) |
Kev tawg |
Kev txiav txim siab sib txawv |
|
Critical pitting temp (CPT) |
~ 50 degree |
~ 25 degree |
825 x 2 x |
[Source] Corrosion- tus nqi sib piv ib HT PIPE, Hangbo, thiab SuperStainlessAlloys cov ntaub ntawv kev qhia: 50% H2SO4@60C 825 0.05 vs 316L 2.5 mm/yr; boiling MgCl2 SCC 825 resistant vs 316L tawg; CPT 825 ~ 50C vs 316L ~ 25C.
Vim li cas 825 Resistant Acid (Mechanism)
Tooj nyob rau hauv 825 txhawb cathodic hydrogen evolution nyob rau saum npoo, uas hloov cov hlau alloy lub peev xwm corrosion mus rau passive ntau yam uas ruaj khov chromium- oxide zaj duab xis. Hauv cov ntsiab lus dawb, tooj liab "yuam" cov hlau los tiv thaiv nws tus kheej hauv sulfuric thiab phosphoric acid. Chromium tuav txhua yam oxidizing tivthaiv; molybdenum fights pitting los ntawm chloride los yog fluoride paug (ntau nyob rau hauv ntub- txheej txheem phosphoric acid). 316L tsis muaj tooj liab, yog li nws tsis tuaj yeem ua tus kheej -passivate hauv kev txo cov kua qaub thiab corrodes sai.
Chloride Stress Corrosion Cracking
Yog lawm, thiab qhov no yog qhov tshwm sim tiag tiag-lub ntiaj teb tsis ua haujlwm uas txhawb kev hloov kho mus rau 825. Austenitic 316L yog qhov tsis txaus ntseeg rau cov tshuaj chloride kev nyuaj siab-corrosion tawg saum toj li 60℃, tshwj xeeb tshaj yog nrog oxygen thiab tensile stress tam sim no; nyob rau hauv lub boiling magnesium -chloride kuaj nws tawg nyob rau hauv lub sij hawm. Incoloy 825, nrog 38-46% npib tsib xee, zoo tiv thaiv cov tshuaj chloride SCC thiab tsis pom muaj qhov tawg hauv tib qhov kev sim. Rau seawater-txias exchangers, qaub qhov dej, thiab pickling kab, qhov no tiv thaiv yog vim li cas cov neeg ua hauj lwm teev 825 es tsis txhob ntawm 316L.
Ob qhov zoo ntawm 825 tshaj 316L hauv kev pabcuam chloride:
- Siab dua PREN (~ 31 vs ~ 24-25) muab 825 roughly 25% zoo pitting kuj nyob rau hauv ib puag ncig chloride.
- Titanium stabilization txhais tau tias 825 tsis rhiab heev tom qab vuam, yog li nws cov corrosion kuj yog khaws cia nyob rau hauv lub tshav kub - cuam tshuam cheeb tsam - tsis zoo li 316L, uas xav tau qis - carbon (L) qib thiab ceev faj vuam kom tsis txhob hnov qab.
Kev txwv kub: Qhov twg Txhua Alloy nres tsis zoo
Vuam thiab Fabrication
Ob qho tib si weld zoo, tab sis 825 muaj qhov txiaj ntsig tseem ceeb: nws cov titanium stabilization tiv thaiv rhiab heev, yog li nws tuaj yeem siv tau raws li -welded mob rau cov kua qaub feem ntau yam tsis muaj kev tshaj tawm -weld heat treatment. Matching filler metal is ERNiFeCr-1 (AWS A5.14, INCOLOY 65); ERNiCrMo-3 lossis ERNiCr-3 yog lwm txoj kev siv tau. Vim tias 825 muaj cov thermal conductivity qis dua thiab nthuav dav dua stainless, tswj cov khoom siv hluav taws xob (qis dua ~ 1.0-1.5 kJ / mm) thiab khaws qhov kub ntawm qhov sib txawv kom txo qis kev cuam tshuam.
Fabrication sau ntawv uas tiv thaiv corrosion kev ua tau zoo:
- Degrease kom huv si; zam kev sib tsoo log siv rau cov pa roj carbon / stainless hlau los tiv thaiv cov kab mob sulfur / hlau.
- Siv argon rov qab - tshem tawm cov hauv paus hla los tiv thaiv sab hauv.
- Rau cov kua qaub hnyav lossis qaub qaub, cov tshuaj anneal (930-980 degree) tom qab vuam rov ua kom muaj qhov siab tshaj plaws corrosion.
Cov lus nug nquag
Q: Puas yog Incoloy 825 zoo dua 316L rau kev pabcuam qaub?
A: Yog. Incoloy 825 (UNS N08825) tau pom zoo raws li NACE MR0175 / ISO 15156 rau qaub (H2S-muaj) cov kev pabcuam hauv cov tshuaj-annealed mob ntawm hardness<=35 HRC, because its 38-46% nickel content makes it virtually immune to sulfide stress cracking. 316L stainless is NOT approved for sour service and is vulnerable to chloride stress-corrosion cracking above about 60 C, so it is the wrong choice wherever H2S and chlorides coexist.
Q: Qhov twg tiv taus sulfuric acid zoo dua, Incoloy 825 lossis 316L?
A: Incoloy 825 yog qhov zoo tshaj plaws. Nyob rau hauv 50% sulfuric acid ntawm 60 C, ntsuas corrosion tus nqi yog hais txog 0.05 mm / xyoo rau 825 piv rau roughly 2.5 mm / xyoo rau 316L - ib tug 50x sib txawv. 316L raug kev kub ceev dav corrosion saum toj no li ntawm 40-50 C ntawm intermediate concentrations, thaum lub sij hawm intermediate concentrations 'sulphate thiab 82' phosphoric acid thoob plaws ntau yam thiab lub hnab ntawv kub.
Q: Puas yog Incoloy 825 tiv thaiv chloride kev nyuaj siab corrosion tawg qhov twg 316L tsis?
A: Yog lawm. 316L yog qhov tsis zoo rau cov tshuaj chloride kev nyuaj siab- corrosion cracking saum toj no li 60 C, tsis nyob rau hauv ib teev nyob rau hauv boiling magnesium- tshuaj ntsuam chloride. Incoloy 825, nrog 38-46% npib tsib xee, zoo tiv thaiv cov tshuaj chloride SCC thiab qhia tias tsis muaj qhov tawg hauv tib qhov kev sim. Qhov no yog ib qho tseem ceeb tshaj plaws vim li cas roj- thiab cov neeg ua haujlwm roj tau teev tseg 825 (tsis yog 316L) rau kev pabcuam qaub thiab dej hiav txwv.
Q: Qhov ntsuas kub ntawm Incoloy 825 piv rau 316L yog dab tsi?
A: Incoloy 825 tswj kev tiv thaiv corrosion hauv kev pabcuam txuas mus txog li 540 C (1000 F), piv rau 425 C (800 F) rau 316L, 115 C kom zoo dua. Tshaj li ntawm 316L txwv, carbide nag lossis daus ua rau sensitization thiab intergranular corrosion; 825's titanium stabilization tiv thaiv qhov no . 825 kuj tseem ua kom muaj zog muaj zog ntawm qhov kub thiab txias.
Q: Puas yog Incoloy 825 tsim nyog tus nqi siab dua 316L?
A: Ntawm thawj tus nqi, 825 tus nqi kwv yees li 2.5-3.5x ntau dua ib kilogram dua li 316L. Tab sis nyob rau hauv aggressive acid lossis chloride kev pab cuam, 825 kav ntev 15-20+ xyoo piv rau 3-5 xyoo rau 316L, zam 2-3 hloov thiab tsis npaj downtime. Tshaj li 20-xyoo lub neej voj voog, 825 feem ntau yog 60-75% pheej yig dua hauv tag nrho cov nqi ntawm cov tswv txawm tias tus nqi yuav siab dua.
Q: Cov qauv ASTM dab tsi suav nrog Incoloy 825 thiab 316L?
A: Incoloy 825: phaj / ntawv ASTM B424, seamless yeeb nkab / raj B423 (thiab condenser raj B163), bar B425, welded yeeb B705, forgings B564, fittings B366. 316L stainless: phaj A240, yeeb nkab A312, raj A27A269 / bar Rau kev pabcuam qaub xav tau UNS (N08825 vs S31603), NACE MR0175 siv qhov twg siv, thiab EN 10204 3.1 cov ntaub ntawv xeem cov ntaub ntawv.
