1. Incoloy 864 (UNS S31254) thiab Incoloy 890 (UNS N08926) yog ob qho tib si suav tias yog "super" austenitic stainless hlau. Dab tsi yog qhov tseem ceeb ntawm qhov sib txawv txhais tau hais tias lawv qhov sib txawv corrosion kuj profiles, thiab qhov no qhia lawv li cas hauv kev ua tshuaj lom neeg thiab offshore roj & roj?
Txawm hais tias ob qho tib si alloys siab -kev ua tau zoo austenitic stainless hlau, lawv cov chromium- mus rau -nickel tshuav nyiaj li cas thiab cov kev sib ntxiv tshwj xeeb tsim cov "corrosion personalities" haum rau qhov sib txawv hnyav.
Incoloy 864 (S31254 / "254 SMO"): Lub Siab -Molybdenum Chloride Warrior
Cov ntsiab lus: ~ 20% Cr, 18% Ni, 6.1% Mo, 0.2% N, 0.7% Cu. Qhov no yog classic "6% Mo super-austenitic" alloy.
Txhais cov yam ntxwv: Nws cov ntsiab lus molybdenum siab heev (Ntau dua lossis sib npaug li 6%) ua ke nrog nitrogen muab qhov tshwj xeeb Pitting Resistance Tus lej sib npaug (PREN Ntau dua lossis sib npaug rau 43). Qhov no ua rau nws lub zog tseem ceeb uas tsis muaj kev sib tw rau hauv cheeb tsam corrosion (pitting thiab crevice corrosion) hauv chloride ib puag ncig.
Daim ntawv qhia kev thov:
Kev Siv Tshuaj: Siv qhov twg cov tshuaj chlorides yog qhov kev hem thawj tseem ceeb-xws li, tshuaj chlorine thiab hypochlorite tuav, chloride- paug sulfuric thiab phosphoric acid ntws, thiab cov txheej txheem siv dej hiav txwv los ua kom txias.
Offshore Roj & Roj: Cov khoom siv tseem ceeb rau cov tshuab dej hiav txwv - cov kav dej hauv hiav txwv, cov dej tua hluav taws, cov kab hluav taws xob, thiab cov kav dej txias. Nws yog tus qauv xaiv rau ambient kub seawater qhov kev ntseeg siab yog qhov tseem ceeb.
Flue Gas Desulfurization (FGD): Zoo heev rau cov ntaub ntub dej hauv cov khoom siv chlorinated scrubber slurry.
Incoloy 890 (N08926): Lub Siab -Chromium, Ntsuas Tag Nrho-Rounder
Cov ntsiab lus: ~ 25% Cr, 25% Ni, 6.5% Mo, 0.2% N, 1.0% Cu. Daim ntawv ceeb toom ntau dua chromium thiab nickel.
Txhais cov yam ntxwv: Lub siab chromium (~ 25%) muab qhov zoo tshaj plaws hauv oxidizing media thiab sulfur tsis kam, thaum tseem tswj tau qhov siab heev PREN (~ 48) los ntawm nws 6.5% Mo. Cov nickel siab dua txhim kho tag nrho cov kev tiv thaiv corrosion thiab kev ntxhov siab corrosion cracking (SCC) kev tiv thaiv.
Daim ntawv qhia kev thov:
Kev Siv Tshuaj: Zoo tagnrho rau cov chaw sib xyaw ua kua qaub uas muaj ob qho tib si oxidizing thiab txo cov neeg ua haujlwm -xws li, nitric / sulfuric acid sib tov, oxidizing siv dej cawv ntau, thiab cov txheej txheem nrog sulfur compounds. Nws siab Cr muab superior tiv thaiv kub nitric acid.
Offshore Roj & Roj: Xaiv rau qhov kev pabcuam qaub hnyav tshaj plaws - cov raj xa dej, ntws, thiab txheej txheem piping qhov twg muaj cov ntsiab lus siab ntawm H₂S, CO₂, chlorides, thiab cov ntsiab lus sulfur coexist ntawm qhov kub siab. Nws cov Cr siab tiv thaiv sulfidation, thaum Mo thiab Ni tuav cov tshuaj chlorides thiab SCC.
Pulp & Ntawv: Zoo heev rau digester thiab bleaching systems nrog complex chloride thiab oxidant chemistry.
Xaiv txoj cai ntawm tus ntiv tes xoo: Xaiv 864 thaum ib puag ncig yog chloride- nplua nuj, oxidizing lossis nruab nrab, thiab qhov kub thiab txias yog nruab nrab. Xaiv 890 thaum ib puag ncig nyuaj-ib txhij txo / oxidizing, siab nyob rau hauv sulfur hom, los yog nyob rau hauv kub siab dua- yuav tsum tau ib tug ntau balanced, robust alloy.
2. Vim li cas Pitting Resistance Equivalent Number (PREN) yog ib qho tsis yog -cov kev qhia tshwj xeeb sib tham tau rau cov hlau no, thiab nws suav thiab txheeb xyuas li cas thaum tsim cov yeeb nkab?
Rau cov tshuaj chloride-cov kev pabcuam kabmob, pitting thiab crevice corrosion yog hom kev ua haujlwm tsis zoo tshaj plaws. Lub PREN muab ib qho, ntau qhov Performance index los teev cov hlau tsis muaj zog, ua rau nws yog ib qho tseem ceeb ntawm kev yuav khoom thiab kev ruaj ntseg zoo.
PREN Formula (rau austenitic stainless hlau):
PREN=%Cr + (3.3 × %Mo) + (16 × %N)
Cov qauv no ntsuas qhov ua tau zoo ntawm txhua lub hauv paus raws li cov ntaub ntawv empirical. Molybdenum yog 3.3 npaug ntau zog tshaj chromium hauv kev tiv thaiv pitting, thiab nitrogen yog 16 npaug ntau zog.
Yam tsawg kawg nkaus PREN yuav tsum muaj:
Incoloy 864 (S31254): Feem ntau teev nrog qhov tsawg kawg nkaus PREN ntawm 43. Qee qhov tshwj xeeb xav tau ntau dua lossis sib npaug rau 43.5.
Incoloy 890 (N08926): Feem ntau teev nrog qhov tsawg kawg nkaus PREN ntawm 47 lossis 48.
Vim Li Cas Nws Tsis Yog -Nyem sib tham hauv Kev Yuav Khoom:
Kev Ua Haujlwm Zoo: Qhia qhov tsawg kawg nkaus PREN kom ntseeg tau tias cov tshuaj yaj yeeb yaj kiab tau ua kom zoo rau thaj tsam corrosion kuj. Cov me me, kev lag luam uas txo qis hauv Mo lossis N tuaj yeem ua haujlwm qis dua.
Kev sib piv kev sib tw: Nws tso cai rau lub hom phiaj kev sib piv ntawm cov khoom sib txawv.
Code & Standard Recognition: Ntau tus qauv thoob ntiaj teb (xws li NORSOK M-630) muaj cov rooj xaiv cov khoom raws li PREN qhov tseem ceeb rau kev pabcuam dej hiav txwv.
Kev txheeb xyuas thaum lub sij hawm tsim cov yeeb nkab:
Thaum tshav kub kub Chemistry Control: Lub khw yaj lub hom phiaj rau nruab nrab ntawm cov khoom muaj pes tsawg leeg los lav qhov PREN yam tsawg kawg nkaus tau ntsib txawm tias muaj ntau qhov sib txawv. Ladle tsom xam yog ua.
Kev Ntsuam Xyuas Khoom Muag: Ib qho ASTM E1473, ib qho piv txwv los ntawm cov khoom tiav (cov yeeb nkab) raug tshuaj xyuas. Qhov feem pua ntawm Cr, Mo, thiab N los ntawm qhov kev tshuaj ntsuam no yog siv rau kev suav nrog PREN tshaj tawm hauv Daim Ntawv Pov Thawj Zeb Xeem (MTC).
MTC Kev Tshaj Tawm: MTC yuav tsum sau cov feem pua ntawm tus kheej ntawm Cr, Mo, thiab N, thiab qhia meej txog qhov suav PREN. Nws yog ib qho yooj yim rau daim ntawv pov thawj kom muaj kab: "PREN (Cr+3.3Mo+16N)=[value]".
Purchaser Audit: Qhov kawg -tus neeg siv lossis tus thib peb- tus neeg soj ntsuam xyuas qhov kev suav los ntawm kev qhia txog chemistry.
Qhov tshwm sim ntawm Tsis yog-Kev Ua Raws Cai: Cov yeeb nkab ua tsis tau raws li qhov tsawg kawg nkaus PREN yog suav tias tsis yog- ua raws thiab tsis tuaj yeem lees txais rau cov kev pabcuam npaj, txawm tias muaj lwm yam kev xeem dhau los. Qhov no ua rau PREN qhov tseem ceeb tshaj plaws kev lees paub cov khoom siv rau cov alloys.
3. Fabrication, tshwj xeeb tshaj yog vuam, ntawm Incoloy 864 thiab 890 kav dej yog ib qho tseem ceeb rau kev tswj lawv cov corrosion kuj. Dab tsi yog qhov tseem ceeb ntawm kev sib tw vuam thiab cov txheej txheem tshwj xeeb uas yuav tsum tau ua los tiv thaiv "weld decay"?
Cov ntsiab lus siab alloy uas muab cov ntaub ntawv no lawv cov kev tiv thaiv corrosion kuj ua rau lawv cov cheeb tsam weld muaj kev cuam tshuam rau kev tsim cov kev puas tsuaj rau theem nrab, ua rau lub zos poob ntawm corrosion resistance- feem ntau hu ua "weld decay." Qhov no tsis yog rhiab heev nyob rau hauv classical 304 kev nkag siab, tab sis feem ntau tsim ntawm intermetallic theem (sigma, chi) thiab nitrides.
Thawj qhov kev sib tw Welding:
Tsim ntawm Intermetallic Phases: Nyob rau hauv tshav kub- cuam tshuam cheeb tsam (HAZ), raug rau qhov kub thiab txias ntawm ~ 600℃thiab 1000℃(1112-}1832℃F) tuaj yeem ua rau nag lossis daus ntawm sigma theem (Fe-Cr-}Mo) thiab chi theem (Cr) {{7}. Cov theem no yog nplua nuj nyob rau hauv chromium thiab molybdenum, depleting lub puag ncig matrix thiab tsim micro-galvanic hlwb uas tsis tshua muaj heev rau pitting ceev.
Nitride Precipitation: Cov qib nitrogen siab yog nquag tsim chromium nitrides (Cr₂N) ntawm cov ciam teb hauv HAZ yog tias txias qeeb dhau, kuj ua rau chromium depletion.
Micro-segregation nyob rau hauv Weld Hlau: Raws li - nrum weld hlau microstructure tuaj yeem muaj qhov tsis yog-kev faib tawm (segregation) ntawm Mo thiab Cr, tsim cov chaw hauv zos nrog qis pitting tsis kam.
Cov txheej txheem tshwj xeeb los tiv thaiv Weld Decay:
Filler Metal Selection (CEEB TOOM):
Tsis txhob siv cov hlau sib txuam rau 864/890. Cov hlau vuam yuav raug rau micro- cais.
Kev coj ua qauv: Siv cov npib tsib xee-raws li, tag nrho cov hlau muab tub lim nrog cov ntsiab lus Mo siab dua los them nyiaj rau kev sib cais thiab xyuas kom cov hlau vuam PREN tshaj lub hauv paus hlau.
Rau Ob leeg 864 & 890: INCONEL 625 (ERNiCrMo-3) muab tub lim yog qhov kev xaiv tshaj plaws thiab pom zoo. Nws cov ntsiab lus 9% Mo kom ntseeg tau tias cov hlau welded pitting tsis kam tshaj lub hauv paus hlau, muab cov khoom siv corrosion-resistant.
Lwm txoj hauv kev: INCO{{0}WELD 686CPT (ERNiCrMo-14) rau kev pabcuam chloride tseem ceeb dua.
Vuam txheej txheem & Thaum tshav kub kub input Control:
Cov txheej txheem nyiam: Gas Tungsten Arc Vuam (GTAW / TIG) rau hauv paus thiab sau hla dhau. Cov txheej txheem zoo li SAW feem ntau raug zam vim muaj cua sov nkag.
Tsawg tshav kub input: Siv stringer hlaws dai, zam weaving. Lub hom phiaj yog kom txo tau lub sij hawm nyob rau hauv qhov kub thiab txias qhov twg cov theem teeb meem tshwm sim.
Interpass Kub: Khaws qhov siab tshaj plaws ntawm 100℃(212℃F). Ua kom txias cov yeeb nkab ntawm kev hla nrog cua.
Joint Design & Fit-Up: Zoo heev haum-ua kom txo qhov ntim ntawm cov hlau uas xav tau thiab txo cov cua sov tag nrho.
Ncej -Wel Cleaning & Passivation:
Tshem Tawm Thaum Tshav Kub Kub: Tag nrho cov xim tsis muaj xim (tuab tshav kub) yuav tsum tau muab tshem tawm los ntawm kev sib tsoo los yog pickling (siv HNO₃ / HF sib tov haum rau siab -Mo alloys). Thaum tshav kub kub tint yog chromium -depleted, oxidized txheej uas yuav pit tam sim ntawd.
Passivation: Kev kho nitric acid passivation pab kho cov xim chromium oxide passive zaj duab xis hla lub vuam thiab HAZ.
Kev Tshawb Fawb: Rau qhov tseem ceeb welds, ferric chloride corrosion test (ASTM G48 Method A) ntawm daim coupon weld tuaj yeem raug teev tseg kom paub tseeb qhov pitting tsis kam ntawm qhov sib koom ua ke.
4. Hauv kev pabcuam roj & roj ntau lawm (H₂S, CO₂, chlorides), qhov tshwj xeeb zoo li cas Incoloy 890 yeeb nkab muaj ntau dua duplex stainless hlau xws li 2205 lossis 2507, tshwj xeeb tshaj yog hais txog kev cia siab ntev -?
Thaum super duplex (2507) muaj lub zog siab thiab zoo chloride tsis kam, Incoloy 890 muab qhov zoo sib xws hauv qhov kev xav tau ntau tshaj plaws, tshwj xeeb tshaj yog hais txog kev tsim kev ntseeg siab thiab ua haujlwm rau hauv - kev pabcuam embrittlement.
| Yam | Incoloy 890 (UNS N08926) Cov. | Super Duplex 2507 (UNS S32750) | Qhov zoo rau 890 hauv Sour Service |
|---|---|---|---|
| Microstructural Stability | Siab austenitic. Tsis muaj theem transformation. Ruaj khov los ntawm cryogenic mus rau melting point. | Dual -phase (+ ). Yuav tsum tuav ~ 50/50 theem sib npaug. Yooj yim rau tsim ntawm brittle intermetallic (sigma, chi) yog rhuab ntawm ~ 600-1000℃. | Greater Fabrication Forgiveness. Vuam los yog cua kub tsis sib haum (xws li, los ntawm kev ua haujlwm kub nyob ze) tsis tshua muaj kev puas tsuaj rau 890. Tsis muaj kev pheej hmoo ntawm kev poob qis. |
| Toughness & Embrittlement | Zoo heev low -temperature toughness. Tsis muaj 475℃embrittlement. | Zoo toughness, tab sis raug rau 475℃(885℃F) embrittlement nrog ntev - lub sij hawm raug. Toughness tuaj yeem degrade dhau sijhawm hauv kev pabcuam kub. | Superior Long -Nyob Zoo. Hauv qhov dej uas muaj qhov kub thiab txias, 890 yuav tsis raug kev txom nyem los ntawm qhov qeeb, qhov kub thiab txias -dependent embrittlement uas tuaj yeem cuam tshuam rau cov hlau duplex. |
| Chloride Stress Corrosion Cracking (Cl-SCC) Resistance | Qhov tseem ceeb tiv thaiv vim muaj cov ntsiab lus nickel siab (~ 25%). | Kev ua haujlwm zoo heev vim muaj cov qauv duplex, tab sis tsis meej. Nws tuaj yeem raug mob hnyav, kub, acidic chloride tej yam kev mob. | Muaj zog dua hauv qhov phem tshaj -Case Scenarios. Muab cov npoo ntxiv ntawm kev nyab xeeb tawm tsam SCC nyob rau hauv ib puag ncig hnyav tsis tau npaj txhij. |
| Sulfide Stress Cracking (SSC) Resistance | Zoo heev, tsim nyog raws li NACE MR0175/ISO 15156 rau siab H₂S ib feem ntawm qhov siab, tshwj xeeb tshaj yog kub dua. | Zoo heev, tab sis nrog kev txwv nruj dua (feem ntau HRC 28 max rau vuam HAZ) los tiv thaiv SSC. | Yooj Yim Welding Qualification. Ua kom tiav qhov xav tau HAZ hardness tswj nyob rau hauv tuab -phab ntsa duplex yeeb nkab vuam yog qhov nyuaj . 890 tus qauv austenitic muaj ntau dua inherent SSC tsis kam nrog cov kev txwv hardness tsawg dua. |
| Resistance rau Elemental Sulfur | Zoo heev. High nickel thiab chromium cov ntsiab lus muab kev ua haujlwm zoo. | Yuav muaj teeb meem. Elemental sulfur tuaj yeem tawm tsam duplex steels, tshwj xeeb tshaj yog nyob rau hauv lub xub ntiag ntawm H₂S. | Txaus siab rau sulfur -cov kabmob qhov dej. 890 yog qhov kev xaiv txhim khu kev qha ntau dua thaum muaj cov tshuaj sulfur hauv cov txheej txheem. |
Summary: Rau ib tug tuab-phab ntsa, siab- siab flowline los yog downhole tubing nyob rau hauv ib tug sib sib zog nqus, kub, qaub qhov twg vuam yog complex, kub tej zaum yuav txawv, thiab ntev -lub sij hawm (20+} xyoo) kev ncaj ncees yog qhov tseem ceeb, Incoloy 890's austenitic stability thiab kwv yees tus cwj pwm laus feem ntau "haum-thiab-tsis nco qab" cov ntaub ntawv dhau super duplex, txawm tias tus nqi pib ntau dua. Nws txo qhov kev pheej hmoo ntawm lub neej.
5. Dab tsi yog qhov cuam tshuam rau ASTM / ASME thiab NACE cov khoom tshwj xeeb rau Incoloy 864 thiab 890 cov kav dej, thiab cov kev xeem tshwj xeeb dab tsi tshaj li chemistry/mechanics yuav tsum muaj rau cov kev pabcuam qaub?
Kev qhia txog cov alloys no yuav tsum tau xa mus rau cov ntaub ntawv cov khoom raug thiab hais txog cov kev xav tau ntxiv rau kev pabcuam corrosive validation.
Yam khoom tseem ceeb Specifications:
Rau Incoloy 864 (S31254) Yeeb Nkab:
ASTM A312 / A312M / ASME SA312 Cov Lus Qhia:Standard Specification rau Seamless, Welded, thiab hnyav hnyav ua hauj lwm Austenitic Stainless hlau kav.Qhov no yog lub ntsiab spec. Qib yog TP S31254.
ASTM A790 / A790M / ASME SA790: Rau welded yeeb nkab tshwj xeeb.
Rau Incoloy 890 (N08926) Yeeb Nkab:
ASTM B423 / B423M / ASME SB423 Cov Lus Qhia:Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy Seamless Pipe thiab Tube.Qhov no yog thawj spec, muab nws nrog lwm cov Ni-Fe-Cr-Mo alloys.
ASTM B804 Cov Lus Qhia:Txheem Specification rau UNS N08325, UNS N08925, UNS N08926, thiab UNS N31254 Welded Pipe.Qhov mus - rau spec rau welded 890 yeeb nkab.
Sour Service Qualification (NACE MR0175 / ISO 15156):
Txhawm rau siv rau hauv kev pabcuam qaub, cov khoom siv yuav tsum ua raws li NACE MR0175 / ISO 15156. Qhov no suav nrog ntau dua li tsuas yog ntsib cov kws kho mob tshwj xeeb.
Cov Kev Ntsuas Tshwj Xeeb & Cov Ntaub Ntawv:
Hardness Testing: Ib qho kev xeem tseem ceeb tshaj plaws.
Qhov yuav tsum tau muaj: Qhov siab tshaj plaws hardness yuav tsum tsis pub tshaj HRC 35 rau lub hauv paus hlau, vuam hlau, thiab Thaum tshav kub kub-Teb chaws cuam tshuam (HAZ).
Cov txheej txheem: Ib ASTM E10 (Brinell) lossis ASTM E18 (Rockwell). Rau welded yeeb nkab, hardness traverses hla lub weld yuav tsum tau ua pov thawj HAZ ua tau raws li qhov txwv.
Kev Tshaj Tawm: Hardness qhov tseem ceeb rau lub hauv paus hlau, vuam, thiab HAZ yuav tsum nyob rau hauv MTC los yog ib daim ntawv qhia txog kev tsim nyog.
Intergranular Corrosion Test (IGC):
Test Standard: ASTM G28 Method A (Ferric Sulfate – Sulfuric Acid Test) yog yuav tsum tau rau nickel-raws li alloys zoo li 890. Rau 864, ASTM A923 Method C (tsis yog feem ntau rau austenitics) tsis siv; Hloov chaw, tooj liab- tooj liab sulfate-sulfuric acid xeem ib ASTM A262 Practice C tej zaum yuav raug teev.
Lub hom phiaj: txhawm rau txheeb xyuas cov khoom nyob rau hauv qhov kev daws teeb meem zoo -annealed mob thiab tsis sensitized. Qhov siab tshaj plaws corrosion (piv txwv li, 2.0 mm / hli rau G28 Txoj Kev A) tau teev tseg.
Pitting Corrosion Test (feem ntau qhia):
Test Standard: ASTM G48 Txoj Kev A (Ferric Chloride Pitting Test) ntawm qhov ntsuas kub (piv txwv li, 50℃rau 864).
Lub hom phiaj: Txhawm rau muab cov pov thawj pom tseeb ntawm PREN, tsis pom qhov pitting lossis poob qis tshaj qhov txwv tom qab 72 teev.
Cov ntaub ntawv siv:
Daim Ntawv Pov Thawj Zeb Xeem yuav tsum qhia meej meej tias kev ua raws li NACE MR0175/ISO 15156, xa mus rau tsab ntawv tsim nyog.
Nws yuav tsum tau sau cov kev kho cua sov (kev daws teeb meem anneal kub thiab quench txoj kev) tseem ceeb rau kev ua tiav corrosion.
Rau welded yeeb nkab, Vuam txheej txheem Specification (WPS) thiab cov txheej txheem tsim nyog cov ntaub ntawv (PQR) kuj yuav tsum tsim nyog raws li NACE, ua pov thawj weld hardness tswj.
Cov Khoom Muag Khoom Piv Txwv: Ib daim ntawv xaj rau kev pabcuam qaub Incoloy 890 yeeb nkab yuav nyeem: "ASTM B804, UNS N08926, Welded Pipe. Cov khoom siv kom ua raws li NACE MR0175/ISO 15156. Cov Lus Qhia Ntxiv: S1 Hydrotest, S4 Hardness Report 5odM SRC5, Max HRC S8 Certification rau EN 10204 3.2."
