1. Q: Dab tsi yog cov tshuaj lom neeg muaj pes tsawg leeg ntawm Incoloy 825 round seamless raj, thiab txhua lub ntsiab lus ua rau nws ua tau zoo li cas?
A:
Incoloy 825 (UNS N08825) yog npib tsib xee- hlau-chromium alloy nrog tswj kev ntxiv ntawm molybdenum, tooj liab, thiab titanium. Ib puag ncig seamless raj ua tau raws li cov hauv qab no muaj pes tsawg leeg:
Nickel (Ni):38.0 - 46.0% - Muab austenitic stability, tsis kam mus rau chloride kev nyuaj siab corrosion cracking (SCC), thiab ua lub hauv paus rau cov alloy qhov kev ua tau zoo heev hauv kev txo cov kua qaub.
Chromium (Cr):19.5 - 23.5% - Qhov tseem ceeb rau kev tsim cov Cr₂O₃ oxide zaj duab xis uas tiv thaiv oxidizing ib puag ncig thiab ua rau muaj kev tiv thaiv corrosion.
Hlau (Fe):tshuav nyiaj li cas (feem ntau 22–32%) - Muab tus nqi- ua haujlwm zoo thiab muaj kev ncaj ncees thaum tso cai rau kev ua haujlwm zoo.
Molybdenum (Molybdenum):2.5 - 3.5% - Tseem ceeb heev rau kev tiv thaiv pitting thiab crevice corrosion nyob rau hauv chloride-muaj ib puag ncig. Molybdenum txhim khu kev ruaj ntseg ntawm cov zaj duab xis passive.
Copper (Cu):1.5 - 3.0% - Muab cov tshuaj tiv thaiv zoo rau sulfuric thiab phosphoric acids. Tooj liab yog lub ntsiab tseem ceeb uas tso cai rau 825 los ua hauv kev txo cov kua qaub tawm.
Titanium (Ti):0.6 - 1.2% - Ntxiv rau cov khoom stabilizing. Titanium nyiam ua ke nrog cov pa roj carbon monoxide los ua TiC, tiv thaiv chromium carbide nag lossis daus ntawm cov ciam teb (sensitization) thaum vuam lossis siab - kub raug.
Cov pa roj carbon (C):Tsawg dua lossis sib npaug li 0.05% (feem ntau 0.02–0.03%) - Khaws qis kom txo qis carbide tsim.
Manganese (Mn):Tsawg dua lossis sib npaug li 1.0%,Silicon (Si):Tsawg dua lossis sib npaug li 0.5%,Sulfur (S):Tsawg dua lossis sib npaug li 0.03% - Tswj raws li cov khoom seem rau kev huv.
Lub titanium stabilization yog ib qho tseem ceeb sib txawv ntawm cov tsis yog -stabilized alloys. Thaum ib puag ncig seamless raj yog welded los yog raug rau qhov kub thiab txias nyob rau hauv lub rhiab heev ntau yam (550-750℃/ 1022-1382℃F), titanium ties li carbon, tawm hauv chromium muaj nyob rau hauv lub matrix kom muaj corrosion kuj. Yog tias tsis muaj qhov ruaj khov no, chromium carbides yuav tsim ntawm cov ciam teb, ua rau muaj kev tawm tsam intergranular.
Pitting Resistance Equivalent Number (PREN)rau 825 feem ntau yog 30–34, xam raws li:
PREN=%Cr + 3.3×%Mo + 16×%N (nrog nitrogen ≈ 0.03%). Qhov no tso 825 saum 316L (PREN 24–26) tab sis hauv qab super- qib austenitic zoo li 6% Mo alloys (PREN 42–48).
2. Q: Dab tsi yog qhov txawv ntawm Incoloy 825 round seamless raj thiab txheem stainless hlau 316L raj nyob rau hauv ib puag ncig corrosive?
A:
Incoloy 825 round seamless raj muaj qhov zoo ntawm kev ua tau zoo tshaj 316L hauv ntau qhov chaw nruj, txawm tias tus nqi pib dua.
1. Sulfuric acid (H₂SO₄) tsis kam:
316Lmuaj kev txwv tsis pub muaj zog hauv sulfuric acid. Ntawm 10-50% concentration thiab kub siab tshaj 50℃(122℃F), 316L muaj kev cuam tshuam dav dav dav dav (tus nqi> 1 hli / xyoo).
lus 825excels vim nws cov ntsiab lus tooj liab (1.5-3.0%). Copper txhawb nqa kev ua haujlwm hauv kev txo cov kua qaub ib puag ncig. 825 yog kev pabcuam hauv 0–70% H₂SO₄ ntawm qhov kub txog li 80℃(176℃F) nrog corrosion feem ntau <0.1 mm / xyoo. Rau 30-50% H₂SO₄ ntawm 60 degree, 825 feem ntau yog cov khoom xaiv.
2. Phosphoric acid (H₃PO₄) tsis kam:
316Lraug kev tawm tsam hnyav hauv ntub- txheej txheem phosphoric acid (muaj chlorides, fluorides, thiab sulfates) ntawm 70-90℃.
lus 825muab kev pabcuam txhim khu kev qha vim muaj kev sib koom ua ke ntawm molybdenum thiab tooj liab. Nws yog dav siv nyob rau hauv phosphoric acid evaporators, tshav kub exchangers, thiab piping.
3. Chloride pitting thiab crevice corrosion:
316L(PREN 24–26) pitting nyob rau hauv dej hiav txwv los yog siab -chloride brines tshwm sim nyob rau hauv lub lis piam mus rau lub hlis ntawm kub siab tshaj 25℃.
lus 825(PREN 30–34) muaj kev txhim kho tseem ceeb. Nws tuaj yeem tuav 20,000-30,000 ppm chlorides ntawm qhov kub txog li 80℃nrog tsawg kawg pitting txaus ntshai. Txawm li cas los xij, rau cov chlorides siab heev lossis dej hiav txwv siab tshaj 40 degree, super- qib austenitic (PREN> 40) raug pom zoo.
4. Chloride stress corrosion cracking (SCC):
316LNws muaj kev cuam tshuam rau SCC hauv cov tshuaj chloride kub siab tshaj 60℃(140℃F), tshwj xeeb tshaj yog thaum muaj oxygen thiab tensile stresses.
lus 825muaj cov ntsiab lus nickel siab (38-46%), uas muab cov tshuaj tiv thaiv zoo rau chloride SCC. Cov hlau tseem nyob twj ywm thiab tawg -dawb txawm nyob rau hauv boiling magnesium chloride kev ntsuam xyuas, qhov twg 316L tsis nyob rau hauv lub sij hawm.
5. Kev sib piv tus nqi:
316l cevyog kwv yees li 1 × lub hauv paus.
cev 825feem ntau yog 3–5 × tus nqi ntawm 316L ntawm ib qho -kilogram hauv paus. Txawm li cas los xij, thaum kev pab cuam lub neej txuas ntxiv los ntawm lub hlis mus rau kaum xyoo, tus nqi ntawm lub neej feem ntau nyiam 825.
Cov ntsiab lus:Xaiv 316L rau kev pabcuam me me (dej huv, dilute acids ntawm chav tsev kub). Xaiv Incoloy 825 rau kev pabcuam sulfuric / phosphoric acid, kub chlorides, lossis ib puag ncig uas muaj kev pheej hmoo SCC.
3. Q: Dab tsi yog cov txheej txheem tsim khoom siv los tsim Incoloy 825 round seamless raj, thiab cov qauv twg tswj hwm nws cov khoom?
A:
Incoloy 825 round seamless raj yog tsim los ntawm kev ua tib zoo tswj ua ntu zus ntawm kev ua haujlwm kub thiab txias.
Kev tsim khoom:
Melting thiab refining- Cov hlau feem ntau yog tsim los ntawm hluav taws xob arc melting (EAF) ua raws li argon oxygen decarburization (AOD) lossis nqus pa oxygen decarburization (VOD) kom ua tiav nruj tswj cov pa roj carbon, sulfur, thiab nitrogen. Rau cov ntawv thov tseem ceeb (nuclear, siab - siab), lub tshuab nqus tsev induction melting (VIM) tuaj yeem siv.
Ingot los yog billet casting- Lub refined yaj yog cam khwb cia rau hauv ib ncig ingots los yog tsis tu ncua cam khwb cia billets. Billets yog tom qab txias (sib tsoo, tig) kom tshem tawm qhov tsis xws luag.
Kub piercing (Mannesmann txheej txheem)- Lub billet yog rhuab mus rau 1150-1250℃(2100-2280℃F) thiab tho hla lub mandrel los tsim lub plhaub hollow. Qhov no yog thawj kauj ruam hauv kev tsim cov raj seamless.
Kub dov los yog kub extrusion- Lub plhaub pierced ntxiv txo qis hauv txoj kab uas hla thiab phab ntsa tuab siv ntau- sawv dov zeb (xws li Assel zeb, ntsaws zeb) lossis ntsug extrusion xovxwm. Rau me me diameters los yog nyias phab ntsa, kub extrusion yog nyiam.
Txias daim duab- Lub raj kub- tiav lawm yog pickled (acid ntxuav) kom tshem tawm nplai, ces txias los ntawm ib tug tuag hla lub mandrel. Ntau qhov kev kos duab txias dhau los, nrog rau nruab nrab annealing (kev daws teeb meem ntawm 950-1050 degree) thiab pickling, ua tiav qhov ntev thiab qhov chaw tiav. Kev ua haujlwm txias kuj tseem txhim kho qhov tseeb qhov tseeb thiab cov khoom siv kho tshuab.
Kev daws kawg annealing- Lub raj tiav lawm yog cov tshuaj annealed ntawm 940-980℃(1724-1796℃F) ua raws li qhov txias txias (dej quench lossis cua txias). Qhov no dissolves tej carbides los yog precipitates, ua ib tug tag nrho austenitic qauv nrog titanium carbonitrides uniformly faib.
Ncaj, txiav, thiab tsis yog -kev kuaj xyuas kev puas tsuaj (NDE)- Cov hlab yog ncaj, txiav kom ntev, thiab tshuaj xyuas los ntawm eddy tam sim no, ultrasonic, los yog hydrostatic kuaj raws li cov qauv siv.
Cov qauv siv tau rau Incoloy 825 round seamless raj:
| Txuj | Kev piav qhia |
|---|---|
| ASTM B 423 3 | Standard Specification rau Nickel-Iron-Chromium-Molybdenum-Copper Alloy (UNS N08825) Seamless Yeeb Nkab thiab Tube |
| ASME SB-423 | Ib yam li ASTM B423, tau txais rau ASME Boiler thiab Pressure Vessel Code |
| ASTM B829 Cov khoom lag luam | Cov kev cai dav dav rau nickel alloy seamless yeeb nkab thiab raj ( siv rau 825) |
| ASTM B163 | Seamless npib tsib xee thiab npib tsib xee alloy condenser thiab kub exchanger raj (suav nrog 825) |
| NACE MR0175 / ISO 15156 | Rau cov ntawv thov kev pabcuam qaub (H₂S ib puag ncig) |
| TS EN 10216-5 | European tus qauv rau seamless steel raj rau lub hom phiaj siab - Ntu 5: Stainless thiab npib tsib xee alloy tubes |
Qhov ntau thiab tsawg muaj:Sab nraud txoj kab uas hla 6.0 mm (0.236 ″) txog 273 mm (10.75 ″), phab ntsa thickness 0.5 mm txog 25 mm (0.020″ txog 1.0″), ntev txog 12–15 meters.
4. Q: Dab tsi yog qhov kev pom zoo vuam kev coj ua thiab cov hlau muab tub lim rau kev koom nrog Incoloy 825 round seamless raj, thiab tom qab- vuam vuam yuav tsum tau kho?
A:
Incoloy 825 yog tsim los rau weldability zoo, tab sis cov txheej txheem tsim nyog yog qhov tseem ceeb los tswj nws cov corrosion kuj.
Vuam txheej txheem:
GTAW (TIG/Tungsten Inert Gas) nyiam dua rau nyias - phab ntsa raj thiab cov ntawv thov tseem ceeb. GMAW (MIG), SMAW (stick), thiab SAW (submerged arc) yog tsim rau cov phab ntsa hnyav dua.
Filler hlau xaiv:
Qhov feem ntau pom zoo muab tub lim hlau rau vuam 825 rau nws tus kheej yogERNiCrMo-3(UNS N06625), kev lag luam hu ua Inconel 625 muab tub lim. Qhov no filler muab:
Cov ntsiab lus molybdenum siab dua (8-10%) dua li cov hlau hauv paus, ua rau cov hlau txuas nrog pitting tsis kam sib npaug los yog zoo dua li cov niam txiv 825.
Lub zog zoo sib xws.
Zoo heev corrosion kuj nyob rau hauv ob qho tib si txo thiab oxidizing ib puag ncig.
Alternative fillers:
ERNiCrMo-4(C-276 muab tub lim) - Rau kev pabcuam tshuaj lom neeg hnyav tshaj plaws; siab molybdenum (15-17%) thiab tungsten.
ENiCrMo-3(SMAW stick electrode) - Rau qhov chaw vuam qhov twg GTAW yog qhov tsis zoo.
Vuam ceev faj:
Kev npaj nto- Ntxuav lub raj kawg thiab thaj chaw uas nyob ib sab (tsawg kawg 25 hli) kom ci hlau siv cov txhuam hniav zoo nkauj stainless hlau los yog sib tsoo. Kev kis kab mob los ntawm cov pa roj carbon steel, roj, lossis av yuav ua rau muaj qhov tsis xws luag.
Tsis muaj preheating- Feem ntau tsis tas yuav preheating. Yog tias ambient kub qis dua 5℃(41℃F), maj mam preheat rau 15-20℃yuav siv tau los tshem tawm cov dej noo.
Interpass kub- Khaws qis dua 150℃(300℃F). Kev kub siab interpass tuaj yeem txhawb kev nkag siab lossis tsis xav tau theem tsim.
Kub input tswj- Siv cov khoom siv hluav taws xob tsawg (feem ntau 0.5-1.5 kJ / mm). Stringer hlaws dai (tsis muaj weaving) thiab ntau cov hlaws nyias ua rau qhov zoo tshaj plaws microstructure.
Rov qab -purging- Rau lub raj vuam, ntxuav sab hauv nrog 100% argon (los yog argon-hydrogen sib tov rau kev txhim kho ntub dej) los tiv thaiv oxidation ntawm cov hauv paus hniav. Cov pa paug ntawm cov hauv paus hniav yuav tsim cov chromium -depleted nplai, txo pitting kuj.
Tiv thaiv roj- 100% argon lossis argon nrog 1-2% nitrogen rau GTAW. Rau GMAW, siv argon-helium sib tov los yog argon + 1–2% CO₂ (tab sis zam nitrogen- muaj roj uas tuaj yeem ua rau porosity).
Tom qab-weld heat treatment (PWHT):
Incoloy 825 yog titanium-stabilized, yog li nws muaj zog heev rau rhiab heev thaum vuam.PWHT feem ntau tsis tas yuav tsum muajrau feem ntau corrosive cov ntawv thov kev pabcuam, suav nrog kev pabcuam qaub rau NACE MR0175.
Txawm li cas los xij, PWHT (kev daws teeb meem ntawm 940-980℃tom qab txias txias) yuav raug teev rau:
Hnyav txias- lub raj ua haujlwm uas tom qab welded (rov qab ua kom muaj zog)
Kev pabcuam hauv qhov chaw muaj kev cuam tshuam ntau heev (piv txwv li, boiling 65% nitric acid test)
Cheebtsam uas tau raug cua sov tsis raug- kho thaum lub sij hawm tsim
Lus ceeb toom:Yog tias PWHT ua tiav, tag nrho cov khoom yuav tsum tau ua kom sov-kho tsis tu ncua. Localized PWHT (piv txwv li, hluav taws xob cua sov ntawm lub vuam) tsis zoo thiab tuaj yeem ua rau muaj kev phom sij ntau dua li qhov zoo.
NACE Requirement:Rau kev pabcuam qaub (H₂S- muaj ib puag ncig), welds yuav tsum tau sim hardness . 825 welds ua nrog ERNiCrMo-3 muab tub lim feem ntau ua tau raws li qhov tsawg dua lossis sib npaug rau 35 HRC qhov xav tau yam tsis muaj PWHT.
5. Q: Hauv cov ntawv thov tshwj xeeb twg yog Incoloy 825 round seamless raj yuav tsum tau ua, thiab hom kev ua haujlwm tsis zoo yuav tsum zam li cas?
A:
Incoloy 825 round seamless raj yog teev rau cov ntawv thov uas cov qauv stainless hlau tsis txaus tab sis siab -nickel superalloys (piv txwv li, C-276) yog qhov tshwj xeeb tshaj thiab kim heev.
Cov ntawv thov raug cai:
| Kev lag luam | Daim ntawv thov | Vim li cas 825 tau teev tseg |
|---|---|---|
| Roj & roj | Downhole tubing, flowlines, kub exchangers nyob rau hauv qaub kev pab cuam (H₂S/CO₂/Cl⁻) | NACE MR0175 pom zoo; resists SSC thiab pitting |
| Kev ua tshuaj lom neeg | Sulfuric acid coolers, phosphoric acid evaporators, pickling da dej piping | Tooj + molybdenum muab cov kua qaub tiv thaiv |
| Kev tsim hluav taws xob | Flue gas desulfurization (FGD) scrubber Cheebtsam, feedwater heaters | Resistant pH thiab chlorides tsawg; txuas txuas qhov sib txawv ntawm 316L thiab C-276 |
| Tubrog nkoj | Seawater cooling piping, firewater systems (tsawg-qhov chaw ceev ceev) | PREN 30–34 muab pitting tsis kam nyob rau hauv dej hiav txwv sov |
| Nuclear | Siv roj reprocessing, radioactive pov tseg | Resistant nitric acid nrog oxidizing hom |
| Pharmaceutical | Reactor hlab ntsha thiab hloov kab rau cov organic acids | Cleanability, general corrosion kuj |
Hom tsis ua hauj lwm hom thiab kev tiv thaiv:
1. Pitting thiab crevice corrosion
Ua rau: Exposure to high-chloride environments (> 50,000 ppm) at elevated temperatures (>80 degree).
Kev Tiv Thaiv:Rau kev pabcuam dej hiav txwv siab tshaj 40℃lossis brines> 50,000 ppm Cl⁻, hloov mus rau super- qib austenitic (6% Mo, PREN> 40). Tsis txhob xav tias 825 tiv thaiv pitting.
2. Kev nyuaj siab corrosion cracking (SCC)
Ua rau:Txawm hais tias 825 muaj kev ua haujlwm zoo SCC, tsis ua hauj lwm tau tshaj tawm nyob rau hauv boiling magnesium chloride los yog siab heev - kev nyuaj siab, siab - kub chloride ib puag ncig.
Kev Tiv Thaiv:Zam kom tsis txhob muaj kev ntxhov siab ntxiv los ntawm kev ua haujlwm txias. Tshuaj anneal tom qab mob hnyav. Khaws qhov kub qis dua 200℃(392℃F) hauv siab -chloride kev pabcuam.
3. Galvanic corrosion
Ua rau:Thaum 825 ua ke nrog cov hlau tsis tshua muaj zog (carbon steel, 316L) hauv cov khoom siv hluav taws xob (seawater, acid), cov hlau tsis tshua muaj txiaj ntsig zoo dua.
Kev Tiv Thaiv:Siv cov khoom siv cais tawm (dielectric flanges, yas bushings) ntawm kev sib txuas ntawm 825 thiab cov hlau tsis sib xws. Tsim rau galvanic compatibility.
4. Crevice corrosion nyob rau hauv gaskets los yog deposits
Ua rau:Oxygen-depleted crevices (xws li, nyob rau hauv PTFE gaskets, biofouling, los yog scale) tso cai chloride concentration thiab pH poob.
Kev Tiv Thaiv:Siv tag nrho - nkag welds es tsis txhob gasketed pob qij txha yog qhov ua tau. Khaws cov nrawm nrawm dua 1.5 m / s kom tiv thaiv cov khib nyiab. Qhia meej meej - qauv tsim dawb.
5. Hydrogen embrittlement
Ua rau:Kev tiv thaiv Cathodic tshaj -kev tiv thaiv (muaj peev xwm < –850 mV Ag/AgCl) los yog kev pabcuam qaub nrog siab H₂S ib nrab siab tuaj yeem qhia hydrogen.
Kev Tiv Thaiv:Tswj cathodic tiv thaiv muaj peev xwm. Rau kev pabcuam qaub hnyav (H₂S > 0.1 MPa), xyuas kom cov khoom ua tau raws li NACE MR0175 hardness yuav tsum tau (tsawg dua lossis sib npaug rau 35 HRC). Siv cov khoom uas muaj hnub nyoog zoo (tsis yog txias- ua haujlwm nkaus xwb).
6. Sensitization (tsis tshua muaj nyob rau hauv 825 vim titanium stabilization)
Ua rau:Kev kho cua sov tsis tsim nyog (tso txias los ntawm 550-750 degree) lossis vuam yam tsis muaj kev ruaj khov.
Kev Tiv Thaiv:Ua raws li cov lus pom zoo annealing (940-980℃+ ceev txias). Titanium stabilization ua rau 825 tiv taus, tab sis kev tsim txom hnyav tseem tuaj yeem ua rau chromium carbide tsim.
Kev txiav txim siab txog tus nqi lifecycle:
Txawm hais tias 825 tus nqi 3-5 × ntau dua 316L, nws lub neej kev pab cuam nyob rau hauv ib puag ncig hnyav yog feem ntau 10-20 × ntev dua. Rau ib tug raug FGD scrubber los yog qaub roj flowline, tag nrho cov nqi ntsia ntawm 825 yog recouped nyob rau hauv 1-3 xyoo los ntawm txo downtime thiab hloov cov nqi. Rau qhov kev pabcuam hnyav dua, 316L lossis 904L tuaj yeem siv nyiaj ntau dua.
Cov lus qhia zaum kawg:Ib txwm txheeb xyuas qhov chaw tshwj xeeb (chloride concentration, pH, kub, H₂S ib nrab siab) tiv thaiv cov ntaub ntawv corrosion luam tawm rau 825. Thaum tsis ntseeg, sab laj nrog cov tuam txhab tsim cov hlau alloy cov txheej txheem kev txhim kho corrosion los yog khiav cov ntawv xeem hauv cov txheej txheem dej.
