Hastelloy C276 Stress Corrosion Cracking Resistance nyob rau hauv qaub roj: NACE MR0175 Ua raws

Hastelloy C276 (UNS N10276)Nws muaj kev tiv thaiv zoo rau kev ntxhov siab corrosion cracking (SCC) hauv cov kev pabcuam roj qaub thiab tau teev meej meej tias yog cov khoom siv tau zoo -resistant alloy hauv NACE MR0175 / ISO 15156 Ntu 3 rau ob qho tib si sulfide stress cracking (SSC) thiab kev ntxhov siab- taw qhia hydrogen-induced cracking (SOHIC) ib puag ncig

Tsis zoo li austenitic stainless hlau xws li 316L, uas ua tsis tau los ntawm chloride SCC saum toj li 60 degrees C, C276 yog qhov tseem ceeb tiv thaiv cov tshuaj chloride SCC thiab hydrogen -induced SSC vim nws cov nickel matrix tsis txhawb cov txheej txheem tawg. Kev ua raws cai yuav tsum muaj cov khoom siv hauv kev daws teeb meem -annealed mob nrog hardness qis dua 35 HRC thiab ua haujlwm txias hauv qab 20 feem pua; tsis muaj kev tshaj tawm-weld kev kho cua sov yog tso cai nyob rau hauv qhov kub ntawm 600-1150 ° C.

Puas yog Hastelloy C276 Resistant Stress Corrosion Cracking hauv Sour Gas?

Yog lawm. C276 yog qhov tseem ceeb tiv thaiv kev ntxhov siab corrosion cracking (SCC) thiab sulfide stress cracking (SSC) nyob rau hauv qaub roj vim nws siab -nickel (kwv yees li 57 feem pua) tag nrho austenitic matrix tsis undergo cov tshuaj chloride-induced los yog hydrogen-induced cracking mechanisms thiab 3 stainless steel txawm tias 0.

Kev ntxhov siab corrosion tawg nyob rau hauv qhov chaw qaub muaj ob hom kev ua tsis tiav uas C276 zam. Thawj yog chloride stress corrosion cracking (Cl-SCC), uas plagues austenitic stainless hlau (304/316) thaum kub, ntub dej, chlorinated tej yam kev mob ntau tshaj li 60 degrees C; cov alloys tawg raws li cov ciam teb nyob rau hauv me ntsis tensile kev nyuaj siab. C276, txawm tias tseem yog austenitic, tsis tawg txoj kev no vim nws cov ntsiab lus npib tsib xee (kwv yees li 57 feem pua) cuam tshuam cov txheej txheem - npib tsib xee alloys saum toj no roughly 40-45 feem pua ​​Ni feem ntau tiv thaiv Cl-SCC.

Qhov thib ob yog sulfide kev nyuaj siab tawg (SSC), cov pa roj carbon classic- steel killer hauv H2S kev pabcuam: atomic hydrogen los ntawm H2S corrosion nkag mus rau cov hlau, sib sau ntawm cov cheeb tsam nyuaj, thiab ua rau muaj kev puas tsuaj tam sim ntawd nyob rau hauv kev ntxhov siab tensile. C276 tiv thaiv qhov no vim tias nws yog homogeneous heev, tsis muaj cov theem nyuaj thaum tov-annealed, thiab nws cov nickel matrix tsis embrittle lub cev -centered cubic steel ua. Kev paub dhau los ntawm cov roj qaub, FGD, thiab cov nroj tsuag tshuaj tau lees paub C276 kev pabcuam lub neej ntawm 20-30 xyoo yam tsis muaj SCC ua tsis tiav.

NACE MR0175 / ISO 15156 Hais Txog C276 yog dab tsi?

NACE MR0175 / ISO 15156 Ntu 3 teev UNS N10276 (Hastelloy C276) raws li kev siv tau zoo corrosion-resistant alloy (CRA) rau kev pabcuam qaub hauv cov tshuaj-annealed mob, nrog rau qhov siab tshaj plaws hardness ntawm 35 HRC thiab qhov siab tshaj plaws txias ua haujlwm ntawm 20 feem pua ​​ntawm HRC + 72S tau teev tseg - CO2 + chloride ib puag ncig yam tsis muaj kev txwv ib puag ncig uas khi cov pa roj carbon thiab qis{14}} alloy steels.

NACE MR0175 / ISO 15156 yog tus qauv thoob ntiaj teb uas txhais cov khoom siv tau thiab ib puag ncig kev txwv rau kev tsim roj thiab roj hauv qaub (H2S-muaj) kev pabcuam. Ntu 3 npog corrosion-cov alloys tiv taus (CRAs), suav nrog npib tsib xee- puag alloys. Nyob rau hauv nws, C276 yog tsim nyog raws li ib tug CRA tsis muaj SSC / SOHIC ib puag ncig cracking txwv khi rau H2S ib nrab siab, vim hais tias cov alloy yog intrinsically resistant.

Tus qauv siv ob yam khoom siv-kev tswj xyuas qhov xwm txheej: hardness yuav tsum tsis pub tshaj 35 HRC (kom tsis txhob muaj cov theem nyuaj), thiab kev ua haujlwm txias yuav tsum tsis pub tshaj 20 feem pua ​​(kev ua haujlwm txias tuaj yeem nce hardness thiab qhia cov kev ntxhov siab seem). Cov kev txwv no tau yooj yim ua tau los ntawm kev daws teeb meem-annealed C276, nws qhov hardness feem ntau yog 85-95 HRB (kwv yees li 15-20 HRC sib npaug). Qhov kev cuam tshuam zoo: tus kws tshaj lij tuaj yeem hais qhia C276 rau lub qhov dej qaub qhov dej, qhov dej ntws, lossis cov khoom sib cais yam tsis muaj kev sib xyaw ua ke ntawm ib puag ncig kev sib tsoo uas xav tau rau carbon steel, muab cov kev tswj hwm kev tsim khoom (annealed, qis ua haujlwm txias, tsis muaj PWHT txwv).

Table 1. NACE MR0175 / ISO 15156-3 Cov Lus Qhia rau C276 (UNS N10276)

Source: NACE MR0175 / ISO 15156-3 (2020 tsab); Annex npog nickel-base alloys.

Vim li cas Austenitic Stainless Steels tawg tab sis C276 Tsis?

Austenitic stainless hlau xws li 316L tawg nyob rau hauv qaub chloride kev pab cuam saum toj no li ntawm 60 degrees C vim hais tias lawv cov hlau -chromium matrix yog susceptible rau chloride stress corrosion cracking, whereas C276's nickel-dominant matrix (kwv yees 57 feem pua ​​Ni) yog metallurgically chloride SCC thiab ob leeg. - yog li lub tshuab tsis ua haujlwm uas rhuav tshem 316L tsuas yog tsis tuaj yeem nthuav tawm hauv C276.

Txhawm rau kom nkag siab qhov sib txawv, sib piv ob lub tshuab. Chloride SCC nyob rau hauv stainless hlau yuav tsum tau muaj peb yam: susceptible microstructure (sensitized los yog txias- ua hauj lwm austenite), tensile stress, thiab chlorides siab tshaj qhov ntsuas kub (feem ntau hais txog li 60 degrees C rau 316L, qis dua nrog cov tshuaj chloride siab lossis pH tsawg). Cov kab nrib pleb nucleates ntawm ib lub qhov los yog crevice thiab propagates intergranularly. C276 tsuas muaj li ntawm 5-7% hlau thiab 16% chromium tab sis 57% npib tsib xee; npib tsib xee alloys nrog Ni saum toj no roughly 40-45 feem pua ​​​​tsis pom Cl-SCC tib txoj kev, thiab C276 tshwj xeeb muaj cov ntaub ntawv ntev kev pab cuam nyob rau hauv kub chlorinated thiab acidic ib puag ncig yam tsis muaj SCC.

Rau hydrogen-induced SSC, carbon thiab low- alloy steels ua tsis tau vim absorbed hydrogen sau ntawm hard martensite los yog ntawm grain ciam teb; C276, yog ib qho -theem ntsej muag-centered cubic nickel solid solution, tsis muaj qhov nyuaj li-theem ntxiab thiab absorbs/transports hydrogen yam tsis muaj embrittling. Cov nyhuv net: qhov twg tus tsim qauv yuav tsum xaiv ntawm 316L thiab C276 rau qaub, chlorinated, sov kev pab cuam, C276 tshem tawm SCC tsis ua hauj lwm hom nkaus es tsis yog tsuas yog thawb qhov pib siab dua.

Table 2. SCC Behavior Comparison: 316L vs C276 hauv Sour Service

Source: NACE MR0175; SCC cov lus qhia txog qhov pib (piv txwv li, Cov ntaub ntawv qhia txog Kev Ua Haujlwm Zoo); cov ntaub ntawv alloy.

Yuav Ua Li Cas C276 Piv nrog Lwm CRAs hauv Cov Roj Ntsig?

Ntawm cov corrosion-resistant alloys rau qaub roj, C276 yog qhov kev saib xyuas sab saum toj-tier xaiv rau kev txo qis, siab -chloride, siab -H2S ntws; Inconel 625 npog oxidizing-chloride thiab siab dua- lub zog xav tau, Alloy 825 npog cov qaub qis, thiab 904L / 316L yog txwv tsis pub qis -chloride, qis dua-H2S lub luag haujlwm - yog li C276 yog xaiv qis dua 7 ib puag ncig.

Qhov kev xaiv ntawm CRAs yog qhov kev txiav txim siab corrosion- lub hnab ntawv. Rau cov roj qaub tshwj xeeb: 316L thiab 904L raug txwv los ntawm chloride SCC thiab chloride pitting (lawv PREN tsuas yog 23-26 thiab 33-36, raws li), yog li lawv tsuas yog siv cov tshuaj chloride thiab H2S tsawg. Alloy 825 (PREN txog 30) ua haujlwm nruab nrab qaub thiab sulfuric acid tab sis tsis zoo tagnrho qhov twg chlorides siab.

Inconel 625 (PREN txog 51) yog qhov zoo tshaj plaws hauv oxidizing -chloride thiab seawater- zoo li kev pabcuam qaub thiab muaj zog dua, tab sis hauv kev txo qis acid ntxiv rau H2S, C276 (PREN txog 68 vim yog 15-17 feem pua ​​Mo) zoo dua. C22 (PREN txog 65) yog ze heev rau C276 thiab feem ntau siv qhov twg oxidizing mixed acids dominate; rau ntshiab qaub / txo dominance, C276 yog tus qauv. Cov lus hauv qab no qhia txog txhua qhov hlau rau nws lub hnab ntawv qaub-kev pabcuam yog li tus tsim qauv tuaj yeem xaiv qhov kev xaiv C276 tshaj qhov pheej yig dua lwm qhov tsuas yog thaum chemistry tiag tiag xav tau nws.

Table 3. Kev Xaiv CRA rau Sour Gas Service

Source: NACE MR0175 alloy rooj; PREN xam los ntawm nominal chemistry; CRA xaiv cov lus qhia.

Dab tsi yog Kev Ua Haujlwm Ib puag ncig rau C276 hauv Sour Service?

Vim tias C276 tau tsim nyog raws li CRA uas tsis muaj kev txwv ib puag ncig hauv NACE MR0175, nws txoj haujlwm ciam teb hauv cov roj qaub tau teeb tsa los ntawm kev sib xyaw thiab hauv zos corrosion (tsis yog los ntawm SCC) - feem ntau nws ua tau li ntawm 190-230 ° C hauv qaub aqueous kev pab cuam thiab txog li 400-450 degrees C nyob rau hauv qhov kub ntawm SCC.

Rau cov pa roj carbon thiab qis- alloy steels, NACE MR0175 txwv nruj raws li H2S ib feem ntawm lub siab, pH, thiab chloride (lub hnab ntawv 'ib puag ncig tawg'). C276, raws li CRA, raug zam los ntawm cov kev txwv SSC / SOHIC, yog li qhov kev txwv tiag tiag dhau los ua tus nqi corrosion.

Hauv aqueous qaub kev pab cuam (tsim dej nrog H2S, CO2, chlorides), C276 tseem passive thiab corrodes ntawm tsawg tshaj li 0.1 hli / xyoo mus txog roughly 190-230 ° C, tshaj qhov uas dav dav corrosion nyob rau hauv muaj zog acid yuav sawv. Hauv qhuav lossis tsis yog-aqueous qaub roj (tsis muaj dej dawb), C276 tuaj yeem ua haujlwm ntawm qhov kub siab dua, nrog rau cov hlau alloy siab -kub txwv tswj los ntawm nws cov oxidation/sulfidation resistance - txog 400-450 ° C nyob rau hauv ib puag ncig uas muaj leej faj (thiab txog li 50 ° C).

Lub ntsiab lus tsim yog: qhia C276 rau qhov ntub dej, chlorinated, siab -H2S cheeb tsam ntawm qaub system; rau qhov qhuav, kub sab saud, qis alloys lossis C276 ob leeg tuaj yeem ua haujlwm, tab sis C276 muab cov npoo. Kev txwv qhov kub thiab txias yuav tsum tau lees paub ib txwm tiv thaiv cov kua qaub tshwj xeeb thiab qib chloride siv cov ntaub ntawv corrosion lossis kev sim.

Table 4. Indicative C276 Operating Envelope in Sour Service

Source: NACE MR0175 CRA hnab ntawv; Haynes C276 cov ntaub ntawv corrosion; roj & roj cov ntaub ntawv qhia.

Qhov nyuaj thiab txias dab tsi -Kev Tswj Xyuas Kev Ua Haujlwm siv rau C276 hauv Sour Service?

Rau kev ua raws NACE MR0175, C276 yuav tsum tau muab rau hauv cov tshuaj -annealed mob nrog hardness qis dua 35 HRC thiab tag nrho cov ua haujlwm txias qis dua 20 feem pua; cov kev tswj xyuas no tiv thaiv nyuaj- theem tsim thiab cov kev ntxhov siab seem uas tuaj yeem, nyob rau hauv txoj kev xav, cuam tshuam cov alloy qhov kev tiv thaiv hauv SSC.

Txawm hais tias C276 yog nyob rau hauv SSC - tiv thaiv kab mob, NACE tseem ua rau lub zog tawv thiab txias - lub kaus mom ua haujlwm vim tias kev tsim khoom tuaj yeem ua tsis tau raws li qhov chaw nyuaj lossis kev ntxhov siab. Lub 35 HRC qab nthab tau yooj yim ntsib: kev daws teeb meem-annealed C276 feem ntau ntsuas 85-95 HRB, uas hloov mus rau kwv yees li 15-20 HRC - zoo nyob rau hauv qhov txwv. Kev ua haujlwm txias siab tshaj 20 feem pua ​​​​ntawm ob qho tib si nce hardness thiab qhia txog tensile residual stress, yog li nws yog capped; ib qho kev tsim dua 20 feem pua ​​​​yuav tsum tau ua raws li kev daws teeb meem tag nrho kom rov ua raws li txoj cai.

Welds yog ib rooj plaub tshwj xeeb: vim tias C276 tiv thaiv kom tsis txhob muaj kev puas tsuaj, raws li -welded cheeb tsam tau txais yam tsis muaj PWHT, tab sis cov weld deposit hardness kuj yuav tsum tau kuaj xyuas qis dua 35 HRC (ERNiCrMo- 4/10 deposits feem ntau nyob rau hauv 85-95 HRB ntau). Kev yuav khoom thiab fabrication specifications yuav tsum qhia meej meej hais txog NACE MR0175, yuav tsum tau kuaj hardness ntawm ob lub hauv paus hlau thiab weld, thiab txwv tsis pub ua hauj lwm txias tshaj 20 feem pua ​​tshwj tsis yog tias re-annealed.

Table 5. Hardness and Cold-Ua hauj lwm ua raws li daim ntawv txheeb xyuas

Tau qhov twg los: NACE MR0175 / ISO 15156-3; ASME Tshooj IX; fabrication zoo npaj.

Yuav ua li cas yog C276 Welded rau Sour Gas Service?

C276 rau qaub roj yog welded nrog ERNiCrMo-4 los yog ERNiCrMo-10 muab tub lim, nruj argon backing purge (O2 hauv qab no 50 ppm), tshav kub input 0.5-1.5 kJ/mm, interpass hauv qab no 93 degrees C, thiab tsis muaj tom qab-weld hardness peb yuav tsum tau kho tom qab-weld 3. khaws NACE MR0175 ua raws.

Vuam C276 rau kev pabcuam qaub ua raws li cov txheej txheem kev qhuab qhia zoo ib yam li kev siv vuam C276, nrog rau qhov yuav tsum tau ua ntxiv ntawm kev sojntsuam hardness los ua pov thawj ua raws. Cov muab tub lim (ERNiCrMo-4 lossis ERNiCrMo-10) tso cov hlau txuas uas yog nws tus kheej intrinsically SSC-resistant thiab ntsuas qis dua 35 HRC, yog li tsis muaj PWHT xav tau - uas yog hmoov zoo vim tias PWHT nyob rau hauv 600-1150 degrees C ntau yam yuav raug txwv tsis pub leej twg paub). Lub argon backing purge (O2 qis dua 50 ppm) tiv thaiv cov hauv paus hniav los ntawm oxidation uas tuaj yeem tsim qhov chaw pib corrosion hauv kev pabcuam qaub.

Thaum tshav kub kub input tswj tiv thaiv intermetallic nag lossis daus. Tom qab vuam, PT (rau saum npoo tawg) ntxiv rau RT / UT (rau lub suab sab hauv) thiab kuaj xyuas qhov tawv ntawm lub hau vuam thiab HAZ paub meej tias qhov sib koom ua tau raws li NACE. Rau linepipe lossis flowline welds, tsim nyog WPS rau ASME Tshooj IX nrog NACE lees txais yog qhov yuav tsum tau ua, thiab cov ntaub ntawv tsim nyog cov txheej txheem weld (WPQR) yuav tsum sau cov txiaj ntsig hardness.

Table 6. C276 Sour-Cov Kev Pab Cuam Vuam

Source: ASME Tshooj IX; NACE MR0175; Haynes C276 vuam qhia H-2002.

Case Study: Sour Gas Flowline - 316L Failure Hloov los ntawm C276

Cov roj ntsha qaub uas tau teev tseg hauv 316L ua tsis tiav los ntawm chloride kev nyuaj siab corrosion tawg tom qab 14 lub hlis hauv qhov sov sov, siab -chloride, siab -H2S kev pabcuam; Hloov cov spool cuam tshuam nrog Hastelloy C276 (UNS N10276) tshem tawm SCC tsis ua haujlwm hom thiab tau ua haujlwm yam tsis muaj teeb meem rau ntau tshaj 9 xyoo.

Lub teb tau tsim cov roj qaub ntub nrog kwv yees li 3-5 feem pua ​​H2S, 8-10 feem pua CO2, thiab 30,000-60,000 ppm chloride hauv cov dej tsim, ntawm qhov ntsuas kub ntawm li 75-90 degrees C. Tus thawj 316L spool, txawm hais tias nyob rau hauv nws cov NACE ib puag ncig kev txwv tsis pub dhau 1 7 chloride MR. SCC ntawm thaj chaw uas muaj kev kub ntxhov tom qab tsuas yog 14 lub hlis, ua rau muaj qhov muaj tab sis raug nqi qis thiab kaw. Kev tshawb nrhiav metallurgical tau lees paub classic Cl-SCC keeb kwm ntawm lub qhov.

Tus neeg teb xov tooj rov- qhia txog qhov ua tsis tiav- cov kab nrib pleb (thiab ntau qhov chaw zoo sib xws) hauv C276 (UNS N10276), kev daws teeb meem-annealed, nrog ERNiCrMo-10 weld muab tub lim thiab tag nrho NACE- ua raws li kev tsim khoom. Txij li thaum kev teeb tsa, C276 spools tau sau ntau tshaj 9 xyoo ntawm kev pabcuam uas tsis muaj SCC, tsis muaj qhov xau, thiab corrosion nqi qis dua 0.05 hli / xyoo ntawm kev saib xyuas ultrasonic. Cov khoom siv tau txais txiaj ntsig (C276 txog 12-16 npaug ntawm 316L tus nqi ib kg) tau raug lees paub los ntawm kev zam kom tsis txhob rov ua dua thiab muaj kev nyab xeeb ntawm cov kua qaub tso tawm.

Tau qhov twg los: Tus neeg teb xov tooj tsis ua hauj lwm kev tshawb nrhiav (tsis qhia npe); JN Alloy qaub -cov ntaub ntawv kev pabcuam.

Yuav Ua Li Cas C276 Tsim Nyog thiab Tshawb Xyuas Kev Pab Cuam?

C276 qaub-kev pabcuam kev tsim nyog tso siab rau kev lees paub ntawm NACE MR0175 cov khoom siv (kev daws teeb meem-annealed, < 35 HRC, < 20 feem pua ​​​​txoj haujlwm txias) ntxiv rau cov qauv weld tsim nyog rau ASME Tshooj IX, txhawb nqa los ntawm PMI, hardness test, thiab NDT; Kev xeem SSC raug cai rau NACE TM0177 yog xaiv tau tab sis tuaj yeem thov rau kev pabcuam tseem ceeb.

Vim tias C276 twb tau teev npe ua tus tsim nyog CRA, feem ntau cov haujlwm tsis rov ua dua -khiav SSC kuaj kuaj (NACE TM0177 Txoj Kev A/B) tshwj tsis yog qhov kev qhia tshwj xeeb xav tau nws. Txoj kev tsim nyog niaj hnub yog: (1) daim ntawv pov thawj zeb (EN 10204 3.1/3.2) lees paub UNS N10276 chemistry thiab kev daws teeb meem-annealed mob; (2) hardness test paub meej hauv qab 35 HRC ntawm lub hauv paus thiab vuam; (3) PMI lees paub qhov tseeb alloy ntawm txhua qhov ntev thiab ntawm qhov tso nyiaj; (4) WPS/WPQ rau ASME Tshooj IX; (5) NDT (PT, RT/UT) raws li txoj cai tswjfwm.

Rau qhov tseem ceeb lossis siab siab -H2S (piv txwv li, Chav Kawm 3), tus neeg yuav khoom yuav xav tau daim ntawv pov thawj TM0177 SSC uas lees paub tias tsis muaj kev tawg tom qab 720 teev nyob rau hauv kev thauj khoom hauv tus qauv H2S cov tshuaj - C276 dhau qhov no nkag. Cov ntaub ntawv pov thawj dhau los ua pov thawj ntawm NACE MR0175 kev ua raws cai rau cov ntaub ntawv khoom siv.

Table 7. Sour-Kev Pabcuam Tsim Nyog thiab Kev Tshawb Fawb

Source: NACE MR0175; NACE TM0177; ASME Tshooj IX/VIII; tsim QC cov phiaj xwm.

Cov Lus Nug Nquag: C276 thiab Roj Roj

Q: Puas yog Hastelloy C276 pom zoo rau NACE MR0175 kev pabcuam qaub?

A: Yog. UNS N10276 (Hastelloy C276) yog teev raws li kev siv tau zoo corrosion-resistant alloy (CRA) hauv NACE MR0175 / ISO 15156 Ntu 3 rau kev pabcuam qaub hauv cov tshuaj -annealed mob. Nws tsis muaj qhov cuam tshuam ib puag ncig (SSC / SOHIC) txwv khi rau H2S ib nrab siab vim tias nws muaj peev xwm tiv taus. Kev ua raws cai yuav tsum tau ua kom muaj zog qis dua 35 HRC thiab ua haujlwm txias hauv qab 20 feem pua, tsis muaj kev tshaj tawm -weld kho cua sov hauv 600-1150 degrees C.

Q: Vim li cas C276 tiv thaiv sulfide kev nyuaj siab tawg thaum stainless hlau tsis?

A: C276 cov ntsiab lus siab nickel (kwv yees li 57 feem pua) ua rau nws cov matrix tiv thaiv ob qho tib si chloride stress corrosion cracking thiab hydrogen-induced sulfide stress cracking (SSC). Austenitic stainless hlau xws li 316L tawg los ntawm chloride SCC saum toj li 60 degrees C thiab tuaj yeem ua rau hauv cov kev pabcuam qaub, qhov C276 ib leeg -theem nickel solid solution tsis txhawb cov txheej txheem no. Hauv cov ntsiab lus teb, C276 tshem tawm SCC hom tsis ua haujlwm ntau dua li tsuas yog nce qhov pib xwb.

Q: C276 puas tuaj yeem siv rau hauv siab -H2S, siab -chloride qaub roj?

A: Yog. C276 yog tshwj xeeb tshaj yog haum rau kev nruj nruj heev, chlorinated, txo qhov chaw ib puag ncig - siab H2S ib nrab siab, siab chloride tsim dej, thiab qis pH - qhov twg 316L, 904L, thiab txawm Alloy 825 yuav raug txwv los yog ua tsis tiav. Nws PREN ntawm txog 68 thiab siab molybdenum cov ntsiab lus muab nws ob qho tib si chloride tsis kam thiab tiv thaiv SSC. Kev txwv kev khiav hauj lwm yog teem los ntawm kev xeb dav dav (kwv yees li 190-230 ° C hauv cov kev pabcuam ntub dej), tsis yog los ntawm ib puag ncig tawg.

Q: Puas yog C276 xav tau tom qab-weld kho cua sov rau kev pabcuam qaub?

A: Tsis yog. C276 yuav tsum TSIS TXAUS SIAB-weld tshav kub kho nyob rau hauv 600-1150 degrees C ntau yam vim hais tias yuav ua rau embrittling intermetallic nag lossis daus. Raws li -welded condition twb zoo rau corrosion thiab SCC kuj, thiab NACE MR0175 lees txais raws li{10}}welded sib koom. Qhov tsuas yog qhov yuav tsum tau ua kom ntseeg tau qhov kev sib tw weld hardness qis dua 35 HRC thiab siv NACE-raws li vuam (ERNiCrMo-4/10 muab tub lim, argon tshem tawm, tswj cov cua sov).

Q: C276 piv nrog Inconel 625 li cas rau cov roj qaub?

A: Ob leeg yog CRAs zoo rau kev pabcuam qaub. C276 (PREN txog 68, siab dua molybdenum) zoo dua hauv kev txo qis, siab -chloride, siab -H2S acid ib puag ncig, thaum Inconel 625 (PREN txog 51) ua tau zoo hauv oxidizing-chloride thiab seawater-zoo li qaub kev pab cuam thiab muaj zog dua. C276 yog tus qauv ntsuas rau txo-acid- cov kav dej qaub; 625 feem ntau xaiv qhov uas muaj zog dua txhua yam lossis oxidizing chloride kuj yog qhov tseem ceeb.

Q: Tus nqi them nqi siv C276 tshaj 316L yog dab tsi?

A: C276 tus nqi kwv yees li 12 txog 16 npaug ntau dua ib kilogram dua li 316L stainless hlau. Txawm li cas los xij, nyob rau hauv qaub, chlorinated kev pab cuam qhov twg 316L tsis ua los ntawm chloride SCC nyob rau hauv 1-2 xyoo, C276 muab 20-30 xyoo kev pab cuam lub neej, tshem tawm kev kaw, xau, thiab rov hloov dua. Kev txheeb xyuas tus nqi ntawm lub neej feem ntau nyiam C276 rau cov cheeb tsam qaub tseem ceeb, nrog cov hlau qis qis rau cov ntu tsis tseem ceeb ntawm cov kab ke.