Daim Ntawv Thov Qhov Zoo Ntawm Ferritic-Austenitic Duplex Stainless Hlau hauv Ntawv Tshuab Tshuab Lub tog raj kheej

Daim ntawv tshuab ziab khaub ncaws lub tog raj kheej yog cov neeg ua haujlwm ntawm cov ntawv tsim khoom- lawv yog cov loj, rotating nruas uas cov ntawv ntub dej qhuav (los ntawm 60-70% noo noo mus rau 5-8%) siv chav dej sab hauv. Tab sis lawv txoj haujlwm yog kev lim hiam: lawv ua haujlwm ntawm 100-150 degree, nyob twj ywm nrog cov ntawv ntub dej thiab cov tshuaj seem (xws li sulfuric acid los ntawm pulping), thiab dais qhov hnyav ntawm daim ntawv lub vev xaib ntxiv rau kev ntxhov siab los ntawm kev sib hloov. Tau ntau xyoo lawm, mills siv cov qauv austenitic stainless hlau (xws li 304 lossis 316L) rau cov thooj voos kheej kheej-tab sis lawv feem ntau ua tsis tiav thaum ntxov: 304 xeb hauv 2-3 xyoos, thiab 316L, thaum muaj kev tiv thaiv corrosion ntau dua, tsis muaj lub zog los tuav hnyav hnyav yam tsis muaj warping.

Qhov ntawd yog qhov chaw ferritic- austenitic duplex stainless hlau (feem ntau tsuas yog hu ua "duplex steel") tuaj. Qib zoo li 2205 (feem ntau rau cov tshuab ziab khaub ncaws) thiab 2304 tam sim no tau dhau los ua tus qauv kub rau cov tshuab ziab khaub ncaws- thiab yog vim li cas. Lawv daws ob qhov mob loj tshaj plaws ntawm cov tsoos steels: lawv tiv taus qhov ntub dej, tshuaj lom neeg- ib puag ncig nplua nuj, thiab lawv muaj zog txaus kom kav ib xyoo caum lossis ntau dua. Cov kab lus no rhuav tshem vim li cas duplex steel ua haujlwm zoo rau lub tog raj kheej tshuab ziab khaub ncaws, nrog cov ntaub ntawv zeb tiag tiag thiab cov txiaj ntsig zoo.

Ua ntej: Dab tsi Ua Duplex Stainless Hlau txawv?​

Ua ntej dhia mus rau qhov zoo, cia peb ua kom yooj yim: duplex steel tsis yog ib hom hlau xwb -nws yog kev sib xyaw ntawm ob lub microstructures:​

Austenitic theem (txog 50% ntawm cov qauv): Muab cov hlau zoo heev corrosion kuj thiab ductility (yog li nws tsis tawg thaum khoov).

Ferritic theem (lwm 50%): Ntxiv lub zog tensile siab thiab tsis kam rau kev ntxhov siab corrosion tawg (ib qho teeb meem tshwm sim hauv cov tsoos steels hauv qab cua sov thiab noo noo).

Sib piv qhov no rau ib txwm 316L (100% austenitic): 2205 duplex steel muaj 2x lub zog tensile (800 MPa vs . 485 MPa rau 316L) thiab zoo dua tiv thaiv "ntub corrosion" uas plagues tshuab ziab khaub ncaws. Nws zoo li muaj cov khoom siv uas yog ob qho "corrosion shield" thiab "strength backbone"-zoo meej rau qhov chaw ziab khaub ncaws hnyav.

Daim Ntawv Thov Tseem Ceeb Qhov Zoo ntawm Duplex Steel hauv Tshuab Lub tog raj kheej

Duplex steel cov txiaj ntsig tsis yog qhov theoretical xwb -lawv txhais mus rau kev txuag nyiaj tiag tiag thiab tsawg dua lub sijhawm rau cov ntawv zeb. Nov yog plaub qhov zoo tshaj plaws, txhawb nqa los ntawm kev paub txog zeb:

1. Superior Resistance rau ntub & tshuaj corrosion (tsis muaj dej ntws ntxiv).

Lub tshuab ziab khaub ncaws yog qhov npau suav phem corrosion:

Internal chav tsim condensation tas li, yog li lub tog raj kheej lub puab nto nyob twj ywm damp.

Cov tshuaj residual los ntawm daim ntawv pulp (xws li sulfur compounds los yog fatty acids) lo rau sab nrauv, reacting nrog ya raws los tsim cov kua qaub me me.

Ib txwm 316L tuav tau ib ntus, tab sis nws feem ntau tsim "pitting corrosion" (qhov me me) ntawm sab hauv tom qab 3-4 xyoo-cov qhov no tig mus rau hauv cov xau, yuam cov mills kaw thiab hloov lub tog raj kheej. Duplex steel (2205) nres qhov no:

Nws cov microstructure sib xyaw ua cov denser, ruaj khov oxide txheej (Cr₂O₃ + MoO₃) uas thaiv cov dej noo thiab tshuaj lom neeg.

Hauv kev ntsuam xyuas, 2205 pom qhov corrosion ntawm 0.005 hli / xyoo hauv simulated tshuab ziab khaub ncaws (120 degree, 5% sulfuric acid tov)-10x qis dua 316L's 0.05 hli / xyoo.

Lub tshuab hluav taws xob Finnish hloov ntawm 316L mus rau 2205 lub tog raj kheej tshuab ziab khaub ncaws hauv 2018. Lawv cov 316L lub tog raj kheej qub tau xau tom qab 3.5 xyoo; 2205 lub tog raj kheej tseem xau-dawb tom qab 6 xyoo, tsis muaj cov cim qhia ntawm pitting. "Peb tau siv los npaj hloov lub tshuab ziab khaub ncaws txhua 3 xyoos," said lub zeb tus saib xyuas tu. "Tam sim no peb tsis txawm xav txog nws-lawv tsuas yog ua haujlwm."​

2. Siab zog=Thinner Phab ntsa & Qhov hnyav tsawg (Txuag Zog).

Lub tog raj kheej tshuab ziab khaub ncaws hnyav - ib txwm 316L thooj voos kheej kheej (rau 5-meter ntev, 1.5-meter txoj kab uas hla tshuab ziab khaub ncaws) hnyav txog 2.800 kg. Lawv cov phab ntsa tuab (15-20 mm) yog xav tau los tswj lub siab hauv chav (feem ntau 0.5-1 MPa) thiab qhov hnyav ntawm daim ntawv web.

Duplex steel lub zog siab dua cia cov mills siv cov phab ntsa nyias (10-12 hli rau 2205) thaum tseem ua tau raws li cov qauv kev nyab xeeb. Nov yog vim li cas qhov tseem ceeb:

Qhov hnyav dua: Ib lub tshuab ziab khaub ncaws 2205 ntawm tib qhov hnyav hnyav ~ 2.100 kg-30% sib dua 316L.

Kev siv hluav taws xob tsawg: Lub tshuab ziab khaub ncaws tsis tas yuav ua hauj lwm nyuaj kom tig lub tog raj kheej sib zog. Lub tshuab Finnish pom 4% poob hauv kev siv hluav taws xob rau lawv cov tshuab ziab khaub ncaws tom qab hloov mus rau 2205.​

Kev hloov hluav taws xob sai dua: cov phab ntsa nyias nyias cia cov cua sov ntawm lub tog raj kheej sab nraud sai dua, txiav cov ntawv ziab lub sij hawm los ntawm 2-3% (txhais mus rau ntau daim ntawv tsim tawm ib teev).

Ib lub teb chaws Asmeskas cov ntaub so ntswg tau ua ib kauj ruam ntxiv: lawv tau siv 2304 duplex steel (qhov qis dua - lub zog, tus nqi ntau dua - qib zoo tshaj 2205) rau lawv cov tshuab ziab khaub ncaws me me. Lawv txo cov phab ntsa thickness ntawm 14 hli mus rau 10 hli, txiav lub tog raj kheej hnyav los ntawm 25%, thiab boosted lawv cov ntaub so ntswg ntau lawm los ntawm 3% ib tug ua haujlwm.

3. Resistance to Stress Corrosion Cracking (Tsis muaj Sudden Failures).

Ib qho ntawm cov teeb meem txaus ntshai tshaj plaws nrog cov hlau tsoos yog kev ntxhov siab corrosion cracking (SCC) - cov kab nrib pleb me me uas tsim thaum cov hlau tsis muaj kev ntxhov siab (los ntawm qhov siab lossis qhov hnyav) thiab raug cov dej noo. SCC tuaj yeem ua rau lub tog raj kheej tshuab ziab khaub ncaws tsis tu ncua, uas tsis yog tsuas yog txaus ntshai tab sis kuj kaw cov khoom siv rau hnub.

Duplex steel lub ferritic theem ua rau nws yuav luag tiv thaiv SCC nyob rau hauv lub tshuab ziab khaub ncaws. Ntawm no yog cov ntaub ntawv:

Hauv kev ntsuas 1.000-teev ntawm 130℃(qhov kub ntawm lub tshuab ziab khaub ncaws) thiab 1 MPa siab, 316L tsim SCC tawg tom qab 450 teev.

2205 tsis pom qhov tawg txawm tias tom qab 1,000 teev ..

Qhov no yog qhov tseem ceeb rau cov mills uas khiav lawv cov tshuab ziab khaub ncaws 24/7. Canadian pulp mills muaj 316L lub tog raj kheej tshuab ziab khaub ncaws poob los ntawm SCC hauv 2020-nqi lawv $ 120.000 hauv lub sijhawm poob thiab kho. Lawv hloov tag nrho lawv lub tshuab ziab khaub ncaws rau 2205. thiab tsis muaj qhov teeb meem SCC txij li thaum.

4. Lub neej ntev & Kev tu qis dua (Kev txuag nyiaj loj).

Qhov zoo tshaj plaws ntawm duplex steel yog nws lub neej ntev. Ib txwm 316L lub tog raj kheej tshuab ziab khaub ncaws kav 3-5 xyoos; 2205 duplex steel kav 10-15 xyoo. Cia peb rhuav tshem cov nqi txuag rau ib lub zeb nrog 10 lub tog raj kheej tshuab ziab khaub ncaws:

Nqi Factor	316L Stainless hlau	2205 Duplex Stainless hlau
Lub tog raj kheej nqi ib chav tsev	$15.000​	$22,000 (30% siab dua ua ntej).
Hloov lub voj voog	Txhua 4 xyoos	Txhua 12 xyoos
Tag nrho lub tog raj kheej raug nqi tshaj 12 xyoo	$450,000 (3 hloov).	$220,000 (1 hloov).
Tus nqi kho mob (ib xyoos).	$8,000 (kho cov xau, polishing).	$3,000 (kev tu ncua tsawg).
Tag nrho cov nqi 12 xyoo	$546.000​	$256.000​

Qhov ntawd yog 53% tus nqi txuag tshaj 12 xyoo-txawm tias tus nqi siab dua ntawm cov hlau duplex. Lub tuam txhab Finnish suav lawv ROI rau kev hloov mus rau 2205: lawv siv

60.000 ntxiv rau pem hauv ntej tab sis txuag 380.000 tshaj 10 xyoo.

Tiag -Cov Ntaub Ntawv Ntiaj Teb: Ib Daim Ntawv Tshuab German Duplex Steel Ua tiav

Cia peb saib tag nrho cov piv txwv: ib nrab - loj German zeb uas tsim cov ntawv ntim. Ua ntej 2019. lawv siv 316L lub tog raj kheej tshuab ziab khaub ncaws thiab ntsib:

Tus nqi tu txhua xyoo ntawm € 15.000 (kho cov dej xau thiab hloov qhov corroded).

Hloov lub tshuab ziab khaub ncaws txhua 4 xyoos, raug nqi € 180.000 rau ib lub teeb (12 lub tog raj kheej).

Nquag downtime (2-3 hnub hauv ib xyoos) rau kev kho tshuab ziab khaub ncaws ..

Lawv hloov mus rau 2205 duplex steel dryers hauv 2019. ua cov kev hloov no:

Txo lub tog raj kheej phab ntsa thickness ntawm 18 hli mus rau 12 hli (siv 2205 lub zog).

Ntxiv ib qho yooj yim nto polished (duplex steel lub du nto txo ​​cov ntawv nplaum, ib qho teeb meem nrog 316L).

Khaws lawv cov chav uas twb muaj lawm (tsis xav tau kev hloov kho tshiab-2205 ua haujlwm zoo ib yam li 316L).

Los ntawm 2024 (5 xyoo tom qab), cov txiaj ntsig tau pom tseeb:

Xoom tshuab ziab khaub ncaws los yog SCC teeb meem.

Cov nqi kho mob poob rau € 4.000 toj ib xyoo ..

Kev tsim khoom poob qis rau cov tshuab ziab khaub ncaws poob rau 0.5 hnub hauv ib xyoos ..

Lawv kwv yees 2205 lub tshuab ziab khaub ncaws yuav kav ntev dua 7-8 xyoo, zam tus nqi hloov pauv € 180.000 txog 2032.​

"Tus nqi ua ntej yog ib qho nyuaj muag thaum xub thawj," said lub zeb tus thawj coj ua haujlwm. "Tab sis tam sim no, pom cov nyiaj txuag thiab tsawg npaum li cas peb kov lub tshuab ziab khaub ncaws- peb yuav tsis rov qab mus rau 316L."​

Yuav Ua Li Cas Xaiv Txoj Cai Duplex Qib rau Tshuab ziab khaub ncaws

Tsis yog tag nrho cov duplex steels yog tib yam -mills yuav tsum xaiv qib raws li lawv cov kev xav tau tshwj xeeb:

2205: Qhov zoo tshaj plaws rau mills nrog hnyav hnyav (cov tshuaj lom neeg siab, 130-150℃kub). Nws muaj ntau dua molybdenum (3%) rau ntxiv corrosion kuj.

2304: Zoo dua rau cov mills nrog cov mob me me (kev siv tshuaj tsawg dua, 100-120℃kub). Nws yog pheej yig dua 2205 (kwv yees li 15% tsawg) thiab tseem muaj 2x lub zog ntawm 316L.

Tsis txhob "qis-qib" duplex: Qee lub mills sim pheej yig duplex qib (xws li 2101) kom txuag tau nyiaj, tab sis cov no muaj kev tiv thaiv corrosion qis dua thiab feem ntau ua tsis tiav hauv 5 xyoos. Ua raws li ASTM A240-certified 2205 lossis 2304

Xaus

Ferritic- austenitic duplex stainless hlau tsis yog "zoo dua" cov khoom siv rau cov ntawv tshuab tshuab ziab khaub ncaws - nws yog ib qho kev daws teeb meem uas kho qhov mob taub hau loj tshaj plaws rau mills: corrosion, nquag hloov, thiab downtime. Nws qhov sib xyaw ua ke ntawm kev tiv thaiv corrosion, siab zog, thiab lub neej ntev txhais tau tias txuag nyiaj tiag: kev saib xyuas tsawg dua, kev siv hluav taws xob qis dua, thiab kev tsim khoom ntau dua.

Rau cov ntawv mills nrhiav kev txiav cov nqi thiab txhawb kev ntseeg siab, duplex steel (tshwj xeeb tshaj yog 2205 thiab 2304) yog ib qho kev nqis peev uas ntse. Nws yuav raug nqi ntau dua, tab sis 10-15 xyoo lifespan thiab 50%+ cov nqi txuag lub sij hawm ua rau nws tsim nyog. Thaum kawg, lub tshuab ziab khaub ncaws lub tog raj kheej uas tsis xau, tsis tawg, thiab tsis tas yuav hloov txhua ob peb xyoos yog ntau tshaj li ib feem - nws yog ib txoj hauv kev kom cov ntawv dov, nruab hnub thiab hnub tawm.