316L yog qhov corrosion-cov neeg ua haujlwm tiv taus ntawm kev lag luam tshuaj lom neeg, tab sis nws tsis yog lub qab nthab ntawm qhov austenitic stainless hlau tuaj yeem ua tiav . 904L, super- qib austenitic nrog ntau dua npib tsib xee, molybdenum, thiab qhov sib txawv ntawm cov tooj liab sib ntxiv, muaj nyob rau hauv qhov kev txwv tshwj xeeb rau cov kua qaub 3 L. sulfuric acid kev pab cuam, aggressive chloride raug, thiab flue gas desulfurization khoom ntawm lawv. Phau ntawv qhia no muab piv rau 904L thiab 316L ncaj qha nyob rau hauv muaj pes tsawg leeg, acid kuj, pitting thiab kev nyuaj siab corrosion cracking cwj pwm, txhua yam khoom, thiab nqi, yog li engineers yuav txiav txim raws nraim thaum tus nqi ntawm 904L yog tsim nyog.
Dab tsi yog Qhov Tseem Ceeb Ntawm Qhov Sib Txawv Ntawm 904L thiab 316L?
904L muaj ntau nickel thiab molybdenum ntau dua li 316L thiab ntxiv ib qho kev txiav txim siab tooj liab ntxiv uas 316L tsis muaj, thiab qhov kev sib xyaw ua ke no - tsis yog "ntau alloy" feem ntau - yog tsim los ua kom tiav kev ua haujlwm rau hauv cov kua qaub ib puag ncig uas 316L tsis txaus.
Ob qib yog qis-carbon austenitic stainless hlau, tab sis 904L raug cais raws li qib super- austenitic vim nws cov ntsiab lus alloy mus zoo tshaj tus qauv 300-series compositions. Nickel cov ntsiab lus kwv yees li ob npaug ntawm 316L mus rau 904L, molybdenum nce li ntawm 50-100%, thiab 904L suav nrog tooj liab ntxiv uas 316L tsis nqa txhua. Txhua qhov sib txawv no tsom rau ib qho kev txhim kho corrosion tshwj xeeb: npib tsib xee txhim kho kev tiv thaiv kom tsis txhob muaj cov kua qaub thiab kev ntxhov siab corrosion tawg, molybdenum txhim kho kev tiv thaiv chloride-induced pitting thiab crevice corrosion, thiab tooj liab tshwj xeeb txhim kho kev tiv thaiv sulfuric thiab phosphoric acid - sib tham hauv kev nthuav dav hauv ob ntu tom ntej.
Ib sab -los ntawm- sab kev sib piv:
|
Element (wt%) |
316L |
904L |
Vim Li Cas Nws Tseem Ceeb |
|
Chromium (Cr) |
16.0–18.0 |
19.0–23.0 |
Base passive- txheej qub; siab dua Cr broadens general corrosion kuj |
|
Nickel (Ni) |
10.0–14.0 |
23.0–28.0 |
Stabilizes austenite thiab txhim kho kev tiv thaiv kom tsis txhob muaj cov kua qaub thiab kev ntxhov siab corrosion tawg ntawm qib siab dua |
|
Molybdenum (hli) |
2.0–3.0 |
4.0–5.0 |
Tus tsav tsheb tseem ceeb ntawm kev tiv thaiv chloride pitting thiab crevice corrosion |
|
Copper (Cu) |
Tsis txhob txhob txwm ntxiv |
1.0–2.0 |
Distinctive 904L ntxiv uas txhim khu kev tiv thaiv rau sulfuric thiab phosphoric acid. |
|
Carbon (C), max |
0.03 |
0.02 |
Ob leeg yog cov qib qis -carbon "L" txo qis kev pheej hmoo ntawm kev raug mob thaum vuam |
|
Nitrogen (N) |
Tsawg dua lossis sib npaug rau 0.10 (tus qauv) |
Tsawg dua lossis sib npaug rau 0.10 (tus qauv) |
Me me contributor rau pitting kuj nyob rau hauv ob qib ntawm PREN formula |
Cov lus 1. Cov neeg sawv cev nominal muaj pes tsawg leeg rau 316L thiab 904L ib hom stainless hlau specifications. Cov txiaj ntsig yog kev piav qhia thiab sib npaug; lees paub qhov txwv tsis pub dhau qhov tam sim no ntawm ASTM A240 / A480 lossis cov lus qhia siv tau ua ntej siv hauv kev yuav khoom lossis tsim cov ntaub ntawv.
Vim li cas 904L Muaj Kev Tiv Thaiv Zoo Tshaj rau Sulfuric Acid piv rau 316L?
904L tiv taus sulfuric acid zoo dua li 316L feem ntau vim nws cov tooj liab sib ntxiv, uas hloov cov alloy tus cwj pwm corrosion hauv kev txo cov acid ib puag ncig hauv txoj kev uas molybdenum thiab npib tsib xee ib leeg tsis ua tiav, ua 904L yog ib qho ntawm cov txheej txheem kev xaiv rau sulfuric acid tuav cov cuab yeej thoob plaws qhov dav thiab qhov kub thiab txias.
Sulfuric acid yog ib qho kev txo cov kua qaub hla ntau ntawm nws cov kev siv ntau yam, thiab cov qib austenitic zoo li 316L, uas feem ntau yog nyob rau ntawm chromium thiab molybdenum rau lawv cov kev tiv thaiv corrosion, tuaj yeem raug kev kub ntxhov hauv qhov tshwj xeeb ntawm ib puag ncig. Copper ntxiv tau ntev tau lees paub nyob rau hauv stainless thiab npib tsib xee- alloy metallurgy tau txais txiaj ntsig tshwj xeeb hauv kev txo cov kua qaub, thiab 904L cov ntsiab lus ntawm cov tooj liab yog cov ntsiab lus tseem ceeb uas txuas ntxiv nws cov khoom siv tau rau hauv sulfuric acid concentrations thiab kub qhov twg 316L corrodes sai heev rau kev pabcuam txhim khu kev qha. Qhov no tsis yog ib qho "siab dua alloy zoo dua" cov nyhuv - nws yog lub hom phiaj metallurgical teb rau ib qho acid chemistry, uas yog vim li cas 904L feem ntau yog thawj qib engineers mus txog rau thaum sulfuric acid tuav yog tus tsim qauv tsim.
Yuav Ua Li Cas 904L thiab 316L Sib piv hauv Kev Ua Haujlwm rau Chloride Pitting thiab Crevice Corrosion?
904L muaj lub ntsiab lus zoo dua rau cov tshuaj chloride pitting thiab crevice corrosion tshaj 316L, suav nrog Pitting Resistance Equivalent Number (PREN), vim tias nws cov ntsiab lus molybdenum thiab nitrogen ntau dua ncaj qha nce tus nqi PREN - siv dav, code- hais txog kev tshuaj ntsuam metric rau hauv cheeb tsam corrosion kuj.
PREN yog xam los ntawm ib tug alloy lub chromium, molybdenum, thiab nitrogen cov ntsiab lus:
PREN=%Cr + 3.3 × %Mo + 16 × %N
Siv cov qauv no nrog cov neeg sawv cev sib xyaw, 316L feem ntau ua rau PREN nyob rau thaj tsam li ntawm 24–26, thaum 904L feem ntau yields PREN nyob rau hauv thaj tsam ntawm kwv yees li 34–36 - cov npoo loj uas txhais tau ncaj qha mus rau ntau dua kev tiv thaiv rau thaj chaw pitting} thiab cridev. dej hiav txwv thiab ntau cov txheej txheem kev lag luam, tuaj yeem ua rau qis dua -PREN qib.
PREN yog cov cuab yeej siv dav hauv kev tshuaj ntsuam xyuas meej vim tias nws condenses ntau qhov sib xyaw ua ke rau hauv ib tus lej sib piv, tab sis nws yog ib qho kev qhia dav dav es tsis yog kev lees paub - qhov tseeb pitting kuj nyob rau hauv kev pab cuam kuj yog nyob ntawm nto tiav, fabrication zoo, thiab qhov tshwj xeeb kub thiab chloride concentration koom nrog, yog li PREN kev sib piv yuav tsum qhia cov khoom xaiv es tsis yog hloov 1} cov ntaub ntawv ib puag ncig corrosion.
Yuav Ua Li Cas Ob Qib Sib Piv hauv Kev Tiv Thaiv Kev Nyuaj Siab Corrosion Cracking?
904L cov ntsiab lus ntau dua nickel muab nws lub ntsiab lus zoo dua rau cov tshuaj chloride-induced stress corrosion cracking dua 316L, uas yog ib qho txiaj ntsig tseem ceeb hauv kub, chloride- muaj ib puag ncig uas cov qib austenitic tau paub tias muaj kev cuam tshuam rau hom kev ua tsis tiav no.
Chloride-induced stress corrosion cracking is a well-documented failure mode in standard austenitic stainless steels operating under tensile stress in hot chloride environments - ib qho kev sib xyaw ua ke hauv ntau cov txheej txheem cua sov, evaporators, thiab cov txheej txheem kub piping. Cov ntsiab lus npib tsib xee muaj qhov muaj zog, zoo- tsim kev sib raug zoo rau qhov kev tiv thaiv no: raws li cov ntsiab lus npib tsib xee nce, kev cuam tshuam rau chloride kev ntxhov siab corrosion feem ntau txo qis, uas yog ib feem ntawm vim li cas siab dua -nickel austenitic thiab duplex/super- qib austenitic feem ntau tau teev nyob rau hauv qhov chaw ntawm cov qauv tsis ua hauj lwm 300- stainless hlau.
904L cov ntsiab lus npib tsib xee, ntawm kwv yees li ob npaug ntawm 316L, muab tso rau hauv qhov muaj txiaj ntsig zoo tiv thaiv kab mob, ua rau nws yog ib qho kev xaiv tshwj xeeb rau cov tshuaj kub chloride -cov txheej txheem cov khoom siv uas muaj kev ntxhov siab corrosion cracking txaus ntshai - tsis yog kev xeb ib leeg - yog kev txhawj xeeb txog kev tsim qauv.
Lub luag haujlwm dab tsi yog tooj liab ua si hauv 904L's Corrosion Resistance?
Copper yog ib qho tshwj xeeb tshaj plaws kev sib xyaw ua ke sib cais 904L los ntawm cov qauv austenitic qib zoo li 316L, thiab nws lub luag haujlwm yog qhov tshwj xeeb es tsis yog dav dav - nws feem ntau txhim kho kev ua tau zoo hauv kev txo cov kua qaub ib puag ncig xws li sulfuric thiab phosphoric acid ntau dua li kev txhim kho txhua qhov kev txhim kho corrosion ntawm alloy yuav ntsib.
Nws yog ib qho tsim nyog yuav tsum paub meej txog qhov tooj liab ua dab tsi thiab tsis ua hauv 904L's alloy system, txij li qhov sib txawv no tsim cov khoom siv raug xaiv. Copper cov txiaj ntsig yog tsom rau hauv kev txo cov kua qaub ib puag ncig - sulfuric thiab phosphoric acid tshwj xeeb - es tsis xa cov kev nthuav dav, kev txhim kho zoo thoob plaws txhua qhov kev txhim kho corrosion. Chloride pitting kuj nyob rau hauv 904L feem ntau yog los ntawm molybdenum thiab nitrogen cov ntsiab lus (nrhiav nyob rau hauv lub PREN xam saum toj no), thiab kev nyuaj siab corrosion cracking kuj los ntawm cov ntsiab lus nickel, tsis yog tooj liab.
Paub txog qhov tshwj xeeb no pab piav qhia vim li cas 904L tau piav qhia tias yog lub hom phiaj acid- qib tiv taus es tsis yog "qib siab dua ntawm 316L" - nws cov qauv tsim alloy qhia txog kev txhob txwm teb rau cov txheej txheem txheej txheem ib puag ncig uas muaj sulfuric acid ntau lawm, phosphoric acid manufacturing, thiab flue gas desulfurization.
Yuav Ua Li Cas 904L thiab 316L Sib Piv hauv Mechanical Properties thiab Fabricability?
904L thiab 316L muaj qhov dav dav zoo sib xws- qhov kub thiab txias ntawm cov khoom siv thiab cov khoom siv dav dav raws li austenitic stainless hlau, txawm hais tias 904L cov ntsiab lus siab dua ntawm cov hlau feem ntau xav tau kev saib xyuas ntau dua rau vuam cov khoom siv hluav taws xob thiab cov khoom siv hlau xaiv los khaws nws cov kev ua haujlwm corrosion thoob plaws vuam thiab cua sov- thaj tsam cuam tshuam.
Ob qib sib piv cov qauv austenitic siv lead ua thiab cov qauv kev coj tus cwj pwm ntawm txhua yam - zoo ductility, zoo low-temperature toughness, thiab non-magnetic cwj pwm nyob rau hauv lub annealed mob - yog li cov cuab yeej cuab tam sib piv ntawm lawv yog nyob deb heev tsis tshua muaj kev cuam tshuam corrosion kuj.
Fabrication kuj zoo ib yam nyob rau hauv cov nqe lus ntawm kev tsim thiab machining tus cwj pwm, tab sis raws li nrog ntau dua - alloy stainless qib, 904L feem ntau tau txais txiaj ntsig los ntawm kev ceev faj txog kev tswj cov vuam tsis zoo thiab kev siv cov khoom sib txuam lossis cov hlau sib xyaw kom ntseeg tau tias cov hlau vuam thiab cov cua sov- cuam tshuam thaj chaw khaws cov hauv paus hlau qhov kev tiv thaiv corrosion feem ntau nyob rau hauv qhov chaw uas muaj feem xyuam rau corrosion. kev cuam tshuam nyob rau hauv ib qho siab - alloy stainless fabrication.
Yuav ua li cas 904L thiab 316L sib piv hauv cov nqi thiab cov ntawv thov zoo li cas?
904L tus nqi ntau dua 316L ib kilogram, tsav ncaj qha los ntawm nws cov nickel ntau dua, molybdenum, thiab tooj liab cov ntsiab lus, thiab nws yog qis dua - ntim khoom tshwj xeeb uas tsis tshua muaj dav, yog li nws raug xaiv rau cov khoom tshwj xeeb thiab cov txheej txheem zones uas nws cov kua qaub thiab chloride tsis kam yog qhov yuav tsum tau ua tiav.
Ib qho kev sib piv ntawm kev tsim nyog nyob rau hauv ib puag ncig kev ua tshuaj lom neeg:
|
Daim Ntawv Thov / Ib puag ncig |
316L Suitability |
904l ua |
|
Dilute sulfuric acid, qis kub |
Feem ntau txaus |
Zoo heev - feem ntau tshaj qhov yuav tsum tau ua |
|
Concentrated los yog kub sulfuric acid |
Txwv tsis pub - yuav ua rau muaj kev txhim kho corrosion |
Zoo haum - tooj liab ntxiv tshwj xeeb rau lub hom phiaj no |
|
Phosphoric acid processing |
Tsim nyog nyob rau hauv cov mob me xwb |
Zoo suited nyob rau hauv ib tug dav dav concentration thiab kub ntau yam |
|
Dej hiav txwv / siab -chloride dej txias |
Muaj kev pheej hmoo ntawm pitting thiab crevice corrosion |
Qhov kev pheej hmoo tsawg dua vim yog PREN siab dua |
|
Cov khoom siv hluav taws xob desulfurization (FGD). |
Feem ntau tsis txaus nyob rau hauv cov cheeb tsam txhoj puab heev |
Dav dav dav raws li kev lag luam- cov khoom siv rau FGD absorber Cheebtsam |
|
Khoom noj khoom haus, dej haus, thiab kev ua tshuaj |
Zoo suited - tus qauv workhorse qib |
Feem ntau tsis tsim nyog tus nqi tshwj tsis yog tias muaj cov kua qaub tshwj xeeb |
Table 2. Tus neeg sawv cev tsim nyog sib piv, 316L vs . 904L, thoob plaws cov chaw ua tshuaj lom neeg.
Hauv kev xyaum, ntau cov txheej txheem siv 316L rau feem ntau ntawm cov kav dej thiab cov cuab yeej siv thaum khaws 904L tshwj xeeb rau cov khoom raug rau qhov hnyav tshaj plaws hauv zos - cov hlab ntsha absorber hauv flue gas desulfurization system, ib lub reactor tshwj xeeb los yog kub exchanger tuav concentrated sulfuric acid, los yog ib tug tivthaiv nyob rau hauv lub siab tshaj plaws concentration ntawm sulfuric acid. Qhov kev xaiv kev qhia tshwj xeeb no khaws tag nrho cov khoom siv tus nqi sib piv rau qhov tseeb hauv zos, echoing tib tus qauv pom hauv lwm qhov siab - kev txiav txim siab xaiv cov khoom siv thoob plaws hauv kev lag luam.
Thaum twg Koj Yuav Tsum Xaiv 904L Tshaj 316L rau Cov Khoom Siv Tshuaj?
904L yuav tsum tau teev tseg thaum cov txheej txheem muaj xws li sulfuric lossis phosphoric acid raug tshaj 316L qhov kev ua tau zoo, siab -chloride ib puag ncig uas pitting lossis crevice corrosion yog qhov tseem ceeb, lossis kub chloride tej yam kev mob uas muaj kev ntxhov siab corrosion cracking yog ib tug credible tsis ua hauj lwm hom - thiab 316L yuav tsum nyob twj ywm tus hwm 9 04L tshwj xeeb rau lwm qhov, txij li thaum 904L yuav tsum nyob twj ywm tus nqi ntawm lwm qhov tsis muaj qhov tshwj xeeb, tam sim no.
Daim ntawv txheeb xyuas kev txiav txim siab:
Xaiv 904L thaum:Cov txheej txheem cuam tshuam nrog sulfuric lossis phosphoric acid ntawm qhov siab lossis qhov kub thiab txias uas paub ntau tshaj 316L lub hnab ntawv pabcuam, thaum chloride concentration thiab kub sib xyaw ua ke los tsim cov ntsiab lus pitting lossis crevice corrosion, lossis thaum kub chloride raug tsim muaj kev ntseeg siab corrosion cracking kev txhawj xeeb nyob rau hauv ib qho kev nyuab siab los yog txwv tsis pub.
Default rau 316L thaum:cov txheej txheem ib puag ncig yog nyob rau hauv 316L qhov zoo- tsim lub hnab ntawv pabcuam - cov zaub mov dav dav, dej haus, tshuaj, thiab kev siv tshuaj ua haujlwm nruab nrab - qhov twg 904L cov ntsiab lus alloy ntxiv yuav ntxiv tus nqi yam tsis muaj qhov yuav tsum tau ua haujlwm zoo.
Xav txog kev xaiv tshwj xeebes tsis yog txhua yam - lossis - tsis muaj dab tsi xaiv nyob rau hauv tag nrho cov kab ke, siv 904L nkaus xwb ntawm cov hlab ntsha tshwj xeeb, cov kav dej khiav, lossis cov khoom raug cuam tshuam rau kev tswj hwm nruj.
Ua pov thawj tiv thaiv ib puag ncig- cov ntaub ntawv tshwj xeeb corrosionlos yog kev sim rau cov xwm txheej ciam teb, txij li PREN thiab kev sib piv qib dav dav yog cov cuab yeej tshuaj ntsuam xyuas muaj txiaj ntsig tab sis tsis yog qhov hloov pauv rau cov ntaub ntawv corrosion tshwj xeeb rau cov txheej txheem chemistry, concentration, thiab kub.
Cov lus nug nquag
Puas yog 904L suav tias yog duplex stainless hlau?
Tsis yog. 904L yog qib austenitic "super-austenitic" tag nrho, tsis yog duplex (austenitic-ferritic) stainless hlau; nws ua tiav nws txoj kev txhim kho corrosion los ntawm kev nce nickel, molybdenum, thiab tooj liab cov ntsiab lus nyob rau hauv ib qho -theem austenitic qauv, txawv ntawm ob-theem microstructure uas txhais cov qib duplex.
904L thiab 316L puas tuaj yeem welded ua ke hauv tib lub cev?
Yog lawm, kev hloov welds ntawm 904L thiab 316L muaj peev xwm ua tau nrog cov hlau muab tub lim tsim nyog, thiab qhov no yog ib qho kev ua tau zoo hauv cov tshuab uas xaiv 904L tsuas yog nyob rau ntawm qhov chaw hnyav tshaj plaws, txawm hais tias tag nrho cov kev ua haujlwm corrosion ntawm thiab nyob ze ntawm qhov sib koom ua ke yuav cuam tshuam qhov kev txwv ntau dua ntawm 316L sab.
Puas yog 904L tshem tawm qhov xav tau rau kev tiv thaiv corrosion hauv cov kua qaub?
Tsis yog. Txawm tias muaj kev xeb zoo heev- cov qib tiv taus zoo li 904L feem ntau tau teev tseg nrog qhov tsim nyog corrosion thiab raug ntsuas tawm tsam ib puag ncig- cov ntaub ntawv tshwj xeeb corrosion tus nqi rau cov txheej txheem chemistry, txij li tsis muaj ib qib kev sib piv rau cov ntaub ntawv kev ua tau zoo nyob rau hauv ib qho tshwj xeeb, zoo - cov txheej txheem txheej txheem.
Puas yog 904L sib nqus zoo li qee cov qib stainless hlau?
904L, zoo li 316L, feem ntau tsis yog- sib nqus (los yog cov hlau nplaum tsis muaj zog nkaus xwb) hauv qhov mob austenitic annealed, txawm tias ua haujlwm txias tuaj yeem qhia qee cov lus teb sib nqus hauv ob qib, zoo ib yam nrog austenitic stainless hlau tus cwj pwm.
Puas muaj cov nqi qis dua - lwm cov nqi rau 904L tsim nyog xav txog cov tshuaj chloride tshwj xeeb?
Qhov kev txhawj xeeb ntawm kev tswj hwm feem ntau yog chloride pitting thiab crevice corrosion ntau dua li sulfuric lossis phosphoric acid tsis kam tshwj xeeb, duplex stainless qib muaj peev xwm qee zaum muab qhov sib piv lossis siab dua PREN ntawm tus nqi kwv yees qis dua 904L, yog li qhov tshwj xeeb tswj kev txhim kho corrosion - tsis chloride tsis kam ib leeg - yuav tsum coj cov kev xaiv ntawm duplex.
