254SMO yam ntxwv / qib sib piv / corrosion kuj
254SMO alloy yam ntxwv:
Cov ntsiab lus siab molybdenum thiab siab chromium thiab nitrogen cov ntsiab lus muab 254SMO zoo heev rau pitting corrosion thiab crevice corrosion. Qhov sib ntxiv ntawm tooj liab txhim kho corrosion kuj nyob rau hauv tej yam acids. Tsis tas li ntawd, vim nws cov ntsiab lus nickel ntau dua thiab siab
Cov ntsiab lus chromium thiab molybdenum ua 254SMO muaj kev tiv thaiv zoo rau kev ntxhov siab corrosion tawg.
1. Muaj ntau qhov kev sim thiab kev siv ntau yam qhia tau hais tias txawm nyob rau ntawm qhov kub thiab txias me ntsis, 254SMO muaj crevice corrosion kuj nyob rau hauv seawater. Tsuas yog ob peb hom stainless hlau muaj qhov ua tau zoo no.
Kev tiv thaiv corrosion ntawm 2.254SMO hauv cov kua qaub thiab oxidizing halide cov kev daws teeb meem xav tau rau daim ntawv tshuaj dawb yog piv rau feem ntau corrosion-resistant nickel-based alloys thiab titanium alloys.
3. Vim tias 254SMO muaj cov ntsiab lus nitrogen ntau dua, nws lub zog muaj zog yog siab dua lwm hom austenitic stainless hlau. Tsis tas li ntawd, 254SMO muaj ductility siab thiab cuam tshuam lub zog thiab zoo weldability.
Lub siab molybdenum cov ntsiab lus ntawm 4.254SMO ua rau nws muaj ntau dua oxidation tus nqi thaum lub sij hawm annealing, uas ua rau ib tug rougher nto tshaj li zoo tib yam stainless hlau tom qab pickling. Tab sis qhov no tsis muaj qhov cuam tshuam rau corrosion kuj ntawm cov hlau.
Metallographic qauv ntawm 254SMO:
254SMO muaj lub ntsej muag-centered cubic lattice qauv. Txhawm rau kom tau txais cov qauv austenitic, 254SMO feem ntau yog annealed ntawm qhov kub ntawm 1150-1200 degrees Celsius. Qee zaum, tej zaum yuav muaj cov kab mob ntawm cov hlau nruab nrab theem (χ thiab theem) nyob rau hauv qhov chaw ntawm cov khoom. Tab sis feem ntau, lawv tsis muaj kev cuam tshuam rau kev cuam tshuam lub zog thiab corrosion kuj. Cov theem no tuaj yeem ua rau nag lossis daus ntawm cov ciam teb thaum muab tso rau hauv thaj tsam ntawm 600-1000 degrees Celsius.
Corrosion tsis kam ntawm 254SMO:
Cov ntsiab lus carbon ntawm 254SMO yog tsawg heev, uas txhais tau hais tias qhov kev pheej hmoo ntawm carbide nag lossis daus vim cua sov tsawg heev. Cov hlau tuaj yeem dhau qhov Strauss Test ASTMA262 Txheej Txheem E txawm tias tom qab ib teev ntawm kev kho mob ntawm 600-1000 degrees Celsius. Txawm li cas los xij, vim cov ntsiab lus siab ntawm cov hlau no. Nyob rau hauv qhov ntsuas kub saum toj no, lub metallic intermediate theem yuav precipitate nyob rau hauv lub grain ciam teb. Cov precipitates no tsis ua rau cov hlau muaj kev pheej hmoo ntawm intergranular corrosion thaum siv hauv xov xwm corrosive. Yog li welding tuaj yeem ua tau yam tsis muaj intercrystalline corrosion.
Txawm li cas los xij, nyob rau hauv kub concentrated nitric acid, cov precipitates yuav ua rau intergranular corrosion nyob rau hauv lub tshav kub cuam tshuam cheeb tsam. Nyob rau hauv cov kev daws teeb meem uas muaj ions xws li chloride, bromide los yog iodide, zoo tib yam stainless hlau yuav tam sim ntawd raug kev txom nyem los ntawm localized corrosion nyob rau hauv daim ntawv ntawm pitting corrosion, crevice corrosion los yog kev nyuaj siab corrosion cracking. Qee qhov xwm txheej, txawm li cas los xij, kev xeb tsis sib xws tuaj yeem ua kom nrawm los ntawm qhov muaj halides. Qhov no yog qhov tseeb tshwj xeeb tshaj yog thaum muaj halides nyob rau hauv non-oxidizing acids.
Nyob rau hauv cov ntshiab sulfuric acid, 254SMO muaj ntau dua corrosion kuj tshaj 316 zoo tib yam stainless hlau. Txawm li cas los xij, piv nrog 904L (NO8904) stainless hlau ntawm qhov siab, qhov kev tiv thaiv corrosion ntawm 254SMO yog me ntsis qaug zog. Ntawm cov sulfuric acids uas muaj chloride ions, 254SMO muaj qhov zoo tshaj plaws corrosion kuj. Vim tias qhov muaj peev xwm ntawm cov xeb hauv zos thiab cov xeb tsis sib xws, 316 zoo tib yam stainless hlau tsis tuaj yeem siv rau hauv hydrochloric acid, tab sis 254SMO tuaj yeem siv rau hauv dilute hydrochloric acid ntawm qhov kub thiab txias. Tsis tas yuav txhawj xeeb txog pitting corrosion nyob rau hauv cov cheeb tsam hauv qab txoj kab ciam teb. Tab sis kev siv zog yuav tsum tau ua kom tsis txhob muaj qhov khoob. Nyob rau hauv fluorosilicic acid (H2SiF4) thiab hydrofluoric acid (HF), corrosion resistance range ntawm zoo tib yam stainless hlau yog heev txwv, thaum 254SMO yuav siv tau nyob rau hauv ib tug haum ntau yam ntawm concentration thiab kub.
254 SMO daim ntawv thov teb:
254SMO alloy yog cov khoom siv ntau yam uas tuaj yeem siv rau hauv ntau qhov chaw lag luam:
1. Petroleum thiab petrochemical khoom, xws li cov twj tso kua mis hauv cov khoom siv petrochemical.
2. Pulp thiab ntawv bleaching khoom, xws li pulp digesters, bleaching khoom, chim thiab siab rollers rau lim washers, thiab lwm yam.
3. Cov khoom siv tseem ceeb hauv cov khoom siv hluav taws xob hluav taws xob flue roj desulfurization yog: lub cev ntauwd ntawm lub tshuab nqus tsev, lub flue, lub phaj baffle, cov khoom sab hauv, cov tshuaj tsuag, thiab lwm yam.
4. Offshore systems lossis seawater kho, xws li nyias-walled condensation kav dej txias los ntawm seawater nyob rau hauv fais fab nroj tsuag, seawater desalination khoom, thiab yuav siv tau txawm nyob rau hauv cov khoom uas seawater yuav tsis ntws.
5. Desalination kev lag luam, xws li ntsev ntau lawm los yog desalination khoom.
6. Thaum tshav kub kub exchangers, tshwj xeeb tshaj yog kub exchangers nyob rau hauv ua hauj lwm ib puag ncig nrog chloride ions.
