Corrosion tsis ua hauj lwm tsom xam ntawm stainless hlau
1. Kev nyuaj siab corrosion:
Stainless hlau tsim kev nyuaj siab corrosion hauv qhov nruab nrab uas muaj cov pa oxygen chloride ions. Kev nyuaj siab tsis ua hauj lwm rau txog 45%.
Cov kev tiv thaiv ib puag ncig:
Cov khoom siv tsim nyog, xaiv cov khoom siv los ntawm kev nyuaj siab corrosion-resistant yog mas siab purity austenitic chromium npib tsib xee hlau, siab silicon austenitic chromium nickel steel, siab chromium ferrite steel thiab ferritic - austenitic ob-theem hlau. Ntawm lawv, ferritic - austenitic duplex steel muaj qhov zoo tshaj plaws tiv thaiv kev ntxhov siab corrosion. Tswj kev ntxhov siab: thaum sib dhos, txo kev ntxhov siab siab kom deb li deb tau, thiab ua rau cov ntu nrog qhov nruab nrab muaj cov kev nyuaj siab tsawg kawg nkaus, tiv thaiv kev sib tsoo thiab khawb, ua raws li cov txheej txheem vuam tshwj xeeb.
Ua nruj me ntsis ua raws cov cai tswj kev ua haujlwm: nruj tswj hwm cov khoom sib xyaw ntawm cov khoom siv, txaus tus nqi, nruab nrab kub, siab, pH tus nqi thiab lwm yam kev ntsuas thev naus laus zis Ntxiv corrosion inhibitor kom deb li deb tau ua raws li cov txheej txheem kev tso cai. Thaum siv chrome-nickel stainless hlau kom yaj aerobic chlorides, huab hwm coj loj ntawm cov pa yuav tsum txo qis kom tsawg dua 1.0 × 10-6. Nws tau raug pov thawj los ntawm kev coj ua tias hauv dej muaj chlorine ion nrog qhov loj ntawm 500. 0 × 10-6, sib xyaw ntawm nitrate nrog qhov huab hwm coj ntawm 150. 0 × 10-6 thiab sodium sulfite nrog huab hwm coj feem ntawm 0.5 × 10-6 tuaj yeem tau txais cov txiaj ntsig zoo.
2. Lub qhov dej tsis zoo thiab kev tiv thaiv kev tiv thaiv
Keyhole corrosion feem ntau tshwm sim hauv kev tshaj xov xwm nyob ruaj ruaj. Lub qhov feem ntau muaj kev txhim kho raws cov kev sib tsoo los yog kev hloov pauv. Thaum tsim lub qhov taub, nws yuav ua kom nrawm ntxiv mus rau hauv qhov tob txiav. , oxide zaj duab xis nyob rau saum npoo ntawm cov hlau tsis xeb tau yaj nyob rau hauv kev daws aqueous uas muaj chloride ions, uas ua rau tsim cov pits me me nrog qhov khoob ntawm 20 nm ~ 30 nm ntawm lub hauv paus hlau. Tsuav muaj qee qhov muaj qee yam ntawm chlorine ion hauv nruab nrab, qhov ua kom tsis haum xeb tuaj yeem hloov kho mus ua xeb.
Cov kev ceev faj: ntxiv molybdenum, nitrogen, silicon thiab lwm yam rau stainless hlau lossis nce cov ntsiab lus chromium thaum ntxiv cov ntsiab lus no. Txo cov ntsiab lus ntawm chlorine ions hauv nruab nrab. Cov tshuaj tiv thaiv corrosion tuaj yeem txhim kho qhov ruaj ntseg ntawm zaj duab xis passivation lossis txhim kho qhov rov ua dua ntawm zaj duab xis passivation puas lawm. Txais los ntawm cathode tiv thaiv tam sim no, tiv thaiv lub qhov ntawm yaig.
3. Ua hauj corrosion
Vim tias tsis pom cov xim hlau tsis haum rau kev hloov pauv hauv cov khoom siv hlau, cov hlau tsis sib txuas tau sai sai ua rau qhov pitting corrosion hauv qab qhov xeb ntawm Cl ions. Nyob hauv qhov kev txiav txim ntawm kev thaiv cov roj teeb, Cl ions sab nraum lub qhov yuav tsiv mus rau hauv lub qhov, thaum hlau ions sab hauv lub qhov nrog cov nqi zoo yuav tsiv mus nyob hauv lub qhov. Hauv cov hlau tsis xeb, cov khoom siv nrog Mo yog qhov zoo dua li cov khoom siv tsis tau Mo hauv kev txhim kho corrosion. Ntau cov ntsiab lus Mo ntxiv, qhov zoo dua corrosion kuj yog.
4. Kev tsim xeb ua haujlwm
Tus txheej txheem ntawm kev ua kom tsis muaj xeb yog qhov zoo li lub qhov pitting corrosion, uas yog tshwm sim los ntawm Cl ion txhim kho vim yog cov txiaj ntsig ntawm cov roj teeb sib xyaw hauv cov roj ntsha. Qhov kev xeb no feem ntau tshwm sim hauv cov kab nrib pleb ntawm flange gaskets, ceg pob qij txha, pob tw thiab txiv ntseej, zoo li hauv cov kab nrib pleb ntawm cov raj kub hloov pauv thiab raj phaj qhov. Cov kab nrib pleb muaj feem cuam tshuam nrog kev xav ntawm cov tshuaj zoo li qub hauv cov kab nrib pleb. Thaum muaj kev txhim kho corrosion ib puag ncig, qhov tshwm sim ntawm inducing kev nyuaj siab corrosion yog siab heev.
Siv tau cov xwm txheej rau ob hom hlau stainless hauv chlorine-muaj cov kua aqueous
Hom 1 304 stainless hlau
Qhov no yog qhov pheej yig thiab feem ntau siv cov austenitic stainless hlau (xws li khoom noj, tshuaj, atomic zog thiab lwm yam khoom lag luam). Haum rau kev tshaj tawm organic thiab inorganic. Piv txwv li, nitric acid nrog concentration <30%, kub="" ≤100="" ℃,="" los="" yog="" siab="" ≥="" 30%,="" ntsuas="" kub=""><50> Ntau cov ntsiab lus ntawm carbonic acid, ammonia thiab cawv thaum muaj huab cua sov ≤100 ℃. Cov tshuaj tiv thaiv tsis zoo hauv cov tshuaj sulfuric acid thiab hydrochloric acid; Nws tshwj xeeb tshaj yog nkag siab kev xeb los ntawm kev txhim kho los ntawm cov tshuaj lom (xws li dej txias).
2 304L stainless hlau.
Kev tiv thaiv xeb thiab siv yog qhov tseem ceeb ib yam li hom 304. Vim tias cov pa roj carbon ntsiab lus tsawg dua (≤ 0.03%), kev tiv thaiv corrosion (tshwj xeeb intergranular corrosion tsis kam, suav nrog weld tsam) thiab weldability zoo dua, uas tuaj yeem siv rau ib nrab lossis welded -welded PHE.
Hom 3 316 stainless hlau
Haum rau kev tshaj tawm organic thiab inorganic. Piv txwv li, ntuj tso dej txias, dej txias ntauwd, muag dej txias; Cov pa roj carbon; Acetic acid thiab kua dej caustic tov nrog kev tsom xam <> Cov kuab tshuaj xws li cawv thiab acetone; Dilute nitric acid (concentration <20% =,="" dilute="" phosphoric="" acid="" (concentration=""><30% =,="" thiab="" lwm="" yam.="" txawm="" li="" cas="" los="" xij,="" yuav="" tsum="" tsis="" txhob="" siv="" cov="" tshuaj="" sulfuric="" acid.="" vim="" tias="" nws="" muaj="" li="" 2%="" mo,="" xeb="" tsis="" kam="" tiv="" thaiv="" hauv="" seawater="" thiab="" lwm="" yam="" tshuaj="" chlorine="" muaj="" kev="" tshaj="" xov="" xwm="" tau="" zoo="" dua="" li="" hom="" 304,="" uas="" tuaj="" yeem="" hloov="" tag="" nrho="" hom="">
4 316L stainless hlau
Kev kho xeb thiab kev siv yog qhov tseem ceeb ib yam li hom 316. Vim tias cov pa roj carbon ntsiab lus tsawg dua (≤ 0.03%), lub weldability thiab corrosion kuj tom qab vuam kuj zoo dua, uas tuaj yeem siv rau semi-welded lossis puv-welded PHE.
Ntaus 5 317 stainless hlau
Haum rau cov kev mob uas xav tau kev pab cuam lub neej ntev dua li hom 316. Vim tias cov ntsiab lus ntawm Cr, Mo thiab Ni yog siab dua me ntsis ntawm cov hom 316, qhov cuam tshuam rau crevice corrosion, pitting corrosion thiab kev nyuaj siab corrosion yog qhov zoo dua.
AISI 904L lossis SUS 890L stainless hlau
Qhov no yog tus nqi ua haujlwm tau zoo austenitic stainless hlau nrog tus nqi thiab corrosion tsis kam, nws qhov kev txhim kho corrosion yog qhov zoo dua li cov ntaub ntawv saum toj no, tshwj xeeb tshaj yog haum rau cov tshuaj sulfuric acid, phosphoric acid thiab lwm cov acids thiab halides (suav nrog Cl -, F -). Vim lub siab cov ntsiab lus ntawm Cr, Ni thiab Mo, nws muaj qhov ua tau zoo rau kev ntxhov siab corrosion, pitting corrosion thiab tawg corrosion.
7 Avesta 254 SMO superior hlau stainless
Qhov no yog ultra-low carbon advanced stainless hlau hloov kho los ntawm kev nce Mo cov ntsiab lus ntawm hom 316, nrog kev ua tau zoo rau chloride pitting thiab crevice corrosion, haum rau nruab nrab muaj brine thiab inorganic acid uas tsis tuaj yeem siv hom 316.
8 Avesta 654 SMO superior hlau stainless
Qhov no yog ultra-low carbon advanced stainless hlau nrog Cr dua, Ni, Mo thiab N cov ntsiab lus tshaj 254 SMO, uas muaj qhov zoo dua rau chloride corrosion tshaj 254 SMO thiab tuaj yeem siv rau hauv dej hiav txwv txias.
9 rs-2 (OCr20Ni26Mo3Cu3Si2Nb) stainless hlau;
Qhov no yog qhov nyeg Cr - Ni - Mo-Cu hlau tsis xeb. Kev tuav pov hwm thiab lub qhov ua hauj corrosion yog tshaj rau hom 316, thiab kev nyuab siab corrosion kuj zoo dua. Yuav siv tau rau cov kua nyeem sulfuric acid hauv qab 80 ℃ (kev sib zog ntawm 90 ~ 98%), qhov xeb txhua xyoo ≤0.04mm / a.
10 Incoloy 825 (S),
Nov yog Ni (40%) - Cr (22%) - Mo (3%) superior stainless hlau. Incoloy yog cov ntawv sau npe ua lag luam ntawm thoob ntiaj teb Nickel Co. Haum rau ntau qhov ntau ntawm sulfuric acid ntawm qhov kub tsawg; Kev daws cov dej qab ntsev zoo (xws li NaOH) nrog rau 50% ~ 70%, nws muaj cov tshuaj tiv thaiv zoo hauv corrosion thiab tsis ua rau muaj kev nyuaj siab corrosion cracking. Txawm li cas los xij, nws yog rhiab rau chloride-induced crevice corrosion. Tsis tas li ntawd, kev ua yeeb yaj kiab tsis zoo heev, yog li nws tsis yog ib qho khoom siv phaj.
11 31 tooj
Hloov kho los ntawm 904L (nce Mo, N ntsiab lus), tus qauv 6% Mo superior stainless hlau (31% ni-27% cr-6.5% mo-32% Fe). Corrosion tsis kam nyob rau hauv ntau cov xov xwm yog zoo dua 904L; Hauv sulfuric acid nrog qhov siab ntawm 20% ~ 80% thiab ntsuas kub ntawm 60 ℃ ~ 100 ℃, qhov kev tiv thaiv corrosion txawm tshaj c-276.
12 33 tooj hlau
Ua kom zoo siab rau chrome-based superior stainless hlau nrog corrosion tsis kam piv rau qhov ntawm qee qhov ni-cr-mo alloys xws li Inconel 625. Hauv cov kua qaub thiab alkaline nruab nrab (suav nrog nitric acid, sib xyaw ntawm nitric acid thiab hydrofluoric acid), nws muaj zoo tsis kam mus rau hauv zos corrosion thiab kev nyuab siab corrosion cracking. Corrosion tsis kam nyob hauv cov concentric nitric acid zoo dua li 304L. Piv txwv li, nws tsim nyog rau sulfuric acid uas qhov kev ntsuas siab tshaj 96% ~ 99%, qhov kub tsawg dua 150 150 thiab sulfur oxide cov ntsiab lus tsawg dua 200 mg / L. Dej kub hiav txwv; ib qho muaj corrosive zoo tshaj plaws kev daws kub siab nrog cov tshuaj ≤ 50%; Phosphoric acid nrog kev kub siab ≤ 85% thiab ntsuas kub ≤150 ℃. Txawm li cas los xij, nws tsis haum rau kev tshaj tawm xov xwm (xws li dilute sulfuric acid, thiab lwm yam). Tus nqi zoo li c-276.
13 C - 2000 alloy
Npib tsib xee hlau ua qauv tsim xyoo 1990 xyoo ntawm tus nqi zoo ib yam li c-276 muaj ib qho kev tiv thaiv zoo tshaj plaws ntawm ib qho ntawm cov ntaub ntawv no. Hauv nruab nrab cov ntsiab lus ntawm sulfuric acid, dilute hydrochloric acid thiab kub kub, phosphoric acid nrog cov concentration tsawg dua 50%, thiab cov kua roj kub muaj cov tshuaj tiv thaiv zoo dua li c-276 thiab c-22, uas qhia qhov hloov pauv c-22 alloy. Txawm li cas los xij, rau sulfuric acid concentration ≥ 70%, qhov kev txhim kho corrosion tsis zoo li c-276.
14 txog 59 alloy
Piv nrog c-2000, tshuaj muaj kuab lom yog qhov tseem ceeb tsuas yog tias cov ntsiab lus ntawm Ni tau siab dua (59%) thiab qis dua hauv Fe, tsis muaj Cu thiab W. Nws yog ib qhov zoo tshaj plaws corrosion tsis kam, thermal stability, stamping thiab weldability cov ntaub ntawv hauv cov xim uas muaj xim nickel. Txij li nws txoj kev lag luam tawm xyoo 1990, nws tau siv dav hauv sulfuric acid, hydrochloric acid, hydrofluoric acid thiab ntau lwm yam tshaj tawm muaj cov tshuaj chlorine, oxygen thiab pH tsawg.
Cov lus ntawm cov khoom xaiv raws li kev ntsuas kub thiab chlorine ion cov ntsiab lus
Hauv Is Taws Nem ~~~
