xeb ntawm stainless hlau tom qab vuam yog ib qho mob taub hau rau ntau tus engineers thiab constructors. Saib ntawm cov xim daj nyob ib ncig ntawm lub vuam ntawm qhov qub du, tib neeg cov tshuaj tiv thaiv thawj zaug feem ntau "yog cov khoom yuav fake?" Qhov tseeb, feem ntau, cov khoom siv yog qhov tseeb, thiab qhov teeb meem yog nyob rau hauv cov txheej txheem tsim nyog ntawm vuam nws tus kheej, uas rhuav tshem qhov sib npaug ntawm cov hlau tsis huv.
1. Lub amulet stainless hlau ua haujlwm li cas?
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Core barrier: chromium oxide zaj duab xis
Cov ntsiab lus chromium hauv stainless hlau feem ntau tshaj 10.5%. Thaum raug huab cua, chromium yuav hnov mob sai heev nrog oxygen, ua rau nyias nyias (kwv yees li 1-3 nanometers) tab sis tuab heev chromium oxide (Cr₂O₃) passivation zaj duab xis rau saum npoo. Cov yeeb yaj kiab no tsis pom ntawm qhov muag liab qab, tab sis nws tuaj yeem txuas ruaj khov zoo li cov cuab yeej cuab tam, zoo cais cov kev sib cuag ntawm steel matrix thiab corrosive media.
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Ib qho piv txwv zoo:
Zaj duab xis passivation zoo li tib neeg daim tawv nqaij. Cov tawv nqaij zoo tuaj yeem tiv taus cov kab mob sab nraud; Vuam yog sib npaug rau "qhov kub hnyiab" hauv cheeb tsam, thiab daim tawv nqaij puas lawm. Yog tias nws tsis kho kom raug raws sijhawm, lub qhov txhab yuav kis tau thiab ua rau mob.
2. Kev soj ntsuam ntawm qhov cuam tshuam ntawm vuam thermal teb ntawm microstructure thiab cov khoom ntawm cov hlau
(1) Qhov tshwm sim ntawm "chromium deficiency" nyob rau hauv tshav kub cuam tshuam cheeb tsam (HAZ)- feem ntau inducement.
Qhov no yog qhov tseem ceeb thiab feem ntau yog vim li cas rau kev sib koom tes xeb. Thaum lub vuam kub nce mus txog qhov rhiab heev ntawm 450℃mus rau 850℃(tshwj xeeb tshaj yog thaum lub caij txias qeeb), chromium hauv stainless hlau yuav ua ke nrog carbon thiab precipitate chromium carbide (CRC) raws cov ciam teb.
- Qhov tshwm sim loj: chromium yog "xauv" hauv carbide thiab tsis tuaj yeem koom nrog hauv kev tsim cov yeeb yaj kiab passive. Qhov no ua rau muaj qhov txo qis hauv cov ntsiab lus chromium hauv thaj tsam ntawm thaj tsam ntawm cov carbide (uas yog, "chromium- tsis zoo"), thiab qee zaum txawm tias qis dua tus nqi tseem ceeb ntawm 10.5% kom muaj kev tiv thaiv xeb.
- Kev ua tau zoo ntawm kev ua tau zoo: nyob rau hauv ib puag ncig corrosive (txawm tias huab cua ntub), chromium - cov ciam teb tsis zoo yuav dhau los ua txoj hauv kev zoo tshaj plaws corrosion. Corrosion tsim sab hauv raws li cov ciam teb, tsim cov kab xeb pom ntawm ob sab ntawm cov vuam, uas yog hu ua "intergranular corrosion". Hauv qhov xwm txheej hnyav, cov khoom siv tseem tuaj yeem tawg raws qhov ciam teb.
(2) "Lub cev hloov" ntawm Weld Lub Cev
- Sib tov- nyob rau hauv cov ntaub ntawv: Yog tias koj siv cov hlau tsis raug ((xws li vuam 304 steel nrog 308 xaim) lossis koj qhov chaw raug kaw, qhov vuam yuav tsis muaj cov khoom qub hauv nws li cov hlau hauv paus, uas tuaj yeem ua rau nws xeb sai dua.
- Cov teeb meem loj ntawm cov nplej: Qhov nruab nrab ntawm cov weld melts thiab hloov kho, ua cov pob zeb loj dua li cov hlau qub. Cov muaju loj feem ntau txhais tau tias tsis muaj zog tiv thaiv xeb.
- Impurity enrichment thiab defects: impurities, porosity thiab slag suav nrog yuav raug qhia thaum vuam, uas dhau los ua qhov pib ntawm corrosion.
(3) Kev puas tsuaj ntawm lub xeev nto
- Oxidation thiab tempering xim: nyob rau hauv qhov kub thiab txias, ib tug tuab oxide nplai (xiav, ntshav, daj thiab lwm yam tempering xim) yuav tsim nyob rau hauv lub weld thiab nws cheeb tsam. Cov nplai oxide no xoob thiab ntxeem tau, thiab cov hlau hauv qab nws tseem nyob hauv chromium - lub xeev tsis zoo, thiab xim nws tus kheej yog qhov pib ntawm corrosion.
- Nce roughness: vuam slag thiab spatter ua rau saum npoo ntxhib, uas ua rau nws yooj yim rau nqus noo noo thiab corrosive ions, thiab nws tsis yooj yim rau kev ua tiav passivation zaj duab xis.
3. kev ua haujlwm uas ua rau muaj teeb meem loj dua hauv kev sib ntaus sib tua
- Tsis siv cov khoom siv vuam tsim nyog: Yog tias cov pa roj carbon zoo tib yam npog electrode siv tsis raug thaum vuam 316L stainless hlau, qhov corrosion kuj ntawm cov vuam yuav raug puas tsuaj.
- Tsis muaj shielding roj los yog tsis txaus tiv thaiv: Nyob rau hauv inert gas shielded vuam, cov pa roj ntws thiab purity tsis txaus los yog lub cover dragging lub sij hawm luv luv, uas yuav ua rau huab cua intrusion ntawm weld ntawm kub thiab oxidation loj.
- Kev siv vuam tsis zoo: cov kab hluav taws xob ntau dhau (siab tam sim no thiab qhov hluav taws xob, qeeb ceev) yuav ua rau thaj chaw kub ntxhov dav dav thiab chromium deficiency hnyav dua.
- Tsis muaj kev kho mob tom qab vuam: nws tau txiav txim siab tias "welding yog txaus", thiab cov vuam thiab cov cheeb tsam ib puag ncig tsis raug ntxuav, pickled los yog passivated, uas yog sib npaug ncaj qha rau qhov "hlawv" qhov txhab.
4. Kev daws teeb meem: los ntawm kev tiv thaiv mus rau kev kho
Kev tiv thaiv theem:
- Cov khoom sib txuam: xaiv qis- carbon lossis stainless hlau uas muaj cov khoom ruaj khov (xws li 304L thiab 316L, lossis 321 thiab 347 uas muaj titanium / niobium). Lawv tuaj yeem txo cov nag lossis daus ntawm chromium carbide.
- Cov txheej txheem tswj: txais yuav tsis tshua muaj tam sim no thiab ceev vuam ceev kom txo cov cua sov nkag; Xyuas kom meej tias kev tiv thaiv roj inert yog txaus thiab siv tau; Yog tias tsim nyog, preheat lub phaj tuab los yog tswj qhov kub ntawm interlayer kom tsis txhob nyob hauv qhov ntsuas kub ntau.
- Kev xaiv cov khoom siv vuam: xaiv cov khoom siv vuam nrog cov tshuaj lom neeg sib xyaw lossis zoo dua (xws li vuam 304 nrog 316 vuam cov khoom kom nce molybdenum cov ntsiab lus).
Tom qab- kev kho vuam:
(1) Kev tu neeg kho tshuab: Siv tshwj xeeb stainless hlau sib tsoo log lossis hlau txhuam (uas yuav tsum yog tshwj xeeb rau cov hlau tsis huv kom tsis txhob muaj cov pa phem carbon steel) kom tshem tawm cov vuam slag thiab txaws.
(2) Acid pickling passivation: qhov no yog cov kauj ruam tseem ceeb los kho corrosion kuj.
- Pickling: siv nitric acid-hydrofluoric acid tov tov kom tshem tawm cov oxide nplai thiab chromium- txheej tsis zoo nyob rau hauv weld thiab tshav kub cuam tshuam cheeb tsam.
- Passivation: Kho nrog cov tshuaj passivation xws li nitric acid los yog citric acid los txhawb qhov chaw kom ua tiav thiab ntom chromium oxide zaj duab xis dua.
(3) Electrolytic polishing: rau siab - cov khoom xav tau, qhov saum npoo tuaj yeem hloov kho los ntawm electrolytic polishing, thiab ib zaj duab xis passivation zoo heev tuaj yeem tau txais tib lub sijhawm.
