904L Stainless Hlau (UNS N08904): Lub Siab -Kev Ua Haujlwm Zoo rau Kev Ua Haujlwm hnyav

 

Dab tsi yog cov ncauj lus kom ntxaws tshuaj muaj pes tsawg leeg thiab qhov kev ntsuas qhov tseem ceeb txhais tau li cas 904L?
The alloy is composed of approximately 20% chromium, 25% nickel, 4.5% molybdenum, and 1.5% copper, with a maximum carbon content of 0.02%. This rich composition gives it a very high Pitting Resistance Equivalent Number (PREN >35). Cov npib tsib xee siab muab kev ruaj ntseg hauv kev txo qis ib puag ncig, qhov siab molybdenum thiab chromium muaj cov tshuaj chloride tsis kam, thiab cov tooj liab tshwj xeeb txhim khu kev tiv thaiv sulfuric acid. Nws qhov kev ntsuas kev ua haujlwm tseem ceeb yog nws qhov dav -spectrum corrosion kuj, ua rau nws siv tau qhov twg ntau lwm cov hlau tsis huv.

Nyob rau hauv daim ntawv thov tshwj xeeb thiab hnyav yog 904L suav tias yog tus qauv lossis cov khoom tseem ceeb?
904L yog qhov tseem ceeb hauv kev lag luam tshuaj rau cov cuab yeej tuav kub, concentrated sulfuric acid thiab phosphoric acid. Nws yog ib qho khoom siv rau cov dej hiav txwv -txias cua kub exchangers thiab piping hauv fais fab nroj tsuag thiab offshore platforms. Nws yog dav siv nyob rau hauv cov pa phem tswj scrubbers, pulp thiab ntawv digesters, thiab zus tau tej cov chiv thiab explosives. Hauv kev lag luam tshuaj, nws raug xaiv rau cov reactors qhov twg cov khoom purity thiab tsis kam mus rau cov tshuaj ntxuav yog qhov tseem ceeb. Nws siv txhais tau tias ib daim ntawv thov qhov kev ntseeg siab yog qhov tseem ceeb.

Nws cov nqi thiab fabricability piv rau tus qauv 316L thiab duplex 2205 stainless hlau li cas?
904L tseem kim dua 316L vim nws cov ntsiab lus nickel thiab molybdenum siab. Nws cov nqi feem ntau yog siab dua duplex 2205 ib yam nkaus, txawm hais tias qhov sib piv nyob ntawm cov nqi lag luam npib tsib xee. Fabrication yog qhov nyuaj dua: nws muaj kev ua haujlwm ntau dua- tus nqi hardening, yuav tsum tau siv cov cuab yeej siv zog ntau dua thiab ua rau cov cuab yeej hnav sai dua. Vuam yuav tsum tau saib xyuas, feem ntau yog siv ntau tshaj -alloyed muab tub lim zoo li ER385 los yog Ni-Cr-Mo alloys los tiv thaiv corrosion nyob rau hauv lub vuam hlau. Nws tsis yog "poob-" hloov pauv thiab xav tau cov neeg tsim khoom paub txog.

Dab tsi yog cov kev txwv tseem ceeb lossis ib puag ncig uas 904L yuav tsum tsis txhob siv?
Txawm hais tias nws muaj peev xwm, 904L tsis yog universally resistant. Nws tsis pom zoo siv rau hauv hydrochloric acid lossis lwm yam muaj zog, tsis yog -oxidizing acids yam tsis muaj inhibitors. Nws tuaj yeem raug cuam tshuam rau kev ntxhov siab corrosion tawg nyob rau hauv kub, concentrated chloride cov kev daws teeb meem, txawm hais tias nws kuj zoo dua li 316L. Ib puag ncig nrog cov roj chlorine ntub dej lossis siab -kub fluorides kuj tseem muaj teeb meem. Rau cov ntawv thov uas muaj cov tshuaj chloride ntau thiab kub, cov nickel alloys zoo li Hastelloy C-276 lossis super duplex steels yuav tsim nyog dua.

Dab tsi yog cov txheej txheem kev txiav txim siab zoo rau kev qhia txog tus nqi 904L alloy?
Kev qhia txog 904L yuav tsum yog qhov xaus ntawm kev soj ntsuam nruj thiab kev lag luam. Ua ntej, kev soj ntsuam ntxaws ntxaws ntawm cov txheej txheem ib puag ncig (tshuaj lom neeg, qhov ntau, qhov kub thiab txias, pH, muaj cov crevices) yuav tsum tau ua. Kev kuaj corrosion nyob rau hauv cov xwm txheej tiag tiag lossis simulated yog qhov xav tau. Yog tias cov qhab nia zoo li 316L lossis duplex 2205 qhia tias tsis tuaj yeem lees txais tus nqi corrosion lossis kev pheej hmoo tsis ua haujlwm, ces 904L dhau los ua tus neeg sib tw. Qhov kev txiav txim zaum kawg hnyav nws tus nqi pib siab tiv thaiv tag nrho cov nqi ntawm lub neej, suav nrog kev siv nyiaj ntau ntawm lub sijhawm tsis tau npaj tseg, cov khoom poob, teeb meem kev nyab xeeb, lossis hloov khoom siv ntxov ntxov. Rau cov cuab yeej tseem ceeb, tsis muaj kev tiv thaiv, 904L feem ntau yog ib qho kev nqis peev uas muaj txiaj ntsig hauv kev cog qoob loo ntev ntev.