904L (UNS N08904): Lub Siab -Alloy Solution rau Kev Siv Tshuaj Txhaum Cai

 

Dab tsi yog cov ncauj lus kom ntxaws thiab kev ua tau zoo ntawm 904L?
904L is composed of approximately 20% Cr, 25% Ni, 4.5% Mo, 1.5% Cu, and a maximum of 0.02% C. This rich chemistry gives it a very high Pitting Resistance Equivalent Number (PREN >35) thiab ua haujlwm zoo rau ob qho tib si oxidizing thiab txo cov kua qaub. Cov ntsiab lus siab nickel thiab tooj liab tshwj xeeb tso cai rau kev ua tau zoo tshaj hauv dilute rau cov concentrated sulfuric acid thoob plaws qhov kub thiab txias. Nws qhov zoo tshaj plaws yog nws qhov dav -spectrum corrosion kuj nyob rau hauv complex, sib xyaw tshuaj ib puag ncig uas txheem molybdenum- bearing steels zoo li 316L yuav poob.

Hauv cov kev lag luam tseem ceeb thiab cov ntawv thov twg yog 904L suav tias yog tus qauv lossis cov khoom tseem ceeb?
Nws yog cov khoom siv hauv kev lag luam tshuaj rau cov khoom siv xws li reactors, kab, thiab kav dej tuav sulfuric thiab phosphoric acids. Nws yog ib qho tseem ceeb hauv dej hiav txwv -cov cua kub sib txawv rau cov chaw tsim hluav taws xob thiab cov chaw tawm ntug dej hiav txwv. Lwm cov ntawv thov tseem ceeb muaj xws li cov ntaub so ntswg thiab cov ntawv digesters, kev tswj cov pa phem, thiab cov khoom siv hauv kev lag luam tshuaj uas yuav tsum tau tiv thaiv cov tshuaj tua kab mob hnyav. Kev siv nws txhais tau hais tias ib daim ntawv thov uas muaj kev ntseeg siab nyob rau hauv cov tshuaj lom neeg raug mob hnyav tsis yog- sib tham.

904L piv rau duplex stainless hlau 2205 li cas ntawm kev ua tau zoo thiab daim ntawv thov?
Thaum ob qho tib si hloov kho los ntawm 316L, lawv ua tau zoo hauv ntau qhov chaw. Duplex 2205 muaj kwv yees li ob npaug ntawm cov khoom muaj zog ntawm 904L thiab zoo heev chloride kev nyuaj siab corrosion cracking (SCC) tsis kam. 904L, txawm li cas los xij, muab kev tiv thaiv zoo tshaj plaws los txo cov kua qaub xws li sulfuric acid, ua tsaug rau nws cov ntsiab lus tooj liab, thiab feem ntau muaj cov tshuaj tiv thaiv corrosion zoo dua hauv chlorides. 904L kuj tsis yog{6}} Qhov kev xaiv pob khawm ntawm ib puag ncig: rau siab -lub zog xav tau hauv kev pabcuam chloride, xaiv 2205; rau complex acid sib tov, xaiv 904L.

Dab tsi yog qhov tseem ceeb ntawm fabrication thiab vuam kev txiav txim siab rau 904L?
Vim nws cov ntsiab lus alloy siab, 904L muaj kev ua haujlwm siab dua -hardening npaum li tus qauv austenitics, xav tau ntau lub zog rau machining thiab sib sau. Vuam yuav tsum tau ua siv tshaj -alloyed muab tub lim hlau (xws li ER385 los yog ib tug npib tsib xee-raws li ERNiCrMo-3) los tiv thaiv corrosion nyob rau hauv lub vuam hlau. Kev tswj xyuas nruj ntawm cov khoom siv hluav taws xob thiab kev tiv thaiv roj kom zoo yog qhov tseem ceeb los tiv thaiv oxidation thiab kev sib cais. Kev ntxuav tom qab vuam yog qhov tseem ceeb kom tshem tawm cov cua sov uas tuaj yeem pib xeb.

Yam dab tsi ua pov thawj qhov kev nqis peev tseem ceeb hauv 904L dua li qis dua - nqi alloys?
Qhov kev ncaj ncees yog ua raws li kev txheeb xyuas cov nqi ntawm lub neej thiab kev pheej hmoo. Yog tias qis dua -qib alloy yuav xav tau kev tshuaj xyuas ntau zaus, tshuaj inhibitors, hloov thaum ntxov, lossis ua rau muaj kev pheej hmoo siab ntawm kev puas tsuaj loj uas ua rau poob lossis kev nyab xeeb tshwm sim, ces 904L yog qhov ncaj ncees. Nws cov nqi pib siab dua yog offset los ntawm kev pab cuam lub neej ntev, txo kev txij nkawm, thiab kev cia siab rau kev ua haujlwm. Rau cov haujlwm tshiab hauv qhov zoo-txhais tau qhov kev nruj nruj, kev qhia txog 904L txij thaum pib yog feem ntau pheej yig dua li rov ua dua nrog nws tom qab.