Hauv kev tswj cov dej hauv kev lag luam, kev xaiv cov khoom siv valve dictates system kev ncaj ncees thiab lifecycle nqi. Carbon steel thiab stainless hlau sawv cev rau ob tsev neeg tseem ceeb, txhua tus txhais los ntawm cov ciam teb sib txawv. Kev xaiv yog ib qho kev suav nrog engineering raws li tsib qhov tseem ceeb.
1. Kev sib xyaw ua kua dej thiab cov tshuab ua kom xeb
Cov txheej txheem kua dej chemistry yog thawj tus tsav tsheb.
Cov pa roj carbon steel (piv txwv li, WCB) tso siab rau ferritic-pearlitic cov qauv uas raug rau electrochemical corrosion nyob rau hauv acidic, caustic, los yog oxygenated ib puag ncig, ua rau phab ntsa thinning thiab foob tsis ua hauj lwm. Nws yog txwv rau qhuav hydrocarbons, chav, thiab tsis yog - roj corrosive.
Stainless hlau (xws li, CF8/304, CF8M/316) siv ib tug passive chromium oxide zaj duab xis los tiv thaiv corrosion kinetics. Cov molybdenum hauv Qib 316 tshwj xeeb tiv thaiv chloride-induced pitting, ua rau nws tseem ceeb rau kev ua tshuaj lom neeg thiab kev pabcuam dej hiav txwv. Kev tsom xam meej ntawm pH thiab chloride concentration yog qhov yuav tsum tau ua raws li cov tshuaj chlorides hauv siab -kub dej feem ntau txwv tsis pub siv carbon steel.
2. Qhov kub thiab txias heev thiab Metallurgical stability
Kub ncaj qha cuam tshuam cov khoom siv kho tshuab. Standard carbon steel undergoes graphitization thiab lub zog poob siab tshaj 425 degree, txaus ntshai creep deformation, whereas austenitic stainless hlau tuav structural kev ncaj ncees tshaj 600 degree. Hloov pauv, cov pa roj carbon steel tau nthuav tawm Cov Khoom Siv Hluav Taws Xob - rau -Brittle Transition Temperature (DBTT) hauv qab -29 degree, ua rau muaj kev pheej hmoo tawg tawg loj hauv cov kev pabcuam cryogenic. Stainless hlau khaws cia zoo heev toughness mus rau -196 degree, tshuav tus qauv rau LNG thiab qis-kub sib cais txheej txheem. Kev ntsuas siab-Tub kub yuav tsum raug soj ntsuam nruj me ntsis tiv thaiv ASME B16.34 rau cov xwm txheej hnyav.
3. Kev siv peev nyiaj piv rau Tag Nrho Tus Nqi ntawm Cov Tswv Cuab
Kev xaiv yuav tsum ua qhov tseem ceeb ntawm Tus Nqi Tag Nrho Cov Tswv Cuab tshaj tus nqi pib qhov khoom. Thaum cov hlau tsis muaj steel hais kom muaj CAPEX tus nqi tseem ceeb, cov pa roj carbon steel li qub hauv cov haujlwm corrosive muaj kev saib xyuas tsis tu ncua, luas hloov, thiab tsis npaj kaw. Cov nqi ua haujlwm ntawm cov khoom poob feem ntau dwarf qhov pib cov khoom txuag. Rau cov txheej txheem tseem ceeb nrog kev tsim lub neej ntau dua 10 xyoo, stainless hlau txuas ntxiv Lub Sijhawm Nruab Nrab Nruab Nrab tsis ua haujlwm muab lub sijhawm ntev dua - rov qab los ntawm kev nqis peev los ntawm kev txo qis kev siv nyiaj ua haujlwm.
4. Cov qauv kev nyiam huv thiab kev ruaj ntseg ntawm qhov chaw
Kev lag luam cov lis dej num tswj hwm qhov yuav tsum tau ua kom nruj rau thaj chaw sib cuag dej. Cov pa roj carbon steel micro-roughness txhawb cov kab mob colonization thiab particulate shedding, rendering nws tsis yog -raws li kev huv huv daim ntaub ntawv. Stainless hlau tso cai rau electropolishing kom ua tiav Ra Tsawg dua lossis sib npaug ntawm 0.4 μm, ua kom muaj txiaj ntsig hauv huv huv-hauv-Qhov chaw thiab Sterilize-hauv-Qhov chaw raws tu qauv xav tau los ntawm GMP thiab FDA cov qauv.
Tsis tas li ntawd, stainless hlau tshem tawm qhov xav tau rau lub sijhawm rov ua dua nyob rau hauv marine lossis siab -cov av noo ib puag ncig, ua kom muaj kev ncaj ncees ntawm qhov chaw.
5. Kev tu ncua ncua sij hawm thiab kev cia siab rau qhov system
Valve kev ntseeg tau hais txog qhov system muaj. Hauv kev ua haujlwm corrosive, cov khoom siv carbon steel yog qhov ua rau lub qhov txhab, qaug dab peg, thiab bolt oxidation, feem ntau xav tau kev puas tsuaj. Stainless hlau trims nthuav tawm ntau dua saum npoo hardness thiab galling tsis kam, tiv thaiv kev txeeb thiab ua kom yooj yim txij nkawm. Qhov no txuas ntxiv lub sijhawm hloov kho dua tshiab thiab tseem ceeb heev rau kev teeb tsa chaw taws teeb lossis cov chaw uas muaj qhov hloov pauv hloov pauv, ncaj qha txhawb nqa Lub Hom Phiaj Siab Muaj.
Xaus
Tsis muaj universally superior khoom. Qhov kev xaiv zoo tshaj yog nyob ntawm thaj tsam engineering tshwj xeeb. Cov pa roj carbon steel muaj cov nqi ua haujlwm rau nruab nrab, tsis yog- cov kev pabcuam corrosive, thaum stainless hlau muab kev nyab xeeb rau hauv qhov chaw corrosive, huab cua kub, thiab siab - kev siv purity. Cov lus qhia zaum kawg yuav tsum siv cov qauv xws li NACE MR0175 thiab API 600 kom ntseeg tau tias muaj kev ruaj ntseg.
