Stainless hlau npauj npaim li qub yuav ua tsis tau xeb thaum siv. Nws yog ib qho tseem ceeb heev kom paub seb dab tsi ua rau cov hlau stainless npauj npaim valve xeb. Los ntawm kev tshuaj xyuas cov khoom siv ntawm tus npauj npaim valve, ntsuas kev kho cua sov, SEM thiab lwm yam kev ntsuas vaj huam sib luag. Vim tias cov carbides raws cov ciam teb cog qoob loo hauv cov khoom ntim cov dej nag los tsim ib thaj chaw cim tseg, qhov no yog qhov laj thawj rau kev xeb ntawm cov hlau tsis muaj stainless npauj npaim valve.
Stainless hlau npauj npaim valvemade ofCF8Mis corroded thaum siv.Austenitic stainless hlau tom qab kev kho cua sov ib txwm, cov ntaub so ntswg yuav tsum nyob ntawm chav sov Austria' lub cev, tiv thaiv xeb zoo. Txhawm rau txheeb xyuas qhov ua rau xeb ntawm npauj npaim valve, tau coj ib qho piv txwv rau nws los tshuaj xyuas.
1 Txoj kev xeem
Kev ntsuas rau kev tshuaj xyuas cov tshuaj lom neeg (txiav txim siab seb nws ua tau raws li cov qauv yuav tsum tau ua), kev tshuaj xyuas cov qauv hlau, ntsuas cov txheej txheem kho cua sov thiab SEManalysis.
2 Xeem cov txiaj ntsig thiab ntsuas
& quot; Table1" Tshuaj lom neeg muaj pes tsawg leeg tshuaj xyuas cov txiaj ntsig/% | ||||||||
Cov khoom xyaw | C | Si | Mn | P | S | Cr | Ni | Mo |
CF8M | 0.08 | 1.5 | 1.5 | 0.04 | 0.04 | 18~21 | 9~12 | 2~3 |
Npauj npaim valve | 0.10 | 0.60 | 0.61 | 0.024 | 0.009 | 18.05 | 9.71 | 1.45 |
2.1Chemical muaj pes tsawg leeg
Cov txiaj ntsig kev tshuaj xyuas tshuaj lom neeg muaj pes tsawg leeg thiab cov qauv muaj nyob hauv" Table1".
2.2Metallographic tsom xam
Cov qauv hlau tau txiav los ntawm cov npauj npaim xeb xeb. Tom qab sib tsoo thiab polishing, lawv tau corroded nrog cov kua aqueous ntawm ferric chloride thiab tau tshuaj xyuas thiab txheeb xyuas ntawm Neophot-32metallographic microscope. Cov qauv siv hlau yog tsim los ntawm austenite thiab lwm yam Cov yam ntxwv ntawm cov dej nag.Qhov kev hais lus, austenitic stainless hlau yuav tsum tau txais cov qauv austenitic zoo ib yam tom qab kev kho cua sov ib txwm muaj. yog thephase, thiab lwm qhov yog carbide.σphase thiab carbide tsim cov xwm txheej sib txawv, tab sis lawv txhua tus muaj qhov sib xws, uas yog, qhov nkag siab ntawm austenitic stainless hlau rau intergranular corrosion.
Ua ntej, siv txoj hauv kev sib txawv los txheeb xyuas qhov theem.Ua haujlwm alkaline aqueous tov ntawm cov ntshav liab ntsev (10g cov ntshav ntshav ntsev - 10g ntawm potassium potassium hydroxide+100ml dej), tom qab cov qauv raug rhaub hauv cov tshuaj no rau 2 mus rau 4 feeb, ferrite yog daj, cov carbides tau corroded, thiab austenite yog xim xim, changesphase hloov los ntawm xim av mus rau dub.Qhov qauv txiav los ntawm npauj npaim valvewas boiledin ib qho alkaline liab ntshav salinesolution rau 4 feeb los ntawm cov txheej txheem saum toj no, thiab tom qab ntawd pom nyob rau hauv lub tshuab tsom me me, cov nag lossis daus tau tswj hwm lawv thawj morphology, thiab tsis muaj kev hloov pauv tseem ceeb tau pom.
2.3 Kev ntsuas ntsuas ntsuas kev kho cua sov
Sigmaphase yog cov khoom sib txuas sib xyaw nrog kwv yees tib lub atomic piv ntawm cov hlau rau chromium.Chemical muaj pes tsawg leeg, ferrite, kev hloov pauv txias, thiab kev hloov pauv kub cuam tshuam rau kev tsim cov qib sib tov tovarying.Qhov txheej txheem txheej txheem tau siv los sim, thiab cov txheej txheem nag lossis daus hloov pauv tsis pom tseeb nyob rau hauv lub tshuab tsom iav, yog li txoj kev kho cua sov tau siv los txheeb xyuas qhov theem.Qhov raws li cov ntaub ntawv cuam tshuam, σphase feem ntau yog tsim thaum lub sijhawm laus -500 ~ 800℃Qhov no yog vim tias kev laus ntawm qhov kub siab dua tuaj yeem ua rau kis tau tus mob chromium.Qhov cua sov ntawm qhov kub dua yuav pib yaj, thiab kev sib tawg yuav tsum yog tsawg kawg 920℃los yog ntau dua.Lub cua sov ntawm qhov kub ruaj khov siab dua li -phase tuaj yeem tshem tawm nws. Txawm hais tias nws yuav siv sij hawm ntev toform thephase, tshem tawm ntawm thephase feem ntau xav tau tsuas yog lub sijhawm cua sov luv. hauv cov qauv tuaj yeem tshem tawm.Qhov qauv txiav los ntawm npauj npaim valve yog rhaub rau 940℃, khaws cia rau 30 feeb, thiab tom qab ntawd tau txais kev pom zoo thiab tshuaj xyuas ntawm Neophot-32metallurgical lub tshuab tsom iav. Tom qab kho cua sov, cov txheej txheem nag lossis daus hauv cov qauv tsis raug tshem tawm thiab qhov qub morphology raug khaws cia, uas ua pov thawj tias cov txheej txheem nag lossis daus hauv cov qauv yuav tsis yog asigmaphase.
2.4 SEManalysis
Qee lub sij hawm thesigmaphase insteelcan tsis tuaj yeem sib txawv los ntawm ib txoj kev zas xim. Nws tuaj yeem txheeb xyuas los ntawm SEManalysis txoj hauv kev vim tias nws tau paub tias qib yog cov hlau thiab chromium, nrog cov ntsiab lus chromium ntawm 42% txog 48%, cov ntsiab lus sib xyaw thiab lawv cov ntsiab lus ntawm theem tsis paub yog ntsuas los ntawm EDSquality thiab ntsuas ntau, yog li txiav txim siab theem tsis paub.
Cov txiaj ntsig ntawm kev tshuaj xyuas thaj tsam ntawm thaj tsam ntawm cov lej thiab cov dej nag tau qhia hauv" Table2" ;.
& quot; Table2" EDSquantitative tsom xam cov txiaj ntsig/% | ||||||
Cov khoom xyaw | Fe | Cr | Ni | Mo | Si | Mn |
Matrix | 70.463 | 16.365 | 10.211 | 1.239 | 0.466 | 1.257 |
Cov theem nag lossis daus | 56.908 | 33.629 | 3.681 | 4.835 | 0.040 | 0.907 |
EDSanalysis pom tias tus nqi ntawm chromium uas muaj nag lossis daus yog 33.6%, qhov tseem ceeb dua li hauv matrixCrcontent ntawm 16.3%, thaum suav cov theem ntawm chromium uas muaj theem yog 42%-48%, yog li tsis lees tias cov nag lossis daus asphase. thiab ntsuas kev kho cua sov, nws ntseeg tias cov txheej txheem nag lossis daus nyob rau hauv cov qauv ntawm cov hlau stainless npauj npaim valve tsis yog thephase.ObservedbySEM, theem ua ntej yog ib hom eutectic qauv, uas feem ntau yog chromium carbide.
Cov npauj npaim npauj npaim stainless hlau yog ua los ntawm npib tsib xee-chromium austenitic stainless hlau, uas feem ntau siv nyob rau hauv lub xeev daws teeb meem.Thaum chav sov, nws cov qauv yog austenitic. Austenitic stainless hlau muaj kev tiv thaiv corrosion zoo nyob rau hauv ntau yam ntawm cov xov xwm corrosive, tshwj xeeb tshaj yog nyob rau hauv qhov chaw.Qhov laj thawj rau kev xeb ntawm stainless hlau npauj npaim li qub yog raws li hauv qab no:
①Raws li cov txiaj ntsig ntawm cov kev ntsuas saum toj no, nws tuaj yeem txiav txim siab tias theem nag lossis daus hauv npauj npaim valve cov qauv tsis yog -theem, yog li qhov xeb tshwm sim ntawm npauj npaim valve tsis yog tshwm sim los ntawm theem.
②Los ntawm SEMobservation, nws tau lees paub tias cov theem nag lossis daus hauv cov qauv ntawm npauj npaim valve feem ntau yog chromium carbide, thiab cov qauv eutectic no tau faib raws cov ciam teb ciam teb. siab dua li ntawm cov matrix.This carbide yog oftypeM23C6.With nag lossis daus ntawm carbides thiab tsis muaj chromium diffusion ntxiv, chromium carbides nag lossis daus raws ciam teb austenite, tsim ib cheeb tsam chromium-depleted nyob ib ncig ntawm cov carbides, yog li ntawd austenitic stainless hlau grain ciam teb Yog li ntawd yooj yim corroded.Tau li ntawd, cov carbide nag lossis daus raws cov ciam teb yog qhov ua rau xeb ntawm npauj npaim valve.
③Rau cov hlau austenitic tom qab kho cov tshuaj, vim tias feem ntau ntawm cov carbides tau yaj thaum ua kom sov ntawm qhov kub siab, austenite tau ntim nrog cov pa roj carbon ntau thiab chromium, thiab theaustenite raug kho vim tom qab txias sai, yog li cov khoom muaj ntau qhov kev tiv thaiv kev xeb ntawm cov lus.Yog li ntawd, txheej txheem kev kho cua sov yuav tsum tau tswj nruj me ntsis. Thaum lub sijhawm kho tshuaj, lub tshuab ua haujlwm tau ua kom sov siab kom tshem tawm tag nrho cov carbide, thiab tom qab ntawd txias kom sai kom tau txais tus qauv Austenite ib yam. Tom qab daws kev kho mob, yog siv cua txias qeeb, chromium carbide yuav ua kom nrawm raws cov ciam teb thaum lub caij txias txheej txheem, uas yuav ua rau txo qis hauv kev tiv thaiv corrosion ntawm cov khoom.
