Dab tsi yog qhov txawv ntawm stainless hlau thiab stainless hlau? Yuav qhia li cas?
Stainless hlau yog ib hom stainless hlau. Cov qauv yog: 409 410 430 444. Nws belongs rau martensitic thiab ferritic stainless hlau. Nws yuav sib nqus thaum siv cov hlau nplaum. Austenitic stainless hlau suav nrog 201 202 304 321 316L, thiab lwm yam.
Stainless hlau (tseem hu ua stainless acid-resistant steel) yog hais txog cov hlau uas tuaj yeem tiv taus corrosion los ntawm cov tshuaj lom neeg xws li cua lossis kua qaub. Stainless hlau tsis xeb-dawb, tab sis nws tus cwj pwm corrosion hauv cov xov xwm sib txawv yog txawv. Feem ntau siv stainless steels Feem ntau siv stainless hlau tuaj yeem muab faib ua peb hom: martensitic stainless hlau, ferritic stainless hlau thiab austenitic stainless hlau raws li lawv lub koom haum cov yam ntxwv.
a. Martensitic stainless hlau
Feem ntau siv martensitic stainless hlau muaj cov ntsiab lus carbon ntawm {{0}}.1 ~ 0.45% thiab cov ntsiab lus chromium ntawm 12 ~ 14%. Nws yog chromium stainless hlau, feem ntau hu ua Cr13 stainless hlau. Cov qib steel muaj xws li 1Cr13, 2Cr13, 3Cr13, 4Cr13, thiab lwm yam. Cov hlau no feem ntau yog siv los ua ntau yam li qub, twj tso kua mis thiab lwm qhov chaw nrog rau qee yam khoom siv stainless hlau uas tuaj yeem tiv taus qhov hnyav thiab xav tau kev tiv thaiv corrosion.
Txhawm rau txhim kho corrosion kuj, cov ntsiab lus carbon ntawm martensitic stainless hlau yog tswj nyob rau hauv ib qho tsawg heev, feem ntau tsis ntau tshaj 0.4%. Qhov qis dua cov ntsiab lus ntawm cov pa roj carbon monoxide, qhov zoo dua qhov corrosion kuj ntawm cov hlau, thiab cov pa roj carbon ntau dua, cov ntsiab lus carbon ntau dua hauv matrix, lub zog thiab hardness ntawm cov hlau ntau dua; qhov siab dua cov ntsiab lus carbon, qhov ntau dua nws yog tsim chromium. Qhov ntau carbides muaj, qhov phem tshaj qhov corrosion ua. Nws tsis yog qhov nyuaj rau pom los ntawm qhov no tias qhov ntsuas lub zog thiab qhov tawv tawv ntawm 4Cr13 yog qhov phem dua li 1Cr13, tab sis nws qhov kev tiv thaiv corrosion tsis zoo li 1Cr13.
1Cr13 thiab 2Cr13 muaj peev xwm tiv thaiv corrosion los ntawm huab cua, chav thiab lwm yam xov xwm, thiab feem ntau yog siv los ua cov qauv hlau tsis zoo. Txhawm rau kom tau txais kev ua tau zoo, quenching + high-temperature tempering (600 ~ 700 degree) feem ntau yog siv kom tau tempered sorbite los tsim chav turbine hniav, boiler tube accessories, thiab lwm yam. Raws li rau 3Cr13 thiab 4Cr13 steel, vim lawv siab dua. carbon cov ntsiab lus, lawv cov corrosion kuj tsis zoo. Los ntawm quenching + tsis kub tempering (200 ~ 300 degree), tempered martensite tau txais, uas muaj zog dua thiab hardness (HRC txog 50), yog li nws feem ntau siv los ua cov cuab yeej hlau los tsim cov cuab yeej kho mob, cov cuab yeej txiav, cov roj kub kub. shafts lwm.
b. Ferritic stainless hlau
Feem ntau siv ferritic stainless hlau muaj cov ntsiab lus carbon tsawg dua {{0}}.15% thiab cov ntsiab lus chromium ntawm 12 txog 30%. Nws tseem yog chromium stainless hlau. Cov qib steel muaj xws li 0Cr13, 1Cr17, 1Cr17Ti, 1Cr28, thiab lwm yam. Raws li cov ntsiab lus carbon tsawg thiab cov ntsiab lus chromium nce raws li, thaum cov hlau tau rhuab los ntawm chav tsev kub mus rau qhov kub siab (960 ~ 1100 degree), nws cov microstructure yog ib txwm ib leeg- Phase ferrite qauv. Nws cov corrosion kuj, plasticity thiab weldability yog zoo dua li martensitic stainless hlau. Rau high-chromium ferritic stainless hlau, nws muaj peev xwm tiv thaiv corrosion hauv oxidizing media muaj zog. Raws li cov ntsiab lus chromium nce, qhov corrosion kuj tseem txhim kho.
Ntxiv titanium rau hlau tuaj yeem kho cov nplej, stabilize carbon thiab nitrogen, thiab txhim kho lub toughness thiab weldability ntawm cov hlau. Ferritic stainless hlau tsis dhau theem hloov thaum cua sov thiab txias, yog li cov hlau tsis tuaj yeem muaj zog los ntawm kev kho cua sov. Yog hais tias cov nplej yog coarsened thaum lub sij hawm cua sov, txias yas deformation thiab recrystallization tsuas yog siv los txhim kho cov qauv thiab kev ua tau zoo. Yog tias hom hlau no nyob ntawm 450 ~ 550 degree, nws yuav ua rau embrittlement ntawm cov hlau, uas yog hu ua "475 degree brittleness". Embrittlement tuaj yeem raug tshem tawm los ntawm cua sov txog li 600 degree thiab tom qab ntawd txias sai sai. Nws yuav tsum tau muab sau tseg tias nyob rau lub sij hawm ntev cua sov ntawm hom hlau no ntawm 600 ~ 800 degree yuav ua rau ib tug nyuaj thiab brittle σ theem, ua rau cov khoom los ua σ theem brittle. Tsis tas li ntawd, thaum quenched saum 9250C, intergranular corrosion tendencies thiab brittleness tshwm sim los ntawm tseem ceeb grain coarsening yuav tshwm sim. Cov phenomena no yog teeb meem loj rau vuam qhov chaw. Cov qub tuaj yeem raug tshem tawm los ntawm lub sijhawm luv luv ntawm 650 ~ 815 degree. Hom hlau no pom tseeb qis dua hauv lub zog tshaj martensitic stainless hlau thiab yog siv los ua cov khoom tiv thaiv corrosion thiab dav siv hauv nitric acid thiab nitrogen chiv industries.
c. Austenitic stainless hlau
Ntxiv 8 ~ 11% Ni rau cov hlau uas muaj 18% Cr yog qhov zoo tshaj plaws austenitic stainless hlau. Piv txwv li, 1Cr18Ni9 yog cov qib steel feem ntau. Vim qhov sib ntxiv ntawm npib tsib xee, hom hlau no nthuav dav thaj tsam austenite, kom cov txheej txheem metastable ib-theem austenite tuaj yeem tau txais ntawm chav tsev kub. Vim nws cov ntsiab lus siab ntawm chromium thiab npib tsib xee thiab nws cov qauv ib-theem austenite, nws muaj tshuaj lom neeg ruaj khov dua thiab zoo dua corrosion dua li chromium stainless hlau. Nws yog tam sim no siv ntau hom stainless hlau.
Hom 18-8 stainless hlau nthuav tawm austenite + carbide qauv hauv lub xeev annealed. Lub xub ntiag ntawm carbides yuav ua rau kev puas tsuaj rau corrosion ntawm cov hlau. Yog li ntawd, kev kho tshuaj feem ntau yog siv, uas yog, cov hlau yog rhuab mus rau 1100 degree. Tom qab dej txias, cov carbides yog yaj hauv austenite tau ntawm qhov kub thiab txias, thiab tom qab ntawd los ntawm kev ua kom txias sai, cov qauv ib-theem austenite tau txais ntawm chav tsev kub.
Feem ntau hu ua stainless hlau hais txog ferritic stainless hlau thiab martensitic stainless hlau. Nws yog siv los qhia qhov txawv ntawm austenitic stainless hlau, uas muaj cov khoom zoo los tiv thaiv xeb thiab feem ntau siv.
