Vim nws zoo corrosion kuj, stainless hlau flange yog dav siv nyob rau hauv cov kua pipeline engineering xws li roj av, tshuaj lom neeg kev lag luam, thiab shipbuilding. Raws li ib feem tseem ceeb ntawm kev sib txuas ntawm cov kav dej, nws muaj qhov zoo ntawm kev sib txuas yooj yim thiab siv tau, tswj xyuas qhov kev sib khi ntawm cov raj xa dej, thiab ua kom yooj yim rau kev tshuaj xyuas thiab hloov cov seem ntawm cov kav dej. Txhawm rau kom pom cov laj thawj ntawm cov plaub muag no, tiv thaiv kev ua kom muaj teeb meem cov khoom lag luam zoo, peb ua cov tshuaj ntsuam xyuas thiab ntsuas phoo kev tshuaj xyuas rau cov pob txha no ntawm cov tsiaj muag cov qauv.
Cov tshuaj ntsuam xyuas cov qauv raug txiav mus rau hauv cov flange corrosion thiab lawv cov tshuaj muaj pes tsawg leeg tau txiav txim siab siv Belder DV - 6 ncaj qha nyeem spark spectrometer los ntawm Tebchaws Meskas. Cov txiaj ntsig tau pom nyob rau hauv rooj I. Raws li cov kev cai ntawm cov tshuaj muaj pes tsawg leeg ntawm 304 stainless hlau nyob rau hauv astma 276 - 2013 "txheej txheem tshwj xeeb rau Stainless Hlau Bars thiab duab", cov ntsiab lus ntawm chromium ntsiab nyob rau hauv lub composition ua tsis tau tejyam flange chemistry yog qis dua tus nqi qauv.
1.2 metallographic tshuaj xyuas
Ib tug longitudinal cross-sectional qauv yog cuam tshuam ntawm qhov chaw corrosion ntawm qhov tsis ua hauj lwm flange, tom qab polishing, nws tsis corrode, nws tau pom nyob rau hauv lub zeiss metallographic microscope, thiab non-metallic inclusions raug soj ntsuam raws li lub Microscopic soj ntsuam txoj kev. /T {{0}} daim ntawv qhia kev muab qhab nia rau kev txiav txim siab cov ntsiab lus ntawm cov khoom tsis yog xim hlau suav nrog hauv cov hlau: sulfides yog qib 1.5; Cov alumina yog qib 0; Cov silicates yog qib 0; Spherical xeb yog 1.5 degrees.
Cov qauv tau eroded los ntawm hlau chloride hydrochloric acid tov thiab soj ntsuam nyob rau hauv ib tug 100 x metallographic microscope, thiab cov austenitic grain nyob rau hauv cov ntaub ntawv tau pom tias tsis tshua muaj sib npaug, thiab qib ntawm grain loj nws tau soj ntsuam raws li GB/t6394 - 2002 qhov nruab nrab hlau grain loj txiav txim siab txoj kev, thiab cov coarse grain cheeb tsam yuav rated raws li 1.5 (saib daim duab 3); Qhov chaw nplua-grained tuaj yeem tsim nyog raws li qib 4.0.
Los ntawm saib cov microstructure nyob ze-nto corrosion, nws tuaj yeem pom tias corrosion pib ntawm cov hlau nto, concentrates ntawm austenitic grain ciam teb, thiab txuas mus rau sab hauv ntawm cov khoom. Cov qoob loo ciam teb nyob rau hauv cheeb tsam no raug puas tsuaj vim yog corrosion, lub zog ntawm cov nplej yuav luag tag, thiab cov hlau hnyav heev txawm tias cov plua plav, uas tuaj yeem yooj yim khawb tawm ntawm cov khoom.
Lub zog loj ntawm cov corroded flange tau soj ntsuam los ntawm 500x metallographic microscope, thiab nws cov microstructure yog precipitated cophase hais nyob rau hauv grain ciam ntawm Austenite ntxiv rau ib tug me me ntawm ferrite.
2 kev tsom xam
Cov txiaj ntsig ntawm lub cev thiab tshuaj ntsuam xyuas tau pom tias cov ntsiab lus ntawm chromium cov ntsiab lus hauv cov tshuaj muaj pes tsawg leeg ntawm stainless hlau flange yog me ntsis qis dua tus nqi tus qauv. lub caij chromium yog qhov tseem ceeb tshaj plaws hauv kev txiav txim siab corrosion tsis kam ntawm stainless hlau. Nws tuaj yeem cuam tshuam nrog oxygen los tsim chromium oxide, tsim cov txheej txheem passive, thiab ua lub luag haujlwm hauv kev tiv thaiv corrosion. Thiab cov ntsiab lus ntawm cov tsis yog hlau sulfides nyob rau hauv cov khoom yog siab, thiab cov tsub zuj zuj ntawm sulfides nyob rau hauv lub zos cheeb tsam yuav ua rau ib tug txo nyob rau hauv lub concentration ntawm chromium ntsiab nyob rau hauv nws cov cheeb tsam ib puag ncig, tsim ib tug tsis zoo chromium cheeb tsam, yog li cuam tshuam rau corrosion kuj. ntawm stainless hlau.
Kev soj ntsuam cov nplej loj ntawm stainless hlau flange, nws tuaj yeem pom tias nws cov nplej loj yog qhov tsis sib xws, thiab cov nplej sib xyaw nrog qhov loj tsis sib xws hauv cov qauv muaj qhov sib txawv ntawm cov peev txheej electrode, tsim cov microcells, uas ua rau electrochemical corrosion. nyob rau saum npoo ntawm cov khoom. Qhov sib xyaw ntxhib thiab nplua nplej ntawm stainless hlau flange feem ntau yog cuam tshuam nrog cov txheej txheem deformation ntawm kub machining, uas yog tshwm sim los ntawm lub zog deformation ntawm cov nplej thaum nws forging.
Los ntawm kev txheeb xyuas qhov microstructure ntawm corrosion nyob ze ntawm lub flange nto, nws tuaj yeem xaus lus tias qhov corrosion pib ntawm flange nto thiab txuas mus rau sab hauv raws li austenitic grain ciam teb. lub zog siab microstructure ntawm cov khoom qhia tias muaj nag lossis daus ntau dua ntawm theem peb ntawm austenitic lis ciam ntawm cov khoom. Qhov thib peb kev sib raug zoo sib sau ua ke ntawm cov ciam teb tuaj yeem yooj yim ua rau nws cov chromium tsis zoo ntawm cov ciam teb, ua rau muaj kev nyiam rau intergranular corrosion thiab zoo heev txo nws cov corrosion kuj.
Qhov thib peb theem ntawm stainless hlau yog feem ntau zoo carbide (m 23c 6), σ Concordia δ Ferrites, thiab lwm yam., muaj kev cuam tshuam ntau dua rau corrosion kuj ntawm stainless hlau. Qhov tsim kub ntawm m23c6 nag lossis daus yog 450 degree C - 850 degree c, feem ntau yog carbide tsim los ntawm cov hlau chromium, feem ntau yog faib rau ntawm cov qoob loo ciam teb ntawm cov siv lead ua, thiab qee qhov nyob rau sab hauv ntawm cov siv lead ua thiab siv lead ua tsis xws luag. , vim carbide yog nplua nuj nyob rau hauv chromium thiab tuaj yeem yooj yim ua rau cov chromium tsis zoo hauv cheeb tsam; σ Cov theem tsim kub yog 500 degree - 925 degree , nyob rau hauv cheeb tsam no kub, ferritin yog ib nrab los yog tag nrho decomposed. σ Theem, nrog cov ntsiab lus chromium ntawm 42 feem pua mus rau 50 feem pua hauv theem 6, yog ib theem nkig ntawm cov tawv tawv siab uas tuaj yeem ua rau txo qhov tawv thiab corrosive ntawm cov khoom; δ Ferritin yog qhov kub-kub ferritin tsim los ntawm crystallization thaum cov kua hlau txias rau 1538 degree c. Cov theem no yog nkig ntau dua, nws yooj yim los ua cov kab nrib pleb thaum lub sij hawm ua, thiab nws yog feem ntau pom corrosion.
3 Kev Sib Tham Sib Tham
Los ntawm kev soj ntsuam tsis ua haujlwm ntawm corroded stainless hlau flange, cov lus xaus hauv qab no tuaj yeem ncav cuag:
(1) stainless hlau flange corrosion yog tshwm sim los ntawm ntau yam, ntawm cov uas thawj precipitated theem ntawm grain ciam ntawm cov khoom yog lub ntsiab ua rau flange tsis ua hauj lwm. Nws raug nquahu kom tswj xyuas cov cua sov kom nruj thaum lub sijhawm ua haujlwm thermal, tsis txhob siab tshaj qhov kub ntawm cov khoom siv cua sov txheej txheem specifications, thaum txias sai sai tom qab kev daws teeb meem, tsis txhob nyob hauv qhov kub ntawm 450 degree - 925 degree rau ib lub sij hawm ntev thiab zam cov nag lossis daus ntawm cov khoom nyob rau theem thib peb.
(2) Cov hmoov nplej sib xyaw hauv cov khoom siv tau yooj yim ua rau electrochemical corrosion ntawm cov khoom siv, thiab qhov sib piv ntawm forging yuav tsum nruj me ntsis tswj thaum lub sij hawm forging txheej txheem.
(3) cov ntsiab lus qis ntawm CR cov ntsiab lus thiab cov ntsiab lus siab ntawm sulfides hauv cov khoom ncaj qha cuam tshuam rau corrosion kuj ntawm flange, thiab yuav tsum tau them nyiaj mloog mus rau kev xaiv cov ntaub ntawv nrog ntshiab metallurgical qib.
