Ua rau thiab kev tiv thaiv ntawm pickling corrosion ntawm 304 stainless hlau flanges

Paub meej: Cov neeg siv khoom tsis ntev los no tau yuav ib pawg ntawm 304 stainless hlau flanges, uas yuav tsum tau khaws thiab ua kom tsis muaj zog ua ntej siv. Yog li ntawd, npuas tshwm nyob rau saum npoo ntawm stainless hlau flanges tom qab muab tso rau hauv lub tank pickling rau ntau tshaj kaum feeb. Tom qab cov flanges raug tshem tawm thiab ntxuav, corrosion tau pom. Txhawm rau nrhiav kom pom qhov ua rau muaj kev xeb ntawm cov hlau nplaum stainless hlau, tiv thaiv cov teeb meem zoo los ntawm kev tshwm sim dua, thiab txo cov nyiaj poob. Cov neeg siv khoom tshwj xeeb tau caw peb los pab nws nrog kev soj ntsuam kuaj thiab tshuaj xyuas metallographic.

Ua ntej, cia kuv qhia 304 stainless hlau flange. Nws muaj kev tiv thaiv corrosion zoo, tiv thaiv tshav kub, thiab tsis tshua muaj hluav taws xob txhua yam khoom. Nws yog corrosion-resistant nyob rau hauv cov huab cua thiab acid-resistant. Nws yog dav siv hauv cov kav dej ua haujlwm xws li roj av thiab tshuaj lom neeg kev lag luam. Raws li ib feem tseem ceeb ntawm kev sib txuas ntawm cov raj xa dej, nws muaj qhov zoo ntawm kev sib txuas yooj yim thiab siv tau, tswj kev ua haujlwm ntawm cov raj xa dej, thiab ua kom yooj yim rau kev tshuaj xyuas thiab hloov ntawm qee ntu ntawm cov kav dej.

Kev tshuaj xyuas

1. Tshawb xyuas cov tshuaj muaj pes tsawg leeg: Ua ntej, ua piv txwv cov corroded flange thiab siv lub spectrometer ncaj qha los txiav txim nws cov tshuaj muaj pes tsawg leeg. Cov txiaj ntsig tau pom hauv daim duab hauv qab no. Piv nrog rau cov kev cai ntawm 304 stainless hlau tshuaj muaj pes tsawg leeg hauv ASTMA276-2013,Cr cov ntsiab lus nyob rau hauv cov tshuaj muaj pes tsawg leeg ntawm lub flange ua tsis tau tejyam yog qis dua tus qauv tus nqi.

2. Kev tshuaj xyuas Metallographic: Ib qho piv txwv longitudinal cross-section tau txiav ntawm qhov chaw corrosion ntawm flange ua tsis tiav. Tom qab polishing, tsis pom muaj corrosion. Cov khoom siv tsis yog xim hlau tau pom nyob rau hauv lub tshuab ntsuas metallographic thiab cov sulfide qeb tau ntsuas raws li 1.5, pawg alumina tau ntsuas raws li 0, pawg acid ntsev tau ntsuas raws li 0, thiab pawg oxide pawg tau ntsuas raws li 1.5; Cov qauv yog etched los ntawm ferric chloride hydrochloric acid aqueous tov thiab pom nyob rau hauv 100x metallographic microscope. Nws tau pom tias cov nplej austenite hauv cov khoom tsis sib xws. Qib grain loj tau soj ntsuam raws li GB / T6394-2002. Lub cheeb tsam coarse tuaj yeem ntsuas raws li 1.5 thiab thaj tsam zoo tuaj yeem ntsuas raws li 4.0. Los ntawm kev soj ntsuam lub microstructure ntawm qhov ze-nto corrosion, nws tuaj yeem pom tias qhov corrosion pib los ntawm cov hlau nto, concentrates ntawm austenite grain ciam teb thiab txuas mus rau sab hauv ntawm cov khoom. Cov ciam teb hauv cheeb tsam no raug puas tsuaj los ntawm corrosion, thiab lub zog sib txuas ntawm cov nplej yuav luag tag. Cov hlau hnyav hnyav heev txawm tias ua cov hmoov, uas yooj yim khawb tawm ntawm cov khoom siv.

3. Kev tsom xam: Cov txiaj ntsig ntawm kev kuaj lub cev thiab tshuaj lom neeg pom tau tias Cr cov ntsiab lus hauv cov tshuaj muaj pes tsawg leeg ntawm stainless hlau flange yog qis dua tus nqi tus qauv. Cov khoom siv Cr yog qhov tseem ceeb tshaj plaws uas txiav txim siab qhov corrosion kuj ntawm stainless hlau. Nws tuaj yeem hnov ​​​​mob nrog oxygen los tsim Cr oxides, tsim ib txheej passivation los tiv thaiv corrosion; Cov ntsiab lus tsis yog xim hlau sulfide hauv cov khoom yog siab, thiab kev sib sau ntawm sulfides hauv cov cheeb tsam hauv zos yuav ua rau txo qis hauv Cr concentration nyob rau hauv ib puag ncig, tsim Cr-tsis zoo cheeb tsam, yog li cuam tshuam rau corrosion kuj ntawm stainless hlau; Kev soj ntsuam cov nplej ntawm stainless hlau flange, nws tuaj yeem pom tias nws cov nplej loj yog qhov tsis sib xws, thiab cov nplej sib xyaw tsis sib xws hauv lub koom haum muaj qhov sib txawv ntawm cov peev txheej electrode, uas ua rau cov roj teeb micro, uas ua rau electrochemical corrosion ntawm. qhov saum npoo ntawm cov khoom. Cov ntxhib thiab zoo sib xyaw nplej ntawm stainless hlau flange feem ntau muaj feem xyuam rau cov txheej txheem kub ua haujlwm deformation, uas yog tshwm sim los ntawm kev hloov pauv sai ntawm cov nplej thaum lub sij hawm forging. Kev soj ntsuam ntawm microstructure ntawm qhov ze-nto corrosion ntawm flange qhia tau hais tias qhov corrosion pib los ntawm flange nto thiab txuas mus rau sab hauv raws li austenite grain ciam teb. Lub high-magnification microstructure ntawm cov khoom qhia tau hais tias muaj ntau tshaj peb theem precipitated nyob rau hauv lub austenite grain ciam teb ntawm cov khoom. Qhov thib peb theem sib sau ua ke ntawm cov qoob loo ciam teb yog nquag ua rau chromium depletion ntawm tus ciam teb nplej, ua rau intergranular corrosion nyiam thiab zoo heev txo nws cov corrosion kuj.

Xaus

Cov lus xaus hauv qab no tuaj yeem kos los ntawm qhov ua rau pickling corrosion ntawm 304 stainless hlau flanges:

1. Lub corrosion ntawm stainless hlau flanges yog tshwm sim los ntawm kev sib koom ua ke ntawm ntau yam, ntawm cov theem thib peb precipitated ntawm cov nplej ciam teb 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 kub, kom tsis txhob siab tshaj qhov ntsuas kub ntawm cov khoom siv cua sov txheej txheem, thiab kom txias sai sai tom qab kev daws teeb meem kom tsis txhob nyob hauv qhov kub ntawm 450 ℃ - 925 ℃ ntev ntev. los tiv thaiv nag lossis daus ntawm theem peb hais.
2. Cov hmoov nplej sib xyaw hauv cov khoom siv yog qhov ua rau electrochemical corrosion ntawm qhov chaw ntawm cov khoom, thiab qhov sib piv ntawm forging yuav tsum nruj me ntsis tswj thaum lub sij hawm forging txheej txheem.
3. Cov ntsiab lus qis Cr thiab siab sulfide cov ntsiab lus hauv cov khoom ncaj qha cuam tshuam rau corrosion kuj ntawm flange. Thaum xaiv cov ntaub ntawv, yuav tsum tau them nyiaj mloog mus rau xaiv cov ntaub ntawv nrog ntshiab metallurgical zoo.