Galvanized Steel Yeeb Nkab Decarburization: Cov Ntsiab Cai thiab Kev Ntsuas

Decarburization, yooj yim muab, yog qhov tshem tawm cov pa roj carbon los ntawm cov hlau.

Hlau yog qhov tseem ceeb ntawm cov hlau - carbon alloy, thiab cov ntsiab lus carbon txiav txim siab lub zog thiab hardness ntawm cov hlau. Thaum cov yeeb nkab steel raug rau qhov kub siab - ib puag ncig, cov pa roj carbon atoms ntawm qhov chaw hnov ​​​​mob nrog oxygen, dej vapor, carbon dioxide, thiab lwm yam nyob rau hauv cov huab cua puag ncig, tig mus rau hauv gases thiab khiav, ua rau inrog kev txo qis hauv cov ntsiab lus ntawm cov pa roj carbon monoxide nyob rau saum npoo txheej piv rau cov matrix sab hauv. Cov txheej txheem ntawm qis - carbon cheeb tsam no hu ua decarburization txheej.

Piv txwv li: Nws zoo li ci qhob cij; sab nraud tau hlawv thiab poob noo noo, thaum sab hauv tseem yog mos - decarburization yog thaum lub "txheej txheej ntawm cov hlau yog hlawv thiab poob nws cov pa roj carbon".

Lub decarburization ntawm galvanized steel kav feem ntau tshwm sim nyob rau hauvob theem siab - kub:

Theem 1: Dub yeeb nkab ntau lawm theem (vuam yeeb nkab / kho cua sov):

Yog hais tias cov hlau sawb tau dhau los ntawm - qhov kub thiab txias ua ntej vuam, los yog kev kho mob tom qab vuam, hauv qhov chaw oxidative, decarburization yuav tshwm sim.

Theem 2: Annealing theem ua ntej kub galvanizing (feem ntau tseem ceeb):
Nyob rau hauv tas li kub galvanizing ntau lawm kab, steel strips / steel kav nkag mus rau hauv lub zinc lauj kaub tom qab dhau los ntawm ib tug annealing rauv (feem ntau ntawm 800-900 degree), nrog rau lub hom phiaj ntawm softening cov hlau, tshem tawm kev ntxhov siab, thiab kho cov nto oxide zaj duab xis. Yog hais tias cov huab cua nyob rau hauv lub cub tawg yog tswj tsis raug, decarburization tshwm sim ntawm no.

Plaub yam tshuaj tiv thaiv kab mob ntawm decarburization:

Core logic:

Qhov kub siab dua, qhov muaj zog oxidizing cua (ntau O₂ / CO₂ / H₂O), thiab lub sijhawm tuav ntev dua, qhov decarburization hnyav dua..Cov pa roj carbon diffuses los ntawm sab hauv ntawm cov khoom siv hauv paus mus rau saum npoo thiab tom qab ntawd "noj" los ntawm cov cua, tsim cov decarburization gradient uas maj mam txo los ntawm qhov chaw mus rau sab hauv.

Sau ntawv ntxiv:

Qhov kub hauv qhovtxheej txheem galvanizingnws tus kheej (immersion zinc, kwv yees li 450 degree) yog qhov qis, thiab feem ntau does tsis ncaj qha ua rau decarburization tseem ceeb. Feem ntau cov teeb meem decarburization nyob rau hauv cov kav dej galvanized yog rooted nyob rau hauv lub annealing los yog dub yeeb nkab theem ua ntej galvanizing.

1. Cov tsos mob txawv txav ntawmtxheej

• Qhov saum npoo tshwm tsaus, greyish, nrog tsis sib xws luster,thiab "grey spots" yuav tshwm sim
• Cov txheej yuav yog tuab heev thiab ntxhibvim tias cov ferrite hauv txheej decarburized muaj ntau thiab cov ntsiab lus carbon tsawg, ua rau kev loj hlob ntawm cov hlau tsis muaj zog -zinc alloy txheej (Fe-Zn intermetallic)
• Hauv qhov xwm txheej hnyav, txheej txheej muajtsis zoo adhesion thiab peels tawm

2. Txo cov khoom siv kho tshuab

• Covnto hardness txo(lub decarburized txheej yog tsuas yog ferrite, uas yog mos thiab tawv)
• Covhnav tsis kam txo,thiab nws yooj yim rau khawb thaum siv
• Lub zog tensile thiab lub zog tawm los ntawm qhov txo qis, cuam tshuam rau tag nrho cov load-cov kabmob muaj peev xwm

3. Cov yam ntxwv ntawm cov qauv metallographic

• Lub pearlite nyob rau hauv decarburized txheej txo los yog ploj, yuav luag tag nrho yog ferrite
• Los ntawm qhov chaw mus rau lub hauv paus, cov ntsiab lus carbon nce hauv gradient
• Ua kom tiav decarburized txheej + Ib nrab decarburized txheej (kev hloov chaw)

4. Txo corrosion kuj

• Zinc txheej tiv thaiv nyob rau hauv qhov chaw txawv txav (qhov chaw grey, qhov chaw tev tawm) ua tsis tiav
• Kev ua haujlwm ntawm electrochemical ntawm cov txheej decarburized nws tus kheej yog txawv ntawm cov khoom siv hauv paus, uas ua rau muaj qhov txawv txav ntawm corrosion.

5. Tshaj tawm - teeb meem kev ua haujlwm

• Lub decarburized txheej yog yooj yim rauwrinkling thiab tawgthaum khoov thiab nthuav dav
• Lub hardness saum npoo yog tsis txaus thaum lub sij hawm xov ua, thiab cov hniav zoo li tsis zoo

1. Tswj qhov cua ntawm lub qhov cub annealing (qhov tseem ceeb tshaj plaws)

• Siv anitrogen-hydrogen tiv thaiv huab cua(N₂ + 5%~15% H₂), tuav ame ntsis txo ib puag ncig
• nruj me ntsis tswj covdew point(feem ntau yuav tsum tau qis dua -30 degree), txo cov dej vapor
• Tswj cov ntsiab lus oxygen thiab CO₂ ib nrab siab kom tsis txhob muaj oxidative cua,

2. Tswj cov cua kub thiab lub sijhawm

• Thaum ua tau raws li cov kev cai annealing, sim ua txo qhov kub thiab txias(tus nqi decarburization nce exponentially nrog kub)
• Shorten lubtuav lub sij hawm nyob rau hauv siab -kubntu kom txo tau cov pa roj carbon diffusion thiab cov tshuaj tiv thaiv

3. Tswj cov khoom siv raw thiab qhov chaw saum npoo

• Thaum muas steel strips, xav tau lub steel zeb raucontrol qhov tob ntawm txheej decarburized(tuaj yeem teev tseg hauv daim ntawv cog lus, xws li Tsawg dua lossis sib npaug li 0.05mm)
• Txo covoxide nplaintawm cov hlau sawb, raws li oxide nplai yuav catalyze cov tshuaj tiv thaiv decarburization
• Tsis txhob noj ntau dhau, vim tias qhov ua kom ntau dhau ntawm qhov chaw yuav ua rau muaj qhov decarburization tom ntej.

4. Ua kom zoo ua ntej- kho ua ntej galvanizing

• Siv qhov tsim nyog muaj pes tsawg leeg ntawm flux (flux), feem ntau ZnCl₂ + NH₄Cl, tswj pH thiab concentration
• Siv qhov ntsuas kub kom tsim nyog kom tsis txhob oxidation saum npoo ua ntej cov yeeb nkab steel nkag mus rau hauv lub lauj kaub zinc
   

5. Cov txheej txheem kev soj ntsuam thiab tshuaj xyuas

• Kev siv tsis tu ncuatxoj kev metallographictxhawm rau txheeb xyuas qhov tob ntawm txheej decarburized (raws li GB / T 224 tus qauv)
• Saib xyuas cov huab cua tsis zoo ntawm lub qhov cub annealing (dew point, oxygen cov ntsiab lus, hydrogen cov ntsiab lus) thiab sau lawv
• Tsom ntsoov rau kev tswj cov qib siab - carbon steel (qhov siab dua cov ntsiab lus carbon, qhov yooj yim dua nws decarburizes) nrog kev saib xyuas ntau dua

Hauv cov ntsiab lus, decarburization yog thaum cov pa roj carbon nyob rau saum npoo ntawm cov hlau yog "noj" los ntawm cov cua ntawm qhov kub thiab txias.Lub hauv paus ua rau yog nyob rau hauv cov huab cua thiab kub tswj ntawm lub annealing rauv; nws manifests raws li grey txheej, tsis zoo adhesion, thiab mos nto; cov kev tiv thaiv yog peb txoj hauv kev -tiv thaiv huab cua + tswj kub + tswj cov khoom raw.