Lub luag haujlwm ntawm Niobium hauv Steel yog dab tsi?

Niobium (Nb) tuaj yeem tsim cov theem nruab nrab nruab nrab xws li NbC lossis NbN hauv cov hlau. Thaum lub sij hawm recrystallization, pinning ntawm dislocations los ntawm NbC thiab NbN thiab inhibition ntawm grain loj hlob zoo heev nce lub sij hawm recrystallization. Thaum siab tshaj qhov kub tseem ceeb, lub luag haujlwm ntawm niobium ntawm recrystallization ntawm cov kua nplaum rub mechanism, thaum qis dua qhov kub tseem ceeb, nag lossis daus pinning mechanism.
Ntawd yog, thaum ib thaj tsam nplej ntsib lub plasma point hauv cov txheej txheem ntawm kev txav, ib feem ntawm cov ciam teb yuav raug txiav tawm. Yog hais tias tus ciam teb ntawm grain yog tawg dawb los ntawm lub plasma point pinning, nws yuav inevitably tsim ib tug tshiab interfacial cheeb tsam, uas nyob rau hauv lem yuav ua rau kom lub tshiab interfacial zog, thiab yog li cov nplej tsuas yog coarsened los ntawm kev muab lub zog tsav tsheb ntau dua. Tus yam ntxwv ntawm niobium nyob rau hauv steel yog ua kom lub recrystallization kub ntawm austenite, nthuav qhov kub ntawm qhov chaw uas tsis yog-recrystallized, txhawb austenite grain deformation thiab defect "sau", thiab thaum kawg kom ua tiav lub hom phiaj ntawm ferrite grain refinement.

Niobium yog ib qho tseem ceeb ntawm microalloying ntsiab lus thiab yog lub hauv paus ntawm kev xaiv rau kev tswj dov ntawm hlau. Nws yog qhov zoo tshaj plaws alloying caij rau grain refinement thiab muaj ib qho tseem ceeb ntxiv zog. Nws cov nyhuv muaj zog heev ntawm retarding austenite recrystallization thiab grain refinement nyob rau hauv cov txheej txheem kev kho cua sov xws li tswj dov thiab normalizing yog ib qho tseem ceeb zoo ntawm niobium. Cov ntsiab lus niobium qis ntawm kwv yees li 0.03%, uas feem ntau siv niaj hnub no, tuaj yeem ua lub luag haujlwm tseem ceeb hauv kev tswj dov thiab normalizing steels. Nyob rau hauv lub dov kub hauv qab 950 degree, txhua tus qauv deformation tom qab dov tsis tshwm sim tom qab recrystallization, yog li ntawd lub elongated austenite nplej vim lub nucleation ntawm grain ciam teb thiab subgranular cheeb tsam, nws muaj peev xwm theem mus rau hauv nplua nplej. Yog li ntawd, rau cov hlau tsis tshua muaj manganese steel, los ntawm kev sib ntxiv ntawm ib qho me me ntawm niobium, tuaj yeem ua tiav hauv lub tshuab dov zoo tib yam kom ua tiav lub hom phiaj ntawm kev tswj dov thiab cov nplej ua kom zoo.