Kev soj ntsuam ntawm microstructure ntawm cov khoom siv Optical Microscope
Raws li cov yam ntxwv ntawm lub koom haum thiab cov ntsiab lus sib txawv, cov hlau carbon hlau tuaj yeem muab faib ua peb pawg: cov hlau ntshiab, hlau, thiab cam khwb cia hlau. Muaj cov hlau ntshiab uas muaj cov ntsiab lus carbon tsawg dua 0.0218% C thiab cov ntsiab lus carbon tsawg dua 2.11% yog hu ua hlau, thaum alloys nrog cov ntsiab lus carbon ntau dua 2.11% hu ua cam khwb cia hlau.
Lub microstructure ntawm carbon steel thiab dawb cam khwb cia hlau nyob rau hauv chav tsev kub yog tsim los ntawm ob theem pib, ferrite (F) thiab cementite (Fe3C).
Txawm li cas los xij, vim muaj cov ntsiab lus sib txawv ntawm cov pa roj carbon monoxide, cov khoom sib txawv, nag lossis daus, thiab kev faib tawm ntawm ferrite thiab cementite sib txawv, ua rau muaj ntau hom microstructure sib txawv.
Ferrite yog ib qho kev daws teeb meem ntawm carbon hauv alpha hlau, feem ntau sawv cev los ntawm lub cim "F". Cov qauv ferrite muaj xws li cov nplej equiaxed thiab lub cev nruab nrab ntawm lub cubic lattice.
Carbide yog ib qho chaw tsim los ntawm hlau thiab carbon, feem ntau sawv cev los ntawm lub cim "Fe3C". Nyob ntawm seb muaj pes tsawg leeg thiab tsim cov xwm txheej, cementite tuaj yeem ua rau ntau hom.
Pearlite yog cov khoom sib xyaw ntawm ferrite thiab cementite, feem ntau sawv cev los ntawm lub cim "P". Nyob rau hauv ib txwm annealing tej yam kev mob, nws yog ib txheej txheej tsim los ntawm alternating kev npaj ntawm ferrite thiab cementite.
Kev etching ntawm cov hlau ntshiab thiab ib qho -theem alloys yog cov txheej txheem tshuaj lom neeg. Thaum cov qauv polished nyob rau hauv kev sib cuag nrog tus neeg sawv cev etching, deformation cuam tshuam txheej ntawm polished nto yog thawj yaj, thiab lub microstructure ntawm cov hlau tsis raug. Tom qab ntawd, cov tshuaj lom neeg cuam tshuam rau ntawm thaj tsam ntawm cov qoob loo tshwm sim, thiab qhov tsis tu ncua ntawm atomic kev npaj ntawm cov ciam teb yog qhov tsis zoo, ua rau muaj kev xeb sai thiab tsim cov grooves. Thaum lub sij hawm no, lub alloy qhia polygonal nplej. Yog tias etching txuas ntxiv, tus neeg sawv cev etching yuav yaj cov nplej lawv tus kheej. Due to the uneven dissolution rate of each grain, after etching, each grain will be exposed on the surface with the densest atomic arrangement. Nyob rau hauv ntsug lub teeb irradiation, nplej nrog txawv ci yuav tshwm.
Cov txheej txheem etching ntawm ob -theem alloys feem ntau yog electrochemical etching. Vim lawv cov khoom sib txawv thiab cov qauv sib txawv, cov theem sib txawv muaj qhov sib txawv electrode muaj peev xwm, tsim ntau khub me me hauv zos hauv cov tshuaj etching. Ferrite muaj lub peev xwm ntau dua electrode raws li cov anode, uas yaj thiab ua tsawg - dag thiab ntxhib thaum lub sij hawm etching, thaum cementite muaj peev xwm zoo li cov cathode thiab tsis yog corroded. Ferrite zoo nkaus li dub dub nyob rau hauv lub teeb tsom iav, thaum cementite zoo li ci dawb.
