Hloov pauv microstructure thiab cov yam ntxwv ntawm kev zam txim lub sijhawm npau taws

Zam Tximtom qab quenching, martensite thiab khaws austenite tsis ruaj tsis khov, lawv muaj lub koom haum tsis hloov pauv hloov mus rau kev ruaj khov, xws li cov roj carbon supersaturated nyob rau hauv martensite los ua kom tsis txhob nyob rau qhov chaw tsis pom kev zoo kom ua rau muaj kev hloov chaw, xws li rau kev npau taws yog lub koom haum tsis sib npaug. kom sib npaug ntawm cov koomhaum cov txheej txheem, cov txheej txheem no yog nyob ntawm qhov nruab nrab atomic migration thiab diffusion ntawm qhov kev tso cai no ua ke nrog koj ua tiav qhov hluav taws kub kub dua, qhov hluav taws xob ntau dua; yauv hloov ntau yam. Raws li qhov xwm txheej ntawm microstructure kev hloov pauv, kev kub ntxhov feem ntau muab faib ua plaub ntu: martensite decomposition, residual austenite decomposition, carbide txuam nrog kev loj hlob thiab ferrite recrystallization.
Thawj theem (200)
(1) forging tempering martensite decompose nyob rau hauv 80 kub tempering, quenching hlau tsis muaj Ming S lub koom haum kev hloov pauv, qhov tshwm sim ntawm cov pa roj carbon hauv martensite tsuas yog ib nrab, thiab tsis muaj pib tawg rau hauv 80-200 tempering, martensite pib kom decompose, nag lossis daus hloov maj mam hloov carbides, txo qhov loj ntawm feem ntawm martensite nyob rau hauv cov pa zam nyob rau theem no, vim yog qhov kub tsis tshua muaj huab cua sov, martensitic nag lossis daus tsuas yog ib feem ntawm supersaturated carbon atoms, yog li nws tseem yog cov pa roj carbon nyob rau hauv a - Fe supersaturated solid solutionThe nag lossis daus ntawm carbide zoo tib yam faib tawm hauv qhov sib npaug ntawm martensite. Cov kev sib xyaw ua ke ntawm qhov tsis txaus siab Martensite thiab cov carbide zoo heev yog hu ua tempered Martensite.

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(2) forging tempering nyob rau theem ob (200-300), qhov teeb meem austenite lub sijhawm thaum kub tau nce mus rau 200-300, qhov kev txiav tawm ntawm martensite txuas mus ntxiv, tab sis cov kev hloov pauv tseem muaj ntawm austenite decomposition ntawm qhov seem ntawm austenite decomposition yog los ntawm kev nthuav dav ntawm cov pa roj carbon atoms tsim ib ntu thaj chaw, thiab tom qab ntawd decomposed rau hauv alpha theem thiab kev sib xyaw ntawm cov koom haum carbide, uas yog tsim muaj bainite steel hardness tsis yog tsawg zuj zus nyob rau theem no
(3) Qhov theem peb (250-400) carbide kev hloov pauv ntawm forging tempering yog hauv qhov kub no. Vim tias qhov kub siab, Carbon atom diffusion muaj peev xwm muaj zog, lub diffusion muaj peev xwm rov qab cov hlau atoms kuj, martensite decompose qhov kev hloov pauv ntawm nag lossis daus carbides thiab residual austenite decomposition yuav hloov mus rau hauv qhov chaw ruaj khov cementite nrog kev sib cais thiab hloov ntawm carbides, qhov txo qis ntawm martensite nyob rau hauv cov roj carbon loj feem, martensite ntxaij ntoo distortion ploj, martensitic kev hloov pauv rau ferrite, tau ferritic matrix faib tsis pub dhau lub pob zeb me me los yog lamellar cementite ntawm lub koom haum, lub koom haum hu ua tempering cia li tshem tawm theem no austenite quenching kev nyuaj siab, qhov nyuaj, plasticity toughness tau zoo tuaj.

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(4) Plaub theem ntawm forging tempering (& GT; 400) loj hlob carbide sib sau ua ke thiab recrystallization ntawm ferrite vim qhov kub tsis txias yog qhov kub heev, cov pa roj carbon thiab hlau atoms muaj lub zog muaj peev xwm ntawm kev loj hlob, theem peb tsim ntawm cementite flakes yuav txuas ntxiv spheroidizing thiab loj hlob nyob rau hauv ntau dua 500-600, alpha recrystallization tshwm sim maj, poob ferrite morphology ntawm thawj phaj sawb lossis ntawv, thiab daim ntawv polygon lis faib rau lub koom haum raws li ferritic matrix granular carbides, cov pab pawg hu ua tempering sorbite tempered sorbite nrog cov cuab yeej zoo muaj txiaj ntsig ntawm theem thiab ntxaij ntoo distortion tshem tawm kev ntxhov siab sab hauv.

(Los ntawm 168 forging net)


Lub sij hawm tshaj tawm: Lub Yim Hli-05-2020

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