ForgingsTom qab quenching, martensite thiab khaws cia austenite tsis ruaj khov, lawv muaj lub koom haum hloov pauv hloov pauv hloov mus rau kev ruaj ntseg, xws li cov pa roj carbon supersaturated hauv martensite kom precipitate residual austenite decomposition txhawm rau txhawb kev hloov pauv, xws li tempering tempering yog lub koom haum tsis sib npaug. txhawm rau sib npaug ntawm lub koom haum cov txheej txheem, cov txheej txheem no nyob ntawm qhov atomic migration thiab diffusion ntawm qhov kev tso cai no ua ke nrog koj ua tiav qhov hluav taws kub kub siab dua, qhov nrawm nrawm dua; Ntawm qhov tsis sib xws, nrog qhov nce ntawm tempering kub, quenching qauv ntawm forgings yuav undergo ib tug series ntawm kev hloov. Raws li qhov xwm txheej ntawm microstructure transformation, tempering feem ntau muab faib ua plaub theem: martensite decomposition, residual austenite decomposition, carbide tsub zuj zuj zuj zus thiab ferrite recrystallization.
Thawj theem (200)
(1) forgingtempering martensite decompose nyob rau hauv 80 kub tempering, quenching steel yam tsis muaj Ming S lub koom haum transformation, tshwm sim ntawm carbon nyob rau hauv martensite tsuas yog ib feem, thiab tsis pib tawg nyob rau hauv lub 80-200 tempering, martensite pib decompose, precipitate tsis tshua muaj siab carbides, txo cov Feem ntau ntawm martensite nyob rau hauv cov pa roj carbon forgings nyob rau theem no, vim tsis muaj tempering kub, martensitic nag lossis daus tsuas yog ib feem ntawm supersaturated carbon atoms, yog li nws tseem yog cov carbon nyob rau hauv ib tug - Fe supersaturated solid solutionThe nag lossis daus ntawm zoo carbide uniformly faib nyob rau hauv lub matrix. ntawm martensite. Cov qauv sib xyaw ntawm qis qis Martensite thiab zoo heev carbide hu ua tempered Martensite.

(2)forgingtempering nyob rau theem thib ob (200-300), qhov seem austenite decomposition thaum kub nce mus rau 200-300, qhov decomposition ntawm martensite txuas ntxiv, tab sis qhov tseem ceeb hloov pauv yog residual austenite decomposition ntawm residual austenite decomposition yog los ntawm kev nthuav dav ntawm carbon atoms. los tsim ib feem ntawm thaj chaw, thiab tom qab ntawd decomposed rau hauv alpha theem thiab sib tov ntawm carbide lub koom haum, uas yog tsim ntawm bainite steel hardness tsis pom tseeb txo nyob rau theem no.
(3)Qhov thib peb theem (250-400) carbide transformation ntawm forging tempering yog nyob rau hauv no kub ntau yam. Vim tias qhov kub thiab txias, Carbon atom diffusion muaj peev xwm muaj zog dua, lub peev xwm diffusion kom rov qab tau cov hlau atoms kuj, martensite decompose cov kev hloov ntawm nag lossis daus carbides thiab residual austenite decomposition yuav tig mus rau hauv ib qho ruaj khov cementite nrog kev sib cais thiab kev hloov pauv ntawm carbides, qhov txo qis. ntawm martensite nyob rau hauv carbon pawg feem, martensite lattice distortion ploj, martensitic transformation rau ferrite, tau ferritic matrix tis nyob rau hauv lub me me granular los yog lamellar cementite ntawm lub koom haum, lub koom haum hu ua tempering yeej tshem tawm cov theem no austenite quenching kev nyuaj siab, hardness, plasticity toughness tau zoo tuaj.

(4)Qib plaub ntawm forging tempering (& GT; 400) loj hlob carbide sib sau ua ke thiab recrystallization ntawm ferrite vim tempering kub yog heev, carbon thiab hlau atoms muaj zog muaj peev xwm ntawm proliferation, lub thib peb theem ntawm cementite flakes yuav tsis tu ncua spheroidizing thiab loj hlob. nce nyob rau hauv ntau tshaj 500-600, alpha recrystallization tshwm sim maj mam, poob ferrite morphology ntawm thawj phaj sawb los yog daim ntawv, thiab tsim polygon grain faib rau lub koom haum raws li ib tug ferritic matrix granular carbides, pab pawg neeg hu ua tempering sorbite tempered sorbite nrog zoo zoo txhua yam cov khoom ntawm theem thiab lattice distortion tshem tawm cov kev ntxhov siab sab hauv.

(los ntawm 168 forging net)