Kawm txog kev cuam tshuam ntawm kev hnav-resistant phaj microstructure ntawm toughness
Hnav-tiv taus daim hlau yog annealed kom tau txais cov qauv martensitic, tab sis rau cov cuab yeej loj, bainite qauv yog tsim vim qhov txias txias. Kev tsim ntawm sab sauv bainite ua rau txo qis hauv toughness, uas yog tshwm sim los ntawm kev nyiam nag lossis daus ntawm carbides nyob rau pem hauv ntej ntawm austenite grain ciam teb. Txhawm rau ua kom tau raws li cov kev xav tau niaj hnub no ntawm lub neej ntev thiab cov cuab yeej zoo, nws yog qhov yuav tsum tau ua kom muaj zog los ntawm micro tswj. Txhawm rau kom paub meej cov txiaj ntsig ntawm qhov txias txias tom qab austenitizing ntawm microstructure, tshwj xeeb tshaj yog nyob rau hauv bainite grain loj, carbide nag lossis daus thiab diffusion, thiab hardness ntawm hnav-resistant phaj, cov kws tshawb fawb tau tshawb fawb thiab tshuaj xyuas hauv qhov no.
Cov tshuaj muaj pes tsawg leeg ntawm AISI H13, H10 thiab H19 steels siv nyob rau hauv kev tshawb fawb tam sim no yog qhia nyob rau hauv Table 1. Cov hlau no raug cam khwb cia rau hauv ingot tom qab hluav taws xob arc rauv smelting, forged mus rau qhov ntev muab rau hauv Table 1 ntawm ib tug tshwj xeeb forging kub siab tshaj 6. , thiab tom qab ntawd annealed ntawm 850 degree C. Cov qauv raug txiav los ntawm qhov chaw ntawm cov khoom kub forging mus rau lub kaum sab xis square lossis saum npoo, thiab nws cov kev sib koom ua ke yog sib npaug mus rau longitudinal.
Kev tsim ntawm bainite ntawm qhov sib txawv txias txias tom qab austenitizing H13 thiab H10 ntawm 1200 degree thiab H19 ntawm 1140 degree tau kawm los ntawm kev soj ntsuam microstructure, hloov qhov loj me thiab ntsuas hardness.
Tom qab quenching thiab tempering ntawm cov cua txias sib txawv, lub dav hlau strain fracture toughness K1c, qaug zog tawg diffusion tus nqi, Charpy cuam tshuam tus nqi, brittle hloov kub ntawm V-notch Charpy kuaj tau ntsuas rau HRC44.
Lub dav hlau strain fracture toughness test tau ua tiav nrog 30mm dav hnav-resistant phaj qauv, thiab ob hom kev sim qaug zog tau ua tiav:
(1) Kev qaug zog tawg kev loj hlob ntawm tib hom qauv siv dav hlau strain tawg toughness kuaj; Kev qaug zog precrack yog siv, uas yog tsim thaum lub sij hawm cyclic stretching ntawm ib zaus ntawm 550-20kg nyob rau hauv hloov load ntawm tus nqi ntawm 5 lub lis piam ib ob.
(2) Rotary dabtsi yog khoov qaug zog kuaj, tus qauv du ntawm Φ10mm yog siv los tig ntawm qhov ceev ntawm 3000 cycles / s, thiaj li tau txais SN nkhaus.
Raws li JISZ2202 No.3, Charpy impact test tau ua nrog U-shaped notched specimens. Charpy brittle transition tests tau ua tiav siv ASTM A307 cov qauv hauv qhov kub ntawm 20 ~ 300 degree. Qhov feem pua ntawm austenite residual yog txiav txim los ntawm X-ray diffraction. Cov ntsiab lus thiab qhov loj ntawm cov carbide residual tau txiav txim siab los ntawm kev txheeb xyuas daim ntawv qhia.
Cov txiaj ntsig kev sim qhia tau hais tias qhov nyuaj ntawm cov ntawv hnav no tuaj yeem txhim kho los ntawm cov txheej txheem hauv qab no: txhim kho cov qauv ntawm martensite thiab bainite slat thiab txhim kho cov qoob loo zoo, ncua kev pom los nag ntawm carbides raws li cov ciam teb ntawm cov thawj austenite thiab bainite. , inhibiting qhov ntom ntom ntawm MC thiab M2C hom nplua carbides hauv matrix, txo cov feem pua cov ntsiab lus ntawm residual carbides thiab txo lawv qhov loj me. Qhov txo qis ntawm chilling tus nqi ua rau maj mam nce ntawm qhov dav ntawm bainite lath qauv, uas ua rau kev hloov pauv ntawm bainite los ntawm slaty mus rau granular thiab ua rau lub deterioration ntawm toughness. Ntawm cov hlau kuaj, H13 steel muaj qhov siab tshaj plaws toughness, uas yog ze ze rau qhov tsis tshua muaj siab ntawm cov carbides zoo nyob rau hauv matrix, qhov loj me me ntawm residual carbides thiab cov ntsiab lus tsis tshua muaj feem pua.
