Yuav ua li cas kom sov kho W18Cr4V siab ceev hlau?
Nyob rau hauv industrial riam, W18Cr4V yog ib cov khoom siv hlau nrov tshaj plaws, nws yog siv rau ntawv riam, riam phom riam, ntoo planer riam, ncig riam mus txiav ntawv ... Ces koj puas paub sov kev kho ntawm W18Cr4V khoom? Thov saib cov ntaub ntawv hauv qab no.
High-speed steel muaj kev kub nyhiab, kom muaj zog, zoo hnav thiab thermal hardness saum HRC60 qis dua 600 ° C. W18Cr4V yog ib qho ntawm cov high-speed steels. Nws tau dhau los ua ntau yam cuab yeej hauv kev tsim khoom. Cov khoom tseem ceeb, tom qab kev kho cua sov, tuaj yeem pom hauv cov yam ntxwv ntawm nws cov ntaub ntawv. Cov high-speed hlau yog hypereutectoid hlau, thiab cov qauv tom qab isothermal spheroidizing annealing yog ib tug zoo carbide alloy ntawm Soxite. Cov kev ua hauv siab yog qis dua 255HB, uas yog qhov zoo rau kev txiav thiab kev npaj rau quenching.
(1) Preheating thiab quenching ntawm kev kub ceev steel
Vim hais tias muaj cov hlau ceev muaj ntau txoj kev ua txhua yam, nws muaj ntau cov hlau carbides, feem ntau hauv daim ntawv ntawm M6C, M23C6, MC, thiab Fe3W3 C ~ Fe4 W2C (tungsten high-speed steel), Fe3Mo3C ~ Fe4Mo2C (molybdenum) Cov high-speed hlau yog lub ntsiab carbide, thiab nws thermal conductivity yog pluag. Txhawm rau tiv thaiv kev ntes ntawm cov khoom uas ua los ntawm cov cua kub tsis sib xws ntawm sab hauv thiab sab nraud, nws yog ib qho tsim nyog yuav tau ua ib qhov kev kho mob ntawm 800 rau 850 ° C. Thaum txoj kev quenching, cov microstructure hloov thaum txoj kev quenching: austenite tsim, carbide dissolution thiab transformation, thiab austenite grain hlob. Qhov kub ntawm qhov pearlite hloov mus rau austenite yog los ntawm 800 txog 860. ° C pib hloov.
Thaum lub cua sov kub saum toj no Ac1, tsim muaj austenite, cov dissolution ntawm carbides, M23C6 yuav ua tau tag rau hauv austenite, thiab M6C thiab MC hom carbides tsuas yog cov yaj. Raws li qhov kub npab ntau dua, qhov nyiaj ntawm cov hlau carbide yaj hauv austenite tsub kom, cov ntsiab lus carbon thiab alloying degree hauv austenite, yog li ntawd lawv ncaj qha rau lub qoob loj ntawm steel thiab Hardness tom qab quenching. Feem ntau, cov qoob loj ntawm cov tshuab tawg yog feem ntau ntawm 8 mus rau 11. Yog hais tias cov noob qoob loo, qhov carbide ntau dhau lawm, qhia tias qhov kub ntxhov siab dhau lawm los yog lub sij hawm tuav ntev dhau los ua haujlwm high-speed hlau; Thaum cov cua kub siab tshaj 1300 ° C, tus nqi ntawm cov carbide hauv cov hlau qis, qhov hindrance ntawm carbide kev loj hlob mus rau qhov loj ntawm lub qe tsis muaj zog, thiab cov khoom siv lead ua yuav txawv txav, ua rau muaj kev nce hauv brittleness thiab txo tus neeg kho tshuab , thiab yog li nyob rau hauv tej qhov chaw. Thaum tshav kub kub kho, yuav tsum tau ntsuas lub ntsuas kub kom tsim nyog raws li qhov kev ua tau zoo thiab kev pab cuam ntawm lub cuab yeej.
W18Cr4V steel muaj ntau hom quenching qhov kub, feem ntau ntawm 1180 thiab 1280 ° C, thermal coefficient coefficient yog 8-15 min / hli, thiab lub sijhawm tsawg kawg yog tsis tsawg dua 1.5 min. Nws yuav tsum raug sau tseg tias yuav kom paub meej tias qhov chaw tsis muaj qhov tsis zoo ntawm oxidative decarburization defects, thiab tias muaj overheating los yog overheating, nws yuav tsum tau deoxidized thaum lub sij hawm muaj preheating thiab cua sov hauv lub taub ntsev da dej, thiab lub cuab tam tsis raug tso cai hu lossis txoj kev ua tus electrode.
Txoj kev quenching thiab cua txias ntawm high-speed hlau yog raws li nram no: 1 tso cov roj txias, cua txias ntawm 300-400 ° C, feem ntau siv rau cov cuab yeej yooj yim, xws li cov cuab yeej siv; 2 thawj kev kho quenching, txias hauv ib ntsev da dej ntawm 400-600 ° C; 3 ntau theem ntawm txoj kev kho kev quenching, ntsig txog, ntawm 300 ~ 500 ° C ntsev da dej rau 30 ~ 60min; 4 rau kev kho mob austenitic austempering. Lub roj-txias los yog staged quenched qauv yog quenched martensite + granular carbide + khaws cia austenite (30%), thaum lub bainite austempered qauv yog bainite + martensite + khaws cia austenite.
(2) Tempering ntawm kev kub ceev
Rau cov cuab yeej ua kom tsis muaj teeb meem, ntau yam kub kub kub yuav tsum tau ua kom tiav lub koom haum uas yuav tsum muaj thiab kev ua tau zoo. Martensite, khaws cia austenite thiab carbides nyob rau hauv lub quenched qauv hloov thaum lub sij hawm tempering. Thaum chim siab hauv qab ntawm 400 ° C, martensite precipitates alloy cementite thiab tsis sib npaug aggregation, uas ua rau lub hardness, lub zog thiab cov hlau ntawm steel kom txo. Thaum tempered ntawm 400-600 ° C, zoo dispersion tshwm sim nyob rau hauv martensite. Carbide ntawm chromium, vanadium thiab tungsten, yog raug faib los ntawm dispersion, tsis yooj yim rau aggregate, hardness yog khees me ntsis lawm, nyob rau hauv cov txheej txheem tempering txias, tus qub austenite transforms rau lwm martensite, ntawm 550-570 ° C, hardness yog 63 ~ ~ 42HRC ( thiaj li hu ua theem ob sab), vim qhov pom ntawm cov nyhuv no, lub carbides ntawm vanadium thiab tungsten yog ruaj khov thiab tsis yoojyim rau aggregate, thiab martensite tom qab carbide precipitation yog nyuaj rau decompose, yog li ntawd cov hlau tseem yuav nyob rau ntawm 600 ° C Ua kom lub siab tawv dhau HRC60.
Qhov kub ntawm high-speed steel yog feem ntau peb lub sij hawm, lub hom phiaj yog los hloov qhov feem ntau ntawm cov quenched khaws cia austenite rau hauv martensite rau thawj zaug; qhov thib ob kev hloov ntawm cov kev hloov maj thawm rau hauv npau npau npau taws, tshem tawm cov nqaij nyuab siab, Ib feem ntawm cov khoom qub tau muab hloov mus ua martensite qauv; qhov thib peb tempering transforms lub secondary quenched martensite rau tempered martensite + carbide kom pab txhawb cov transformation ntawm qub austenite rau hauv martensite. Tus nqi ntawm cov khoom qub uas muab khaws cia tom qab peb qhov kub nyhiab yog raug txo kom tsawg, thiab lub zog tsis txo thiab lub zog thiab kev zoo dua qub lawm.
Tus qauv ntawm W18Cr4V hlau tom qab coj tus cwj pwm tsis txav ntawm lub cev, ua rau lub cev dawb dawb ci carbide sib npaug, yog hais tias lub hauv paus seem tshwm dawb, thiab ib qho me me ntawm cov ciam av tsis zoo kiag li, ua rau kev txo hwj chim, uas yog tsis txaus, yuav tsum tau Ua dua cov ntaub ntawv kho mob ntxiv.
