Kev Tshawb Fawb Txog Cov Txheej Txheem Tseem Ceeb ntawmlub hauv ncoo thaiv Cov kabmob:

Yuav ua li cas Martensitic Kub Kho Tsim Ib Lub "Hardcore" Bearing

Hauv lub tshuab ua khoom sivlub hauv ncoo thaiv Cov kabmob, kev kho cua sov yog qhov kawg uas txiav txim siab qhov kev ua tau zoo tshaj plaws ntawm cov kabmob. Peb siv cov hlau chromium siab (GCr15 series) ua cov khoom siv tseem ceeb thiab siv martensitic quenching ua ke nrog kev kub qis ua cov txheej txheem kho cua sov kawg. Txoj hauv kev no cuam tshuam ncaj qha rau qhov sib npaug ntawm qhov nyuaj, kev tiv thaiv kev hnav, thiab kev ruaj khov ntawm qhov ntev.

Kev Tshawb Fawb Txog Kev Kho Mob Martensitic

Lub ntsiab lus ntawm kev kho cua sov martensitic yog ua kom cov hlau bearing kub mus rau nws qhov kub austenitizing thiab tom qab ntawd txias nws sai sai, tiv thaiv atomic diffusion thiab ua rau muaj kev hloov pauv theem shear-type los ua cov martensite siab hardness. Peb cov txheej txheem muaj peb theem tseem ceeb.

Theem 1: Kev Ua Kub Austenitizing

Cov nplhaib bearing lossis cov khoom dov tau raug cua sov rau qhov kub thiab txias ntawm 830–880°C thiab tuav rau ib lub sijhawm tshwj xeeb, cia cov carbides yaj tag nrho rau hauv austenite thaum tswj hwm qhov ntau ntawm cov carbide uas tsis yaj. Lub qhov rais kub no tseem ceeb heev: qis dhau, thiab cov pa roj carbon thiab cov hlau sib xyaw hauv austenite yuav tsis txaus, ua rau tsis muaj zog tom qab quenching; siab dhau, thiab austenite noob loj zuj zus, ua rau cov koob martensite ntxhib thiab poob qis hauv kev tawv thiab lub zog qaug zog. Lub sijhawm tuav tau suav meej raws li phab ntsa tuab ntawm cov khoom ua haujlwm kom ntseeg tau tias qhov kub sib npaug thoob plaws hauv cov khoom.

Theem 2: Kev Quenching thiab Martensitic Transformation

Tom qab tuav, cov khoom siv ntawm cov kabmob raug muab tso rau hauv roj tam sim ntawd rau kev tua hluav taws. Kev tua hluav taws roj muab lub peev xwm txias txaus kom ua tiav qhov kev hloov pauv martensitic hauv qab Ms point, thaum zam kev pheej hmoo tawg uas cuam tshuam nrog kev tua hluav taws dej. Lub microstructure tom qab tua hluav taws muaj cov matrix martensite, khaws cia austenite, thiab cov carbides tsis yaj, ua tiav qhov nyuaj ntawm HRC 64–67.

Txawm li cas los xij, lub xeev quenched tsis yog qhov kawg. Nyob rau theem no, cov ntsiab lus austenite seem feem ntau yog li ntawm 6% txog 15%. Ib qho nruab nrab ntawm cov austenite khaws cia zoo pab txhawb rau kev tuav lub zog los ntawm kev txhim kho kev tiv thaiv kab nrib pleb. Txawm li cas los xij, thaum lub sijhawm pabcuam, cov austenite seem yuav raug hloov pauv los ntawm kev ntxhov siab, ua rau muaj kev hloov pauv loj. Yog li ntawd, tempering yuav tsum ua raws li quenching tam sim ntawd.

Theem 3: Kev Kub Ntxhov Qis thiab Kev Ruaj Ntseg Microstructural

Tam sim ntawd tom qab quenching, cov khoom raug tempering qis-kub ntawm 150–180°C rau 2–4 teev. Kauj ruam no ua haujlwm rau peb lub hom phiaj: thawj zaug, txo cov kev ntxhov siab sab hauv uas tsim thaum lub sijhawm quenching thiab txo qhov brittleness; qhov thib ob, precipitating nanoscaleε-carbides hauv lub matrix martensite, yog li txhim kho qhov tawv yam tsis muaj kev txi qhov nyuaj; qhov thib peb, ntxiv decomposing residual austenite kom txhim kho qhov ruaj khov.

Rau cov bearings precision uas xav tau kev kam rau siab heev, peb kuj suav nrog kev kho mob cryogenic tob tom qab quenching—txias cov khoom rau -60°C txog -70°C kom hloov pauv tag nrho cov austenite seem mus rau hauv martensite ua ntej tempering. Qhov no tso cai rau peb ua tiav kev tswj hwm qhov ntev dua.

Qhov kawg tempered martensite qauv ua tiav qhov ruaj khov hauv qhov ntau ntawm HRC 61–65, ua tau raws li qhov yuav tsum tau ua ntawm Zhenkuai bearings nyob rau hauv high-load, kev ua haujlwm tas mus li txog kev nyuaj thiab hnav tsis kam.

Kev Kho Mob Martensitic Kub Ua Rau Dab Tsilub hauv ncoo thaivkuv Bearings

Tom qab cov txheej txheem martensitic quench-temper no, lub zog qaug zog ntawm Zhenkuai bearings tuaj yeem tshaj 1800 MPa, nrog rau kev hnav tsis kam zoo dua 30%.–50% piv rau cov hlau siv carbon. Qhov tseem ceeb tshaj, cov martensite matrix uas zoo sib xws ua ke nrog cov carbide me me uas tawg ua rau cov kabmob no tuav tau qhov nyuaj ntawm qhov chaw thaum muaj kev cuam tshuam thiab kev ntxhov siab cyclic, thaum tseem muab cov matrix toughness txaus los nqus lub zog, txo qhov kev pheej hmoo ntawm kev tawg lossis tawg thaum ntxov.

Txij li cov ntaub ntawv mus rau kev ua tiav, kev kho cua sov martensitic tsim lub hauv paus thev naus laus zis tom qab peb cov lus cog tseg ntawm kev ua haujlwm ntev raucov kabmob thaiv hauv ncoo