Kev kub ceev steel txiav cov cuab yeej feem ntau tsis dhau qhov kev ntsuas lub zog tensile, tab sis feem ntau yog kuaj metallographic thiab hardness.
Tom qab kev kho cua sov kom raug, Rockwell hardness ntawm tungsten-based thiab molybdenum-based high-speed steel tuaj yeem ncav cuag 63, thiab cov hlau cobalt-based high-speed steel tuaj yeem ncav cuag tshaj 65. Cov kua qaub-leached low-magnification qauv ntawm steel. yuav tsum tsis txhob pom qhov shrinkage kab noj hniav los yog tawv nqaij. Qhov nruab nrab yog xoob, thiab feem ntau qhov xoob yuav tsum tsawg dua qib 1.
Cov ntsiab lus ntawm kev kuaj metallographic feem ntau suav nrog peb yam: decarburization txheej, microstructure thiab carbide unevenness.
1. High-speed steel yuav tsum tsis muaj qhov pom tseeb decarburization. Lub microstructure yuav tsum tsis muaj cov ntses pob txha eutectic ledeburite.
2. Carbide unevenness nyob rau hauv high-ceev steel muaj feem xyuam rau qhov zoo. Tam sim no, metallurgical thiab mechanical departments muab qhov tseem ceeb rau qib ntawm carbide unevenness. Cov kev xav tau sib txawv ntawm cov carbide tsis sib xws tuaj yeem muab tso rau pem hauv ntej raws li kev siv hlau sib txawv. Feem ntau, nws yuav tsum tsawg dua qib 3.
3. High-speed steel yog siv los ua cov cuab yeej txiav. Ntxiv nrog rau nws cov hardness siab, siab hnav tsis kam thiab txaus toughness, lwm qhov tseem ceeb yog nws cov xim liab. (Liab hardness hais txog lub peev xwm ntawm kev txiav ntug los tiv thaiv softening nyob rau hauv lub kub kub kub thaum lub sij hawm high-ceev txiav.)
Ib txoj hauv kev los ntsuas qhov tawv tawv liab yog thawj zaug kom sov cov hlau mus rau 580 ~ 650 degree, ua kom sov li 1 teev, thiab tom qab ntawd txias. Rov ua qhov no plaub zaug thiab tom qab ntawd ntsuas tus nqi hardness. Lub quenching kub ntawm high-speed steel feem ntau yog ze rau lub melting point ntawm cov hlau. Piv txwv li, quenching kub ntawm tungsten series high-speed steel yog 1210 ~ 1240 degree, thiab high-molybdenum series high-speed steel yog 1180 ~ 1210 degree. Tom qab quenching, nws feem ntau yuav tsum tau tempered peb zaug ntawm 540 ~ 560 degree. Ua kom lub quenching kub tuaj yeem ua rau cov xim liab hardness. Txhawm rau txhim kho kev pabcuam lub neej ntawm cov cuab yeej siv high-speed steel, qhov saum npoo tuaj yeem ua kom muaj zog, xws li kub-kub cyanidation, nitriding, sulfur-nitrocarburizing, thiab lwm yam.
