12L13 12L14 12L15 yog dawb txiav cov qauv hlau.Dawb txiav steel yog ib hom hlau uas yooj yim rau kev txiav (xws li tig, milling, rub, npaj, drilling, thiab lwm yam), tseem hu ua tsis siv neeg tshuab cuab yeej ua hlau, abbreviated li tsis siv neeg hlau.yog ib qho yooj yim txiav cov qauv hlau, yooj yim txiav steel yog ib qho yooj yim los ua (tig, milling, kos duab, npaj, drilling, thiab lwm yam) txiav ua steel, los yog lub tshuab tsis siv neeg cov cuab yeej ua hlau, hu ua tsis siv neeg hlau.Nws yog tsim los hloov mus rau machining automation thiab ntws kab ntau lawm.