Kuyimitsa kutentha koyambitsa

Kutentha kozimitsa kumatsimikiziridwa makamaka malinga ndi kusintha kwachitsulo. Kutentha kozimitsa kwachitsulo cha hypoeutectoid nthawi zambiri kumakhala AC3 (30-50), ndipo chitsulo cha hypereutectoid ndi AC1 (30-50). Chifukwa cha kutsimikiza uku ndi chakuti zitsulo za hypoeutectoid, ngati kutentha kwa kutentha kuli kochepa kuposa Ac3, kutentha kwa dziko kumapangidwa ndi austenite ndi ferrite, ndipo ferrite imasungidwa pambuyo pozimitsidwa ndi kuziziritsa, kotero kuti kuuma kwa gawolo pambuyo pozimitsa si. yunifolomu, ndipo mphamvu ndi Kuuma kumachepa. Cholinga cha 30-50 apamwamba kuposa nsonga ya Ac3 ndikuwonetsetsa kuti maziko a workpiece afika kutentha pamwamba pa Ac3 point mkati mwa nthawi yotentha yodziwika, ferrite imatha kusungunuka mu austenite, mawonekedwe a austenite ndi ofanana, komanso mbewu za austenite siziri. wandiweyani. Kwa chitsulo cha hypereutectoid, pamene kutentha kozimitsa kutentha kuli pakati pa AC1 ndi AC3, malo otentha ndi mbewu zabwino za austenite ndi carbides zosasunthika, ndi cryptocrystalline martensite ndi mpweya wofanana wogawidwa wozungulira umapezeka pambuyo pozimitsidwa. Kapangidwe kameneka kamakhala ndi mphamvu zambiri, kuuma kwakukulu, kukana kuvala kwapamwamba, komanso kumakhala ndi mphamvu zabwino. Ngati kutentha kozimitsira kutentha kuli kwakukulu kwambiri, ma carbides adzasungunuka, mbewu za austenite zidzakula, ndipo flaky martensite (twin martensite) idzapezedwa pambuyo pozimitsidwa, ndipo ma microcracks ake, brittleness ndi quenching cracking chizolowezi chidzawonjezekanso. Chifukwa cha kusungunuka kwa carbides, zomwe zili mu kaboni mu austenite zimawonjezeka, kuchuluka kwa austenite yosungidwa pambuyo pozimitsa kumawonjezeka, ndipo kuuma ndi kuvala kukana kwachitsulo kumachepa. Cholinga cha 30-50 apamwamba kuposa Ac1 ndi chofanana ndi chachitsulo cha hypoeutectoid, chomwe ndikuwonetsetsa kuti kutentha kwa zigawo zonse mu workpiece ndipamwamba kuposa Ac1.