Ukucima ukuqaliswa kobushushu

Ukushisa okucimayo kunqunywe ngokukodwa ngokubhekiselele kwindawo yokuguqulwa kwentsimbi. Ukucima ukushisa kokushisa kwensimbi ye-hypoeutectoid ngokuqhelekileyo yi-AC3 (30-50), kunye nentsimbi ye-hypereutectoid yi-AC1 (30-50). Isizathu solu kuzimisela kukuba insimbi ye-hypoeutectoid, ukuba ubushushu bokufudumala bungaphantsi kwe-Ac3, imeko yokufudumala ihlanganiswe ne-austenite kunye ne-ferrite, kwaye i-ferrite igcinwa emva kokucima kunye nokupholisa, ukwenzela ukuba ubunzima benxalenye emva kokucima kungabikho. iyunifomu, kwaye amandla kunye Ukuqina kuncipha. Injongo ye-30-50 ephezulu kunendawo ye-Ac3 kukuqinisekisa ukuba i-workpiece core ifikelela kwiqondo lokushisa ngaphezu kwendawo ye-Ac3 ngexesha lokufudumeza elichaziweyo, i-ferrite inokuchithwa ngokupheleleyo kwi-austenite, ukubunjwa kwe-austenite kufana ngokufanayo, kwaye iinkozo austenite azikho. ngqindilili. Kwintsimbi ye-hypereutectoid, xa ubushushu bokucima ubushushu buphakathi kwe-AC1 kunye ne-AC3, imeko yokufudumeza ilungile iinkozo ze-austenite kunye ne-carbides ezinganyibilikiyo, kunye ne-cryptocrystalline martensite kunye nekhabhoni engqukuva esasazwe ngokufanayo ifunyenwe emva kokucinywa. Esi sakhiwo asinayo kuphela amandla aphezulu, ubunzima obuphezulu, ukuchasana nokugqoka okuphezulu, kodwa kunokuqina okulungileyo. Ukuba iqondo lokushisa lokucima liphezulu kakhulu, i-carbides iya kuchithwa, i-austenite grains iya kukhula, kunye ne-flaky martensite (i-twin martensite) iya kufumaneka emva kokucima, kunye ne-microcracks yayo, i-brittleness kunye nokucima ukuthambekela kokuqhekeka kuya kwanda. Ngenxa yokuchithwa kwe-carbides, umxholo wekhabhoni kwi-austenite uyanda, inani le-austenite egciniweyo emva kokunyuka kokucima, kunye nobunzima kunye nokuxhatshazwa kokugqoka kwensimbi kuncipha. Injongo ye-30-50 ephezulu kune-Ac1 ifana neyensimbi ye-hypoeutectoid, oko kukuqinisekisa ukuba ukushisa kwazo zonke iindawo kwindawo yokusebenza kuphezulu kune-Ac1.