Austempered Ductile Iron - ADI Castings

Austempered ductile iron, yomwe imadziwikanso kuti ADI, imatanthawuza chitsulo chosungunuka pambuyo pa njira ya austenitizing ductile iron (850 ℃-950 ℃) kenako ndikuyiyika mwachangu mumadzi osambira amchere (232 ℃-450 ℃) kuti isinthe kutentha. Kuphatikiza apo, ndi kuwonjezera kuchuluka kokwanira kwa Cu, Ni, Mo ndi zinthu zina, chitsulo cha austempered austenitic ductile chitsulo chingathenso kupezeka pansi pazikhalidwe zozizirira mosalekeza.

Austempered ductile ironzoponyaali ndi zida zabwino zamakina, ndipo kulemera kwawo kwa zokolola ndizochepa kwambiri. Kupeza magiredi osiyanasiyana austempered ductile iron kumadalira kutentha kwa austempering ndipo kulibe chochita ndi mankhwala. Nthawi zambiri, kapangidwe kake ka austempered ductile iron ndi motere:
C: 3.5% -3.8%
Chiyembekezo: 2.4-3.0%
Mayi: ＜0.30%
P: <0.07%
S: <0.02%

Silicon ndi chimodzi mwazinthu zofunika kwambiri zachitsulo cha austempered ductile iron. Silicon imalepheretsa mapangidwe a Bainite carbides, potero amathandizira kupanga acicular ferrite. Kuchulukitsa za silicon kumatha kukulitsa kulimba kwa chitsulo cha austempered ductile cast iron ndikuchepetsa kutalika. Udindo wa Manganese uli ndi mbali ziwiri. Kumbali imodzi, imatha kusintha kwambiri kuuma; Kumbali ina, Manganese amalimbikitsa mapangidwe a carbides ndikulepheretsa kusintha kwa isothermal panthawi yolimba. Choncho, pamene chiwerengero cha zigawo za graphite ndizochepa ndipo makulidwe a khoma ndi aakulu, kugawanika kwa manganese pamalire a tirigu kumayambitsa shrinkage porosity, carbides ndi kusakhazikika kwa austenite mu ductile iron cast. Izi microstructure zolakwika ndi inhomogeneities kuchepetsa machinability ndi makina katundu. Chifukwa chake, kuchuluka kwa manganese kuyenera kuyendetsedwa pansi pa 3%.

Mu kupanga kwenikweni kuponyera, kuti apeze khola ndi apamwamba austemperedductile iron castings, pali mfundo ziwiri zomwe zimafunikira chisamaliro chapadera:
1) Yang'anirani kapangidwe ka chitsulo cha ductile musanayambe chithandizo cha isothermal. Mlingo wa spheroidization uyenera kukhala wapamwamba kuposa 80%. Chiwerengero cha ma graphite pheres chiyenera kukhala choposa 100 pa millimeter imodzi. Zina zomwe zikuphatikizapo: kukhazikika kwa mankhwala; kuponyedwa kuyenera kukhala kopanda carbides, porosity ndi inclusions; ndi chiŵerengero chokhazikika cha pearlite/ferrite.
2) Dziwani zofunikira zopangira kutentha molingana ndi kapangidwe kake ndi kapangidwe ka chitsulo cha ductile, ndikuchita njira yochiritsira yokhazikika komanso yosasunthika.