Mankhwala kutentha mankhwala a castings zitsulo

The mankhwala kutentha mankhwala a castings zitsulo amatanthauza kuyika castings mu sing'anga yogwira pa kutentha kwina pofuna kuteteza kutentha, kuti chimodzi kapena zingapo mankhwala akhoza kulowa pamwamba. Mankhwala kutentha mankhwala angasinthe mankhwala zikuchokera, metallographic dongosolo ndi mawotchi zimatha padziko kuponya. Nthawi zambiri amagwiritsidwa ntchito pochiza kutentha kwamankhwala kumaphatikizapo carburizing, nitriding, carbonitriding, boronizing ndi metalizing. Pochita chithandizo cha kutentha kwa mankhwala pa castings, mawonekedwe, kukula, mawonekedwe a pamwamba, ndi kutentha kwapamwamba kwa kuponyera kumayenera kuganiziridwa mozama.

 

1. Carburizing

Carburizing imatanthawuza kutenthetsa ndi kutsekereza kuponyera mu sing'anga yobisa, kenako ndikulowetsa maatomu a kaboni pamwamba. Cholinga chachikulu cha carburizing ndikuwonjezera mpweya wa carbon pamwamba pa kuponyera, ndikupanga mpweya wina wa carbon poponyera. Mpweya wa carbon mu carburizing zitsulo nthawi zambiri ndi 0.1% -0.25% kuonetsetsa kuti pakatikati pa kuponyera kumakhala ndi kulimba ndi mphamvu zokwanira.

Kuuma kwa pamwamba kwa wosanjikiza wa carburized nthawi zambiri ndi 56HRC-63HRC. Kapangidwe kazitsulo kagawo kakang'ono ka carburized ndi singano yabwino ya singano + yocheperako ya austenite yosungidwa ndikugawidwa mofananamo granular carbides. Network carbides saloledwa, ndi gawo la voliyumu ya austenite yosungidwa nthawi zambiri sichidutsa 15% -20%.

Kulimba kwapakati pakuponyedwa pambuyo pobisala nthawi zambiri kumakhala 30HRC-45HRC. Mapangidwe a metallographic ayenera kukhala otsika-carbon martensite kapena otsika bainite. Sizololedwa kukhala ndi ferrite yayikulu kapena yam'mphepete mwa malire a tirigu.

Pakupanga kwenikweni, pali njira zitatu zodziwika bwino za carburizing: zolimba carburizing, madzi carburizing ndi mpweya carburizing.

2. Nitriding

Nitriding imatanthawuza njira yochizira kutentha yomwe imalowetsa maatomu a nayitrogeni pamwamba pa kuponyera. Nitriding nthawi zambiri imachitika pansi pa kutentha kwa Ac1, ndipo cholinga chake chachikulu ndikuwongolera kulimba, kukana kuvala, mphamvu ya kutopa, kukana kugwidwa ndi kukana kwa dzimbiri mumlengalenga. Nitriding of castings zitsulo nthawi zambiri imachitika pa 480°C-580°C. Zopangira zokhala ndi aluminiyamu, chromium, titaniyamu, molybdenum, ndi tungsten, monga chitsulo chochepa cha alloy, chitsulo chosapanga dzimbiri, ndi chitsulo chotentha cha nkhungu, ndizoyenera kuyika nitriding.

Pofuna kuonetsetsa kuti pachimake cha kuponyera ali ndi zofunika makina katundu ndi dongosolo metallographic, ndi kuchepetsa mapindikidwe pambuyo nitriding, chisanadze mankhwala pamaso nitriding chofunika. Pakuti structural zitsulo, quenching ndi kutentha mankhwala chofunika pamaso nitriding kuti apeze yunifolomu ndi chabwino kupsa mtima sorbite dongosolo; kwa castings zomwe zimasokonekera mosavuta panthawi ya chithandizo cha nitriding, chithandizo chamankhwala ochepetsa nkhawa chimafunikanso pambuyo pozimitsa ndi kutentha; kwa zitsulo zosapanga dzimbiri ndi zitsulo zosagwira Kutentha zimatha kuzimitsidwa ndikutenthedwa kuti zipititse patsogolo kapangidwe kake ndi mphamvu; kwa chitsulo chosapanga dzimbiri cha austenitic, njira yothetsera kutentha ingagwiritsidwe ntchito.