Pali njira zingapo zochizira kutentha kwa ductile iron.
Mu kapangidwe ka chitsulo cha ductile, graphite ndi yozungulira, ndipo kufooketsa ndi kuwononga kwake pa masanjidwewo kumakhala kofooka kuposa kwa flake graphite. Kuchita kwa chitsulo cha ductile makamaka kumadalira kapangidwe ka matrix, ndipo mphamvu ya graphite ndi yachiwiri. Kupititsa patsogolo kapangidwe ka chitsulo cha ductile chitsulo kudzera mu njira zosiyanasiyana zochizira kutentha kumatha kusintha mawonekedwe ake amakina mosiyanasiyana. Chifukwa cha chikoka cha mankhwala, mlingo kuzirala, spheroidizing wothandizila ndi zinthu zina, dongosolo losakanikirana la ferrite + pearlite + cementite + graphite nthawi zambiri limapezeka mu dongosolo monga-cast, makamaka pa khoma woonda wa kuponyera. Cholinga cha chithandizo cha kutentha ndikupeza kapangidwe kofunikira ndipo potero kuwongolera zida zamakina.
Njira zomwe zimagwiritsidwa ntchito pochiza kutentha kwa chitsulo cha ductile ndi izi.
(1) Otsika kutentha graphitization annealing Kutentha kutentha 720 ~ 760 ℃. Imatenthedwa mu ng'anjo mpaka pansi pa 500 ℃ kenako imatenthedwa ndi mpweya. Wondani eutectoid cementite kuti mupeze chitsulo cha ductile chokhala ndi ferrite matrix kuti mukhale wolimba.
(2) Kutentha kwapamwamba kwa graphitization annealing pa 880 ~ 930 ℃, kenako kumasamutsidwa ku 720 ~ 760 ℃ kuti atetezere kutentha, ndiyeno utakhazikika ndi ng'anjo mpaka pansi pa 500 ℃ ndi mpweya utakhazikika kunja kwa ng'anjo. Chotsani mawonekedwe oyera ndikupeza chitsulo cha ductile chokhala ndi matrix a ferrite, omwe amawongolera pulasitiki, amachepetsa kuuma ndikuwonjezera kulimba.
(3) Complete austenitization ndi normalizing pa 880 ~ 930 ℃, kuzirala njira: nkhungu kuzirala, mpweya kuzirala kapena mpweya kuzirala. Kuti muchepetse kupsinjika, yonjezerani njira yochepetsera: 500 ~ 600 ℃ kuti mupeze pearlite + pang'ono ferrite + mawonekedwe ozungulira Graphite, omwe amawonjezera mphamvu, kuuma ndi kuvala kukana.
(4) austenitization chosakwanira, normalizing ndi Kutentha pa 820 ~ 860 ℃, kuzirala njira: nkhungu kuzirala, mpweya kuzirala kapena mpweya kuzirala. Kuti muchepetse kupsinjika, yonjezerani njira yochepetsera: 500 ~ 600 ℃ kuti mupeze pearlite + pang'ono chitsulo chomwazika Kapangidwe ka thupi kamakhala ndi makina abwino kwambiri.
(5) Kuzimitsa ndi kutentha mankhwala: Kutentha pa 840 ~ 880 ° C, njira yozizira: mafuta kapena madzi kuziziritsa, kutentha kutentha pambuyo kuzimitsa: 550 ~ 600 ° C, kupeza mpweya wotentha wa sorbite ndikuwongolera makina ambiri.
(6) Isothermal kuzimitsa: Kutentha pa 840 ~ 880 ℃ ndi kuzimitsa mu kusamba mchere pa 250 ~ 350 ℃ kupeza mabuku katundu mawotchi, makamaka kusintha mphamvu, kulimba ndi kuvala kukana.
Pa kutentha ndi kutentha, kutentha kwa ng'anjo yolowa m'ng'anjo nthawi zambiri kumakhala kosakwana 350 ° C. Kuthamanga kwa kutentha kumatengera kukula ndi zovuta za kuponyera, ndipo amasankhidwa pakati pa 30 ~ 120 ° C / h. Kutentha kwa ng'anjo ya ng'anjo kwa zigawo zazikulu ndi zovuta ziyenera kukhala zochepa ndipo kutentha kumayenera kukhala kocheperapo. Kutentha kwa kutentha kumadalira kapangidwe ka matrix ndi mankhwala. Nthawi yogwira imadalira makulidwe a khoma la kuponyera.
Kuphatikiza apo, ma ductile iron castings amathanso kuzimitsidwa pamtunda pogwiritsa ntchito ma frequency apamwamba, ma frequency apakati, malawi ndi njira zina kuti apeze kuuma kwakukulu, kukana kuvala komanso kutopa. Itha kuthandizidwanso ndi nitriding yofewa kuti muchepetse kukana kwa ma castings.
1.Kuzimitsa ndi kutentha mankhwala a ductile iron
Kuponyedwa kwa ductile kumafuna kuuma kwakukulu ngati mayendedwe, ndipo zitsulo zotayidwa nthawi zambiri zimazimitsidwa ndi kutenthedwa pa kutentha kochepa. Njirayi ndi: Kutenthetsa kuponyera ku kutentha kwa 860-900 ° C, ndikuyiyika kuti ilole kuti matrix onse oyambirira awonongeke, ndiyeno kuziziritsa mu mafuta kapena mchere wosungunula kuti muthe kuzimitsa, ndikuwotcha ndikusunga pa 250-350. °C pakuwotcha, ndipo matrix oyambilira amasinthidwa kukhala Fire martensite ndikusungidwa austenite mawonekedwe, mawonekedwe ozungulira ozungulira a graphite amakhalabe osasinthika. Zoponyedwa zoperekedwa zimakhala ndi kuuma kwambiri komanso kulimba kwina, zimasunga zokometsera za graphite, ndipo zasintha kukana kuvala.
Ma ductile iron castings, monga ma shaft, monga ma crankshafts ndi ndodo zolumikizira zamainjini a dizilo, amafunikira makina amakina okhala ndi mphamvu zambiri komanso kulimba kwabwino. Zigawo zachitsulo zosungunuka ziyenera kuzimitsidwa ndi kutenthedwa. Njirayi ndi: chitsulo chosungunula chimatenthedwa ndi kutentha kwa 860-900 ° C ndikusungunulidwa kuti austenitize masanjidwewo, kenako utakhazikika mu mafuta kapena mchere wosungunula kukwaniritsa kuzimitsidwa, ndiyeno kutenthedwa pa kutentha kwakukulu kwa 500-600 ° C. kupeza mawonekedwe amtundu wa troostite. (Nthawi zambiri pamakhalabe ferrite yaying'ono yoyera), ndipo mawonekedwe a graphite yozungulira yoyambirira amakhalabe osasinthika. Pambuyo pa chithandizo, mphamvu ndi kulimba zimagwirizana bwino ndipo ndizoyenera kugwira ntchito kwa magawo a shaft.
2. Annealing wa ductile iron kuti kulimba
Panthawi yoponyera chitsulo cha ductile, chitsulo wamba wa imvi chimakhala ndi chizolowezi choyera komanso kupsinjika kwakukulu kwamkati. Ndizovuta kupeza matrix oyera a ferrite kapena pearlite pazigawo zachitsulo. Kuti apititse patsogolo ductility kapena kulimba kwa zitsulo zachitsulo, chitsulo chosungunula nthawi zambiri Zigawozo zimatenthedwanso mpaka 900-950 ° C ndipo zimatenthedwa kwa nthawi yokwanira kuti zitheke kutentha kwambiri, kenako zitakhazikika mpaka 600 ° C ndikuzizizira. wa ng'anjo. Panthawiyi, simenti ya matrix imawola kukhala graphite, ndipo graphite imachokera ku austenite. Ma graphite awa amasonkhana mozungulira graphite yozungulira yoyambirira, ndipo masanjidwewo amasinthidwa kukhala ferrite.
Ngati mawonekedwe a as-cast apangidwa ndi (ferrite + pearlite) masanjidwewo ndi graphite yozungulira, kuti apititse patsogolo kulimba, simenti ya pearlite imangofunika kutha ndikusinthidwa kukhala graphite ya ferrite ndi yozungulira. Pachifukwa ichi, gawo lachitsulo chosungunuka liyenera kutenthedwanso. Pambuyo poyikidwa mmwamba ndi pansi kutentha kwa eutectoid 700-760 ℃, ng'anjoyo imakhazikika mpaka 600 ℃ kenako ndikuzizidwa kunja kwa ng'anjo.
3. Normalizing kusintha mphamvu ya ductile chitsulo
Cholinga cha normalizing ductile iron ndikusintha mawonekedwe a matrix kukhala mawonekedwe abwino a pearlite. Njirayi ndikutenthetsanso chitsulo cha ductile ndi matrix a ferrite ndi pearlite ku kutentha kwa 850-900 ° C. Ferrite yoyambirira ndi pearlite imasinthidwa kukhala austenite, ndipo ma graphite ena ozungulira amasungunuka mu austenite. Pambuyo posungira kutentha, mpweya wozizira wa austenite umasandulika kukhala pearlite yabwino, kotero mphamvu ya ductile kuponyera kumawonjezeka.
Nthawi yotumiza: May-08-2024
