Insimbi ye-H13 ikhombisa ukuqina okuphezulu, ukuguguleka okuhle kakhulu nokumelana nokushisa, igcina ubulukhuni namandla aphezulu ngaphansi kwama-600°C, kanye nokumelana nokubanda nokukhathala okuphezulu nokushisa kanye nokuqina okuhle kokushisa. Isetshenziswa kabanzi ekubunjweni kwe-die casting kwe-aluminium, ithusi, kanye ne-alloys yazo, okuletha izinzuzo ezinkulu zomnotho. Kodwa-ke, amamojula e-H13 akhiqizwe yinkampani abonise ukuqhekeka kwendawo, i-spheroidization engaphelele, kanye ne-microstructure engalingani ngesikhathi sokukhiqizwa kwesilingo. Leli phepha lethula ukulinganisa izinga lokushisa eliphezulu okulandelwa inqubo ye-spheroidizing annealing ukuthuthukisa ikhwalithi yemojula nokufeza i-microstructure efanayo.

1. Izinkinga zatholakala ngesikhathi senqubo yokuthuthukiswa kweprototype.

Imodyuli yokuhlola yenziwe ngensimbi ye-H13 enobukhulu obungu-400 mm × 1000 mm × 3000 mm, kanti izinga lokushisa lokugcina lokufaka lalicishe libe ngu-950°C. Ngenxa yokungabikho kokwelashwa kokushisa ngemuva kokufaka ngesikhathi esifanele, ukuqhekeka kwendawo kwenzeka ngemuva kokupholisa umoya kuya ekushiseni kwegumbi, kwadlulela ngaphakathi kwemodyuli. Ukuhlaziywa kwembule ukuthi insimbi ye-H13 iyinsimbi eqinile, okusho ukuthi isakhiwo sayo se-martensitic sakha ngesikhathi sokupholisa umoya. Ukucindezeleka okukhulu kwesakhiwo esincane okwakhiqizwa ngesikhathi senqubo yokupholisa umoya ngemuva kokufaka kwaholela ekuqhekekeni kwendawo yemodyuli.

Ukuze kuvinjelwe ukuqhekeka, amamojula ensimbi e-H13 afakwa ngqo ekupholiseni kancane esithandweni ngemva kokubumba, kulandelwe ukuphola okuncishisiwe. Ngemva kokuphola okuncishisiwe, ubulukhuni bemojula bungalinganiswa kusetshenziswa umhloli wobulukhuni beBrinell; kwahlolwa amasampula amathathu, kwathathwa izilinganiso zobulukhuni ngamaphuzu ayisishiyagalombili ngalinye (bheka Ithebula 1). Njengoba kuboniswe kuThebula 1, ubulukhuni buvame ukuhlangabezana nezidingo, kodwa ukufana kwakungagculisi ngenxa yokwehluka okukhulu kobulukhuni, ngamaphuzu ngamanye adlula umkhawulo ocacisiwe (≤220 HB). Ukuhlaziywa kwe-Metallographic kwamamojula kwembule isakhiwo esincane njengoba kuboniswe kuThebula 1.

Isithombe 1 sibonisa isakhiwo esincane ngemva kokufakwa kwe-spheroidizing annealing kwe-isothermal, kanye nenqubo ye-spheroidizing equkethe isigaba sokushisa esiphakeme ku-870°C amahora angu-8 kanye nesigaba sokushisa okuphansi ku-730°C amahora angu-14. Ku-Figure 1(a), ukuhlukaniswa kwenethiwekhi ye-carbide enzima kanye nokuxuba okubalulekile kokusanhlamvu kuyabonakala. Isithombe 1(b) sembula izinhlayiya ze-carbide eziningi ezihlakazekile, okubonisa ukuthi umphumela we-spheroidizing uhlangabezana nomgomo ohlosiwe; noma kunjalo, ukuhlukaniswa kusalokhu kuvelele, kanti amanye ama-carbide akha ukusatshalaliswa okufana nenethiwekhi okunciphisa ukusebenza kwe-spheroidization kulezo zindawo. Ama-carbide axhunyiwe abeka izingozi ezinkulu ekubumbeni insimbi, njengoba esebenza kalula njengemithombo yokuqhekeka ngesikhathi sesevisi, okuholela ekwehlulekeni kwezinto. Ngakho-ke, amanethiwekhi anjalo e-carbide kumele alawulwe ngaphakathi kwemingcele eyamukelekayo. Lolu cwaningo lufake i-H13 steel batch ebonisa ukuhlukaniswa kwe-carbide okukhulu ekujwayelekile kokushisa okuphezulu kulandelwe yi-isothermal spheroidizing annealing ukuze kuhlolwe ukuthuthukiswa kwesakhiwo sayo esincane ngaphansi kwalezi zimo.

2 Izinto Zokuhlola Nezindlela

Amasampula amancane athathwe kumamojula abonisa ukuhlukaniswa okukhulu kokuhlaziywa kwe-spectral; ukwakheka kwawo kwamakhemikhali kuboniswe kuThebula 2. Ukwakheka kwamakhemikhali kwale nsimbi ye-H13 kuhambisana ne-GB/T 1299–2000 "Insimbi Yensimbi Ehlanganisiwe." Amamojula ahlukaniswe ngamaqembu amathathu futhi afakwa ekujwayelekile kokushisa okuphezulu ku-970 °C, ngezikhathi zokubamba ezingamahora ama-5, 7, kanye ne-10, ngokulandelana. Inqubo yokwelapha ukushisa yayihlanganisa ukujwayelekile kokushisa okuphezulu (okupholishwe emoyeni) kulandelwe ukunamathela kwe-isothermal spheroidizing. Amapharamitha okunamathela kwe-isothermal spheroidizing ayeyi: isigaba sokushisa okuphezulu ku-870 °C amahora ayi-8, kanye nesigaba sokushisa okuphansi ku-730 °C amahora ayi-14. Ngokusekelwe emphumeleni wesikhathi sokujwayelekile kokushisa okuphezulu kusakhiwo esincane samamojula, inqubo entsha yokwelapha ukushisa yasungulwa.

Ngemva kwamahora ama-5 okushintshashintsha kwezinga lokushisa eliphezulu, izinga lokuhlukanisa (bheka uMfanekiso 2(a)) libonise ukuthuthuka okukhulu uma kuqhathaniswa noMfanekiso 1, nakuba ukuhlukaniswa kwaqhubeka. Lapho isikhathi sokubamba esijwayelekile sandiswa saba amahora angu-7, ukuhlukaniswa kwaqedwa cishe; noma kunjalo, inethiwekhi ye-carbide yahlala ihlukile, amanethiwekhi amancane e-carbide yesibili encibilika ngokuphelele ku-matrix ngesikhathi senqubo ye-austenitization, kuyilapho amanethiwekhi e-carbide aqinile ahlala enganyibiliki—ewela esigabeni esingahambisani nezindinganiso ze-North American Die Casting Association. Ukwandisa isikhathi sokubamba saba amahora ayi-10 kwasusa amanethiwekhi amaningi e-carbide, kwashiya kuphela amanethiwekhi e-carbide aqinile ekuqaleni. Ukufakwa kwe-spheroidizing okwalandela kwaholela ekwakheni i-spheroidized microstructure efanayo, kwathola izinto ezingeni le-AS4 ngaphansi kwezindinganiso ze-North American Die Casting Association futhi kwahlangabezana nezindinganiso zokwamukelwa. Ukuhlaziywa kubonisa ukuthi ukuguquguquka kwezinga lokushisa eliphezulu kususa ngempumelelo ukuhlukaniswa futhi kuthuthukisa isimo kanye nokusatshalaliswa kwamanethiwekhi e-carbide. Njengoba isikhathi sokubamba sanda, izinhlayiya ze-carbide ziyancibilika kancane kancane, okuholela ekususweni okuqhubekayo kokuhlukaniswa kanye namanethiwekhi e-carbide, ngaleyo ndlela kuthuthukisa kakhulu isakhiwo se-microstructure yezinto.

Ngemva kokwenza insimbi, insimbi ye-H13 ithambekele ekwakhekeni kokusanhlamvu okuqinile ngenxa yokushisa okuphezulu kakhulu kokugcina kokwenza insimbi kanye namazinga okupholisa ahamba kancane. Njengensimbi ye-hypereutectoid, i-H13 ikhombisa imvula yesibili efana nenethiwekhi ngesikhathi sokupholisa okuhamba kancane, futhi okuqukethwe kwayo okuphezulu kwe-alloy kuholela ekuhlukaniseni izinto. Ukuze kuthuthukiswe isakhiwo se-post-forging samamojula ensimbi ye-H13, kunconywa ukwelashwa kokulungisa izinga lokushisa eliphezulu ukuze kufezwe isakhiwo se-micro esifanayo.

Ukuze kususwe ama-carbide angama-reticular, umsebenzi kufanele ushiswe ufike ezingeni lokushisa elanele ukuncibilikisa ama-carbide esibili. Kodwa-ke, izinga lokushisa le-spheroidizing annealing (870 °C) alanele ukufeza lokhu kuncibilika. Ngenxa yalokho, ngaphandle kokujwayelekile kokushisa okuphezulu, inethiwekhi ye-carbide ihlala inzima ukuyisusa, futhi ukuhlukaniswa akukwazi ukuthuthukiswa, okuholela ekutheni imojuli ye-H13 yehluleke ukuhlangabezana namazinga. Ngemva kokujwayelekile kokushisa okuphezulu, izinhlayiya ze-carbide ezincane zincibilika ngokuphelele ku-matrix, inethiwekhi ye-carbide iyacwengisiswa kancane kancane kuze kube yilapho iphuka, futhi isakhiwo esincane siba yinto efanayo. Ngemva kwesikhathi sokubamba esijwayelekile, ukupholisa komoya okusheshayo kuvimbela ukwakheka kwama-carbide esibili angama-reticular. Ngemva kwalokho, i-spheroidizing annealing ikhuthaza ukukhula kwama-carbide ahlakazeke ngokulinganayo kusuka ku-matrix kuya ezakhiweni eziyindilinga, ngaleyo ndlela kuthuthukiswe isakhiwo esincane esihlanganisiwe.

Ngamafuphi, ukupholisa kancane ngemva kokubumba kuholela ezakhiweni ezincane eziqinile kanye nokwakheka kwama-carbide anenethiwekhi, kanti ukuvuselela izinga lokushisa eliphezulu kuthuthukisa ama-carbide anenethiwekhi kanye nokuhlukaniswa kwezinto. Ngakho-ke, isakhiwo esincane sokubumba singathuthukiswa ngezindlela ezimbili: ukupholisa okusheshayo okufanele ngemva kokubumba, kulandelwe ukuvuselela izinga lokushisa eliphezulu kanye nokuvuselela kokugcina kwe-spheroidizing. Ngokusekelwe ekuhlaziyweni kwalezi zibonelo, inqubo engcono kakhulu yasungulwa njengoba kuboniswe kuMfanekiso 3. Ngemva kokubumba, izinto zipholiswa emoyeni futhi zigcinwe ngaphezu kwe-Ms point isikhathi esithile ukuvimbela ukuguqulwa kwe-martensitic, kulandelwe ukuvuselela izinga lokushisa eliphezulu kanye nokuvuselela kwe-isothermal kwe-spheroidizing. Umfanekiso 4 ubonisa isakhiwo esincane esitholwe ngaphansi kwale nqubo entsha, esibonisa ukuguquguquka okukhulu kakhulu ngesilinganiso se-spheroidization esidlula u-95% kanye nosayizi wezinhlamvu cishe webanga lesi-7. Njengoba ihlukaniswe njenge-AS1 ngokwezindinganiso ze-North American Die Casting Association, umkhiqizo uthole impendulo enhle evela kumakhasimende.

4 Isiphetho

1) Ukupholisa kancane kwensimbi ye-H13 ngemuva kokubumba kuholela ekwakhekeni kwemvula efana nenethiwekhi ye-carbide. Uma izinga lokupholisa lihamba kancane, kulapho inethiwekhi ye-carbide iba sobala khona. Nakuba ukuvuselela okulandelayo kungakuthuthukisa lokhu, ezinye izakhiwo ezincane ezingavamile ziyaqhubeka ku-matrix futhi kunzima ukuzisusa. Ngaphezu kwalokho, ukupholisa kancane kuphumela kobukhulu obukhulu obungavamile bokusanhlamvu, obuzuzwe njengefa futhi obuyinselele ukubulungisa kamuva.

2) Ukulungisa izinga lokushisa eliphezulu kuthuthukisa ukuhlukaniswa kanye nama-carbide axhunyiwe akhona esakhiweni esincane sensimbi ye-H13 ngemuva kokubumba. Ngaphakathi nesikhathi esithile, ukuthuthuka kwesakhi esincane kuba sobala kakhulu njengoba isikhathi sokubamba esijwayelekile sanda.

3) Ngemva kokufakelwa, insimbi ye-H13 ipholiswa emoyeni ngaphezu kwezinga lokushisa le-Ms bese ifakwa esimweni sokushisa okuphezulu, okuholela esakhiweni esifana kakhulu nesihlakazekile esine-spheroid enomthelela ongcono kakhulu we-spheroidization.