Inqubo yokukhomba yokwelashwa kokushisa kweziphethu ezinkulu zobubanzi obunomshini omkhulu wokwenza lukhuni imvamisa

Iziphethu ezinobubanzi obukhulu zenziwa ngamakhoyili ashisayo. Njengoba iziphethu zamaphayiphu amakhulu, kufanele zimelane nokunwebeka okuphindaphindiwe nokucindezelwa ngesikhathi sokusebenza. Ngakho-ke, kufanele babe namandla okuqina nokunethezeka. Izindlela zokwehluleka kwentwasahlobo ikakhulu ukuphuka kokukhathala nokuphumula kwengcindezi, futhi cishe ama-90% emithombo ayiphumeleli ngenxa yokwephuka kokukhathala. Ngokuya ngezimo zayo zensiza, kufanele kukhethwe insimbi yasentwasahlobo engu-50CrVA enokuqina okuhle, ukusikeka okuncane nezakhiwo ezinhle zomshini. Ngemuva kokuqeda + ukushisa okuphakathi okushisa nge umshini wokwenza lukhuni imvamisa ephezulu, ingahlangabezana ngokugcwele nezidingo zayo zomsebenzi. Namuhla, ngizokutshela ngenqubo yokwelashwa kokushisa okuphezulu kakhulu.

(1) Inqubo yokwelashwa ngokushisa

a. Intwasahlobo ngaphambi kokugingqika yenziwa ngezinto ezihuqayo, kanti ukufudumeza kwentwasahlobo kwenziwa ngomshini oqinisa imvamisa ephezulu. Inezici zesikhathi esifushane sokushisa nezinhlamvu ezinhle ze-austenite. Ngenxa yezinhlamvu ezinhle ze-austenite, umzimba wenyama uyakhuphuka. Inani lezinhlamvu zesakhiwo nendawo yemingcele yokusanhlamvu kunciphisa ukugxila kwengcindezi futhi kwandise ukumelana nokunyakaza kwe-dislocation. Ukushisa okushisa kungu (900 ± 10) ℃. Ngalesi sikhathi, amandla okushisa okuphezulu kwempahla kanye neplastiki enhle asetshenziselwa ukwenza ukugoqa kube lula. Kodwa-ke, ukushisa kokushisa akufanele kube phezulu kakhulu noma isikhathi sokubamba side kakhulu, ngaphandle kwalokho okubalulekile kuzofudumeza ngokweqile noma ngaphezulu kwe-Oxidation kanye ne-decarburization kungahle kuholele ekuqothulweni nasekuqothulweni.

b. Ukucima + ukufudumala ezingeni lokushisa eliphakathi nendawo. Ukushisa kwenziwa emshinini wokuqina onzima kakhulu, izinga lokushisa lokushisa lingu-850-880 ℃, i-coefficient yokulondolozwa kokushisa ibalwa ku-1.5min / mm, ngokususelwa ekudubuleni, indawo yokupholisa inethonya elibalulekile ebukhuni futhi ukusebenza kwentwasahlobo, nokupholisa uwoyela kungakhethwa. Hlangana nezidingo zenqubo.

c. I-Tempering yenziwa futhi ngomshini wokuqeda imvamisa ephezulu. Ngokuya ngezidingo zobulukhuni, ubukhulu kanye negebe, sebenzisa isici se-tempering esikhethekile ukulungisa nokubeka kahle. Ukushisa okushisa kungu-400-440 ℃, futhi amanzi apholile ngemuva kokulondolozwa kokushisa. Izinga lokushisa lokushisa lemithombo evamile ngokuvamile liyi-400-500 ℃, futhi amandla aphezulu okukhathala angatholakala ngemuva kokubila.

(2) Amaphuzu wokuhlaziya nokwenziwa kwenqubo yokwelashwa kokushisa kwentwasahlobo

① Ngoba insimbi engu-50CrVA inezakhi eziningi zokuxubana, ukuqina kwensimbi kuyathuthukiswa. I-Chromium iyinto eqinile ye-carbide, futhi ama-carbide awo akhona eduze komngcele wokusanhlamvu, ngakho-ke ingavimbela ngempumelelo ukukhula kwezinhlamvu, ngakho-ke ithuthukiswe ngokufanele ukushisa kwamazinga okushisa futhi ukwelula isikhathi sokubamba ngeke kubangele ukukhula kwezinhlamvu ze-crystal.

Ngenqubo yokufudumeza yemithombo yamakhoyili ashisayo, kufanele kubhekwe ebudlelwaneni obuphakathi kwe-decarburization yendawo nokucima ukushisa kokushisa nesikhathi. Ukuzijwayeza kukhombisile ukuthi izinga lokushisa eliphakeme lokuqeda nesikhathi sokushisa eside kuzobangela ukuthi i-decarburization ikhuphuke. Ngakho-ke, lapho umshini wokuqeda imvamisa ephezulu usetshenziselwa ukufudumeza, imingcele yenqubo kufanele ilawulwe ngokuqinile. Ngaphezu kwalokho, ukumboza noma ukupakisha ukuvikela ukushisa kungasetshenziswa ukunciphisa i-oxidation kanye ne-decarburization ebusweni. Kunemibhalo yokuthi ukwehliswa komhlaba kwentwasahlobo kunciphisa impilo yenkonzo yayo, futhi kulula ukuba ngumthombo wemifantu yokukhathala.

TemperatureUkushisa okuphakathi nendawo kwentwasahlobo ukuthola ukwakheka kwe-microstructure nokusebenza. Uma ucabanga ukuthi insimbi engu-50CrVA yinto ekhiqiza ukuthukuthela kwesibili, kufanele ipholile ngokushesha (ukupholisa uwoyela noma amanzi) ngemuva kokushisa ukuvimbela ukuthukuthela (kubangele ukuqina komthelela wayo kuncishisiwe), futhi kungadala ukucindezelwa okusalile ebusweni, okuzuzisa ukuthuthukisa amandla okukhathala. Imvamisa, kusetshenziswa ukupholisa amanzi esikhundleni sokupholisa uwoyela. Isakhiwo ngemuva kwe-tempering siyi-troostite enomoya onobunzima be-40-46HRC. Inokunwebeka okuhle namandla anele nobulukhuni. Ngaphezu kwalokho, uma isikhathi se-tempering sifushane kakhulu, ukwakheka okufanayo nokusebenza kungatholakali, futhi ukusebenza kungathuthukiswa uma isikhathi siside kakhulu. Ngakho-ke, ukuhlolwa kwenqubo kufanele kwenziwe ukuthola isikhathi esifanele.