Zeziphi izinto ezibangela iziphene zokuqhekeka kwentsimbi?

Ukwenzeka kweziphene zokuqhekeka kwiindawo zentsimbi etyhidiweyo yingxaki eqhelekileyo kwaye entsonkothileyo, ebandakanya yonke ikhonkco lemveliso ukusuka kwi-smelting, inkqubo yokuphosa ukuya kunyango olulandelayo. Iintanda zibangelwa ngokusisiseko luxinzelelo lwangaphakathi (ikakhulukazi i-thermal kunye noxinzelelo lwe-shrinkage) oludlula umda wamandla wezinto kwiqondo lokushisa.

Ngokuqhelekileyo, iintanda zahlulwe zibe ngamacandelo amabini: iintanda ezishushu kunye neentanda ezibandayo.

I-1, Ukuqhekeka okutshisayo kwenzeka kwinqanaba lokugqibela okanye kungekudala emva kokuqiniswa kwentsimbi etyhidiweyo, xa isinyithi sikwimeko yokuhlalisana okuqinileyo kunye namandla aphantsi kunye neplastiki. Ubushushu bokwenzeka: ngokuqhelekileyo kufutshane nomgca we-solidus (malunga ne-1300-1450 ° C). Iimpawu: Icandelo lokuqhekeka lixutywe kakhulu, libonakala limnyama okanye liluhlaza okwesibhakabhaka, linesimo esibuhlungu kunye nesingaqhelekanga.

owona nobangela:

1. Uyilo lolwakhiwo lwee-castings: Umahluko ogqithisileyo kubunzima bodonga kunye notshintsho olungalinganiyo kunxibelelwano lubangela ukupholisa okungalinganiyo kunye noxinzelelo olukhulu lobushushu.

2. Uyilo olungekho ngqiqweni lwesixokelelwano sokugalela: I-sprue igxininiswe kakhulu okanye ibekwe ngendlela engafanelekanga, okukhokelela ekushiseni okugqithisileyo kwendawo, ethi ekugqibeleni iqine kuloo ndawo.

Ayikwazi ukufumana ucinezelo kunye nenkxaso.

3. Ukuhlehla okungalunganga kwe-sand mold / core: Amandla obumba besanti aphezulu kakhulu, okuthintela ukushwabana kwawo simahla ngexesha lokugalela ukuqina kunye nokuncipha, okukhokelela kuxinzelelo kunye nokuqhekeka. Esi sisizathu esixhaphake kakhulu.

4. Ukwakhiwa kweekhemikhali ze-alloy: Umxholo ophezulu wezinto ezinobungozi ezifana ne-sulfure (S) kunye ne-phosphorus (P): Zenza i-sulfides ephantsi yokunyibilika kunye ne-phosphides, zenze iifilimu ezinqabileyo ezinolwelo kwimida yeenkozo, zinciphisa kakhulu amandla okudibanisa i-intergranular, kwaye zizinto ezibaluleke kakhulu ezikhokelela ekuqhekekeni kwe-thermal. Umxholo weCarbon (C): Ngomxholo ophezulu wekhabhoni, uluhlu lweqondo lokushisa oluqinisiweyo luba banzi, i-dendrites iba yi-coarse, kwaye kukho ukuthambekela okwandisiweyo kokuqhekeka kwe-thermal. 5. Ukusetyenziswa ngendlela engafanelekanga kwesikhuphukeli kunye nentsimbi yokupholisa: Ukuba intamo yokunyuka ide kakhulu okanye imfutshane kakhulu, kwaye intsimbi yokupholisa ayibekwanga kakuhle, iya kwandisa ukupholisa okungalinganiyo.

2、 Ukuqhekeka okubandayo kwenzeka emva kokuba ukuphosa kuqiniswe ngokupheleleyo kwaye kupholile kwimo enwebekayo, ngokuqhelekileyo kwinqanaba eliphantsi lobushushu obungaphantsi kwe-600 ° C. Iqondo lokushisa: ubushushu obuphantsi. Iimpawu: Icandelo lokuqhekeka licocekile, licwebezela ngesinyithi okanye umbala oxidation omncinci, kwaye ukuqhekeka kuthe tye kwaye kuyaqhubeka kumgca othe tye.

owona nobangela:

1. Uxinzelelo olugqithisiweyo lokuphosa: Uxinzelelo lwe-thermal: olubangelwa ngamazinga okupholisa angahambelaniyo kwiindawo ezahlukeneyo zokuphosa. Uxinzelelo lwe-Shrinkage: Imiqobo ye-Mechanical ekulahlekeni kwe-shrinkage ebangelwa yi-molds, i-sand cores, iinkqubo ze-sprue, kunye nokumisa ibhokisi. Uxinzelelo lwenguqu: Uxinzelelo olubangelwa utshintsho kumthamo othile ngexesha lenkqubo yokupholisa xa kukho ukuguqulwa kwesakhiwo (njenge-austenite yokuguqulwa kwi-martensite).

2. Umgangatho we-Metallurgical wensimbi: Umxholo ophezulu wegesi, ngakumbi i-hydrogen (H), inokubangela "i-hydrogen induced cracking" kunye nokunciphisa ukuqina kwezinto. Kukho izinto ezininzi ezingenayo i-metallic inclusions: njengeendawo zokuxininisa uxinzelelo, ukufakwa kunokunciphisa kakhulu amandla kunye nokuxhatshazwa kwe-crack yezinto.

3. Ukufakwa kwesanti kwangaphambi kwexesha ngexesha lomdlalo wamanqindi: Ukuphosa ayikapholiswa ukuya kwiqondo lobushushu eliphantsi ngokwaneleyo, kwaye uxinzelelo lwangaphakathi alupheli ngokupheleleyo phambi kokuba ukungcangcazela kwangaphambi kwexesha kunye nesanti kunokubangela lula ukuqhekeka okubandayo.

4. Inkqubo yonyango lobushushu obungafanelekanga: Ukufudumeza okugqithisileyo okanye izinga lokupholisa: Ngokukodwa ngexesha lokuxilisa kunye nonyango oluqhelekileyo, ukuba ukufudumeza okanye ukupholisa akulingani, kuya kuvelisa uxinzelelo olukhulu lonyango lobushushu, oluya kugxininisa uxinzelelo lwangaphambili lokuphosa kwaye lubangele ukuqhekeka.

Ukucima i-crack: Olu luhlobo olukhethekileyo lokuqhekeka okubandayo, okwenza i-martensite ephezulu yokuqina ngenxa yesantya sokupholisa ngokukhawuleza sokucima, sikhatshwa luxinzelelo olukhulu lwesakhiwo, okwenza kube lula kakhulu ukuqhekeka.

Isishwankathelo kunye nemibono yesisombululo

Xa iintanda zifunyenwe kwiindawo zentsimbi, izizathu kufuneka ziphandwe ngokucokisekileyo kule miba ilandelayo:

1. Ukwakhiwa kweekhemikhali: Lawula ngokungqongqo umxholo wezinto ezinobungozi ezifana ne-S kunye ne-P.

2. Inkqubo yokunyibilika: Iindlela zokucoca zisetyenziselwa ukunciphisa umxholo weegesi kunye nokufakwa kwintsimbi etyhidiweyo. 3. Isakhiwo sokuphosa: Lungiselela uyilo ukunqanda utshintsho olukhawulezileyo kubunzima bodonga kunye nokusebenzisa iinguqu ezijikelezileyo.

4. Inkqubo yokuphosa: i-sprue kunye nenkqubo yokunyuka: Yenzelwe ngokufanelekileyo ukufezekisa ukuqiniswa okulandelelanayo okanye ukuqina kwangaxeshanye, ukuphepha ukufudumala kwendawo. Isanti yokubumba/isanti engundoqo: Qinisekisa isivuno esaneleyo kunye nokubola. Intsimbi ebandayo kunye nesikhuphukeli: Ukusetyenziswa ngokufanelekileyo ukulawula ulandelelwano lokupholisa.

5. Ukususwa nokucocwa kwesanti: Qinisekisa ukuba iicastings zipholiswe kwiqondo lobushushu elisezantsi ngokwaneleyo (elifana nelingaphantsi kwe-400 ° C) kumngundo wesanti phambi komdlalo wamanqindi. Xa usika izikhuphukeli kunye nokulungiswa kwe-welding, kuyafuneka ukuba ugweme ukuvelisa uxinzelelo olutsha.

6. Inkqubo yonyango lobushushu: Phuhlisa inkcazo yonyango olufanelekileyo lobushushu, ngakumbi lawula amazinga okufudumeza kunye nokupholisa. Kwiindawo ezintsonkothileyo okanye iinxalenye zentsimbi ephezulu, thatha inyathelo lokufudumeza kunye nendlela yokupholisa kancinci.

Ukucacisa ngokuchanekileyo isizathu esithile, kudla ngokuyimfuneko ukudibanisa i-macroscopic kunye ne-microscopic morphology analysis of cracks (uviwo lwe-metallographic), ukuhlaziywa kwenkqubo, kunye nohlalutyo lokubunjwa kweekhemikhali ukwenza isigwebo esibanzi.