Yog vim li cas thiab kev daws teeb meem rau Unqualified Zinc Alloy Tuag Castings
Ua rau blistering nyob rau hauv zinc alloy tuag castings:
1. Ua los ntawm qhov: feem ntau yog vim lub stomata thiab shrinkage mechanism, lub stomata feem ntau ncig, thaum lub shrinkage yog feem ntau tsis xwm yeem. (1) Ua rau cov pores: Thaum lub sij hawm txhaws thiab solidification txheej txheem ntawm cov hlau molten, qhov yog generated nyob rau saum npoo los yog sab hauv ntawm lub casting vim yog intrusion ntawm roj. B tawm tsam ntawm cov pa roj tsis hloov pauv los ntawm cov xim. c Cov ntsiab lus roj ntawm cov kua alloy yog siab dhau, thiab cov coagulation precipitates. Cov pa roj hauv cov kab noj hniav, cov roj tsis hloov pauv ntawm cov xim, cov hlau alloy solidifies thiab precipitates, thiab thaum cov pwm tso tawm tsis zoo, nws yuav nws thiaj li nyob twj ywm nyob rau hauv tsim ntawm casting pores. (2) Yog vim li cas rau shrinkage: Thaum lub sij hawm solidification txheej txheem ntawm cov kua hlau, vim lub ntim txo los yog tsis muaj kua hlau cov ntaub ntawv nyob rau hauv lub kawg solidified ib feem, thiab shrinkage qhov. B castings nrog lub thickness tsis sib npaug los yog lub zos overheating ntawm lub castings, uas ua rau qeeb solidification qhov chaw, thiab muaj kev nyuaj siab nyob rau saum npoo thaum lub ntim shrinks. Vim muaj cov pores thiab shrinkage kab noj hniav, thaum cov tuag-casting qhov chaw yog raug rau saum npoo, cov pores yuav nkag mus rau hauv dej. Tom qab pleev xim thiab electroplating yog ci, cov pa hauv qhov pores nthuav los ntawm cua sov; los yog cov dej nyob rau hauv lub pores ua dej vapor thiab nthuav nyob rau hauv ntim, yog li ua rau blistering ntawm lub casting nto.
2. Kev puas tsuaj impurities nyob rau hauv intergranular corrosion ntawm zinc alloy muaj pes tsawg leeg: txhuas, cadmium, tin yuav sib sau ua ke nyob rau hauv lub grain ciam teb ua rau intergranular corrosion, intergranular corrosion thiab tawg hlau matrix thiab txheej, accelerate qhov kev puas tsuaj, intergranular corrosion nyob rau hauv cheeb tsam yuav nthuav. Npog sab saum toj, ua rau blistering ntawm qhov chaw ntawm casting. Tshwj xeeb tshaj yog nyob rau hauv ib puag ncig humid, intergranular corrosion tuaj yeem deform, tawg, thiab txawm tawg castings.
3. Reasons for cracks: water, cold separation, hot cracks. 1) Water, cold grain separation: During the filling process, the molten metal enters the first contact wall and solidifies prematurely, and then the solidification of the liquid metal and the metal can be integrated into one, and the moiré in the form of joints on the surface of the casting , a stripe defect occurs. The water is generally shallow on the surface of the casting; and the cold barrier may penetrate into the interior of the casting. 2) Hot cracks: When the wall thickness of the casting is uneven, the stress produces a solidification process; B is pushed out prematurely, and the metal strength is not enough; C, the mold temperature with uneven pushing force is high, and the grains are coarse; E The existence of harmful impurities. These parameters may be cracked. When there are water lines, cold separation lines, and hot cracks in the die casting, the plating solution will penetrate into the cracks, which will be transformed into steam baking, and the top-deposited metal will form blisters.
Kev daws rau qhov tsis xws ntawm zinc alloy tuag castings:
1. Kev tswj cov txheej txheem porosity: Qhov tseem ceeb yog txo cov roj sib xyaw hauv cov casting. Cov hlau zoo tshaj plaws yuav tsum tsis tu ncua nrawm lub nozzle thiab nkag mus rau hauv kab noj hniav los ntawm shunt lub khob hliav qab thiab cov neeg khiav dej num los tsim cov hlau ntws zoo. Conical runner tsim yog saws. Ntawd yog, cov dej ntws yuav tsum txuas ntxiv kom nrawm lub nozzle mus rau lub qhov rooj thiab maj mam txo, uas tuaj yeem ua tiav lub hom phiaj no. Nyob rau hauv lub filling system, cov roj sib tov yog tsim los ntawm turbulent flow thiab cov kua hlau theem tsim pores, thiab lub rooj vag system nkag mus rau hauv lub kab noj hniav kom simulate cov kua hlau thaum lub sij hawm tuag casting txheej txheem. Obviously, zoo heev ua rau kev hloov pauv ntawm lub rooj vag khiav tuaj yeem ua rau cov hlau ua kua dej turbulent. Thaum nkag mus rau cov pa roj, cov kua hlau yog du, uas yog qhov zoo rau cov roj nkag mus rau hauv lub qhov dej ntws tawm thiab lub qhov tso pa tawm ntawm lub qhov rooj thiab cov kab noj hniav, thiab raug tshem tawm ntawm cov pwm.
2. Shrinkage: Ua kom tag nrho cov seem ntawm zinc alloy tuag casting thiab solidification txheej txheem kom deb li deb tau thaum dissipating tshav kub tusyees thiab solidifying nyob rau tib lub sij hawm. Los ntawm tsim nyog nozzle tsim, pwm tsim, rooj vag thickness thiab qhov chaw, pwm tswj kub thiab txias kom tsis txhob shrinkage. Rau intergranular corrosion tshwm sim: cov ntsiab lus impurity tseem ceeb tswj cov khoom siv phom sij, tshwj xeeb tshaj yog cov hlau lead<0.003%. pay="" attention="" to="" waste="" and="" impurity="">
3. Dej, txias muab faib: Nws tuaj yeem ua rau pwm kub, ua kom lub rooj vag nrawm, lossis ua kom cov dej ntws tawm hauv qhov chaw txias txias kom txo tau qhov txias txias thiab kaw cov nplej.
4. Kub tawg: Lub thickness ntawm zinc alloy tuag castings tsis hloov sai, txo cov tiam ntawm kev ntxhov siab; tuag casting txheej txheem tsis thiab hloov kho; txo cov pwm kub.
