共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
Laihua Wang Thang Nguyen Gary Savage Cameron Davidson 《International Journal of Cast Metals Research》2013,26(4):409-417
Air entrapment and premature solidification in the shot sleeve of the cold chamber high pressure die casting process are problems affecting the casting quality. These issues are addressed from several viewpoints, including heat loss during metal ladling, turbulence generation and gas escape during pouring, wave formation and propagation during metal pouring and injection, and heat loss and solid creation in the shot sleeve during metal injection. Measurements and simulations have been conducted for a typical industrial case where the fill ratio of the shot sleeve is about 30%. It has been found that the settling time of the aluminium alloy in the shot sleeve has a profound influence on the air entrapment. The settling time also has a negative effect on the metal quality the solid formation (premature solidification or cold flakes) in the shot sleeve. Fast pouring and quick injection (no settling time) are recommended as a good approach to minimise the air entrapment and cold flakes in the shot sleeve in this particular case. IJCMR/474 相似文献
3.
1 INTRODUCTIONIndiecastingprocess,thediesexperiencease riesofcomplicatechanges.Thetemperatureonthecavitysurfacesofdiesincreasesrapidlyduetocontact ingandwashingbetweenthemoltenmeltanddies,andthehot yieldstrengthincontactzoneofthecavi tyisreducedrapidly .I… 相似文献
4.
1. IntroductionDie castings are widely used because of their highstrength and good performance. Die casting is oftenapplied in magnesium-aluminum alloys, especially forthose thin-walled components with complicate shape,because of their excellent casting ability [1].Die casting is a complex process containing severalstages. Considering the design of the vent gate and overflowin the mold, Garber simulated the tilling process [2,3]. Andhe considered the changes of melt when cast using aplunger. … 相似文献
5.
Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process(HPDC), the B390 alloy finger-plate casting was cast against an H13 steel die on a cold-chamber HPDC machine. The interfacial heat transfer behavior at different positions of the die was carefully studied using an inverse approach based on the temperature measurements inside the die. Furthermore, the filling process and the solidification rate in different finger-plates were also given to explain the distribution of interfacial heat flux(q) and interfacial heat transfer coefficient(h). Measurement results at the side of sprue indicates that qmax and hmax could reach 9.2 MW·m~(-2) and 64.3 kW ·m~(-2)·K~(-1), respectively. The simulation of melt flow in the die reveals that the thinnest(T_1) finger plate could accelerate the melt flow from 50 m·s~(-1) to 110 m·s~(-1). Due to this high velocity, the interfacial heat flux at the end of T_1 could firstly reach a highest value 7.92 MW·m~(-2) among the ends of T_n(n=2,3,4,5). In addition, the q_(max) and h_(max) values of T_2, T_4 and T_5 finger-plates increase with the increasing thickness of the finger plate. Finally, at the rapid decreasing stage of interfacial heat transfer coefficient(h), the decreasing rate of h has an exponential relationship with the increasing rate of solid fraction(f). 相似文献
6.
The modelling of high pressure die casting using SPH is extended to three dimensions. This increases the complexity of the geometry specification and the visualisation, but not of the simulation method. Filling of four simple die/gate combinations is presented. The dies range from a rectangular cavity to a simple machinery component. 相似文献
7.
8.
9.
In this paper,the research progress of the interfacial heat transfer in high pressure die casting(HPDC)is reviewed.Results including determination of the interfacial heat transfer coefficient(IHTC),influence of casting thickness,process parameters and casting alloys on the IHTC are summarized and discussed.A thermal boundary condition model was developed based on the two correlations:(a)IHTC and casting solid fraction and(b)IHTC peak value and initial die surface temperature.The boundary model was then applied during the determination of the temperature field in HPDC and excellent agreement was found. 相似文献
10.
Temperature change and stress distribution analysis of die surface in Al-alloy die casting process and experimental study on die heat check 总被引:1,自引:0,他引:1
The temperature change of the die surface in practical aluminum alloy die casting process was analyzed, and a 2D model was formulated on the basis of a deep concave round cavity without sliding core to analyze the stress distributions along the die surface in detail. Equipment was designed to test the thermal state of the die steel in different thermal loading conditions. The results of stress analysis showed that, the value of thermal stress (maximum 1.5 GPa) caused in the die filling and die spraying stages was larger than the mechanical stress (maximum 85 MPa) caused in the die locking stage. The results of the thermal check experiment showed that there were three stages of die dissolving, and that the stress distribution shown by the samples' cracking routine was close to the die surface stress analysis. 相似文献
11.
12.
铝合金轮毂压铸模温度场数值分析 总被引:2,自引:2,他引:0
运用有限元分析软件ProCAST对压铸模进行了压铸过程模具温度场分析,研究了模具预热温度、浇注温度对模具温度场的影响。结果表明,模具型腔表面温度受金属液充填的影响较大,距型腔表面距离超过20mm后,模具温度受金属液的影响较小。模具预热温度影响模具内的温度梯度和升温速率,预热温度越高,型腔表面升温速率越小,模具内的温度梯度越小。浇注温度越高,模具型腔表面的升温幅度和升温速率越大。 相似文献
13.
14.
15.
16.
介绍了一副在卧式冷室压铸机上使用的二次分型、一模多腔点浇口压铸模。浇注系统的布置及模具结构可使浇注系统自行脱落,通过理论计算确定了浇注系统的相关参数。 相似文献
17.
给出了微电机转子实用的模具结构和压铸工艺,论述了模具的设计要点.采用镶块、镶套结构,不仅节省模具钢,而且改善了模具的排气性,提高了产品的质量. 相似文献
18.
During high-pressure die-casting (HPDC) of aluminium alloys, there is a tendency for the molten alloy to react with the tool steel die, core pins and inserts. This occurrence within the high pressure die casting (HPDC) industry is referred to as ‘soldering’. It is of concern to high-pressure die casters because of down-time due to the regular removal of the soldered layer and its detrimental affect on die life and casting quality. In this investigation, several physical vapour deposited (PVD) coatings, namely, TiN, CrN and TiCN, were evaluated for their ability to eliminate soldering during HPDC of aluminium alloys. Accelerated semi-industrial trials were carried out in a 250-t Toshiba HPDC machine using a specially designed die made of P20 tool steel with removable core pins. The results from these trials showed that PVD coatings can act as a physical barrier coating preventing any reaction between the molten aluminium alloy and the tool steel. Thus the problem of soldering on such tools as core pins can be eliminated in high HPDC of aluminium alloys. In the accelerated trials, it was found that soldering was replaced by a built-up layer of cast aluminium alloy, which was less detrimental to tool life and reduced machine down-time due to the reduced need for tool polishing. The experimental results were confirmed by conducting in-plant HPDC trials. 相似文献
19.
20.
覆砂金属型工艺设计及其数值模拟 总被引:1,自引:0,他引:1
论述了覆砂金属型铸造工艺及其传热机理,对其数值模拟技术进行了分析,并利用ANSYS软件模拟了球铁曲轴的覆砂金属型铸造温度场,确定了其工艺参数. 相似文献