scholarly journals Quantitative Prediction Method for Shrinkage Porosity Considering Molten Metal Supply by Pressure in Squeeze Casting

2007 ◽  
Vol 48 (8) ◽  
pp. 2186-2193 ◽  
Author(s):  
Shaomin Li ◽  
Kenichiro Mine ◽  
Shinji Sanakanishi ◽  
Koichi Anzai
Keyword(s):  
Molten Metal ◽  
Squeeze Casting ◽  
Prediction Method ◽  
Shrinkage Porosity ◽  
Quantitative Prediction

Effects of the Profile of Workpiece Surface on Material Removal Rate Distribution in Polishing Process

2016 ◽  
Vol 851 ◽  
pp. 149-154
Author(s):  
Zhen Gang Wu ◽  
Dong Shan He ◽  
Ping Zhou ◽  
Dong Ming Guo
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Profile ◽  
Prediction Method ◽  
Quantitative Prediction ◽  
Polishing Process ◽  
Workpiece Surface ◽  
Coefficient Distribution ◽  
Polishing Pad

Accurate prediction of the material removal rate (MRR) distribution is very important for the control of the polishing process. However, the widely used prediction method of MRR based on the Preston equation is still incapable of predicting the roll-off phenomenon in polishing process. One of the reasons is that many of the researchers’ neglected the effect of the surface profile of the workpiece on the MRR. In this paper, the evolutionary process of MRR distribution with the change of surface profile using two different polishing pad is studied, it is found that MRR varies gradually with the change of surface profile and tends to be uniform finally. Based on the analysis of contact pressure considering the actual surface profile of workpiece and modified Preston equation, the distribution of MRR is analyzed. It is found that the Preston coefficient distribution on workpiece surface is stable when the surface profile variation is small and shows obvious differences from the center to the edge of the workpiece. Through the comparison it is found that correlation between the regularities of Preston coefficient distribution and the type of polishing pad is significant. The research results in this paper will play an important guiding role in the quantitative prediction method research of polishing process.

scholarly journals Experimental Investigation and Optimization of the Semisolid Multicavity Squeeze Casting Process for Wrought Aluminum Alloy Scroll

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5278
Author(s):  
Yi Guo ◽  
Yongfei Wang ◽  
Shengdun Zhao
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Squeeze Casting ◽  
Shrinkage Porosity ◽  
Optimal Process ◽  
Squeeze Pressure ◽  
Wrought Aluminum

Scroll compressors are popularly applied in air-conditioning systems. The conventional fabrication process causes gas and shrinkage porosity in the scroll. In this paper, the electromagnetic stirring (EMS)-based semisolid multicavity squeeze casting (SMSC) process is proposed for effectively manufacturing wrought aluminum alloy scrolls. Insulation temperature, squeeze pressure, and the treatment of the micromorphology and mechanical properties of the scroll were investigated experimentally. It was found that reducing the insulation temperature can decrease the grain size, increase the shape factor, and improve mechanical properties. The minimum grain size was found as 111 ± 3 μm at the insulation temperature of 595 °C. The maximum tensile strength, yield strength, and hardness were observed as 386 ± 8 MPa, 228 ± 5 MPa, and 117 ± 5 HV, respectively, at the squeeze pressure of 100 MPa. The tensile strength and hardness of the scroll could be improved, and the elongation was reduced by the T6 heat treatment. The optimal process parameters are recommended at an insulation temperature in the range of 595–600 °C and a squeeze pressure of 100 MPa. Under the optimal process parameters, scroll casting was completely filled, and there was no obvious shrinkage defect observed inside. Its microstructure is composed of fine and spherical grains.

Study of Quantitative Numerical Prediction of Cavitation Erosion in Cavitating Flow

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Naoya Ochiai ◽  
Yuka Iga ◽  
Motohiko Nohmi ◽  
Toshiaki Ikohagi
Keyword(s):  
Erosion Rate ◽  
Cavitation Erosion ◽  
Prediction Method ◽  
Cavitating Flow ◽  
Quantitative Prediction ◽  
Bubble Collapse ◽  
Coupled Analysis ◽  
Material Surface ◽  
Two Phase ◽  
Navier Stokes Equation

Cavitation erosion is a material damage phenomenon caused by the repeated application of impulsive pressure on a material surface induced by bubble collapse, and the establishment of a method by which to numerically predict cavitation erosion is desired. In the present study, a numerical quantitative prediction method of cavitation erosion in a cavitating flow is proposed. In the present method, a one-way coupled analysis of a cavitating flow field based on a gas-liquid two-phase Navier–Stokes equation (Eulerian) and bubbles in the cavitating flow by bubble dynamics (Lagrangian) is used to treat temporally and spatially different scale phenomena, such as the macroscopic phenomenon of a cavitating flow and the microscopic phenomenon of bubble collapse. Impulsive pressures acting on a material surface are evaluated based on the bubble collapse position, time, and intensity, and the erosion rate is quantitatively predicted using an existing material-dependent relationship between the impulsive energy (square of the impulsive force) and the maximum erosion rate. The erosion rate on a NACA0015 hydrofoil surface in an unsteady transient cavitating flow is predicted by the proposed method. The distribution of the predicted erosion rate corresponds qualitatively to the distribution of an experimental surface roughness increment of the same hydrofoil. Furthermore, the predicted erosion rate considering the bubble nuclei distribution is found to be of the same order of magnitude as the actual erosion rate, which indicates that considering bubble nuclei distribution is important for the prediction of cavitation erosion and that the present prediction method is valid to some degree.

Filling Characteristics of Magnesium Alloy Molten Metal in Squeeze Casting

2012 ◽  
Vol 502 ◽  
pp. 335-341
Author(s):  
Yun Chen ◽  
Ding Fang Chen ◽  
Juan Du ◽  
Ji Xiang Luo
Keyword(s):  
Magnesium Alloy ◽  
Fluid Mechanics ◽  
Molten Metal ◽  
Wall Thickness ◽  
Squeeze Casting ◽  
Air Entrainment ◽  
Filling Process ◽  
Fluid Level ◽  
Filling Characteristics

Based on fluid mechanics, the filling process of magnesium alloy step-plate casting molten metal was analyzed, and the filling characteristics were studied by numerical simulating. The results show the filling velocity and the wall thickness of casting have a great effect on the filling characteristics of magnesium alloy. When the filling velocity is less than 0.3 m/s, the liquid frontier of molten metal and the fluid level of thick upper surface fluctuate greatly, and the defects of air entrainment and oxide impurities will appear. When the filling velocity is more than 0.58 m/s, the molten metal fills in turbulent way, and the defects of sputter and air entrainment will appear. The correlation between the wall thickness of casting and the critical filling velocity presented in this paper can be used for the optimization of filling velocity.

Effect of Runner Distance on Microstructure and Properties of Semi-Solid Squeeze Casting CuSn10P1 Alloy

2022 ◽  
Vol 327 ◽  
pp. 156-162
Author(s):  
Yong Kun Li ◽  
Pei Lin Cai ◽  
Zhi Long He ◽  
Rong Feng Zhou ◽  
Lu Li ◽  
...  
Keyword(s):  
Squeeze Casting ◽  
Solid Phase ◽  
High Strength ◽  
Shrinkage Porosity ◽  
Microstructure And Properties ◽  
Shrinkage Defects ◽  
Porosity Defects ◽  
Semi Solid ◽  
Slope Channel ◽  
Better Than

It is easy to form reverse segregation and shrinkage porosity defects during the solidification of CuSn10P1 alloy, which leads to the poor properties and limits its application in high strength and toughness parts. In this paper, semi-solid CuSn10P1 alloy slurry was prepared by enclosed cooling slope channel (for short ECSC). The effect of runner distance on microstructure and properties by liquid squeeze casting and semi-solid squeeze casting was studied. The results showed that the microstructure of semi-solid squeeze casting is finer than that of liquid squeeze casting, and the shrinkage defects are improved. The solid fraction with 65 mm runner is lower than that without runner in liquid squeeze casting and semi-solid squeeze casting due to the retention effect of solid phase in semi-solid slurry flow, but the properties with 65 mm runner is better than that without runner. The ultimate tensile strength, yield strength and elongation of semi-solid squeeze casting CuSn10P1 alloy with 65 mm runner distance reached 466.5 MPa, 273.6 MPa and 13.4%, which were improved by 26%, 19% and 97%, respectively, as compared to that of liquid squeeze casting.

Effect of Squeeze Casting and Solution Treatment on the Microstructure and Properties of ZA27 Worm Wheel

2015 ◽  
Vol 817 ◽  
pp. 63-70
Author(s):  
Quan Li Zhu ◽  
Zi Yong Wu ◽  
Jia Jian Chen
Keyword(s):  
Mechanical Properties ◽  
Friction And Wear ◽  
Squeeze Casting ◽  
Solution Treatment ◽  
Shrinkage Porosity ◽  
Solution Temperature ◽  
Permanent Mold ◽  
Za27 Alloy ◽  
Mold Casting ◽  
Ε Phase

Compared with permanent mold casting, the microstructure, mechanical properties, friction and wear of squeeze casting ZA27 alloy were studied. The results showed that squeeze casting can reduce or eliminate shrinkage porosity defect, refine or improve the microstructure and the shape and distribution of copper-rich ε phase which leads to the obvious improvement of the performance. In addition, with the increase of solution temperature, higher degree of super-saturation can enhance the tensile strength and hardness of ZA27 alloy. The better deformation coordination is an important factor to the enhancement of elongation. Remelting among grain boundaries leads to the deterioration of performance rapidly.

scholarly journals Quantitative Prediction Method for Distribution Power Grid Risk

2021 ◽  
Vol 236 ◽  
pp. 01014
Author(s):  
Tang Xuesong ◽  
Wu Bin ◽  
Yu Guangming ◽  
Zou Jianwei ◽  
Zhou Han ◽  
...  
Keyword(s):  
Bp Neural Network ◽  
Power Distribution ◽  
Learning Algorithm ◽  
Prediction Method ◽  
Principal Component ◽  
Quantitative Prediction ◽  
Distribution Grid ◽  
Value Prediction ◽  
Electric Power Distribution ◽  
The Status

The electric power distribution grid is directly oriented to the majority of the ordinary users. Traditional operation and maintenance are performed mainly based on experience, which disable to rationally evaluate the status of the line and predict faults. Based on big data, the risk of the line is evaluated through principal component analysis in this paper, so that a machine learning algorithm is carried out to calculate the risk value of the distribution grid line unit. Finally, GA-BP neural network is used to build a line risk value prediction model for improvement.

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