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Numerical simulation and optimization technology of Lost foam casting Hong-ze CHEN 1,a, Hong-zhao DONG 2, b, Zhong-de SHAN 3, c 1,2College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China 3 China academy of machinery science and technology, Beijing, 100044, China a chenhongze110@sina.com, b its@zjut.edu.cn (Corresponding author) c shanzd@cam.com.cn, Keywords: Numerical Simulation, Lost Foam Casting (LFC), Defect Analysis, Process Optimization Abstract: The filling and solidification process of casting that is closely related to lots of casting defects and has significant effect on the mechanical properties of castings.
The filling and solidification process can be studied qualitatively and semi quantitatively by computer numerical simulation technology without restriction on the experimental condition, various influencing factors of the casting defect can be found and analyzed, it is significant to both the development of LFC process theory and the guidance of practical production [3, 4, 5].
The mainly influencing factors of filling and solidification process of LFC are given in figure 2: (1) The gas evolution and chemical reaction of different density of the foam pattern materials are diverse. (2) The air permeability and strength of the coating is vital. (3) The quality of the castings would be affected by different pouring way, sprue-runner-gate area ratio, pouring rate and pouring temperature. (4) Also the vacuum degree, the breathability of the molding sand and the molten metal material are crucial. 3D modeling Influencing factors Meshing Disqualified Checking Casting material Molding sand Vacuum degree Gating system Coating Foam material Qualified Parameter setting Sprue-runner-gate area ratio Pouring temperature Pouring rate Pouring way Computation Results Fig. 1 Simulation flow chart Fig. 2 Influencing factors of LFC simulation The fundamental key points of an effective numerical simulation of LFC
How different alloy materials, pouring system affect the filling and solidification process of LFC and how to choose the optimum casting parameters were given by J.H.
Because of the coexistent of liquid and solid metal, the mechanical property of the castings is hard to measure during the simulation process and still the proper mechanical model can't be completely established.

This mainly depends on several factors, such as material properties, processing parameters, and cooling conditions.
Introduction Surface hardening is a heat treatment process aimed to enhance mechanical properties of materials, particularly by increasing surface hardness and wear resistance without affecting the core of material.
For that, the effects of laser power (W), scanning speed (mm/s), number of passes and type of laser source technology will be investigated in relation to the depth and mechanical properties of the hardened zone.
Laser power seems to mainly affects the hardening depth, while the maximum hardness is limited by the material’s intrinsic properties, particularly its carbon content.
However, this hardness level is probably limited by the material's properties.

Key words: Single-slag Process, high-aluminum cold heading steel, composition control, property Abstract: Based on the actual process for smelting cold heading steel, this article adopts the single-slag process to smelt the low-carbon, low-silicon and high-alumina cold heading steel SWRCH6A, so as to study the effect of technological factors of the smelting process on the change of molten steel component in various working procedures and steel properties.
All the mechanical properties of cold heading steel exceed the ML08Al standard.
For mechanical properties of each item, see Table 3.
Table 3 Mechanical Properties of High-Aluminum cold heading Steel Smelting by Single-slag Process Batch No.
All the mechanical properties of the cold heading steel exceed the ML08Al standard.

The shape is better, and the microstructure is circular and symmetrical pore, which is help to improve the mechanical property of quartz porous ceramics.
For most of these applications, the ceramic materials need to fulfill specific requirements regarding their microstructure, porosity, permeability and mechanical properties. [9].
To tailor the properties for each application it is necessary to control the factors affecting the sintering process such as the initial particle characteristics, the microstructure, the additives and the processing technique [10].
The shape is better, and the microstructure is circular and symmetrical pore, which is help to improve the mechanical property of quartz porous ceramics.
The shape is better, and the microstructure is circular and symmetrical pore, which is help to improve the mechanical property of quartz porous ceramics.

Among those waste materials, slag has cementitious or pozzolanicity properties, and imparted superior qualities to the high cost of Portland cement with partial or full replacement [2].
The paper described the rheology, mechanical behavior and micro properties of blended cements made from slag, the test results indicated that high performance blended material can be gained with the technology of superplasticizer, alkali-activation, etc.
Properties of Hardened Blended Cement Paste Hydration of Common Blended Cement.
Pozzolanic properties of slag is far lower than cement[4], when blended with slag, the amount of cement clinker cut down, result in hydration slow down, hydration products decrease and growth rate of mechanical strength cut down [5,6].
Alkali activator can activate potential pozzolanicity of slag, and improve early mechanical strength, secondary hydration between slag and hydration products produced by cement can improve micro structure, results in improving macro properties.

In transportation industry such as aerospace environment, the material has to present damage tolerance corresponding at least to the standard 2024-T3 material properties.
It can be even so noticed that Krs in 6056-T78 is higher than in the both other materials; it is in accordance with the tensile properties.
The curves are even more comparable between the factors studied with CCT specimens.
Both heat treatments conditions as-welded and post-welded, applied to material 6056-T78, showed the comparable crack propagation, even if post-welded treatment is recommended in term of mechanical properties.
[7] Lafly A-L, Alléhaux D, Marie F, Dalle Donne C, Döker H: " Impact of Friction Stir Welding Techniaues on microstructure changes and mechanical properties", 58th Annual Assembly and International Conference of International Institute of Welding (IIW), Prague, 10-15 July 2005

These combined factors have affected the machining accuracy and may to harm to the environment.
In the last decade, however, the goal of researches has been strongly limiting the use of cooling and/or lubricating fluids in metal-mechanical production processes.
When abrasive tools are used, a reduction in grinding fluid may make it difficult to keep the grinding wheel pores clean, favoring the tendency for clogging and thus strongly contributing to the aforementioned negative factors[3].
Residual compressive stresses are considered beneficial for the mechanical properties of materials, increasing their fatigue strength and the service life of components.
(4) The use of MQL does not negatively affect the surface integrity.

It has also been shown that the average grain size formed by the SPD is a determining factor in the strength properties of these alloys; an increasing Hf concentration in the copper matrix is not always a condition for higher hardness values.
The values of the calculation results affecting the estimation of the Cu5Hf phase precipitation and that obtained from the experimental diagram are similar enough.
Therefore, it can be concluded that for the Cu-Hf system, the grain size formed by SPD is the determining factor that affects the hardening of these alloys.
However, higher concentrations of hafnium dissolved in the copper matrix will be determinative of higher mechanical properties when the dispersion hardening of the alloys is realized.
Dobatkin, Structure and properties of Cu-Cr alloys subjected to shear under pressure and subsequent heating, Russian Metallurgy (Metally). 2010 (2010) 1046-1052

Many researchers are dedicating themselves to study about preparation and properties of graphite/copper composites [8-12].
Considering such factors as more brittle & harder compound powders after mechanical milling, porosity of powders and poor plasticity of pressed compacts, creative results about powder consolidation and preparation of composites could be achieved if subsequent plastic deformation and densification are utilized with hot pressed sintering & hot extrusion.
Results and discussion Influence of mechanical milling on microstructures of composites.
This can be maintained to subsequent hot pressed sintering and hot extrusion, and affects the microstructures of extruded bars finally.
It is expected that heterogeneity of graphite will play a negative role in property of composites.

The surface settlement is affected by many factors due to EPB shield.
The result indicates that soil warehouse pressure and the efficiency of grouting is important factors of the surface displacement.
In many factors about ground settlement caused by shield construction, the soil mass displacement of excavation face and back grouting of shield are two important factors.
Table 1 Mechanical and physical properties of soil strata soil layer unit weight [kN/m3] cohesion [kPa] angle of internal friction [°] elastic modulus [MPa] Poisson’s Ratio silty clay 1.82 19 20 16 0.33 residual soil 1.90 36.5 20.2 43 0.32 cohesive soil 1.92 36.5 20.2 40 0.32 fully weathered zone 1.96 39.4 22.7 79 0.32 strongly weathered zone 2.40 50 28 170 0.31 medium weathered zone 2.52 500 30 104 0.30 Analysis of Influencing Factors Soil warehouse pressure.
We can transform the unit type and mechanical parameters to simulate the equivalent layer.