Papers by Keyword: Lost Foam Casting (LFC)

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. In this paper, the research status and development direction of numerical simulation technology of casting, especially of lost foam casting were reviewed and discussed. Also a brief introduction of the basic situations and product characteristics of several outstanding cast filling and solidification simulation softwares were summarized. In addition, the actual domestic application status of numerical simulation technology of lost foam casting in the foundry enterprises was analyzed and some suggestions were given as well.

Abstract: In the whole process of the LFC (or evaporative pattern casting, EPC), the quality of the foam pattern play a decisive role to the final casting quality. The present processing methods for the foam pattern are discussed, including foaming molding, manual cutting, and CNC machining, rapid prototyping, also the advantages and disadvantages of these processing methods are analyzed. As CNC machining become the main trend for foam pattern processing, some CNC machine oriented tools are summarized, including the hot wire foam cutter, the hot knife foam cutter, and the modified tools based on the traditional tools.

Abstract: The article studies the method which hydroturbine part is manufactured by lost foam casting for obtaining higher quality product.The lost model material is polystyrene foam plastics,the EPS diameters are selected in 0.5-0.76mm,the casting raw material is lower carbon martensite stainless steel(ZG06Cr13Ni4Mo).The style of open pouring system is adopted, ∑F_in-gate：∑F_cross-gate：∑F_down-sprue=1：1.1：1.2, fireproof coating is mixed and coated,square sand box is used. The pouring temperature of liquid is 1600-1650°C.If the technology is strictly according to the design,good quality casting can be gotten.

Abstract: The microstructures and mechanical properties of Mg9AlZnGdY alloy after T6 heat treatment in lost foam casting (LFC) are compared with that of AZ91D magnesium alloy. The results show that the microstructures of Mg9AlZnGdY alloy after T6 heat treatment consist of the α-Mg solid solution, β-Mg₁₇Al₁₂ precipitation phase, a small amount of rod Al₂Y and block Al₂Gd phases, which are distributed over grain boundaries of the α-Mg phase. The thermal stability of Al₂Y and Al₂Gd phases offers the pinning effect on the grain boundary under high temperature, and therefore, the grain boundary sliding is eliminated and the high-temperature strength is increased. After the T6 heat treatment, the tensile strength of Mg9AlZnGdY alloy was 235MPa at room temperature, and 156MPa at 200°C. Compared with that of AZ91D alloy, the tensile strength was increased by 19.3% and 38.1% respectively.

Abstract: Wear-resistant casting was made by V-EPC infiltration process. The matrix material was high boron steel casting. Surface composite materials layer was ceramic particles, such as WC, Ferrochromium, and Borax, etc. High boron molten metal was infiltrated into the composite layer and a good cast-infiltration layer may be formed by the interaction of vacuum and high temperature. The wear-resistant casting made with this process has high strength, hardness, and good wear-resistance. It is a new process that wear-resistant casting will be made of.

Abstract: Apply an organic whole technological medium of computer aided three dimensions design 、computer aided solidification process numerical value simulation engineering ＆ computer aided numerical control programming manufacturing, by means of optimization product pattern structure、foundry processing parameters 、die auxiliary equipment and tool、riser gating system ＆ die cavity numerical control cutter location source file , the type of Z8A goods train low-carbon alloy adapter lost foam casting has been under development .Compare lost foam technology to ordinary sand mold casting ,the casting monomer weight lightened 3kg , grade of casting weight precision come to MT7 , grade of casting size precision come to CT8 ,foundry processing yield come to 65% ；Casting defects easily appeared in the course of large quantities production has been analysed ＆ offered solution methods in this article.

Abstract: This paper presents the experimental investigation conducted on Al-Si cast alloy (LM6) cast using lost foam process. The main objective of the research is to investigate the effect of pouring temperature, section thickness and melt treatment on the microstructure of the lost foam casting of Al-Si alloy. Step pattern with five different sections was prepared from 20 kg/m³ density foam and poured at five different temperatures; 700, 720, 740, 760, and 780 with and without the addition of AlTiB as grain refiner. Analysis on microstructure, eutectic silicon spacing and porosity percentage were conducted to determine the effect of both parameters. The results show that pouring temperature has significant influence on the quality as well as microstructure of the lost foam casting of LM6 Al-Si alloy. Lower pouring temperature was found to produce finer microstructure casting. However, the addition of AlTiB as grain refiner did not affect the produced castings significantly whether in terms casting quality or microstructure.

Abstract: The lost foam casting (LFC) process utilizes the expanded polystyrene (EPS) foam pattern for the production of metallic components. The thermal degradation of the foam pattern has a significant effect on microstructure of the component. Dendrite coherency is important for the determination of the formation of the solidification structure and cast ability of alloys. The effects of the dendrite coherency on grain size in Mg-4Al alloy have been studied using the two-thermocouple thermal analysis technique in the solidified sample. The results also indicate that the grain size increases with the temperature interval between liquids (T_N) and dendrite coherency point (T_DCP), The solid fraction at DCP (f_s^DCP) expressed in percent strongly dependents on the dendrite morphology during solidification.

Abstract: For obtaining higher quality casting, the lost foam casting is used to produce reaper underpan. While the raw materials are selected, the fireproof coating and sand are chosen well, the sand box is designed according to the technology, pouring system is calculated, under the above operation strictly, such as air hole can be avoided.

Abstract: This paper has analyzed key techniques in foam mold development for Lost Foam Casting for different types of casting, which are complex box, pipe faucet junction ,wear-resisting and refractory alloy steel casting, Focused on complex castings with free-form surface, key points during whole technical route, which includes three-dimensional modeling, foamed pattern design, mold design and CNC program, have been discussed by utilizing modeling & manufacturing module on Unigraphics. Because of its perfect free-form surface functions and plentiful toolpath operations in CNC programming, Foam mold of complex casting with free-form surface has been designed, manufactured and assembled successfully for LFC, Qualified foamed pattern of vortical shell has been produced successfully. Several effective methods and experiences have been achieved by utilizing CAD/CAM technology.