Cast Shop Technology: Foundry and Shape Casting
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: David Gildemeister, Arconic Technology Center
Monday 2:00 PM
February 27, 2017
Location: San Diego Convention Ctr
Session Chair: Ning Sun, Worcester Polytechnic Institute
2:00 PM Introductory Comments
Operational and Economic Impact of Super Vacuum Die Casting Technologies: Muhammad Farooq1; Randolph Kirchain1; Richard Roth1; Alan Luo2; Diran Apelian3; Andrew Klarner2; Joshua Curto3; Libo Wang3; Di Wu1; 1Massachusetts Institute of Technology; 2The Ohio State University; 3Worcester Polytechnic Institute
Light weighting of manufactured components is a major driver to reduce carbon footprint and fuel efficiency. One approach is to have strong materials that can be used in thin sections. However, the wall thickness of castings is dictated not by performance requirements, rather by processing limitations. Super vacuum die-casting (SVDC) is a recent process development, producing thin walled cast components that are heat treatable. While such technologies add some cost directly, this may afford savings in reduced material requirements and changes in downstream processing. This paper will report on operational developments associated with the casting process (modifications of dies and process settings) as well as downstream heat treatment processing. Using both experimental findings as well as a numerical sensitivity analysis, the key drivers of cost and cost savings are discussed. Among the main findings of the study is that these SVDC technologies outweighs investments, operational, maintenance and heat treatment factors.
Multi-Component High Pressure Die Casting (M-HPDC): Influencing Factors on the Material Temperature during the Joining of Metal-plastic-hybrids: Patrick Messer1; Uwe Vroomen1; Andreas Bührig-Polaczek1; 1Foundry Institute RWTH Aachen University
M-HPDC is an In-Mold manufacturing process combining High Pressure Die Casting (HPDC) and Injection Molding (IM) within one manufacturing plant. The biggest influence within a metal-plastic-bond realized by micro bracing is ascribed to a suitable temperature management within the die. Therefore a suitable temperature control concept for a sample die, made to manufacture an overlap shear tensile sample, will be presented. In order to investigate the temperature influence, the die provides several options to influence the actual temperature. A number of independent cooling circuits, an alternating temperature management unit and a contour adapted heating cartridge are integrated. Besides that, the temperature within the joining area can be raised by exchangeable die inserts for the usage of either an inductor or a heating ceramic. For the purpose of quantification, the temperature will be monitored by thermocouples close to the actual cavity surface. The die concept and first results of the simulative approaches will be shown.
X-Ray Computed Tomographic Investigation of High Pressure Die Castings: Shouxun Ji1; Douglas Watson2; Zhongyun Fan1; 1Brunel University; 2Jaguar Cars Ltd
In high pressure die castings, the distribution of casting defects are usually random and difficult to be controlled and predicted, which results in an uncertainty in the mechanical properties. The porosities and intermetallic phases in a high pressure die cast Al-Mg-Si-Mn alloy was investigated using 3D X-ray computed tomography with different scanning resolutions, The experimental results demonstrated the porosity level and phase detection of dependency upon voxel sizes. The porosity levels were 0.4%, 0.5% and 0.8% and the intermetallic phases were 0.3%, 0.4% and 0.6% when the same casting sample was scanned at 15μm/vox, 7.2 μm/vox and 2.1 μm/vox, respectively. However, the structural parameters should be assessed to determine the necessary and/or possible image quality, weighing factors such as scan time, field of view, and voxel sizes.
3:20 PM Cancelled
The Comparison of Intensive Riser Cooling of Castings after Solidification in Three Classic Metals: Haolong Shangguan1; Kang Jinwu1; 1Tsinghua University
The cooling of castings especially heavy steel castings is usually very slow and nonuniform after solidification, which results in low production efficiency and great residual stress or deformation. Furthermore, great thermal gradient appears across their thick sections and between the thick and thin areas, that may cause significant residual stress or deformation or even cracks. A new method-Post Solidification Intensive Riser Cooling (PSIRC) was proposed for heavy steel castings. In this article, PSIRC will be applied to three materials'stress frame which has a thick bar and two thin bars, a riser is set at the middle of the thick bar. The materials are GS38 carbon steel, H13 alloy steel and A356 Al alloy. Three kinds of interface heat transfer coefficients of 20,200,2000 W/(㎡·K) are applied on the riser to research the cooling rate and temperture uniform. We will find the relationship between PSIRC and three materials on three different interface heat transfer coefficients.
3:45 PM Break
Sequential Gravity Casting in Functionally Graded Aluminum Alloys Development: Mario Rosso1; Silvia Lombardo1; Federico Gobber1; 1POLITECNICO di Torino
Aluminum alloys are widely used in the automotive field, for the excellent relationship between mechanical strength and lightness. In the recent years, the request for cleaner, lighter and more powerful engines, has led to the design of components subjected to higher thermo-mechanical stresses. Demanding exercise conditions can imply the presence of different properties that are never fulfilled by a single, homogeneous material. Various solutions have been developed using composites, surface modification techniques and Functionally Graded Materials (FGMs). This study has apply FGM concept to the traditional casting technology, in order to obtain a more performing product. To reach this goal, two different alloys were sequentially poured by gravity casting, each one delivering locally its properties to a specific volume of the casting. Beyond the morphological and microstructural analysis of the contact interface between the two alloys, the mechanical testing has shown promising results for future applications.
4:25 PM Cancelled
Assessment of Eutectic Modification Level in Al-Si Alloys via Thermal Analysis: Maiada Abdelrahman1; Mahmoud Abdu1; Waleed Khalifa1; 1Cairo University
The modification level (ML) of A356, A319, and A413 Al-Si alloys was investigated via thermal analysis (TA) and microstructural investigation. The modification treatment was carried out using different levels of Sr in the form of Al-10wt%Sr master alloy. The melt was poured into three different types of molds to give different cooling rates (CRs) to simulate the actual casting conditions. Increasing the level of Sr improved the ML of the eutectic Si. Slower CRs required higher additions of Sr to produce the same ML obtained from the higher CRs. An attempt was made to assess the ML at the high CRs with the aid of the TA parameters measured at the slow CR. Thermal analysis was found to provide successful quantitative measure for the modification level in A356. In A319 and A413, thermal analysis could provide successful quantitative measure of ML when the ML is below 4.0. It could provide only qualitative indication of the occurrence of modification when the ML was 4.0-6.0. The latter findings were found independent of cooling rate.