Papers by Keyword: Die Casting

Abstract: Si ranging from 0.2 mass% to 2.0 mass% was added to Al-5%Mg alloy (5182) and strip was cast by a vertical type high-speed twin-roll caster at a speed of 80 m/min. The as-cast strip was cold-rolled down to 1 mm thickness and annealed. The mechanical properties were investigated using cup tests and tension tests. The limiting draw ratio (LDR) of the 5182 alloy was 2.0 and the LDR became smaller as the Si content increased. When the Si content was 2.0 mass%, the LDR was 1.8, which shows that Si-added 5182 can be used for sheet forming, if the Si content is less than 2.0 mass%. The tensile strength and elongation were almost constant when the Si content was less than 1 mass%, but decreased at 2.0 mass% Si. However, the elongation was greater than 20% at 2.0 mass% Si. For die casting, 2.0 mass% Si was determined as the appropriate content from the results of the tension tests. When the Si content is in the range from 1.0 mass% to 2.0 mass%, then the Si added Al-5%Mg has the ability to be used for both die casting and sheet forming.

Abstract: Die soldering is a sticking phenomenon between molten aluminum with the surface of steel die in the die casting process, which results in damage to the cast products and l the steel die. In this research, two die materials, H13 and Cr-Mo-V steels were used. Those dies were then treated by two process variables, shot pinning and nitriding-shot pinning. To simulate the die casting process, the samples were dipped into molten Aluminum-Si alloy, ADC12 at 680oC for 30, 300, and 1800 seconds. Characterizations were focused on the surface of the steel, which includes microstructure observation by a microscope, microhardness profile, compound identification, and weight loss measurements. It was found that H13 steel and Cr-Mo-V steel treated by nitriding–shot pinning have higher hardness up to 100% and thinner intermetallic layer. On H13 steel, the compact layer thickness decreased from 19 μm to 17 μm and from 96 μm to 80 μm for the broken layer. Similar trends occurred for Cr-Mo-V steel, where the thickness of the compact layer and broken layer decreased from 38 μm to 19 μm and 119 μm to 45 μm respectively. These results indicate that H13 and Cr-Mo-V steels that were treated by nitriding–shot pinning have a better resistance to die soldering.

Abstract: A die to estimate the thickness of the thinnest fin of a heat sink made by die casting aluminum alloys is proposed. The die consists of a taper-off thin fin and a cooling area. It was shown that this die can be used to estimate the smallest fin thickness of different aluminum alloys.

Abstract: The quest for the lighter materials have motivated the researchers worldwide to develop a newer composites. with the discovery of carbon nanotubes, a class of novel material it has been possible to fabricate the components for the field of automotive and aircraft industries where the strength to weight ratio becomes prominent. In the present work the Al7075 alloy was reinforced with the electroless Ni coated Multiwalled carbon nanotubes in 2wt%,4wt% and 6wt% the nanocomposites were prepared via die casting technique and the resulting composites were tested for the strength and hardness the tensile strength for 6wt% reinforcement found to be 240Mpa a 33% increase compared to unreinforced composite and micro hardness was as high as 61. The SEM analysis revealed that the improvements in the hardness could be attributed to the carbon atoms inclusion in composite lattices.The finite element analysis was carried out for the idealized composite commercial brake rotor the max stress bearing capacity was 172.74 N/mm² and max deformation was 1.85x10^-5 for the 6wt% of reinforcement. Keywords: nanocomposites, die casting, microhardness, aluminium brake rotors.

Abstract: In the past, there have been a lot of effort to solve gas and shrinkage porosity defects in die casting. The common solutions are vacuum technology, jet cooling technology, and application of squeeze pins. However, these solutions often increase the die casting production costs. A new solution that has recently been introduced worldwide is GISS Technology. This technology applies the superheated slurry casting process. Gas and shrinkage porosity defects can be reduced. Furthermore, the production costs are lowered due to die life extension, cycle time reduction, melting energy reduction, and lubrication usage reduction. This paper describes the principle of GISS Technology, and selected applications and case studies are also be presented.

Abstract: Controlling the morphology of the microstructure of the slurry is important during semi-solid die casting. For this project, semi-solid slugs were produced using the SEED (Swirled Enthalpy Equilibrium Device) process, where a fully liquid metal is poured into a steel crucible and cooled into the semi-solid temperature range, and the crucible and slurry are then swirled and cooled to the appropriate temperature (and solid fraction) for semi-solid casting. The pouring temperature of the melt into the crucible during SEED processing has been shown to influence the morphology and size of the aluminum solid particles within the slurry, which can influence the distribution and segregation of the solid particles during die casting. In this study, a specially-designed die with a serpentine-shaped flow channel has been used to study the distribution of the solid particles during semi-solid die casting. The experimental results show that a dendritic structure is formed when the liquid is poured from a high temperature, while a globular semi-solid morphology is more easily formed when poured from a low superheat. The current results also show that a dendritic structure leads to severe segregation during die casting.

Abstract: The Al-alloy die casting die is a sector where the operating environment imposes a very severe aggression to hot working tools. Steel grades for such application, techniques for their surface modification and specifically conceived lubricants are continuously improved so as to limit Al soldering. Within this scenario the interaction between lubricant and die surface and the effect of finishing levels of such surface is poorly studied. This paper deals with a study of the influence of dies surface roughness on the working behavior of a die casting lubricant and on surface damages of a tool steel grade. Tool steel samples were prepared for the research and two different levels of surface roughness (as polished and as finely sand blasted) were investigated. Apart from the base characterization of steels and surface, two specific test rigs were used to study the lubricant-tool steel surface-Al alloy interactions. One of test rig was devoted to study the coupling principles of tool die surface-lubricant, while the other test rig was used to perform a cyclic immersion test in molten Al-alloy. The derived data were compared to the experimental investigation of cracks and craters as provided by cycling with a correlation with the surface finishing level of samples.

Abstract: Aluminum-Silicon Alloy, ADC12 is one of the most popular alloys for pressure die casting due to its high castability and high productivity. ADC12 is a hypoeutectic aluminum-silicon alloy that contains 10-12wt% of Si and has an occasional problem for a mechanical properties failure such as crack and shrinkage porosity. This study presents the investigation of the microstructure of ADC12 parts produced by pressured die casting with different process parameters and chemical compositions. The microstructure was observed using optical microscopy (OM) and scanning electron microscopy (SEM) with energy – dispersive X-ray (EDX) and electron backscatter diffraction (EBSD) to determine phases, grain, and crystallographic information in order to understand the microstructural evolution after die casting with different process conditions. Changes in casting pressure and a reduction of iron content contributed to enhanced mechanical properties and less shrinkage porosity. This was due to different processing parameters, mainly casting pressure. The average grain size of aluminum matrix was also reduced due to a higher pressure during casting with a moderately fast cooling rate.

Abstract: This paper describes the necessary measures to create an adaptable material flow and energy simulation for melting and die-casting plants. Based on two reference plants, the structural and intralogistical differences are emphasized and examined. These differences specify the necessary extensions to a previously created simulation environment in order to be able to analyze variable plant configurations. Special emphasis is put on the creation of a simplified energy model that allows the modeling of melting furnaces based on rudimentary datasets. Using the adaptable material flow and energy simulation two measures and their effects on the in-plant energy efficiency as well as productivity are analyzed. The simulation results suggest energy savings potentials for both plants and measures to increase productivity for one of the analyzed plants.

Abstract: With a pressure die casting process, one of the important factors affecting the quality of castings represented by porosity is plunger pressing velocity determines the regime die cavity filling and correct determination of dose mass of a molten metal required for one casting cycle. The mass is given by a total of the net mass of a casting, overflows, a gate system and a metal rest inside a filling chamber (the tablet height). As a rule, the tablet height represents the largest mass ratio regarding the waste metal. A correct determination of the tablet height is important from both economical and qualitative aspect of a pressure die casting process.