High Pressure Die Casting Research Articles

Towards a Data Lake for High Pressure Die Casting

The High Pressure Die Casting (HPDC) process is characterized by a high degree of automation and therefore represents a data rich production technology. From concepts such as Industry 4.0 and the Internet of Production (IoP), it is well known that the utilization of process data can facilitate improvements in product quality and productivity. In this work, we present a concept and its first steps of implementation to enable data management via a data lake for HPDC. Our goal was to design a system capable of acquiring, transmitting and storing static as well as dynamic process variables. The measurements originate from multiple data sources based on the Open Platform Communication Unified Architecture (OPC UA) within the HPDC cell and are transmitted via a streaming pipeline implemented in Node-Red and Apache Kafka. The data are consecutively stored in a data lake for HPDC that is based on a MinIO object store. In initial tests the implemented system proved it to be reliable, flexible and scalable. On standard consumer hardware, data handling of several thousand measurements per minute is possible. The use of the visual programming language Node-Red enables swift reconfiguration and deployment of the data processing pipeline.

Bonding of cast iron-aluminum in bimetallic castings by high-pressure die casting process

A practical bimetallic casting consisting of aluminum matrix and cast iron inserts was manufactured via high-pressure die casting (HPDC) process. Different surface treatment methods for the cast iron inserts, including salt membrane plating and electrogalvanizing, were adopted to improve the bonding quality of bimetallic castings. Microstructure characterization on the bonding interface was conducted at different locations of bimetallic castings. Results indicate that compounds with flawless and continuously metallurgical bonding interface can be successfully fabricated by the HPDC process with the zinc rack plating treatment on the surface of cast iron inserts which results in a dense zinc coating with an average thickness of 8 μm. The melt flow speed and heat transition during solidification of the HPDC process are two key factors in determining the bonding integrity of bimetallic castings. With the dissolution and diffusion of the very thin zinc coating during solidification, there is no obvious aggregation of zinc element at the metallurgical bonding interface. Instead, a reaction layer with an irregular tongue-like morphology is formed with an average thickness of approximately 1 μm while it mainly consists of intermetallic phases Al60Cu30Fe10, Fe2Al5, and Al2FeSi.

Rapid die preheating using a high-power infrared lamp array

• Preheating HPDC dies for automotive transmission components was investigated. • Radiation heat transfer into HDPC dies was simulated using the Monte Carlo method. • Heater configuration was optimized to increase heat rate while minimizing hot spots. • Radiation shield was effective in minimizing hot spots on protruding surfaces. High pressure die casting (HPDC) is a highly violent process that causes significant wear on the die from chemical attacks and from repeated cycling at high pressure and temperature. In practice, HPDC dies are usually preheated by injecting aluminum into the die as warm-up shots. Although warm-up shots transfer heat into the die at a high rate, the warm-up shots are often rejected as scrap due to defects caused by the lower-than-optimal die temperature. The present work aims to develop an auxiliary heating system using an array of high-power, electric infrared lamps to preheat an HPDC die. The potential advantage of this method is a reduction in scrap material and a reduction in thermal cycles on the casting die. Experiments were conducted to quantify the heating rate for various infrared electric heater configurations. A numerical model was also developed to simulate the radiation heat transfer from the lamp array to the die. The model was validated against experiments and subsequently used to optimize the configuration of the heater. The heating system was improved by adding a small radiation shield to minimize hot spots on protruding surfaces while still maintaining a fast heating time. The validated numerical model can be used in the future to develop custom heater solutions for different die geometries.

Evaluation of Ejection Force for Die Castings by FEM Thermal Stress Analysis with Elasto-Plastic-Creep Model

In the die design of high pressure die casting (HPDC), in order to prevent the casting from the warpage, it is essential to predict ejection force of each ejector pin before locating it. Recently, Shiga et al. revealed that their developed elasto-plastic-creep model is more accurate than conventional elasto-plastic models to estimate the thermal stress of casting during cooling with constraint of dies.

Al-Mn Intermetallics in High Pressure Die Cast AZ91 and Direct Chill Cast AZ80

Manganese-bearing intermetallic compounds (IMCs) are important for ensuring adequate corrosion performance of magnesium-aluminium alloys and can be deleterious to mechanical performance if they are large and/or form clusters. Here, we explore the formation of Al-Mn IMCs in Mg-9Al-0.7Zn-0.2Mn produced by two industrial casting processes, high-pressure die casting (HPDC) and direct chill (DC) casting. As Al8Mn5 starts forming above the α-Mg liquidus temperature in this alloy, we consider its formation during melt handling as well as during casting and heat treatment. In HPDC, we focus on sludge formation in the holding pot, partial solidification of IMCs in the shot chamber, and Al-Mn IMC solidification in the die cavity. In DC casting, we focus on interactions between Al-Mn IMCs and oxide films in the launder system, Al-Mn IMC solidification in the billet, and the partial transformation of Al8Mn5 into Al11Mn4 during solution heat treatment. The results show that minimising pre-solidification in the shot sleeve of HPDC and controlling pouring and filtration in DC casting are important for ensuring small Al-Mn intermetallic particles in these casting processes.

About Residual Stress State of Castings: The Case of HPDC Parts and Possible Advantages through Semi-Solid Processes

Nowadays, one of the most crucial focus in the aluminium-foundry sector is the production of high-quality castings. Mainly, High-Pressure Die Casting (HPDC) is broadly adopted, since by this process is possible to realize aluminium castings with thin walls and high specific mechanical properties. On the other hand, this casting process may cause tensile states into the castings, namely residual stresses. Residual stresses may strongly affect the life of the product causing premature failure of the casting. Various methods can assess these tensile states, but the non-destructive X-Ray method is the most commonly adopted. Namely, in this work, the residual stress analysis has been performed through Sinto-Pulstec μ-X360s. Detailed measurements have been done on powertrain components realized in aluminium alloy EN AC 46000 through HPDC processes to understand and prevent dangerous residual stress state into the aluminium castings. Furthermore, a comparison with stresses induced by Rheocasting processes is underway. In fact, it is well known that Semi-Solid metal forming combines the advantages of casting and forging, solving safety and environmental problems and possibly even the residual stress state can be positively affected.

Evaluating the Joinability of Thin-Walled High Pressure Die Cast Aluminium for Automotive Structures Using Self-Piercing Rivets

Evaluating the Joinability of Thin-Walled High Pressure Die Cast Aluminium for Automotive Structures Using Self-Piercing Rivets

Joining light metals with polymer composites through metal overcasting

• Joining light-weight metals to fiber reinforced polymer composites without using mechanical fasteners or adhesives. • High-pressure die-casting is used to overcast molten metals (Al, Mg) on polymer composites without burning away the latter. • High cooling rates are important to prevent thermal degradation of the polymer composite. This work investigates a unique technique to join aluminum (Al) and magnesium (Mg) alloys to carbon fiber reinforced polymer (CFRP) composites without the use of adhesives or mechanical fasteners. The joints were made using an overcasting technique where the molten alloys were cast around the polymer composites using high pressure die casting method. Rapid cooling during casting allowed the composite to be embedded inside the cast metal without causing any gross damage to the former even though the molten metal temperature exceeded the melting point of the composite matrix by several 100’s of deg. C. The metal/composite interface was examined using optical and scanning electron microscopy and x-ray imaging, and the joint strength was examined through tensile testing. Although evidence of polymer melting was visible in the x-ray images and through microscopy, this melting was limited to the CFRP surface only while the bulk of the embedded section of the composite coupons retained their overall shape and integrity. Preliminary tension tests on Al/CFRP composites showed strength degradation of the CFRP and it failed a few mm outside the joint. This strength degradation in the CFRP suggests that the overcasting process needs further optimization to minimize thermal excursion in the CFRP section outside the joint. Nevertheless, the overcasting process shows great promise as a unique joining technique with application in fabricating light-weight structures for automotive and transportation industries.

Characterization of externally solidified crystals in a high-pressure die-cast AlSi10MnMg alloy and their effect on porosities and mechanical properties

The characterization of externally solidified crystals (ESCs) and porosities in a high-pressure die-cast AlSi10MnMg alloy was investigated using optical microscope (OM) and computed tomography (CT) with particular attention on the effect of shot speeds on the ESCs and fracture behavior. Results showed that ESCs tended to agglomerate at the center region and changed from fine globular grains into large size dendrites from surface to center. The formation of the ESCs is found to be coarser as the "slow shot speed" in the first stage of high-pressure die casting (HPDC) or the "fast shot speed" in the second stage of HPDC is reduced, consequently, the corresponding ESC area fraction increased. From the fractured morphology, the plate specimen with a higher ESC content exhibited a rough fracture and a large volume fraction of shrinkage porosities was discovered beneath the fracture surface especially when a lower fast shot speed was applied. In in-situ tensile test, the large size shrinkage porosity served as a crack source and it further expanded in an inter-granular mode along ESC boundaries/other porosities (which caused a tortuous crack route) or in a trans-granular mode across the ESC grains/fine (α-Al) II grains (which caused a flat crack route). In addition, the gas porosities in the specimen promoted the crack propagation as a crack concentration area and experienced almost no deformation during the tensile process.

Effects of Al addition on the microstructure, mechanical properties and thermal conductivity of high pressure die cast Mg–3RE–0.5Zn alloy ultrathin–walled component

Strength and heat dissipation capability are the key parameters for metal materials used as the structural components of 5G stations and smartphones, while balancing the high strength and high thermal conductivity is still a long-term challenge. In the present study, we attempted to achieve high–thermal–conductivity Mg alloys combined with high strength for high pressure die cast (HPDC) ultrathin-walled components. The effects of Al addition on the microstructure, tensile properties, thermal conductivity, and electrical conductivity of HPDC Mg–3RE–0.5Zn (wt%) alloy were investigated and discussed carefully. We found that the HPDC Mg–3RE–0.5Zn showed the highest thermal conductivity of 143.6 W(m·K)−1 and electrical conductivity of 18.9 MS·m−1. With the increasing Al addition, the thermal conductivity and electrical conductivity gradually decreased while still kept a high level of 126.1–117.8 W(m·K)−1 and 17.5–16.3 MS·m−1. Furthermore, Al addition simultaneously improved the strength and elongation of HPDC Mg–3RE–0.5Zn alloy, where the HPDC Mg–3RE–0.5Zn–2Al alloy exhibited the best tensile properties with yield strength, ultimate tensile strength, and elongation of 156 MPa, 240 MPa, and 10.8%, respectively. The Al addition modified the intermetallic phases from continuous networked Mg12RE to discontinuous blocky Al2RE and/or lamellar Al11RE3 phases, which contributed to enhancing tensile properties. The results will be helpful for developing high performance HPDC Mg alloys and extending their practical application.

A Study of Microstructure and Porosity Formation in High-Pressure Die-Casting

A Study of Microstructure and Porosity Formation in High-Pressure Die-Casting

Large tensile plasticity in Zr-based metallic glass/stainless steel interpenetrating-phase composites prepared by high pressure die casting

The ambient-temperature brittleness of bulk metallic glasses (BMGs) is a long-standing problem in materials engineering. Herein, we report a route to overcome this Achilles’ heel of BMGs via high-pressure die casting (HPDC) at a high filling rate and pressure to create bi-continuous interpenetrating-phase composites. Our results show that large tensile plasticity of 5.1% can be achieved in the Zr-based BMG/stainless steel interpenetrating-phase composite prepared by HPDC, which is superior to most of as-reported ex-situ secondary phase reinforced BMG composites. The excellent mechanical properties of the BMG composite mainly originate from excellent metallurgical bonding between matrix and reinforcement as well as high efficiency suppression of shear band propagation by three-dimensional metal skeleton. Our findings provide a promising approach for developing cost-effective BMG composites suitable for industrial applications. • Interpenetrating-phase BMG composites with large tensile plasticity were prepared successfully by high pressure die casting. • The composites display metallurgical bonding between matrix and reinforcement. • The excellent mechanical properties mainly originate from a proposed mutual-reinforcement mechanism. • The developed process has great advantages on engineering application.

Influence of different high pressure die casting processes on 3D porosity distribution of Mg-3.0Nd-0.3Zn-0.6Zr alloy

3D reconstruction was adopted to characterize the microstructural morphologies of Mg-3.0Nd-0.3Zn-0.6Zr alloy castings produced by high pressure die casting (HPDC) processes with different parameters, including low slow-shot speed, solidification pressurization and fast slow-shot speed. At low slow-shot speeds of 0.1 m·s−1, 0.2 m·s−1 and 0.3 m·s−1, the porosity is concentrated in the center of the castings with one spiral staggered shape along the liquid flow direction. The porosity volume simultaneously decreases with the reduction of quantity and size of externally solidified crystals (ESCs), while the shrinkage pores become more and more dispersed with the increasing low slow-shot speed. Pressurization not only reduces the porosity volume due to the improvement of feeding ability, but also transformes the center gathered porosity into one layer-by-layer distribution form. Accompanied with the increasing fast slow-shot speed, the central porosity dramatically decreases and transforms into a large-scale spiral staggered shape along the liquid flow direction. However, the porosity is much more dispersed when the speed is increased from 2 m·s−1 to 3 m·s−1.

Metamodels’ Development for High Pressure Die Casting of Aluminum Alloy

Simulation is a very useful tool in the design of the part and process conditions of high-pressure die casting (HPDC), due to the intrinsic complexity of this manufacturing process. Usually, physics-based models solved by finite element or finite volume methods are used, but their main drawback is the long calculation time. In order to apply optimization strategies in the design process or to implement online predictive systems, faster models are required. One solution is the use of surrogate models, also called metamodels or grey-box models. The novelty of the work presented here lies in the development of several metamodels for the HPDC process. These metamodels are based on a gradient boosting regressor technique and derived from a physics-based finite element model. The results show that the developed metamodels are able to predict with high accuracy the secondary dendrite arm spacing (SDAS) of the cast parts and, with good accuracy, the misrun risk and the shrinkage level. Results obtained in the predictions of microporosity and macroporosity, eutectic percentage, and grain density were less accurate. The metamodels were very fast (less than 1 s); therefore, they can be used for optimization activities or be integrated into online prediction systems for the HPDC industry. The case study corresponds to several parts of aluminum cast alloys, used in the automotive industry, manufactured by high-pressure die casting in a multicavity mold.

Layout Design and Die Casting Using CAE Simulation for Household Appliances

Due to the development and industrialization of science and technology, aluminum alloys have been developed in various fields. Recently, the government has been pursuing ways to decrease the weight and increase the recyclability of various components in order to conserve resources, energy, and the environmental. In keeping with this trend, cast iron products are being replaced by aluminum products in the foundry industry by using high-pressure die casting (HPDC). Casting layout design, relies on the experience and knowledge of mold designers in the casting industry, which proves insufficient to respond to the rapidly changing needs of the era and to increasing production costs. Designing and producing casting layouts using CAD/CAM/CAE technology has become a critical issue. Computer-Aided Engineering (CAE) technology is rapidly increasing with the development of computer software and hardware. CAE technology not only predicts defects in mass production but also performs filling or solidification analysis during the mold design stage before production, enabling optimal mold design methods. New technologies that combine the emerging casting processes of filling and solidification analysis using computer simulation with existing technology and practical experience in the field are rapidly increasing in the foundry industry. Based on empirical knowledge, the layout and design of casting products has traditionally progressed through trial and error. The solutions achieved through scientific calculation and analysis using CAE technology can save a great deal of money and time in the building of die-casting molds and in their design and fabrication. In this study, numerical analysis of household appliances (cooking grills) quickly and accurately predicts problems arising from the filling and solidification of the melted metal in the casting process, thereby ensuring the quality of the final cast product. These results can be used to quickly establish a sound casting layout with reduced production costs.

Understanding of surface segregation of Cu and Zn on nano Si precipitates to the mechanical property improvement of high pressure die casting Al9Si3CuFe alloy

To understand Si precipitation and its influence on mechanical property improvement in high pressure die casting (HPDC) Al9Si3CuFe alloy under direct ageing heat treatment, the precipitates in Al9Si3CuFe alloy containing in-situ MgAl2O4 particles is analyzed via atomic-resolution scanning transmission electron microscopy. It is shown that lath-like Si precipitates form in an average size of 50 nm in length, and a good orientation relationship of {010}<001>Al//{111}<01–1>Si is observed between Si precipitate and matrix. Interestingly, Cu and Zn are observed to segregate onto Si/Al interface, which has a coarsening resisting effect on precipitate growth. The presence of these Si precipitates is the main factor contributing to the further improvement of mechanical properties of Al9Si3CuFe alloy, which results in an increase of 70 MPa in yield strength compared to the alloy without Si precipitates.

RHEINFELDEN CASTASIL-37

Abstract Rheinfelden Castasil-37 (AlSi9MnMoZr) is an aluminum-silicon-manganese-molybdenum-zirconium high pressure die casting (HPDC) alloy. It was developed by Rheinfelden Alloys GmbH for the production of large and complex high pressure die castings for automotive structural applications. This alloy is used in the as-cast condition, and exhibits good mechanical properties, especially elongation, which are superior to those of conventional aluminum-silicon alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, heat treating, and joining. Filing Code: Al-481. Producer or source: Rheinfelden Alloys GmbH &amp; Co. KG.

The investigation of microstructure and high temperature mechanical properties of novel Mg-Al-Sn-Ce alloy produced by HPDC

ABSTRACT Different weight ratios of cerium (0.5, 1 and 2 wt.%) were produced in a controlled atmosphere by High Pressure Die Cast method to Mg-6Al-0.3Mn-1Sn alloy. The influence of cerium on microstructure and high-temperature mechanical properties was investigated. The microstructure study revealed that the main alloy contains intermetallic phases such as α-Mg, β- Mg17Al12, Mg2Sn and Al11Ce3. The hardness values of the alloys were increased with the addition of 0.5%, 1 and 2 cerium. With the addition of 0.5 wt.% Ce, the yield strength increased to 145 MPa. With the addition of 2 wt.% of Ce, it was found to be 160 MPa with an increase of 14%. Tensile strength was obtained as 190 MPa. Elevated temperature tensile test was carried out at 120°C, 180°C and 240°C, to all the alloys. It was found that increased Ce ratio increased the high-temperature mechanical strength. At 120°C, the highest tensile and yield strength values were obtained with 159 MPa and 147 MPa, respectively, in the alloy with 2% wt. cerium added. In the tensile test performed at 180°C, the highest tensile and yield strength were measured as 91 MPa and 77 MPa, respectively. The operating temperature of Mg alloys produced industrially by HPDC has a significant effect on mechanical properties. High operating temperatures reduce mechanical properties. However, the mechanical properties at high test temperatures were increased by the addition of Ce metal to the AM60-1Sn-XCe alloy produced with HPDC.

Study on the Austemperability of Thin-wall Ductile Cast Iron Produced by High-Pressure Die-casting

The production of thin-wall ductile iron (TWDI) by high-pressure die-casting (HPDC) is complex because of several metallurgical and microstructural challenges. The present work aims to evaluate the austemperability of components (4 mm thickness) produced by HPDC process. The graphitization kinetics, the pearlite formation during continuous cooling, and the effect of austempering on the evolution of the ausferritic microstructure were investigated using dilatometric tests, microstructural analysis as well as Vickers hardness tests and tensile tests. Results show that components exhibit a brittle behavior because of white structures, small shrinkage cavities, and microporosity in the as-cast condition. Graphitization at 1100 °C allows rapid formation of small graphite particles within a short time (40 s). The critical cooling time (t8/5) to avoid the formation of pearlite upon cooling was found to be 5 s at a martensite start temperature of 193 ± 14 °C. Austempering at 360 °C for 40 min results in an ausferritic microstructure with stable carbon-enriched austenite which provides a high hardness (355 ± 4 HV10) and tensile strength (Rm = 709 ± 65 MPa). The results represent main criteria regarding the producibility of die-casted TWDI, which are helpful for future alloy and heat treatment design.

A high pressure die cast magnesium alloy with superior thermal conductivity and high strength

Thermal conductivity is a key parameter for high performance material needed for electronic devices. While most commercially used Mg foundry alloys exhibit low thermal conductivities. In this work, we developed an Mg–3RE–0.5Zn alloy that is suitable for high pressure die cast (HPDC) ultrathin wall cellphone components. The thermal conductivity of this alloy was measured to be 133.9 W/(m·K) at room temperature, approximately 85% that of pure Mg (156 W/(m·K)). Meanwhile, it exhibited acceptable room-temperature mechanical properties with high yield strength of ∼153 MPa, ultimate tensile strength of ∼195 MPa, and elongation of ∼4.3%. The excellent combination of superior thermal conductivity and high strength is attributed to low solute atoms in the α-Mg matrix and the formation of networked (Mg, Zn)12RE eutectic phase. The results from this study will be helpful for developing new HPDC Mg alloys with more excellent performances and promoting the wider application of Mg alloys.