Wednesday October 21
Advanced Processes for Environmental Considerations
9:00 am – 10:30 am CDT
Session Chair: Hal Gerber
Reduction of CO2 Emissions and Use of Secondary Aluminum for Structural Castings
Stuart Wiesner (Rheinfelden Alloys); Richard Miller (Nikkei MC Aluminium)
The protection of the environment has become an essential requirement in the automobile industry. Regarding aluminum casting alloys, there are two main directions to reduce CO2 emissions: Improvement of lightweight construction and reduction of CO2 emissions during the production of aluminum (gray energy).
Through improvement of lightweight construction the fuel consumption of combustion engines and the range of electric vehicles can be improved. Recently developed high strength alloys and their effect on weight reduction of structural components are presented. Characteristics such as static and dynamic mechanical properties, joining technologies and casting ability are shown.
The reduction of gray energy can be realized by CO2-free energy sources (e.g. hydropower). Using such green energy even primary aluminum can have a very low carbon footprint. Another option represents the alloy production out of secondary material. In case of structural components and the need for high ductility the use of 100 percent scrap is demanding. The effect of the iron content is shown for different alloys such as AlSi10MnMg (Castaman-35) or AlSi9Mn (Castasil-37) as well as for the high strength alloys AlSi10MnMgZn (Silafont-38) or AlMg6Si2MnZr (Magsimal-plus).
The alloy AlMg4Fe2 (Castaduct-42) opens new possibilities for the application of secondary aluminum for structural components.
E-Mobility vs. HPDC – Special Case: Rotor Casting
Joerg Beck, Bernd Reinwald (AWEBA Werkzeugbau)
Regardless of which mobility concept - BEV, PHEV, etc. - will ultimately prevail, increasing electrification of vehicles can be assumed, particularly with regard to a requested CO2 reduction in emissions.
In this context, rotor casting is also of new importance. Die casting of rotors has been a firmly established technology in the electric motor industry for decades, but until today it has only represented a niche in comparison with the entire die casting industry. Nowadays, a distinction is made between industrial and automotive - rotor casting. In this lecture, the new requirements for rotor castings in the area of automotive applications are presented and, in addition to basic process definitions, the special features, influencing and error variables as well as various tool concepts are discussed. AWEBA’s many years of experience in this area also benefit from the feedback from current projects. Process development in interaction with simulation tools also represents an essential part. Furthermore, a comparison of different tool concepts and their evaluation are carried out.
Semi-Solid Metal Injection Molding (SSM-IM) - The Future of Lightweight Metal Parts
Ashley Stone (MAXImolding)
It is all about quality, as they say. When production output is low and input is high, productivity is very low. Improve quality and you reverse this situation. Output goes up, input goes down, and productivity shoots up. The idea to build quality by inspection is wrong and the results are poor quality and high costs. Dr. W. Edwards Deming is best known for his work in Japan, which commenced in 1950, and created a revolution in quality and economic production.
The four semisolid metal casting processes thixomolding, thixocasting, rheocasting and stress induced melt activation, as well as the cold chamber die casting, hot chamber die casting and other processes such as vacuum die casting, did not fulfill end user expectations for quality, simplicity, energy savings, people safety, economy and environmental cleanliness.
We dedicated all our working life to solve two problems: production of high-integrity net-shape light metal parts while stopping emitting of dangerous gases into the atmosphere, and reducing porosities in moldings (castings). Working to eliminate non-sustainable current approach, Mold-Inspect-Separate Good from Bad and Re-melt Bad Parts we invented and patented a new vertical, environmentally and people friendly Semi-Solid Metal Injection Molding Machine¹ (SSM-IMM). Molding processing parameters optimize without a human operator by closing a real-time x-ray feedback control loop based on parts quality indicators and proper AI algorithms². This is an intrinsically safe, energy and material efficient, environmentally sound magnesium-molding self-learning smart factory with no emission of gases outside of factory parameters.
Advanced Die Materials
10:45 am – 12:15 pm CDT
Session Chair: Steve Midson
The Effect of the Residual Stress which is Induced by Shot Peening at Water Cooling Hole on the Die Casting Die
Yuji Kobayashi (Sintokogio)
The temperature of die-casting die should keep lower than aluminum molten during processing die-casting method in order to prevent adhesion between die material and aluminum molten. Therefore, water cooling hole carry out for cooling die. Usually, water cooling hole carry out from back side of die.
Tensile stress will occur at the surface of water-cooling hole, not only the top area but also side area due to the temperature drift between die and water. As a result, water-cooling hole will break by stress corrosion cracking and fatigue by cyclic thermal stress. Usually, the minimum diameter of water-cooling hole is 3mm and the maximum hole depth is 300mm.
Shot peening is one of the methods to improve fatigue strength by using plastic deformation. In this study, shot peening carry out to prevent stress corrosion cracking on water cooling hole is tried.
In the previous experiment, 1500MPa residual stress is induced on inside of water-cooling hole. Finally, expanding of die life that was applied shot peening can be confirmed on actual production.
The New Premium Grade CS1 – Solution for Die Casting Dies with Highest Surface Requirements
Ingolf Schruff (Kind&Co.)
The die casting industry is facing significant changes of its product portfolio. The development of alternative automotive power systems supplants traditional die cast components of the power train. More and more ambitious structural components, produced by die casting, contribute to weight reduction of passenger cars. Medical appliances or new telecommunication technologies require new challenging die cast components.
Due to technical and aesthetic demands the surface quality of the cast components high importance. Cracks on the surface of dies are directly transferred onto the castings, causing expensive post processing and limiting tool life. Innovations like minimum quantity spray cooling avoid thermal shocks on the die surfaces and contribute to improved surface quality of dies and castings. Simultaneously an increase of the die temperature has to be expected bringing traditional die steels like H11 and H13 closer to their end of applicability.
With premium grades like TQ1 and HP1 Kind&Co has been providing excellent tool materials contributing to improved die performance and die life. In order to match with further increased demands of surface quality Kind&Co has developed the new premium hot-work tool steel CS1. Due to the alloy concept and production process of CS1 dies can be hardened up to 56 HRC developing a very high high-temperature strength, excellent toughness, and thermal shock resistance.
This paper describes the properties of the new premium steel CS1 as well as results of industrial applications in which enormous improvements in lifetime of the dies were achieved and maintenance costs had been reduced drastically.
A New Generation of 3-D Printed High Performance Aluminum Die Cast Dies for Flexible Manufacturing
Harald Lemke (Formetrix Metals)
The presentation highlights case studies outlining the benefits that users experience when easy to print Al Die casting dies were printed using a new tool steel powder material. This new tool steel powder, Formetrix L-40, enables the 3D printing of Al-Die cast dies featuring the highly desirable combination of high hardness and high ductility. More specifically, aluminium die cast dies can now be manufactured featuring a hardness of HRC 48 and a v-notch toughness of >40 - 60 Joule without any further heat treatment enabling thereby the rapid manufacturing of even conformally cooled dies within days. More specifically, the presentation will summarize the superior properties of the new tool steel, Formetrix L-40, as a powder and in its 3D printed condition and benchmark the properties against dies that were 3D printed with M-300 Maraging steel powder or were manufactured from wrought H13. Finally, L-40 case studies with 3D printed conformally cooled, large and small Al die casting dies will be discussed and first technical and economic feedback from auto part production runs will be shared as well as other tooling applications will be introduced.
Use of Additive Manufacturing in Die Casting
1:15 pm – 2:45 pm CDT
Session Chair: Corey Vian
Evaluating Material and Powder Size Characteristics for 3D Printed Die Inserts
Yeou-Li Chu, Patrick Cheng (Ryobi Die Casting); Jianyue Zhang, Xiaoming Wang (Purdue University); Chris Beck (Innovative 3D Manufacturing)
3D Printing/Additive Manufacturing is a fast-growing advanced manufacturing process technology, which offers tremendous freedom to create components with free form and intricate features, directly from CAD and without the need for extensive machining. According to 3D Printing Industry report, the usage of 3D printing equipment is growing very fast. In 2017, it increased by 38% and in 2018, it increased by 52%. Metallic Additive Manufacturing based on powder bed fusion and its application to die casting process has been gaining momentum in recent years as well. There are many successful stories reported, such as eliminating die soldering and reducing cycle time. Whereas, there are still lots of questions regarding how to wisely implement this new manufacturing technology into die casting process. For example, 1) what is the optimal powder characteristics to achieve the best quality of die insert with conformal cooling line? 2) There are two popular materials: Maraging steel and H13 steel, that can be used in die insert 3D printing. Which one is better for die casting process and in what style? This project aims to find answers to these two questions via experimental investigations.
H13-Anviloy Wire Clad HAZ Hardness Minimization using HW-GTAW Temperbead Procedures
Jerry Kovacich, Dennis Harwig (The Ohio State University); Corey Vian (Fiat Chrysler Automotive); Ross Wayman (Astaras)
Die maintenance and repair is one of the largest costs for casting operators. Die life extension and improved repair procedures are valuable pursuits for reducing die casting costs. In this study, H13 tool steel was clad using a new W-Ni-Fe (Anviloy) wire with mechanized hot wire gas tungsten arc welding (HW-GTAW) process. Different welding parameters and sequences were developed to understand how cladding procedures affect H13 Heat Affected Zone (HAZ) hardness. A range of double layer procedures were explored in an attempt to mitigate Post-weld Heat Treatment (PWHT) with temperbead welding techniques. Temperbead welding is often employed in a wide variety of structural steel repair applications to improve HAZ and weld metal properties, but literature on Temperbead welding of hot work tool steels was absent. Anviloy cladded samples were characterized using microhardness mapping to understand the effect of welding on H13 HAZ hardness. Hardness mapping revealed as-welded single pass overlays had a hardness range from approximately 200-700HV, with a continuous high hardness band along the weld fusion boundary. Preferred Temperbead welding parameters using two-layers resulted in H13 HAZ hardness from 200HV-590HV, with isolated regions with hardness above 600HV. Preferred Temperbead parameters resulted in 1% hardness map over 600HV vs. 15% for non-optimized procedures. In-plant trials are planned to evaluate performance of die shot blocks that will be repaired with the preferred Anviloy cladding procedures. These trials will compare the service life of as-welded versus PWHT’d die repairs using optimized procedures.
Control of Thermomechanical Stresses via Conformal Cooling Line Design
Carl Soderhjelm (Worcester Polytechnic Institute); Diran Apelian (University of California Irvine)
Thermal management is essential for high integrity die castings. Higher quality castings require careful control of the solidification front which is controlled by the direction of heat flow. To increase productivity in die castings, rapid heat removal is crucial which requires well placed cooling lines. Metal additive manufacturing enables precise placement of cooling and heating channels within tools and dies. However, inserts with conformal cooling channels could suffer early failure due to high levels of internal stress. Thermomechanical stress arises due to thermal expansion of the material in a temperature gradient. The temperature gradient is determined by the heat flow through the mold and the shape of the cavity with the cooling line placement will determine the thermomechanical stress state in the die. Additive manufacturing enables cooling lines to be place cooling lines in very close proximity to the surface of the cavity. The close proximity of cooling lines to the solidifying casting can cause large thermal gradients and thermomechanical stress. The influence of cooling line design and placement on thermomechanical stress will be reviewed and discussed.