Author links open overlay panelJian Yang abc, Bo Liu ac, Dongwei Shu b, Qin Yang d, Tiegang Hu dShow moreAdd to MendeleyShareCite
https://doi.org/10.1016/j.jallcom.2025.178552Get rights and content
Abstract
The Giga-casting process, proposed by Tesla, has become a transformative technology with great potential for improving the lightweighting of super-sized complex thin-walled vehicle parts. Recently, the application of lightweight alloys, especially Al alloys, in the vehicle industry is gradually expanding, but there are fewer reports reacting to super-size Al alloy parts. The overall goal of this paper is to provide a detailed summary of the development and advancement of the revolutionary giga-casting technology. This paper summarizes the development process of die casting Al alloy materials, die casting machines and molds, and discusses the latest research on giga-casting technology in terms of materials, processes, structural optimization, property analysis, and applications. In addition, the whole process development technology route for super-sized castings is introduced through actual production cases to enhance the confidence of companies in developing new parts. Finally, the multiple challenges facing giga-casting technology and how to face them are sorted out. Overall, this paper provides an in-depth discussion of giga-casting technologies, highlighting their potential and future expanded applications in automobiles.
Introduction
Aluminum (Al) alloy die casting is one of the hot technologies for body lightweighting, imposing increasingly stringent requirements for lightweight, high toughness, and corrosion-resistant castings [1], [2], [3]. Die casting process is defined as filling fluid metal or semi-fluid metal into a mold under high pressure and high speed, forming and solidifying under pressure, and finally obtaining a casting [4], [5]. Due to the casting has the advantages of high dimensional accuracy, high strength, high material utilization, so die casting technology is widely used in the manufacture of complex shape, bear moderate load components [6], [7].
In the realm of vehicle lightweighting, die casting technology is developing in the direction of large size and high degree of integration [8], [9]. In 2019, Tesla creatively proposed giga-casting technology [10]. Tesla used the giga-casting process to produce the rear floor plate, reducing the number of parts from 70 to just 1. The distinguishing feature of giga-casting is its ability to produce exceptionally large parts. It was a brave decision to extend this technology to even larger parts [11], [12].
Tesla's application has garnered unprecedented attention to the integrated die casting process, especially in China, where giga-casting technology has entered a phase of rapid development, with continuous new research advancements. NIO automobile, ZEEKR automobile, HiPhi automobile, Xiaomi automobile and other Original Equipment Manufacturers (OEMs) are increasingly adopting the giga-casting process to produce ultra-large parts, such as front nacelles and rear floors. The tonnage of the die casting machine has also developed from the original 4000 T to the present 13000 T.
Simultaneously, interest in pursuing more advanced non-heat treatable Al alloys is growing through research into the materials currently used for super-large vehicle components [13], [14]. Specifically, two categories of materials can significantly contribute to automotive lightweighting [15]. The first is lightweight materials with low density and high strength, such as Al alloys, Magnesium (Mg) alloys and ceramic materials. The second category involves high-strength steels that share similar density, modulus of elasticity, and excellent processability. In automotive, aerospace and other industries, Al alloy die casting parts offer exceptional weight reduction capabilities and are among the primary materials employed to meet stringent lightweighting requirements [16], [17]. Recently, Chongqing University published research progress on the High Pressure Die Casting (HPDC) process of Mg alloys, offering valuable insights into the future potential of integrating Mg alloys into HPDC components for super-sized automobiles [18]. This research also provides ample evidence of the promise of lightweight alloys for giga-casting technology. Meanwhile, studies have demonstrated that thin-walled HPDC Mg/Al alloy parts perform well in high-temperature strength, ductility and creep resistance [19], [20], [21]. This is mainly attributed to the fine dendritic arm spacing and the strengthening phase [22], [23]. However, the application of Mg/Al alloys to high-temperature environments remains fraught with considerable uncertainties and potential risks [24]. These challenges must be carefully evaluated in the context of specific application scenarios and temperature requirements. Thus, the development of Mg/Al alloys has a huge potential in advancing the vehicle industry's search for effective lightweighting solutions.
Currently, although there exist several literature reviews of lightweight alloys in automotive, aerospace, and construction machinery, these primarily focus on industrial case studies [25], [26], [27], [28], [29]. There are fewer review articles on lightweight alloys, especially die casting Al alloys, for vehicle applications. Several factors contribute to this gap, including the rapid development of giga-casting process, the limited number of vehicle super-sized Al alloy parts in mass production, the complexity of giga-casting technology, the failure to form a research and development system, and the difficulty of real-time tracking of related literature. Thus, it is essential to conduct a comprehensive review of the application of die casting Al alloy in vehicle parts, and also provide a reference for OEMs to study giga-casting technology.
The overall goal of this paper is to provide a novel roadmap for the development and advancement of giga-casting technology with advanced capabilities. This paper reviews the current development process of non-heat treatable die casting Al alloy material, die casting machine and mold, and elaborates on the current research status and development prospect of giga-casting technology in material, process, structure optimization, property analysis and application. Of particular significance is the introduction of a comprehensive development roadmap for super-sized components, illustrated through actual OEM cases, which provides valuable insights for companies and manufacturers engaged in vehicle lightweighting research. Meanwhile, the challenges faced by giga-casting technology and how to overcome them are discussed in terms of technological barriers, national policies and regulations, and environmental and energy protection, as well as the outlook for the future. Fig. 1 illustrates the giga-casting process knowledge tree system. Section 2 describes the characterization and development process of non-heat treatable materials. In Section 3, the research on giga-casting techniques for production flow and process optimization is reviewed. Section 4 discusses the contribution of mode flow simulation techniques in structural optimization. Section 5 explores various technical approaches for analyzing both the overall and localized properties of a part. Section 6 presents a detailed overview of casting application cases in automobiles and shares the company's actual production experience. Section 7 describes the prospects and difficulties in the application of giga-casting technology. Finally, Section 8 summarizes the whole paper.
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Section snippets
Development progress of non-heat treatable die casting Al alloy materials
While maintaining vehicle performance, the use of lightweight materials can reduce energy consumption [30]. The material lightweight can reduce the difficulty of the relevant departments in the production process, and reduce the cost to a certain extent [31]. In conventional production methods, the mechanical properties of Al alloy die castings are often not guaranteed. Thus, the parts are generally heat-treated to meet the properties requirements [32], [33], [34], [35]. Previous studies have
Die casting process and structure optimization
Giga-casting technology is derived from HPDC technology, which is vacuum-assisted based on HPDC to solve problems such as air rolls and porosity caused by high speed and high pressure [74]. Structure optimization, mold flow simulation and process parameter settings directly affect the die casting results [75]. Reasonable setting of these parameters can optimize the die casting results and effectively control the quality of die castings [76].
Structural optimization
The use of castings can markedly reduce the number of components required in a body-in-white structure, resulting in significant savings in both manufacturing time and costs [142]. In vehicle design, part structures must meet numerous objectives, including requirements for vehicle dynamic stiffness, dynamic response, and driving comfort. However, taking multiple requirements into account at the same time usually results in a higher weight. To fully harness the potential of lightweighting,
Influence of processes and defects on mechanical properties
Defects within the casting after molding can affect the mechanical properties of the part, and fracture toughness assessment of lightweight alloys is a critical step in controlling the material and process [60], [106], [129], [163]. As illustrated in Fig. 8, through a large number of investigations, the analysis of mechanical properties of die casting alloys is mainly divided into four directions: (1) Experimental design: Through the process parameter regulation, investigate the effect of
Vehicle application extension and typical case
Die castings are widely used in automobile, home appliance, electronics, machinery and many other industries [231]. Accordingly, this section focuses on the application and extension of giga-casting technology in automobile and other fields. Furthermore, this paper presents a case study of the full-process development of an Al alloy giga-casting front nacelle for Chongqing Changan automobile. It includes forward integrated design, material selection, simulation analysis, mold design,
Advantages
Production cost advantage: Giga-casting technology eliminates the need for extensive welding auxiliary equipment, robotic systems, and other production machinery, thereby optimizing plant space utilization and substantially lowering production costs [267], [268]. Moreover, the giga-casting process achieves a material utilization and recycling efficiency exceeding 95 %. The large reduction in the number of welding points on the car body also reduces the need for a large number of workers.
Conclusion
- 1)The giga-casting process represents a disruptive innovation in the field of automobile manufacturing, with die casting machines anticipated to evolve into pivotal equipment in this domain. In alignment with the promotion of the “dual carbon” goals, giga-casting technology demonstrates significant advantages in areas such as efficiency, safety, cost reduction, and emission reduction. Nevertheless, giga-casting technology faces substantial barriers, including software development and application,
CRediT authorship contribution statement
Dongwei Shu: Writing – review & editing, Validation, Supervision, Resources, Methodology, Formal analysis. Bo Liu: Supervision, Software, Resources, Project administration, Methodology, Investigation, Funding acquisition, Formal analysis, Data curation, Conceptualization. Jian Yang: Writing – review & editing, Writing – original draft, Visualization, Validation, Software, Methodology, Investigation, Formal analysis, Data curation. Tiegang Hu: Methodology, Formal analysis. Qin Yang: Validation,
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgement
This work is supported in part by the project is supported partly by the Fundamental Research Funds for Central Universities (No.00007735) and Chongqing Technology innovation and application development project (No. 08400110). And this research paper is funded by the China Scholarship Council. All research cases in this paper were provided by the corresponding author Bo Liu and the companies, And they are all publicly available and unclassified data.
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