On December 10, the project of "120km/h powder metallurgy aluminum matrix composite brake discs" undertaken by Hunan Jintian Aluminum High-tech Co., Ltd. (hereinafter referred to as "Jintian Aluminum"), a subsidiary of Hunan Xiangtou Holding Group, successfully passed the scientific and technological achievement evaluation meeting organized by Hunan Productivity Promotion Center.
Huang Boyun, academician of the Chinese Academy of Engineering, Xiao Jiayu, professor of the National University of Defense Technology, and other 7 experts composed of experts reviewed the data, inspected the scene, listened to the report of the project completion unit, after questioning, discussion, independent scoring, the expert group agreed that the project in the industry for the first time using powder metallurgy technology to prepare 120km/h rail transit vehicle aluminum matrix composite brake disc, in the aluminum matrix composite composition design, Forming technology and industrial continuous production and other aspects of the formation of a complete set of powder metallurgy aluminum matrix composite brake disc production technology, the overall technology of the project ranks in the international advanced level, some technologies reached the international leading level.
High performance powder metallurgy aluminum matrix composites
Rail transit equipment is lightweight
As a major rail transit country, as of the first half of 2021, China has a total of 49 cities in Chinese mainland put into operation 8448.67 kilometers of urban rail transit lines. According to CRRC's 2020 annual report, the sales volume of urban rail vehicles exceeded 9,000, and it is expected that during the "14th Five-Year Plan" period, the annual number of new urban rail vehicles in China will be stable at about 10,000.
The rail transit industry is huge and faces complex technical challenges. With the introduction of the "double carbon" policy and the development trend of greening and intelligent rail transit vehicles, the demand for lightweight rail transit vehicles has become more and more urgent.
In order to promote the lightweight development of rail transit equipment and key components, the "Made in China 2025" and "13th Five-Year" National Strategic Emerging Industry Development Plan issued by the State Council all mention accelerating the application of new materials, new technologies and new processes for lightweighting advanced rail transit equipment.
As a key component under the spring of rail transit vehicles, the brake disc has attracted much attention from the industry. According to CRRC's relevant data, if the aluminum matrix composite brake disc is used to replace the traditional cast iron brake disc, the weight can be reduced by about 60%, which can not only reduce the weight under the spring of the vehicle, meet the requirements of the axle weight limit, but also significantly reduce the energy consumption of subway operation. Relevant calculations show that a 6-group subway train with aluminum matrix composite brake discs can achieve weight reduction of about 2.4 tons, save about 50,000 kWh of electricity per year, and reduce carbon dioxide emissions by about 50 tons.
Keeping in mind the entrustment of General Secretary Xi Jinping, Jintian Aluminum implements the "three highs and four new" strategy of Hunan Province and contributes to the realization of the goal of "carbon peaking and carbon neutrality". Jiang Zhaoru, chairman of the company, said, "The company has always been adhering to the development concept of 'seeking innovation and innovation only', focusing on the strategic needs of national high-end transportation equipment lightweighting, focusing on high-performance powder metallurgy aluminum matrix composite brake discs, and vigorously supporting the lightweight development of core brake components of national advanced rail transit vehicles." ”
Powder metallurgy process realization
Technological innovation in lightweight aluminum matrix composite brake discs
Jintian Aluminum innovatively used powder metallurgy process to prepare aluminum matrix composite brake discs for 120km/h rail transit vehicles for the first time in the industry, which solved the technical bottlenecks such as the easy aggregation of the existing aluminum matrix composite brake disc reinforcement phase, the limited enhancement phase addition content and the metallurgical defects that are difficult to avoid in the preparation process, and greatly improved the mechanical, wear-resistant, high-temperature and other properties of the aluminum matrix composite brake disc, and the relevant indicators were significantly better than the standard requirements of CRRC and the existing aluminum matrix composite brake discs. Successfully realized the preparation technology innovation and performance upgrade.
Professor Liu Yuxiang, chief technical expert of CRRC, said that as one of the important directions of vehicle lightweighting, aluminum-based composite brake discs have important significance for localization. The powder metallurgy aluminum matrix composite brake disc independently developed by Jintian Aluminum has been applied to the Shenzhen urban rail comprehensive testing vehicle, which is in good condition and can be completely replaced by imported products.
Professor Huo Shuhai, chief expert of Jintian Aluminum, introduced that the project team has invested nearly 5 years to break through the common technical problems of metallurgical combination of aluminum powder oxide film affecting the process of powder metallurgy, established a multi-series database of high-performance aluminum matrix composite materials, and the volume fraction of silicon carbide can reach up to 70%; developed the key process technology of large size, complex structure, integrated powder metallurgy near net forming, and realized the stable and efficient continuous production of aluminum matrix composite brake discs.
Professor Huo Shuhai said that the previous research and development results have laid a solid foundation for the development of aluminum matrix composite brake discs for rail transit vehicles with higher speed grades, and it is expected to be the first in the world to develop aluminum matrix composite brake discs for rail transit vehicles with a speed grade of 160km/h in the future.
It is estimated that by 2025, the annual demand for aluminum matrix composite brake discs for rail transit vehicles in China will exceed 45,000 pieces. Liu Chunxuan, general manager of Jintian Aluminum, said that the follow-up company will continue to increase investment in research and development, improve product performance, reduce production costs, accelerate the release of production capacity, and the future of powder metallurgy aluminum matrix composite brake discs can be expected.
Jintian Aluminum Company Profile
Hunan Jintian Aluminum High-tech Co., Ltd. is a subsidiary of Hunan Xiangtou Holding Group Co., Ltd., founded in 2000, is the first enterprise in China to produce fine spherical aluminum powder by industrialized nitrogen atomization technology, and has exclusively drafted and formulated the industry standard of "Nitrogen Atomized Aluminum Powder", and led the drafting and formulation of the national standard of "Nitrogen Atomized Aluminum Powder".
During the "13th Five-Year Plan" period, the company laid out to the downstream of the industrial chain, carried out the research and development of powder metallurgy aluminum matrix composites and related products, and built the first large-size powder metallurgy aluminum matrix composite lightweight brake disc production line in China, with an annual production capacity of about 12,000 pieces.
The company has built 3 provincial scientific research and innovation platforms, set up a light metal composite materials and key components of Hunan Province science and technology innovation and entrepreneurship team, the existing technology research and development personnel 61 people, foreign experts 1, 7 doctors, 16 masters, 7 senior titles. Relying on the scientific research and innovation platform and the innovation and entrepreneurship team, the company has applied for more than 60 patents in the field of powder metallurgy, and undertaken more than 10 scientific and technological projects at or above the provincial level.
Looking forward to the "14th Five-Year Plan", the company will continue to carry out technology research and development and application promotion around powder metallurgy aluminum matrix composites, and march towards the goal of champion enterprises in the field of powder metallurgy aluminum matrix composites and their products in China and even the world.