Recently, the construction of China’s largest-diameter open hard rock boring machine (TBM) officially started in Changshu City, Jiangsu Province.
The most milestone breakthrough of this large and heavy machine with an excavation diameter of 13.2 meters is that it is equipped with the 7600 domestic rare earth special steel main bearing for the first time, becoming the first ultra-large diameter excavation equipment in China to use domestic main bearings.
The main bearing of tunnel boring machine is equipped with “heart”
The implementation of localization and the overcoming of a full set of core technologies not only broke the decades-long technology monopoly of foreign companies, but also marked the realization of my country’s independent control of the entire industry chain in the field of ultra-large-diameter underground engineering equipment, providing core technical support for major national infrastructure such as rail transit, water conservancy projects, and cross-river and sea passages.
Full-section hard rock boring machines (TBM) and shield boring machines are the core equipment of modern underground engineering and are widely used in key national infrastructure scenarios such as mountain tunnels, water diversion projects, urban subways, and cross-river passages.
As the core component of the cutterhead drive system, the main bearing undertakes the key functions of rotating cutting, load bearing, and stable operation, which directly determines the reliability, service life, and construction efficiency of the equipment.
For a long time, the core technology of the main bearings of ultra-large-diameter boring machines has been monopolized by international giants. my country’s high-end main bearings have long relied on imports. There are problems such as high procurement costs, long delivery cycles, technical blockades, and limited after-sales, which have become the core bottleneck restricting the independent controllability of my country’s boring machine industry.
With the acceleration of major national infrastructure projects, the localization of main bearings has become an inevitable choice.
The 7600 type domestic rare earth special steel main bearing installed on the 13.2-meter TBM was developed by the Institute of Metal Research, Chinese Academy of Sciences after more than ten years of technical research and development.
At the material technology level, we have made breakthroughs in the key technologies of low-oxygen rare earth steel and greatly improved material performance; at the engineering application level, we have fully mastered the entire process technology and formed a complete independent intellectual property system.
The 13.2-meter open hard rock TBM started by CCCC Tianhe has 100% localization of core components, opening up the national domestic production of underground engineering equipment in my country.
“The last mile”.
From the perspective of industry development pattern, the localization rate of my country’s domestic excavation equipment continues to increase. This time it is equipped with domestic main bearings, which makes up for the shortcomings of the core components of high-end equipment and enhances the global competitiveness of my country’s high-end excavation equipment.
The localization of the main bearings of tunnel boring machines has led to the upgrading of the entire industry chain, benefiting many leading A-share companies.
Complete machine manufacturing leaders such as China Railway Industry, China Railway Construction Heavy Industry, and CCCC Tianhe; Xinqianglian, the leader in main bearing core components; CITIC Special Steel and Baotou Steel Co., Ltd., the leaders in rare earth special steel materials; Hengli Hydraulics, China Tungsten High-tech, the leaders in supporting core components, all played an important role in this technological breakthrough.
The localization of ultra-large diameter main bearings has three core strategic values: ensuring the safety of major national projects, enhancing the global competitiveness of the industry, and cultivating new productivity for high-end equipment.
In the future, my country’s tunnel boring machine main bearing industry will show a development trend of larger sizes, intelligent operation, and diversified applications.
In 2026, the construction of the largest domestically produced hard rock boring machine equipped with domestically produced main bearings will begin, which is a milestone breakthrough in the field of high-end equipment manufacturing in my country.
This achievement provides core support for major national infrastructure projects, drives the growth of A-share enterprises throughout the industry chain, and promotes the transformation from Made in China to Created in China.
In the future, my country’s underground engineering equipment industry will occupy a dominant position in the global high-end equipment competition and provide solid equipment and technology support for China’s modernization drive.
