"Shenyang Fan Style" equips shield tunneling machine with "Chinese heart"

- The first 3-meter main bearing for tunneling machine in China has successfully completed the demonstration application project of the extension line of Line 1 of Shenyang Metro.

Hu Xiaohuang (right) led the research team to advance the research and development of large main bearings for domestic shield tunneling machines.

The shield tunneling machine is a divine tool for excavating tunnels, and the main bearing the core key component of the shield tunneling machine's cutter head drive system, known as the "heart of the shield tunneling machine." For a long time, the "heart the shield tunneling machine" has been the only core component in domestic shield tunneling machines that has not been domestically produced. It has not only been "choked" in technology has also been restricted by foreign enterprises in terms of product price, delivery cycle, and after-sales service.

On May 8th, the ceremony for the successful connection of demonstration application section of the "High-end Bearing Independent Controllable Manufacturing" strategic leading science and technology special project of the Chinese Academy of Sciences (hereinafter referred to the leading special project) was held at the Institute of Metal of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Metal). The first 3- main bearing for shield tunneling machine in China has successfully completed the demonstration application section of the extension line of Line 1 of Shenyang Metro, setting a benchmark for the local transformation and of scientific and technological achievements and demonstrating the "Shenyang Style" of key basic component research and development and application of major equipment in China

 Over the past few days, journalists have had face-to-face exchanges with this research team, which is made up of12 different scientific research units and more than 200 scientific researchers, and has a steel will. They have learned how they broke through numerous difficulties and achieved the most, important, and difficult link in the road to full domestic production of tunnel boring machines, turning a new page in the history of 100% autonomous manufacturing of tunnel boring.

 "Three lines" link up to create an innovative safeguard mechanism

As the lead unit of the pilot project, the Metal Institute, based on the administrative command line and technical command line, pioneered the Party Committee safeguard line, which links up the top and bottom, the Party and government, and multiple parties to provide a solid safeguard for the successful of the pilot project.

 In 2020, the pilot project of the Chinese Academy of Sciences was launched, aiming at the independent research and development of three types high-end bearings, and breaking through the "last mile" of autonomous controllable manufacturing of high-end bearings.

The pilot project is of great significance and cannot be lightly. The Metal Institute has a heavy responsibility and is determined to move forward.

 Materials are the foundation and starting point for the autonomous controllable manufacturing of high-end. Led by the chief scientist of the pilot project, researcher Li Dianzhong of the Metal Institute, and Academician Li Yiyi of the Chinese Academy of Sciences, technical command line started with the source of materials to solve key technological problems.

 The research team deeply realized that the development of domestic high-end bearings must follow their own route, and not follow others. They firmly believe that the rare earth bearing steel developed by the Metal Institute has the potential to become a "game-changer" technology for Chinas high-end bearing steel.

 The Metal Institute has a history of more than 60 years of research on rare earth steel, spanning four generations of scientific researchers. Dianzhong's team found that the reason for the instability of the performance of rare earth steel is that there are large particles of inclusions in the material, which are after the addition of rare earth raw materials. The research team visited the main rare earth production enterprises across the country and went deep into the rare earth production workshops, finding the cause of excessive oxygen content in rare earth materials. Subsequently, the research team developed key technologies for low oxygen rare earth steel, and prepared low oxygen rare earth steel with excellent performance and good. Using low oxygen rare earth steel to prepare bearings, its pull-press fatigue performance is improved by more than 40 times, and its rolling contact fatigue performance is increased by 40%.

As the chief engineer for the research and development of the main bearings of the shield tunneling machine, Hu Xiaqiang, researcher at the Institute of Metal Research, has been tirelessly dedicated to the development of the first domestically produced large-scale main bearings for shield tunneling machines since the project was launched He said, "Faced with challenges, we have carried forward the spirit of the older generation of scientists at the Institute of Metal Research to focus on the front line, identify and problems, and lead scientific research. We are the 'national team' for material science research, and it is our duty to take the lead in solving the 'bottleneck problems in the field of materials. We must stand up."

Hu Xiaqiang introduced that from high-end materials to high-end bearings, there are more than 00 processes including forging, machining, heat treatment, etc., and none of the design, evaluation, and application can be neglected. In terms of design, the team initially did not know much, and there was no clear concept of why various parameters were like this. The project team did not fully grasp the basic situation of which work can be by the scientific research team, research institutions, and enterprises in the domestic bearing industry chain. Faced with the current situation of tight schedule, heavy tasks, and weak foundation, Xiaqiang and team members started with finding literature and conducted extensive investigations and studies all over the country. In more than three months, they traveled to 16 provinces and municipalities Hard work pays off. With Hu Xiaqiang's efforts, a particularly combat-capable and dedicated combat team was organized.

Hu Xiaqiang led the team to production front line and successfully broke through the problems of high-precision machining and precision retention of large main bearings, breaking through the first-level precision machining technology of large roll.

The machining accuracy of the 8-meter diameter main bearings is particularly high, but in the past, domestic manufacturers were limited by imported equipment, and the machining could only reach the second level. If the 900-plus rollers with different sizes and specifications, with a maximum diameter of 130 millimeters, cannot precisely machined to meet the shape and performance standard requirements, the development of large main bearings will fail. After repeated experiments, the scientific research team maintained consistency in the machining and precisely controlled the machining process, and finally achieved the dimensional stability and precision retention of the rollers. Hu Xiaqiang said: "The first-level precision machining an important breakthrough, which provides more possibilities for the research and development of major equipment and key components in other fields."

 Whether it was the "extreme poverty" when the main bearings with a diameter of 3 meters were first developed, or various problems encountered when aiming for the main bearings with a diameter of 8 meters, such as the mismatch of processing equipment, all put great pressure on Hu Xiaqiang and his members. Hu Xiaqiang always keeps in mind the spirit of the older generation of scientists who are rooted on the front line to contribute to the country. He dives in deeply sets an example, and leads his team members to overcome one difficulty after another. "During the development of the 8-meter diameter main bearings, the equipment of the cooperative could not meet the requirements, which made our efforts hit a wall again and again. But every time we saw the Party flag standing on the site, we felt strength welling up within and were full of energy."

In nearly 3 years, the project team used up 1,467.4 tons of rare earth bearing steel and developed41 large bearing rings, 7,996 rollers, 492 copper-steel composite retainers, and 10 sets of large main bearings for tunneling machines. Among them, the 8-meter main bearings weigh up to 41 tons, which is currently the first largest diameter and single largest main bearings for shield tunneling manufactured in China.

The full power of the technical command line could not be separated from the firm support and comprehensive service of the administrative command line and the Party committee's line.

The Metal Institute has formulated the "Special Management Measures for Independent and Controllable Manufacturing of High-end Bearings" and 10 management implementation rules, institutional guarantee for the high-end bearing attack tasks. A three-level efficient collaborative management structure has been built, and a coordination group has been set up to coordinate with various units push forward, formulate demonstration application plans and risk control contingency plan.

The Party Committee of the Metal Institute organized and coordinated 12 teams from different scientific research units within the and more than 200 scientific researchers to participate in the attack, established a temporary Party branch for the manufacturing of high-end bearings and the "Li Xun Large Heavyduty Bearing Attack Emergency Team" named after the first director of the Metal Institute, Li Xun. The emergency team put forward the fighting slogan of "dive in deeply forge ahead with determination". The team members sacrificed their small homes for the greater good, and fought their way through difficulties, all for the common goal. Team member Gao Yang responsible for following up on the development of the bearing rings and was stationed in a cooperative enterprise in Luoyang for a long time, almost missing the birth of his child. And a few days after the child was born, he said goodbye to his family and returned to the front line, all for the attack on high-end bearings. Examples like Gao are too numerous to mention.

 New System Exploring the Model of Scientific and Technological Attack

 The exploration of an efficient organization mode scientific and technological attack under the new national governance system has led to the establishment of a model for technological attack represented by high-end bearings as key basic components.

 Zuo Liang, director of the Institute of Metal Research, said that the pilot project has brought together seven research institutes of the Chinese Academy of Sciences, and carried out collaborative research and development with universities, research institutes and enterprises across the country. More than 40 institutions in the research. It only took three years to solve the problem of the serious dependence on imported bearings in three typical categories, and a number of significant achievements with distinct results have been.

Hu Xiaoqiang still vividly remembers the selfless dedication of the participating units. He said that when the 8-meter main bearings were being developed, the production capacity in China at that time could only reach the 5-meter level. To produce the 8-meter main bearings, it was necessary to transform the existing equipment, the power supply system, the rotating platform, and the control system. "After learning about our needs, the enterprise did not hesitate and worked together with the on-site scientific researchers study how to upgrade, without even considering the loss of equipment and the subsequent investment."

The successful demonstration and application of the large main bearings in the shield tunneling machine has excitedang Jiyong, general manager of Shenyang Hanwang Precision Bearing Co., Ltd., a subsidiary of Liaoning Hanwang Investment Co., Ltd. " successful demonstration and application of domestic main bearings is a big event in the field of independent controllable manufacturing of high-end bearings in China, which will inject a stronger driving force the development of enterprises in the bearing industry chain."

Over the years, Hanwang Precision has maintained a close cooperative relationship with the Institute of Metal Research in the field of bearing and development for wind power equipment. Hanwang Precision's advantages in bearing design, processing, and manufacturing have been recognized by the pilot project team for the large main shaft of the tunneling machine. "Faced with the first-class precision machining requirements that had never been reached before, the scientific researchers from both sides thought and worked together during the research and process, striving for excellence in the process of quenching, tempering, and temperature control, and striving to do every detail well." Liang Jiyong introduced that in than a month, the scientific research team insisted on the front line, repeatedly cutting the test materials, observing the internal tissue structure of the materials, and looking for breakthroughs in process. With the joint efforts of both sides, the large roller first-class precision machining technology was "born" in Hanwang Precision.

"We have gained experience and mature machining team, and have formed a first-class precision machining process, which has greatly improved the technical capabilities of the enterprise and is a great help to the development of enterprise. In the future, we can undertake more high-precision precision machining business in other fields." said Liang Jiyong. The research and development and demonstration application the large main bearings of the shield tunneling machine have solved the problem of the high-end bearings being "held hostage" and achieved import substitution. At the same time, the promotion implementation of the project have also benefited the participating units in the industrial chain. Hanwang Precision has upgraded its technology and equipment in the process of developing domestic main bearings, which has made driving force for the development of the enterprise stronger. "As an enterprise in the bearing industry chain, we are very optimistic about the industrialization of domestic large main bearings and hope participate in it and contribute to the development of the bearing industry." 

Daring to take on responsibilities and lead by example in application In Shenyang, the demonstration application of domestic main bearings has smoothly promoted, with the key being the government's leadership and promotion. The technical system of domestic main bearings is already complete, fully meeting the conditions for industrialization. most difficult part of the entire chain of key basic components of major equipment is the first application, and the risks contained are self-evident. However, without the first practical application new technologies, new products, and new equipment are like castles in the air, and will also cause tremendous scientific research waste. Large shield tunneling machines can only move forward during tunneling process and cannot retreat. Once the main bearing fails, the loss is unmeasurable. The first application of domestic large main bearings, the risk and difficulty are imaginable.Shenyang Metro Group is the project owner unit of the 3-meter main bearing, China Railway No.1 Bureau is the construction unit, and Beihe Heavy Industry is the shield tunneling machine manufacturer. Faced with the first demonstration application of large main bearings, they all bear tremendous pressure and risk. Scientific judgment in all aspects, breaking the existing framework, daring to provide a place for the application of domestic main bearings, and laying the foundation for the industrialization of domestic main bearings, Shenyang Metro Group and units feel that it is both pressure and motivation. In the bidding documents for the demonstration application section, Shenyang Metro Group wrote "supporting the innovation and application of domestic large bearings" in it, fully supporting the demonstration application of domestic main bearings. China Railway No.1 Bureau, when receiving the shield tunneling machine, asked Beihe Heavy Industry and the Metal Institute for detailed notes on the matters needing attention during use. During the construction process, when encountering the rock stratum, according to the requirements, appropriately adjust the of the cutter head; monitor the working state of the main bearings throughout the process, and do a good job of "nanny" for the application of domestic main bearings. of the installation and use of brand new main bearings, the shield tunneling machine was changed from buying to renting, but Beihe Heavy Industry Group had no complaints. They cooperate with Metal Institute, reserve interfaces on the shield tunneling machine, install sensors, and collect data on the operation of the main bearings.

Xu Chengfa, general manager of Beiyang Heavy Industry Tunnel Engineering Technology Co., Ltd., that the application of domestic bearings in the construction of Shenyang Metro is of a high standard. The main reason is that the geological conditions of the project are relatively complex, with section of rock stratum. The successful completion of the construction task under these conditions shows that domestic large bearings can be used in some relatively complex working conditions.

Xu Cheng told reporters that domestic bearings have a latecomer advantage in price and after-sales service, but to win market reputation and achieve industrialization smoothly, more successful cases of scene are needed to gain more recognition from construction units.

Hu Xiaqiang believes that the independent controllability of the whole process of processing, manufacturing, assembly, commissioning, testing evaluation of large bearings for shield machines is a research system with commonality. It not only achieves the ability of independent research and development of large bearings for shield machines, but also can to the independent research and development of other key basic components of domestic major equipment. At the same time, through the integration of various chains, the ability of industrialization of large bearings shield machines has been formed, which provides a sample for the industrialization of key basic components of major equipment. The smooth application of domestic large bearings fully reflects the charm and tension deep integration of industry, education, research and application under the leadership of the government. The demonstration application of 3-meter-level main bearings provides very valuable application experience for the and promotion of domestic large bearings and other key basic components of major equipment, and creates a "Shenyang model", which is of great promotion value. "A very good application may form a virtuous cycle from research and development to industrialization. With the organization and leadership of the government, institutional mechanism innovation, multi-factor collaborative attack, and efficient application, we believe that the future of domestic large bearings will be brighter."

At the ceremony of the successful connection of the large main bearings of the shield machine, Academician Yiyi said with deep feeling that it was with the strong support of the Shenyang Municipal Party Committee and the Municipal Government and the unity of all participating research institutes that demonstration application of domestic bearings was finally successfully realized. The largest domestically made 8-meter-level main bearings, which were independently developed by the Metal Institute, have now been to be used in the tunnel boring project under the lake.

(Shenyang Daily reporter Yue Yu. All photos in this section are taken by Li Hao, director the Photography Department of Shenyang Daily and Shenyang News Media)