The Wheel Changes the World! Explore the Hard-core Technology Behind the Iron Dragon

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In the grand map of modern transportation, high-speed rail, subway, light rail, etc. are like giant dragons, efficiently shuttling between cities and villages, weaving the dream of regional interconnection. The reason why these "steel dragons" can run as fast as the wind is inseparable from a group of precise and complex parts, and even more inseparable from advanced rail transportation equipment technology.

What secrets do these parts contain to support the operation of such a huge machine? What kind of technology allows them to withstand thousands of times of pressure and impact? Recently, the reporter went to Shanxi Province to explore the hard-core technology behind these parts and how it supports the development of transportation in a big country.

Subway wheels. Photo provided by the interviewee

Rumble, rumble, subway trains shuttle back and forth on the tracks. The wheels roll, like the heartbeat of a giant dragon. Although they are not visible, they are the core and key components of the train structure. Every rotation carries the heavy responsibility of safety and stability. However, it is not easy to ensure that these key components can operate stably for a long time.

"During the operation of the subway, due to frequent starts and stops, some parts of the wheels wear quickly and some parts wear slowly, which can easily lead to a relative deterioration of the entire profile. This is a problem that has long plagued the entire industry." Wei Huacheng, director of the Technical Center of Taiyuan Heavy Industry Rail Transit Equipment Co., Ltd. (hereinafter referred to as "Taiyuan Heavy Industry Rail Transit Company"), told reporters that this requires subway wheels to have high wear resistance and resistance to out-of-roundness.

The so-called anti-out-of-roundness refers to the ability of the wheel to resist wear and deformation and maintain its original profile during long-term operation. Wen Qi, a material research specialist at Taizhong Rail Company, added: "If the anti-out-of-roundness is insufficient, the wheel circumference will be partially flattened and the overall circumference will develop into a polygon, causing the vibration and noise of the subway train to increase, and even threatening driving safety."

To effectively solve this problem, the R&D team has taken a series of targeted measures. They have given the steel body extraordinary toughness through materials, processes, technology and the ultimate pursuit of excellence.

"First, we started with material design and developed customized high-strength and toughness wheel steel for subway wheels, and improved the overall performance of the wheels by precisely controlling the chemical composition. In addition, we optimized the heat treatment process to increase the hardness of the wheel while also increasing the toughness of the material by more than 20%, taking into account the wear resistance and crack resistance of the wheel." Wen Qi said.

When subway trains run at high speeds, cutting through the four seasons of cold and heat, anti-out-of-roundness is not only a game between wheels against time and pressure, but also a fusion of technology and art.

In view of the different terrain and climate environments in my country, the R&D team also has corresponding technical considerations for subway wheels. Wen Qi told reporters, "For example, in cities with more mountainous areas, we need to focus on the ability of the wheels to resist damage. In northern cities such as Harbin and Shenyang, we need to consider the low-temperature performance of the wheels, and we will add low-temperature impact tests during the experimental stage."

From the laboratory to the application field, these wheels not only cross the geographical longitude and latitude, but also forge ahead in the unknown areas of materials science.

From theoretical exploration in the laboratory to practical application, an important threshold needs to be crossed: the production workshop. In the smart factory of Taizhong Rail Company, miracles happen every 52 seconds. With just a click of the mouse, a brand new wheel is born in the digital production line.

Wei Wei, a heat treatment worker at Taizhong Rail Company, told reporters that the full automation of the wheel production process means that there is no need for human intervention in the transportation, heating, rolling and forming of each steel billet.

The deep integration of intelligence and digitalization has not only greatly improved production efficiency, allowing front-line workers to transform from "specific executors" to "process managers", but also achieved a multi-party balance between quality control, scrap rate reduction and cost control.

At the Taizhong Rail Wheel Production Line, the reporter noticed that a "small black box" was attached to the core transmission components of the key forging and rolling equipment. Zhang Xiaofeng, wheel process supervisor of Taizhong Rail Company, told the reporter that these "small black boxes" are actually temperature and vibration sensors, whose main function is to collect the operating data of the equipment and determine the abnormality of the equipment through analysis. "For example, if abnormal vibration of a bearing is detected, the relevant parts can be analyzed and some maintenance suggestions can be given to avoid equipment failure."

By deploying more than 260 such sensors, the smart production workshop can monitor and respond to various potential risks in real time, providing comprehensive protection for the safety of workers while also improving the comfort of the working environment.

Therefore, in the process of building a smart production workshop, a big challenge is to deploy enough sensors to collect richer and more subtle data, so as to provide a solid foundation for model optimization training, and then realize data self-diagnosis, self-analysis, self-prediction and model self-iteration. It is this extreme control of details and unremitting pursuit of perfection that makes the smart factory of Taizhong Rail Company stand out in the global manufacturing industry, and won the title of "Lighthouse Factory" representing the top strength of global smart manufacturing and the highest level of digitalization in the industrial field, and ranked among the "most advanced factories in the world".

The smart factory of Taiyuan Heavy Industry Rail Transportation Equipment Co., Ltd. was awarded the title of "Lighthouse Factory". Photo provided by the interviewee

The wheels roll forward, and the "lighthouse" shines brightly. From the ingenuity of precision manufacturing to the efficient innovation of intelligent production, this place has witnessed the gorgeous transformation of China's rail transportation equipment industry, and also witnessed China's outstanding innovative spirit and efficient innovation speed.