Thousand-degree heat conquered! Steel Rail steel unveils its digital twin

The turnouts, known as the‘steering wheel' of a train，bear the safety of thousands of passengers. Even a crack thinner than a hair inside

could lead to an accident under the repeated rolling of trains day after day.

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At the turnout production base of CRBBG Nanjing Company, the painting line has increased the efficiency of rail spraying by 2.84 times, and the magnetic particle inspection line is moving towards AI intelligent automated testing. However, a more groundbreaking change is taking place in a process once regarded as an‘automation forbidden zone'—amidst thousand-degree heat, engineers have created a‘digital twin' for the turnouts.

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The‘Measurement Forbidden Zone' Under Thousand-Degree Heat

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In the field of turnout manufacturing, high-temperature forging is a core process that determines the forming quality of steel rails—heating the steel rail to over 1000°C and shaping it like kneading dough, which can be called the‘bone remodeling' of steel.

For a long time, the scorching high-temperature environment has been a recognized ‘forbidden zone' for testing in the industry. The common practice is to wait for the steel rails to cool completely and then randomly inspect a few pieces from a batch of products. Once a problem is found, the entire batch may be traced back and scrapped—this leads to serious material waste, and quality risks are also difficult to eradicate.

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"In the past, when working in forging, the most agonizing part was waiting for the test results," recalled a veteran technician. "It would take hours for the steel rails to cool completely, and random inspection felt like a lottery draw. If a problem was found, the entire batch would have to be sent back to the furnace. Back then, we thought, how great it would be if we could see clearly while it's still hot. But how do you measure something over a thousand degrees? To be honest, at the time, we thought this idea was a bit far-fetched."

Faced with this challenge, CRHIC has built an intelligent integrated forging production line, realizing full-process automation of feeding, forging, and testing. The production line is equipped with 360°surround industrial cameras, which can perform real-time 3D scanning on the red-hot high-temperature steel rails, accurately replicating a high-precision 'digital twin' of the steel rail in the digital space.

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The extreme environment of glare, high temperature, and thermal radiation once left testing equipment helpless. Now, it has been overcome one by one by a self-developed vision system. The software reconstructs a 3D model in a matter of seconds, and every arc, every cross-section, and every millimeter of dimensional deviation of the steel rail is clearly displayed. "From ‘bold imagination' to ‘seeing it with our own eyes', it took us several years."

The Quality Control Revolution: From Sampling to 100% Inspection

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Relying on this technology, measurement accuracy and comprehensive testing efficiency have been significantly improved. ‘Random inspection after cooling' has been replaced by ‘100% inspection at high temperature', and the quality of each steel rail is determined the moment it is formed. Supported by the digital twin, the mold maintenance method has also fundamentally changed—upgrading from ‘replacing only when broken' to predicting lifespan based on data and arranging precise maintenance. The lifespan of molds is continuously extended, and the utilization rate of steel has reached the leading domestic level.

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To date, this technology has obtained 25 national patents and published 1 article in a core journal. It has been applied to the urban rail transit turnout market in the Yangtze River Delta, serving domestic projects such as the Chuzhou-Nanjing Intercity Railway and Guangzhou Metro, as well as overseas projects in Southeast Asia and Africa. This makes it a pioneering case in the domestic industry to achieve 100% automated and unmanned inspection for high-temperature forging.

From ‘swinging a sledgehammer' to ‘clicking a mouse', from ‘relying on experience' to 'relying on algorithms', from ‘post-facto random inspection' to ‘real-time 100% inspection'—the transformative journey of a set of turnouts is a vivid microcosm of CRHIC cultivating new quality productive forces and promoting the high-quality development of high-end manufacturing.