Quality control on rails hot from the rolling mill: voestalpine Schienen GmbH uses digital analysis to prevent defects occurring early in the production stage.
Rail network operators increasingly demand high quality standards for rails. High levels of safety and low life-cycle costs are key.
Quality for long rail life
Each year Europe’s market leader voestalpine produces up to 600,000 tons of rails. Such volumes make seamless quality control a particular challenge. During daily rail operations, surface imperfections can cause defects such as head checks and rolling contact fatigue. Such faults mean that a desired service lifetime for rails of around 40 years can be achieved only through increased maintenance.
Using image processing know-how
Fully automated 3D surface checking of the final products was installed at the rail rolling mills at voestalpine Schienen GmbH 15 years ago. It was an investment required in order to start producing 120 m-long rails.
"“Because of their length, it wasn’t possible to subsequently turn these rails. This meant it was no longer possible to identify all defects simply by examining the rails as they left.”"
Even at that time the voestalpine specialists were already applying their knowledge of digital image processing. By examining the distribution of light in images they were able to compute 3D structures of the rail surfaces, thereby identifying defects completely automatically. Digitalized fault detection on hot surfaces The latest generation of this analytical process is known as DIRIS 3D HOT. It shifts the fault detection procedure upstream, to the rolling process. This allows countermeasures to taken even earlier. The facility offers 100% quality control coverage.
"“This is a huge support for the controller who sees the defect in high resolution on a monitor, and can then inspect it in detail.” "
The DIRIS 3D HOT system projects laser lines onto the glowing rail surface, recording them with high-end cameras. This laser structure is scanned and digitally processed down to a few tenths of a millimeter. Big data—huge quantities of data—are the result. They are reduced to “smart” and manageable quantities of data, and analyzed within only a few seconds. Consequently, defects in the rolled material can be quickly identified and remedied.
More on digitalization at voestalpine: www.voestalpine.com/digitalization