Quenching and tempering of wheels for high-speed trains – Hardening in combination with mathematical model enhances process security
The newly developed wheel rim hardening machines from Tenova LOI Thermprocess adapt flexibly to rolling stock wheels of different shapes and sizes, allowing operation without interruptions to production even if wheel sizes are frequently changed. In combination with a mathematical quenching model, the new machines significantly reduce the time required for tests and also ensure higher process security.
With the individually controlled nozzles, the wheel rim hardening machines are so flexible that they can be used for treating wheels of almost any dimensions. The new control system allows the cooling table program and the adjustment of the nozzles to be changed from batch to batch. This means that batch changes can be completed automatically without any interruption to production. Nevertheless, precise repeatability of the quenching and tempering processes is ensured for each specific batch.
The designers of the hardening tables were faced with the task of developing an extremely robust system without using any sensitive mechanisms. As a result, the new tables have significantly fewer parts than those previously used. The tables consist mainly of standard components available from stock, meaning that spare parts can be delivered quickly.
Especially for plants in countries with high ambient temperatures, it is important to note that the new tables use water temperature ranging from 30 to 35°C. It is no longer necessary to cool the water to 20°C.
Mathematical model saves time and enhances process security
The new hardening tables immediately proved themselves in practice on a recently installed fully-automated quenching and tempering line for railway rolling stock wheel rims. LOI used a mathematical model developed especially for hardening as well as a quenching program computer. Using this computer, quenching parameters are calculated to ensure that the wheels reach the specified values, even after product changes.
Using this model, LOI has reduced commissioning times from up to one year to a few weeks. The customer saves material and laboratory time and can also start production earlier.
Background
The furnace technology used in heat treatment plants has already reached a very high standard. In contrast, on many manual or semi-automatic treatment lines, the quality of quenching still depends on the qualification and experience of a few employees. The hardness required is normally reached but the microstructure does not always meet the requirements set out in standards. Especially for high-speed train wheels, it is crucially important for process parameters to be reproducible within very tight limits.
To date, the development of programs for new products and the running-in phase following product changes have been extremely time-consuming and have resulted in considerable material losses. Until wheels meet the required specifications, they must be destructively tested so that metallurgical parameters can be inspected over the cross-section of the wheel.
The model developed by LOI receives the specified properties of the finished wheel as inputs and calculates quenching parameters from the geometry of the wheel and the material composition. This procedure is independent of the various national standards which need to be applied.
About LOI
LOI Thermprocess is a company of the Tenova Group focusing on the heat treatment of steels and aluminium. More than 4,000 industrial furnaces bear the LOI name, making LOI a brand that stands for quality, economics and continuity.
The treatment of metals calls for a profound knowledge of metallurgy, physical and chemical processes and a number of engineering disciplines. Many years of practical experience are equally important. The unique background of the LOI team has laid the foundations for the company’s strong position on the international market.
LOI has developed mathematical models for the highest possible quality levels in production on the basis of precise knowledge of the physical relationships involved. LOI sees itself as a technological partner to the customer and its plant designs are closely linked to the requirements faced by customers’ products.
We not only have the know-how to build economical, reliable industrial furnaces. We also have in-depth knowledge in the following areas:
– Quenching processes using liquid and gaseous media
– Coating and thermochemical surface treatment processes
– Thermal surface cleaning in reactive atmospheres
– Automation and throughput optimization
– Burner technology
Firmenkontakt
LOI Thermprocess GmbH
Andrea Kehry
Am Lichtbogen 29
45141 Essen
+49.201.1891-301
+49.201.1891-5301
andrea.kehry@tenova.com
www.tenova.com
Pressekontakt
VIP-Kommunikation
Regina Reinhardt
Süsterfeldstraße 83
52072 Aachen
+49.241.89468-24
+49.241.89468-44
reinhardt@vip-kommunikation.de
www.vip-kommunikation.de
