EuroWire May 2023

Technology News

Ultra-fine-grained high-strength steel When standard steels need to have specific characteristics, expensive alloying additions and supplementary heat treat- ment are generally used. Steeltec AG, a company of the Swiss Steel Group, has developed an alternative technology for this purpose. • Components can be re-dimensioned without losing mechanical-technical properties, making component design more flexible

the Swiss Steel Group use austenitisation to determine the material properties and grain size of the steel microstructure. The steel bar is then immediately cooled to the desired forming temperature and fed into the high-reduction roller unit. Steels suitable for XTP treatment are unalloyed steels, precipitation-hardened ferrite-pearlite steels, bainitic steels, quenched and tempered steels, tool steels, austenitic stainless steels, ferritic stainless steels and high-speed steels. Swiss Steel Holding AG https://swisssteelgroup.com

• Given the straightness of the bars, lengths of up to 8,000mm (-0/+200) are available with tolerances compliant to DIN EN ISO 286-2 *h11 • No thermal distortion and no need for additional heat treatment While XTP-treated steel looks like conventional steel on the outside, the ultra-fine-grained steel microstructure provides extra material resistance and strength.

The company, which developed “Extreme Performance Technology” (XTP®), has found a way to produce an ultra-fine grained and tough high-grade steel that removes the need for additional alloys and special treatment by using a controlled thermomechanical processing phase. Systematic temperature control and alternative forming processes produce an ultra-fine-grain microstructure with grain sizes of less than 5µm. Steel produced in this way is noted for improved properties with better dynamic and mechanical characteristics, including: • Improved tensile strength of up to 2,050 MPa • Improved dynamic load capacity by at least ten per cent, leading to longer service life and higher operational safety • Improved properties despite higher tensile strength • Formability and machinability

XTP steel withstands challenges such as intense vibration, high internal pressure or extreme cold. Even at ultra-low tem- peratures of -101°C, at which conventionally produced steel can become brittle and crack or break, the technically optimised steel grades have a high toughness (notched bar impact work of more than 27 joule in notched bar impact testing). to induction heating, the experts of When subjecting steel

Sectional images showing the microstructure

Accumulator with just ten newtons of tension force

to allow, for example, a spool change to be carried out while the extrusion line continues to produce. The accumulators process products with a diameter of up to 15mm and can also simultaneously take over the function of a dancer for payoffs or take-ups within a production line. For optimal process monitoring, the accumulators can be equipped with tension measurement and control. Kurre Systems supplies accumulators in various designs, both as individual units and as part of complete systems. These can be individually adapted to the customer’s needs. In addition to the required storage capacity and the material and product properties, structural condi- tions such as available shop floor size are taken into account. Kurre Spezialmaschinenbau GmbH www.kurre-systems.de

construction and a revised design of the dancer unit. The accumulator retains its usual stability and functionality. With approximately 100m of capacity for the vertical accumulator and 240m for the horizontal accumulator, both machines ensure that enough product is buffered

For the processing of particularly sensitive products, Kurre Systems has reduced the minimum tension force for the vertical and horizontal accumulators to 10 newtons. This has been made possible by the combination of a smoother and lighter

Lower friction and lighter design make low tensile forces possible for thin products

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May 2023