Hot Rolling Lines

Flatness measurement under hot conditions often leads to inaccurate and unreliable results. Speed, rapid and large temperature variations, heat shimmering, cumbersome calibration, water and moist are factors that complicates the measurement. This applies to all applications in hot strip and plate mills, eg. after roughing mill, finishing mill, after laminar cooling and hot leveling.

To overcome this, Shapeline has developed a solution, VeriShape, for measurement on hot material based on laser lines instead of laser points or white light. VeriShape is based on ShapeCAT, a novel approach based on smart-camera technology developed by Shapeline specifically for flatness measurement. ShapeCAT enables high-speed and high-resolution laser line triangulation and still maintaining excellent accuracy. In addition, the resolution provided enables edge-detection which is used to compute shape, camber, off-center and width. All in the same sensor. VeriShape also incorporates a new way of calibration, mechanics and a solution to drastically reduce heat-shimmering.

VeriShape can be used in quarto mills, such as roughers or plate mills, but also in high speed finishing strip mills.

An interesting application is a combination of measurement before and after accelerated cooling to improve shape for direct quenched material.

A VeriShape-system can be installed, operated, serviced and maintained without work on the roller table. It can even be calibrated and serviced while the line is running!

The heat-shimmering effect is reduced by moving cold air into the measurement field, which drastically improves the accuracy.

The approach is now demonstrated by a full scale installation in a measurement house after the exit of the last roll-stand at SSAB hot strip mill in Borlänge, Sweden. A novel approach for calibration has also been developed and integrated in the measurement house that enables precision calibration under production conditions. This simplifies and shortens installation as well as calibration times drastically.

The concept was presented for the first time by Dr. Pär Kierkegaard, company founder and vice president, on the Rolling 2016 conference in Graz, Austria, in June, 2016.

The paper can be found here.

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Result from measurements.