Sandvik supplies compound rings produced by powder metallurgically based hot isostatic pressing (PM HIP) for stressometer systems. The compound rings form the measurement roll shell for the system used for flatness measurement and control in cold rolling mills for flat products. The system ensures that steel strips have the correct flatness.

In a cold rolling mill, the metal (e.g. steel, aluminium) strip is rolled between two adjustable rolls to the desired thickness. In the rolling process, the strip passes over the flatness measurement roll, which detects the stress in the strip.

A cylindrical measurement roll is the heart of a stressometer system. The stress in the strip is measured via force transducers installed below the shell of the roll; a flat strip must have the same stress in all zones.

The compound rings with diameter 300 or 400 mm (11.8 or 15.75 in.) have a tough core to prevent the rings from breaking and a hard and wear-resistant surface to ensure the best possible surface quality of the strip. The compound rings produced by PM HIP technology can be reground several times during their life cycle.

HIP advantages

Using HIP products instead of, for example, castings and forgings mean several advantages, such as less machining and welding.