Abstract: A method for increasing the boundary layer strength of a workpiece made of brittle, hard material by applying a plastic deformation to a narrowly limited surface area, in order to generate internal compressive strain within a workpiece where the temperature of the workpiece is not elevated prior to the application of mechanical force.

Abstract: For guiding webs of paper or cardboard, a guide cylinder extending across half of the web grips onto the surface of the web and achieves moving corrections on the webs by rotation or swinging. The long, linear support zone of the guide cylinder causes a high mechanical stress, whereby the guide cylinder exerts almost no corrective effect in its center zone. By dividing the guide cylinder into at least two spaced-apart, parallel guide rolls having their axes disposed perpendicular to the running direction of the material web, a suitable larger effective area is obtained for correction of the direction of movement.