Veränderung der Glasoberfläche beim Ritzen mit Diamantkegel, Achatkegel, Oxidkeramikkegel. Martens-Ritzhärtemeßgerät. Plastisches Verhalten beim Ritzvorgang; Ritzbahnen. Irreversibilität der Verformung. Steigerung des Flächendruckes. Seitenrisse.

The film shows the changes occurring in the surface of glass which is deformed by means of scratching tools. The investigation was carried out with a scratching device having a similar mode of action to that of the Martens scratch hardness tester. Whilst elastic deformations occur at pressures of up to 350 kp/ mm2, plastic traces are formed at pressure above this figure. The pressure is manifested by an undulation of the glass workpiece behind the tool. The deformation which arises does not re-arrange itself once more. When the pressure on the surface is raised to over 500 kp/mm2, lateral cracks appear in the scratch trace on the glass. Diamond, agate and oxide ceramic cones were used as scratching tools.