|KRAUS Martin||VSB - Technical University of Ostrava|
In general, the surface and subsurface layers of material are affected during cutting and machining. It is mainly due to the heat input of thermal cutting kinds to the cut location. At mechanical methods it is again mechanical deformation. This together with other agents put there major or minor affection of prime surface. These changes consequently can affect properties of the final product negatively. The relevance of these changes is depends naturally on a ratio of a general materials volume and a cutting area size (volume of affected zone). They can suggest results of mechanical properties tests for testing specimens also, which were prepared by some of mentioned method. This article deals with the cutting method and machining influence on the properties of wide sheets from tool steels. In the concrete the steel 90 MnCrV8+A were chosen. Several cutting methods were compared – thermal, mechanical, electro-erosion. The tests of mechanical properties were made with accent on hardness and tensile tests. The microstructure were evaluated by optical and electron microscopy (SEM). Also the observation of tensile test rods cracking surfaces brought interesting results.