|Spoluautoři LOŠÁK Petr, HORSKÝ Jaroslav|
Oxide scale growth and its removal from steel surface during heat treatment of steel is a complex and exacting process requiring a lot of information and analyses. Therefore many methods and approaches were developed to solve it. In order to improve the final quality of the surfaces after descaling it is necessary to pay attention to all aspects related to descaling. The basic aspects include scale growth, properties and behavior, parameters affecting its removal. This paper is focused on the study of fracture toughness of oxide scales. Study of fracture toughness is fundamental for understanding the behavior of oxide scales. For the analysis of fracture toughness Small Punch Testing was used. Small Punch Tests are generally used in energy industry, when it is necessary to determine the mechanical properties of the material that has been exposed to environmental influences or load without significant damage of the device. The typical result of the Small Punch tests is force vs. displacement curve. Out of this curve it is also possible to evaluate the fracture toughness using several methods. Experimental measurements of mechanical properties of oxide scales were based on two types of steel. The first type represents the structural steel, the second type of steel is characterized by higher silicon content. For both materials the specimens with oxide scales layer were prepared. The Small Punch Tests were carried out and force vs. displacement curve was obtained. Out of these curves the fracture toughness of each material was evaluated.