Vliv obsahu uhlíku na teplotní roztažnost a transformační teplotu Ar3 podeutektoidních ocelí

Abstract

Bachelor thesis aim on the influence of carbon content on transformation temperature Ar3 and thermal expansion of hypoeutectiod steels. This thesis is also aimed on the influence of the cooling rate on on transformation temperature Ar3. Theoretical part is discribing CCT diagrams, methods of thermal expansion determination, importance of thermal expansion during forming, methods of phase transformation finding and necessary physical quantities. Research is based on comparing of dilatation curves for steels with different carbon content. Tests were made with cooling rates 2 and 8 °C/s. Comparison was also made by metallography analysis of individual samples. Results show the carbon contend and cooling rate had influence on temperature Ar3. Higher cooling rate or higher carbon contend were making Ar3 lower. Higher carbon rate means also higher expansion coefficient.