This article presents an analysis of experimental data with reference to material properties, short-time creep and relaxation phenomena of 1.4122 steel (AISI 420RM) at high temperatures. The behaviour of the material subjected to uniaxial stress is indicated by engineering stress – strain diagrams. The data referring to tensile strength, 0.2 percent offset yield strength, the modulus of elasticity and total deformation, are shown through tables and curves presenting the dependence of these quantities on temperature. Creep and relaxation curves regarding certain level of stresses at selected temperatures are also shown. In addition, modelling of both creep and relaxation phenomena is presented.