Abstract                                                                                                                        
	In the article is presented the comparison of relationships obtained in the hot torsion and compression tests between the flow stress, strain rate and temperature for an exemplary austenitic steel 18-8 grade. The torsion test was performed with use of torsion plastometers being the research equipment in Institut fûr Metallformung TU Bergakademie Freiberg (Germany), the Process Modelling and Medical Engineering Dept. at Silesian Technical University (Poland), while the compression test was made on servo-hydraulic machine in TU Bergakademie Freiberg. Applicable range of temperatures was 900, 1000, 1050, 1100 and 1150°C, while the range of strain rates was 0.036, 0.36 and 3.6 s-1. The results obtained from the torsion and compression tests were taken as basis for determination of analytic function of the flow stress known in the literature as Hensel-Spittel function. The constants in flow stress relation were determined using the method of multiple linear regression. Demonstrated are essential differences both, in the curves of flow stress relations and in the quantities defining the plasticity of material, such as: peak flow stress, deformation corresponding to peak stress and the strain to fracture. Diversification of the flow curves as defined in experiments leads to obtainment of essentially diversified constants in the Hensel-Spittel equation. Obtained differences are due to application of different research methods: compression and torsion; from the technical advance of research equipment, applicable research procedures, including the geometry of samples and the method for conversion of recorded measurement signals into relation between the flow stress and strain, accounting for the thermal effect and differentiation of strain rates. The appearing incompatibilities are leading to diversification of parameters of Hensel-Spittel function.