Abstract
In the paper the dependencies of the cyclic stress-strain curve parameters and parameters of the new equation of fatigue lifetime on ramp loading values and carbon content in non-alloyed steels are presented. It is proved that an increase of loading ramp develops a decrease of the factor of cyclic strength and of the exponent of cyclic strengthening. An increase of ramp loading causes a decrease of the factor H_x and an increase of the fatigue lifetime exponent. Increasing the carbon content in non-alloyed steel, the factor of cyclic strength, exponent of cyclic strengthening as well as the factor H_x is decreasing while the exponent of fatigue lifetime is increasing.

Key words
cyclic stress-strain curve parameters, fatigue lifetime, ramp loading values, carbon non-alloyed steels

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