The internal friction method was used to study the deformation behavior of fine pearlite in U8 steel produced by a low-temperature transformation at 500 degreesC (patented state). The effect of plastic deformation on the amplitude dependence of internal friction (ADIF) was analyzed. The deviations of the ADIF from the exponential law can indicate a possible dissolution (dissociation) of cementite and the transfer of carbon atoms to dislocations into ferrite upon plastic deformation.