INHOMOGENEITY OF MECHANICAL-PROPERTIES IN STAINLESS-STEEL RODS AFTER DRAWING

The results of an investigation of the inhomogeneity of the mechanical properties of stainless steel rods after drawing are presented in this paper, the properties investigated including the 0.2% offset stress, the yield strength and the elongation in the tension test. 16 drawing schedules were performed, with reductions ranging from 5.7% to 24.4%, using dies with angles ranging from 6-degrees to 20-degrees. The local values of the mechanical properties were determined from tension tests performed on mini-specimens of square cross-section, which were cut from the rods parallel to their axes. In addition, the distributions of the hardness HV5 over the transverse and longitudinal cross-sections were measured. Hardness curves HV5 = f(epsilon(i)) were determined from the measurements, these curves enabling the evaluation of the local values of the total effective strain on the basis of the measurements of the hardness. Functions describing coefficients relating the 0.2% offset stress and the yield strength to the hardness HV5 are derived in the paper.