Effect of rotary swaging on structure and properties of low-carbon steel

Abstract The structural transformation and mechanical properties of a low-carbon 0.2% C steel and a 0.09% C-Mn-V steel in coarse- and ultrafine-grained (UFG) states were studied. The UFG structure with structural elements about 210-375 nm in size was obtained by rotary swaging (RS) and equal-channel angular pressing (ECAP). ECAP was used to compare the influence of the industrial deformation and SPD methods on the micro structure and properties of low-carbon steels. It was shown that an increase in true strain ratio and a decrease in final temperature of RS improve strength properties and reduce plasticity of these steels. In both steels after RS, σ UTS within the range from 800 up to 920 MPa with elongation in the range of 15-17% at the final deformation temperature of 400 °C was obtained. It was found that the strength of 0.2% C steel after ECAP was on the same level with that steel after RS. The strength properties of low- carbon 0.09% C-Mn-V steel after ECAP were significantly higher than those after RS.