Structure and properties of low-alloy steel 10G2FBYu after rolling in embossed rolls under conditions of electroplasticity

Abstract

The article describes the features of grain structure formation and mechanical properties of low-alloy steel 10G2FBYu after rolling in flat and embossed rolls under the conditions of ordinary and electroplastic deformation. When rolling in embossed rolls, a significant non-uniformity of deformation is achieved over the rolling cross-section, expressed in localized macroshifts directed at an angle of 45° to the rolling plane. It is shown that local shear deformation during rolling in embossed rolls leads to an increase in the ultimate strength of the steel under study with a decrease in plasticity of the rolled material. Rolling 10G2FBYu steel in embossed rolls under conditions of electroplasticity provides maximum strength characteristics with a high hardening coefficient at the stage of macrodeformation. At the same time, the plasticity is maintained at a level sufficient for technological purposes. Structural metallographic and electron microscopic studies showed that increase in strength of steel when rolling in embossed rolls under conditions of electroplastic effect is caused by the refinement of ferrite grains to sizes less than 0.5 µm. Fractographic studies revealed changes in the nature of fracture in steel during rolling in embossed rolls, which is expressed in appearance of areas of brittle fracture in the rolled samples. Rolling under conditions of electroplasticity increases the proportion of ductile fracture and ductility of 10G2FBYu steel.