Change of Mechanical Properties of Wire Under Cryogenic Cooling in the Process of Drawing

The influence of a new technology of carbon steel wire processing on the change of its mechanical properties is investigated. This technology consists in the application of cryogenic cooling immediately after the wire exit from the die. Deformation was carried out at cryogenic temperature and for comparison at room temperature. The results of the laboratory experiment show that the application of cryogenic deformation treatment after wire drawing improves the mechanical properties compared to conventional drawing. So at processing of wire from low-carbon steel the tensile strength increases on 10%, conditional yield strength – on 11,5%, relative contraction after a break decreases on 6%. The homogeneity of the formed structure along the wire cross-section after the developed method is confirmed by the results of microhardness measurement. Cryogenic cooling of 5.0 mm diameter St3 steel wire causes an increase of microhardness in the central region from 1320 MPa to 1745 MPa, and on the surface the change of microhardness is from 1347 MPa to 1842 MPa.