The Influence of Si on Microstructure and Mechanical Properties of Hot-Rolled Wire Rods for Cable Steel Wire Ropes

Abstract

The cross section and longitudinal section microstructure morphology of two different Si contents hot-rolled wire rods were observed using scanning electron microscopy and energy spectrum （EBSD） instruments. The tensile properties of the hot-rolled wire rods were tested using a universal testing machine. The results show that with the increase of Si content， the undercooling of pearlite transformation increases， and the size of pearlite colony and pearlite interlamellar spacing in hot-rolled wire rods decrease.The Si element causes the Mn element to segregate in the cementite， increasing its stability and reducing the spheroidization of the cementite lamellae. The Si element weakens the texture strength of the pearlite in the transverse and longitudinal sections of the wire rod， leading the pearlite structure more uniform and the orientation more random. The Si element can greatly improve the strength of hot-rolled wire rods and finished steel wires， while slightly improving plasticity. The tensile strength of low Si wire rod is 1134 MPa， and the uniform elongation is 7.1%； The tensile strength of high Si wire rod is 1263 MPa， and the uniform elongation is 7.3%. The tensile strength of the low Si wire is 1937 MPa， and the uniform elongation is 2.2%； The tensile strength of the high Si wire is 2106 MPa， and the uniform elongation is 2.3%.

Keywords

• cable steel wire rope； hot-rolled wire rod； si element； pearlite； microstructure and mechanical properties