关键词: 微合金元素, 珠光体, 片层间距, 拉伸性能, 母相奥氏体

Abstract: Three kinds of high carbon wire rod steels with different content of microalloying elements V, Nb were designed. The strengthening effects of microalloying elements on the wire rod steel were analyzed through tensile testing, microstructure observation and prior austenite grain size statistics. The results show that the tensile strength of the V-steel is 1282.7 MPa, which is increased by 156.5 MPa compared with the base steel and accompanied with a slight increase of total elongation of 13.08%. The tensile strength and total elongation of the V+high Nb steel are 1287.0 MPa and 12.38%, which are increased by 160.8 MPa and 0.25% compared with the base steel, respectively. For high-carbon pearlitic steel, adding an appropriate amount of V can refine the pearlite lamellar spacing, however, adding more Nb will not further refine the pearlite lamellar spacing. Besides, the more addition of Nb has no significant effect on the improvement of tensile strength. Therefore, there is no need to add Nb after adding 0.1%V in the high carbon pearlite wire rod. The addition of microalloying element V not only refines the prior austenite grain, but also improves the work-hardening ability of the wire rod steel, mainly because the pearlite lamellar spacing is refined, so that it shows better deformation resistance.

Key words: microalloy, pearlite, lamellar spacing, tensile property, parent austenite