高铁螺纹道钉钢TD16的高温塑性变形行为

High-temperature plastic deformation behavior of high-speed rail screw spike steel TD16

采用Gleeble-3500型热模拟试验机对高铁螺纹道钉钢TD16进行热压缩变形实验,探索该材料在不同温度和应变速率条件下的热塑性变形行为。研究温度与应变速率对真应力-真应变曲线的影响规律,结合显微组织分析,阐明真应力-真应变曲线发生变化的原因。结果表明,在低应变速率下,流变应力峰值较明显,具有明显的动态再结晶特征。在较高应变速率下,峰值应力不明显,流变应力曲线属于动态回复型,未发生动态再结晶。通过回归分析,建立高铁螺纹道钉钢TD16在实验条件范围内的峰值流变应力本构关系的数学模型。所建立的流变应力本构方程与实验值吻合较好,最大相对误差为7.03%,可以用该本构方程来预测高铁螺纹道钉钢TD16的高温流变行为。

Hot compression deformation of a high-speed rail screw spike steel TD16 was carried out on a Gleeble-3500 thermal simulation testing machine. The hot-plastic deformation behavior of the steel TD16 at different temperatures and strain rates was investigated. The effect of deformation temperature and strain rate on true stress-strain curves of the steel was examined. Combined with the observation of microstructure of the deformed steel at low strain rates, the true stress-strain curves were characterized. The results show that the peak flow stresses of the true stress-strain curves are sharply presented for the compression-deformed steel at low strain rates, indicating the occurring of the dynamic reerystallization. No obvious peak flow stress are observed for the steel deformed at high strain rates, which indicates the flow stress curves belong to the dynamic recovery, and no dynamic recrystallization occurs. A mathematical model of the peak flow stress constitutive relationship of the TD16 steel in the range of experimental conditions is established by regression analysis and calculation. The flow stress predicted by the constitutive equation is in good agreement with the experimental value with the maximum error of 7.03% , which can be used to predict high-temperature flow behavior of the high-speed rail screw spike steel.