X70M管线钢管高温拉伸性能研究

为了探究管线钢管在高温条件下的强度及塑性，采用X70M管线钢管进行了室温（20 ℃）与高温（300～600 °C）条件下的拉伸试验，用Boltzmann函数对强度折减系数进行了S曲线拟合。试验结果表明:随着温度的升高，X70M管线钢的屈服强度、抗拉强度均呈下降趋势，屈服强度先于抗拉强度出现下降；断后伸长率随着温度升高无明显变化，但当温度升高至600 ℃时明显升高；均匀伸长率随着温度的升高呈下降趋势，应力-应变曲线由圆屋顶型变为更加陡峭的形状，形变强化和抵抗变形的能力随着温度的升高而下降。

Research on High Temperature Tensile Properties of X70M Pipeline Steel Pipe

In order to explore the strength and plasticity of pipeline steel pipe at high temperature, X70M pipeline steel pipe was used for tensile test at room temperature （20 ℃） and high temperature （300~600 ℃）, and the strength reduction coefficient was fitted by S-curve with Boltzmann function. The test results show that the yield strength and tensile strength of X70M pipeline steel decrease with the increase of temperature, and the yield strength decreases before the tensile strength. The elongation after fracture has no obvious change with the increase of temperature, but it increases obviously when the temperature rises to 600 ℃. The uniform elongation decreases with the increase of temperature, the stress-strain curve changes from a round-house shape to steeper shape, and the ability of deformation strengthening and resistance to deformation decreases with the increase of temperature.