Q345钢连铸坯压缩状态下的高温力学性能

Q345钢应用广泛,其在拉伸状态下的高温力学性能已有部分研究,但高温压缩力学性能数据匮乏。利用Gleeble-3500热模拟机对Q345钢连铸坯试样进行了热压缩试验,研究了应变速率为0.01 s-1时试样在压缩状态下的屈服强度、抗压强度和弹性模量等随温度(973~1 673 K)的变化规律,同时探讨了试样在1 473 K时不同应变速率(0.001、0.01和0.05 s-1)下的高温力学性能。结果表明,在973~1 373 K温度内,屈服强度和抗压强度都表现出对温度的敏感性。屈服强度由90降到24 MPa,抗压强度由202降到40 MPa。在1 373~1 673 K温度内,屈服强度和抗压强度降幅都很小。弹性模量随温度的升高而减小,其值在1 473和1 573 K温度下相差最大,达1 712 MPa。屈服强度对应变速率的变化并不敏感,均在20 MPa左右,而极限抗压强度由28增加到45 MPa。最后根据试验数据绘制了Q345钢连铸坯在热压缩状态下的屈服强度等高温性能参数随温度变化的关系曲线,可为轻/重压下等技术提供参考数据。

High temperature mechanical properties of Q345 continuous casting slab under compression

Q345 steel is widely used, and its mechanical properties at high temperature under tensile condition have been studied. However, data on mechanical properties of high temperature compression are scarce. Thermal compression tests of Q345 continuous casting slab have been conducted with Gleeble-3500 thermal simulator. The variation of yield strength, compressive strength and elastic modulus with temperature (973~1 673 K) under compression with strain rate of 0.01 s-1 was studied, and the mechanical properties of the sample at 1 473 K with the strain rate (0.001, 0.01 and 0.05 s-1) were also discussed. The results show that both yield strength and compressive strength are sensitive to temperature in the range of 973-1 373 K.The yield strength decreased from 90 to 24 MPa, and the compressive strength decreased from 202 to 40 MPa.At the range of 1 373-1 673 K, the decrease of yield strength and compressive strength is smooth.The elastic modulus decreases with the increase of temperature, its value differs the most(1 712 MPa) at 1 473 and 1 573 K.With the increase of strain rate, the yield strength did not change significantly, all around 20 MPa, while the ultimate compressive strength increased from 28 to 45 MPa.Based on the experimental data, the relationship curve of high-temperature performance parameters, such as yield strength, and temperature variation of Q345 steel continuous casting billet under thermal compression was drawn, providing reference data for such technologies as soft or heavy reduction process.