应变速率对Q460连铸坯高温力学性能的影响

摘要：采用Gleeble-3500热模拟试验机和金相法测试了不同应变速率下建筑用钢Q460连铸坯的高温力学性能，获得了600~1200℃范围内Q460连铸坯的高温强度、热塑性和最终室温组织随拉伸温度和应变速率的变化规律。结果表明，当Q460连铸坯在较高的应变速率（10s-1）下进行高温拉伸时，试样的断面收缩率随着拉伸温度的升高而升高，没有出现高温脆性区；在较低的应变速率（10-3s-1）下进行高温拉伸时，试样的断面收缩率出现了2个脆性区，第1个在1100℃至熔点温度，第2个脆性区间在700℃附近。总体来说，实验钢种的高温断面收缩率均大于65%，表明建筑用钢Q460连铸坯具有较好的高温热塑性。此外，同一应变速率下，Q460连铸坯的抗拉强度随着拉伸温度的升高而降低，而伸长率随着拉伸温度的升高而升高。

Effect of strain rate on high temperature mechanical properties of Q460 continuous cast slab

Abstract： Gleeble 3500 thermal simulation testing machine and metallographic method were used to test the high temperature mechanical properties of construction steel Q460 continuous cast slab at different strain rates, and the high temperature strength, hot ductility and final room temperature microstructure of Q460 continuous cast slab at different strain rates in the range of 600℃ to 1200℃ were obtained. The results show that when Q460 continuous cast slab is performed at a higher strain rate (10s-1), the reduction of area increases with the increase of the tensile temperature without obvious high temperature brittle zone. But when the strain rate is (10-3s-1), the curves of the reduction of area has two brittle regions. The first one is located at 1100℃ to the melting point temperature, and the second is near 700℃. In general, the reduction of area of this steel grade is greater than 65%, indicating that construction steel Q460 continuous cast slab has good high temperature hot ductility. In addition, under the same strain rate, the tensile strength of Q460 continuous cast slab decreases with the increase of tensile temperature, while the elongation increases with the increase of tensile temperature.