摘要:
研究了四种应变速率(10-3, 5, 50, 200 s-1)下HC340LA低合金高强度钢板的拉伸性能、显微组织和断口形貌。结果表明: 与准静态拉伸(应变速率10-3 s-1)相比, 高应变速率(应变速率5, 50, 200 s-1)下试验钢表现出更好的塑性、更高的抗拉强度和屈强比; 而在高速拉伸时随着应变速率的增加, 其塑性和抗拉强度降低, 主要原因是铁素体的晶粒尺寸减小且分布不均匀, 晶界增多; HC340LA钢板的断裂服从韧性断裂机理, 与应变速率200 s-1时相比, 应变速率50 s-1时断口中的韧窝较为均匀, 尺寸大而深。
Abstract:
The tensile properties, microstructure and fracture morphology of high strength low alloy steel plate HC340LA were studied at four strain rates (10-3, 5, 50, 200 s-1). The results show that the test steel had better plasticity, higher tensile strength and yield ratio when tensiled at high strain rates (5, 50, 200 s-1) than in quasi-static tension (10-3 s-1). The plasticity and tensile strength decreased during high speed tension with the increase of strain rate, because the ferrite decreased in grain size, distributed unevenly and the grain boundaries increased. The rupture of HC340LA steel plates followed ductile fracture mechanism. The fracture with the strain rate of 50 s-1 displayed uniform dimples which was bigger and deeper, compared with the strain rate of 200 s-1.
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