【摘要】 对20g钢高温断裂韧性随加载速率的变化规律进行了实验研究.在400℃和500℃下,分别测量了几种加载速率下20g钢的Ji值.实验结果表明:Ji值随应变速率的增大而有较大幅度的降低;在同一应变速率下,400℃时的Ji值小于500℃时的Ji值;400℃时裂纹扩展比500℃时更快.因此,当温度在400℃附近时更应注意避免超载.更多还原

【Abstract】 The influences of loading rate on fracture toughness for the pressure vessel steel 20g at high temperature have been investigated. The fracture toughness Ji have been measured at 400℃ and 500℃ under four constant loading rates. The experimental results show that the fracture toughness Ji decreases greatly as the strain rate increases; Ji value at 400℃ is less than that at 500℃ under the same strain rate; crack growth at 400℃ is faster than that at 500℃. Thus, it is important to avoid overloading near 400℃.更多还原