在不同温度下测试了X70级管线钢的动态断裂韧度。研究表明: 加载速率对动态断裂韧度的影响与温度对其的影响同样重要; 在恒温下，增大加载速率可以诱发韧脆断裂转变; 当温度由298 K向193 K逐渐降低，或加载速率从0.01 mm/s向1 000 mm/s增大时，均将导致材料的韧脆断裂转变。

The dynamic fracture toughness of X70 pipeline steel were measured at different temperatures. It was found that loading rate was important as temperature to dynamic fracture toughness. At constant temperature, increasing loading rate can induce the fracture transition from ductile to brittle. It causes fracture transition when decreasing temperature from 298 K to 193 K and increasing loading rate from 0.01 mm/s to 1 000 mm/s.