中文摘要：

目的研究焊接高强度钢材Q460C低温下的断裂性能特征,以获得其对接焊件韧性受低温变化影响的规律,为此种钢材在低温环境下的应用提供试验依据.方法制备焊缝区及热影响区标准冲击试件,利用力学实验室低温环境保温箱及SANS型号摆锤式冲击试验机设备,对不同温度点下的试件进行冲击试验;并对试验数据用玻尔兹曼函数拟合,且对冲击试件断口电镜扫描分析.结果热影响区和焊缝区冲击韧性均随温度降低的下降而降低,而且热影响区的冲击功值较焊缝区的低;-60℃与-40℃温度下冲断的断口均呈现出显著的脆断特征.结论 Q460C高强度钢材焊缝区与热影响区有较明显的低温冷脆倾向.

英文摘要：

Fracture toughness properties of high strength steel Q460C butt weld under low tempera- ture were studied, in order to provide experimental references for application of this kind steel under low temperature. Specimens for heat-affected zone as well as welding zone were prepared. Ex- perimental studies at different low temperature points were carried out by a SANS type pendulum impact testing machine and a low temperature incubator. Obtained test data were fitted by Boltzmann function. Electronic microscope photos of specimen fracture surfaces were analyzed. Results show that impact values of all specimens decrease with the temperature descending. At the temper- ature - 40 ℃ and - 60 ℃, all specimens show obvious brittle fracture. But impact toughness of the heat-affect zone is lower than that of the weld zone. Conclusions indicates that toughness of the Q460C steel weld zone and the heat affected zone has a clear brittle tendency under low temperature.