采用冲击试验及扫描电镜分析等方法研究了室温下试样厚度对U165和Q275结构钢夏比摆锤冲击吸收能量的影响。结果表明：相对较薄的试样不存在冲击载荷突降现象，但试样厚度为20 mm的Q275钢的冲击载荷突降高达80%以上；当试样厚度≤10 mm时，冲击吸收能量随试样厚度的增加总体呈线性变化，但不同材料冲击吸收能量随厚度变化的比例系数显著不同；当试样厚度>10 mm时，冲击吸收能量随厚度增加偏离了线性规律；此外，随着厚度的增加，不同材料冲击吸收能量的增量和断口形貌显著不同，这归因于材料的冲击韧性及其冲击断裂机制不同。对于厚度不满足标准试样的材料，标准试样的冲击吸收能量可通过测试不同厚度的非标试样，然后再用拟合公式计算得到。

The effect of sample thickness on charpy pendulum impact energy absorption of U165 and Q275 structural steels at room temperature was studied by impact test and scanning electron microscopy analysis. The results show that there was no sudden drop of impact load in relatively thin samples, but the impact load sudden drop of Q275 steel with 20 mm sample thickness was more than 80%; when the thickness of the sample was less than 10 mm, the impact absorption energy changed linearly with the increase of the thickness of the sample, but the proportion coefficient of the impact absorption energy changed with the thickness of different materials was significantly different; when the sample thickness was greater than 10 mm, the impact absorption energy deviated from the linear law with the increase of thickness; in addition, with the increase of thickness, the increment of impact absorption energy and fracture morphology of different materials were significantly different, which was attributed to the different impact toughness and impact fracture mechanism of materials. For the material whose thickness did not meet the standard sample, the impact absorption energy of the standard sample could be obtained by testing the non-standard samples with different thicknesses and then calculating by fitting formula.