韧脆转变区材料的韧性值呈双峰分布时,用通常的三根试样评定韧性会带来很大的不可信度,本文首次运用概率论和随机模拟方法,详细分析了用矩估计法估计韧性分布为双峰分布时的数学期望的精度和相应的可信度,并结合HQ70、HQ80C钢V缺口Charpy冲击韧性试验在韧脆转变区相应于不同的精度和可信度所需试样的最少个数进行了讨论. When the toughness value of the ductile-brittle transition zone is bimodal, the evaluation of the toughness by the usual three specimens will bring a great deal of uncertainty. In this paper, the probability theory and the stochastic simulation method are used for the first time to analyze the moment estimation method The ductility distribution for the bimodal distribution when the mathematical expectations of the accuracy and the corresponding reliability, combined with HQ70, HQ80C steel V-notch Charpy impact toughness test in the ductile-brittle transition zone corresponds to the sample with the required accuracy and reliability The minimum number is discussed.