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本文分析了各国关于V型缺口冲击试样的缺口加工方法及表面粗糙度的要求。选择了现行加工V型缺口较普遍的四种方法,磨、铣、拉和电火花切割;分别测试了各种试样从室温到低温下的冲击功、冲击值、侧向膨胀值、纤维断口百分率;给出了两种材料(16Mn和3.5Ni)在四种加工方法下的冷脆转变曲线。本文指出,在冷脆转变曲线的上半部分,各种加工方法对材料的冲击韧性影响不大(<10％)。随着温度的降低,加工方法(主要是表面粗糙度)对材料的冲击韧性影响增大,所以要使冲击试验尽可能达到标准要求,保证低温下冲击韧性的要求,必须保证V型缺口的表面粗糙度(R_a<16μm)。
In this paper, the requirements of notched processing methods and surface roughness of V-notch impact samples in various countries are analyzed. Select the current processing of V-notch more common four methods, grinding, milling, drawing and EDM; were tested for a variety of samples from room temperature to low temperature impact energy, impact value, lateral expansion, fiber fracture Percentage; The cold brittle transition curves of two materials (16Mn and 3.5Ni) under four processing methods are given. This paper points out that in the upper half of the cold-brittle transition curve, various processing methods have little effect on the material’s impact toughness (<10%). As the temperature decreases, the impact of processing methods (mainly surface roughness) on the impact toughness of the material increases, so to make the impact test as standard as possible, to ensure low temperature impact toughness requirements, we must ensure that the surface of the V-notch Roughness (R_a <16μm).