一前言冲击韧性α_K值作为一个力学性能指标,用来评定材料的韧性虽然存在不足之处,但由于在实践中长期使用,积累了大量有价值的资料和数据。这种试验方法对于材料质量、宏观缺陷和显微组织的差异比较敏感,因而用α_K来控制冶炼、热加工工艺的质量,判定工艺规范的执行情况是有效的。低温系列冲击试验还被用来评定钢材的低温脆断趋势,对防止低温脆断有一定的实用价值。同时它还能反映材料对一次或少次数大能量冲击破坏的抗力,及对于一些在特殊条件下服役的机件,有一定的参考价值。由于它具有上述优点而且设备简单,操作方便,所以被广泛应用于材料试验中。U型缺口或V型缺口冲击弯曲试验是标准的试验方法,另外,冲击拉伸试验在理论研究方面也常 A preface impact toughness α_K value as a mechanical performance index, used to assess the toughness of the material although there are deficiencies, but due to long-term use in practice, has accumulated a large amount of valuable information and data. This test method for the material quality, macroscopic defects and microstructure differences are more sensitive, so the use of α_K to control the quality of smelting, thermal processing, to determine the implementation of the process is valid. Low temperature impact test series have also been used to assess the trend of brittle fracture of low temperature steel, to prevent low temperature brittle fracture has some practical value. At the same time, it can also reflect the resistance of the material to one or a few times the impact of large energy impact damage, and for some service in special conditions of the machine, have some reference value. Because of its advantages and simple equipment, easy operation, it is widely used in material testing. U-notch or V-notch impact bending test is the standard test method, in addition, the impact of tensile test in the theoretical study is also often