金属材料仪器化冲击试验方法国内外标准比较

Comparison among Domestic and Overseas Standards of Instrumented Impact Test of Metallic Materials

对EN ISO 14556:2015,GB/T 19748-2005,ASTM E2298-15仪器化冲击试验方法标准的主要区别进行了对比,特别是各标准的仪器设备要求、适用的试样尺寸及类型、力-位移曲线类型的判定、韧性断面率的评价等,对正在修订国标中新增的内容也予以了说明。结果表明:ASTM标准在仪器设备方面要求更高,但ISO及GB的可行性更好;ISO及ASTM标准覆盖了小夏比V型缺口试样(MCVN试样)的试验部分,使得试验内容更加丰富,但实际试验情况显示小尺寸试样的力-位移特征曲线稳定性不如10mm×10mm×55mm尺寸标准试样的;利用各标准中提供的计算公式对韧性断面率进行评价时,计算公式及特征系数K值的选择对试验结果有很大影响;正在修订国标中加入了裂纹形成能Wi及裂纹扩展能Wp的概念,使得在力-位移特征曲线Fm的后段部分进一步得到细化,具有一定的理论研究价值。

The main differences of instrumented impact testing standards for EN ISO 14556：2015,GB/T19748-2005 and ASTM E2298-15 were compared,especially the equipment requirements,applicable sample size and type,determination of force-displacement type,determination of percent shear area on fracture surface and so on,the new content in GB was also explained.The results show that ASTM standard has higher instrumentation requirements,but the feasibility of ISO and GB is better,ISO and ASTM standards include the testing part of miniaturized Charpy V-notch specimens,which has enriched contents of test.But the actual testing results show that the force-displacement curve of small size sample is less stable than the standard sample of 10 mm×10 mm×55 mm,the choice of formula and characteristic coefficient K have great influence on the determination of the percent shear area on fracture surface,the new definition of crack forming energy Wiand crack propagation energy Wp were added into GB,so that the back section of force-displacement characteristic curve was further refined,which has certain theoretical research value.