ASTM和ISO标准断裂韧度测试方法比较研究

发布时间：2018-11-22 20:00

【摘要】：ASTM E1820-11和ISO 12135-2002标准是测试断裂韧度的主要标准,然而这两个测试标准在钝化线、有效数据区间和阻力曲线拟合等方面存在较大的差异,导致断裂韧度测试结果的较大不同。研究这两个测试标准钝化线的依据,比较它们的差异。ASTM标准采用理想弹塑性材料假设,ISO标准基于材料的真应力应变关系满足幂次定律,ISO标准钝化线斜率比ASTM标准钝化线斜率大;ASTM标准采用两参数方程阻力曲线,而ISO标准采用三参数方程阻力曲线。提出根据材料应力应变特性来选择合适的试验标准,对于带屈服平台的材料可选用ASTM标准,不带屈服平台的材料可选用ISO标准。选取Q345R钢进行断裂韧度试验,用ASTM和ISO两个标准对试验结果进行评估,试验结果表明:Q345R的应力应变曲线在屈服阶段存在屈服平台,ASTM钝化线能更好反映裂纹尖端钝化。ASTM和ISO两个标准测得的断裂韧度分别为235.29 kJ/m~2和179.37 kJ/m~2,两者相差24%。
[Abstract]:ASTM E1820-11 and ISO 12135-2002 are the main standards for testing fracture toughness. However, there are great differences in passivation line, effective data interval and resistance curve fitting between the two standards. The results of fracture toughness test are different. This paper studies the basis of the passivation line of the two test standards and compares their differences. The ASTM standard adopts the assumption of ideal elastic-plastic material and the ISO standard satisfies the power law based on the true stress-strain relation of the material. The slope of ISO standard passivation line is larger than that of ASTM standard passivation line. ASTM standard adopts two parameter equation resistance curve, while ISO standard adopts three parameter equation resistance curve. According to the stress-strain characteristic of the material, the suitable test standard is selected. The ASTM standard can be used for the material with yield platform, and the ISO standard can be used for the material without the yield platform. The fracture toughness test of Q345R steel is carried out, and the test results are evaluated by ASTM and ISO. The results show that the stress-strain curve of Q345R has a yield platform in the yield stage. The ASTM passivation line can better reflect the crack tip passivation. The fracture toughness measured by ASTM and ISO is 235.29 kJ/m~2 and 179.37 kJ/m~2, respectively.
【作者单位】：浙江工业大学化工机械设计研究所;浙江工业大学过程装备及其再制造教育部工程研究中心;
【基金】：国家自然科学基金(51575489) 浙江省公益类重点(2014C23001)资助项目
【分类号】：TG142.15

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