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700L汽车大梁钢低温夏比V型冲击试验结果的概率统计分析与数据处理

Probability statistical analysis and data processing of low-temperature Charpy V-notch impact test results for 700L automobile frame steel

  • 摘要: 700L钢在-40 ℃条件下的摆锤冲击试验结果离散度较高,通常采用求冲击功算术平均值来表征材料的冲击试验结果,然而,低温环境下试验影响因素复杂多样,导致试验测量值往往难以准确反映材料的抗冲击性能。为更可靠地获取材料的冲击功试验结果,本文采用摆锤冲击试验机,对纵向和横向取样开展-40 ℃低温夏比V型冲击试验;试验过程中,重点探讨了2 mm摆锤刀刃下的V型缺口试样的冲击功检验结果的分布特性,系统研究了纵、横向两种取样方式对700L钢对冲击功取值离散度的影响,并求得对应置信度为90%的安全冲击功来评价材料相应的抗冲击性能。结果表明:两种取样方法的冲击功均符合正态分布特征,对应90%置信度时,纵向与横向试样的安全冲击功分别为31.58 J和38.83 J。该分析结果为700L钢夏比冲击试验的应用以及结果的准确获取提供了理论与实践指导。

     

    Abstract: The results of pendulum impact test of 700L steel at -40 ℃ show a high degree of dispersion. Usually, the arithmetic mean of impact energy is used to characterize the impact test results of materials. However, the test influencing factors in low-temperature environment are complex and diverse, which makes the measured values often difficult to accurately reflect the impact resistance performance of materials. To obtain more reliable impact energy test results of materials, -40 ℃ low temperature Charpy V-notch impact tests on longitudinal and transverse samples were conducted by pendulum impact testing machine. During the test, the distribution characteristics of the impact energy test results of V-notch specimens with 2 mm pendulum blade were mainly discussed. The influence of the two sampling methods of longitudinal and transverse sampling on the dispersion of impact energy values of 700L steel was systematically investigated, and the corresponding safe impact energy with 90% confidence level was obtained to evaluate the corresponding impact resistance performance of materials. The results showed that the impact energies of both sampling methods conformed to the normal distribution characteristics. At the corresponding 90% confidence level, the safe impact energies of longitudinal and transverse specimens were 31.58 J and 38.83 J, respectively. This analysis result provides theoretical and practical guidance for the application of Charpy impact test of 700L steel and the accurate acquisition of results.

     

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