ISO 12135:2021 金属材料 断裂韧度统一测定试验

标准编号：ISO 12135:2021

中文名称：金属材料 断裂韧度统一测定试验

英文名称：Metallic materials — Unified method of test for the determination of quasistatic fracture toughness

发布日期：2021-07

标准范围

本文件规定了根据K、δ、J和R曲线确定承受准静态载荷的均质金属材料断裂韧性的方法。试样被缺口，疲劳预裂，并在缓慢增加的位移下进行测试。在延性裂纹扩展开始时或之后，或者在延性裂纹不稳定性或不稳定裂纹扩展开始时，测定单个试样的断裂韧性。在韧性撕裂条件下裂纹以稳定方式增长的情况下，测量描述作为裂纹扩展的函数的断裂韧性的阻力曲线。在铁素体材料测试中的某些情况下，不稳定的裂纹扩展可通过解理或延性裂纹萌生和扩展发生，并被解理扩展中断。本文件不包括止裂时的断裂韧性。在测试焊件时，特殊的测试要求和分析程序是必要的，这些在ISO？15653是对本文件的补充。结果的统计可变性很大程度上取决于断裂类型，例如，与铁素体钢中解理断裂相关的断裂韧性可以显示出很大的变化。对于要求高可靠性的应用，可以使用统计方法来量化韧脆过渡区断裂韧性的可变性，如ASTM？E1921.然而，本文件的目的不是指定要进行的测试的数量，也不是如何应用或解释测试结果。

This document specifies methods for determining fracture toughness in terms of K, δ, J and R-curves for homogeneous metallic materials subjected to quasistatic loading. Specimens are notched, precracked by fatigue and tested under slowly increasing displacement. The fracture toughness is determined for individual specimens at or after the onset of ductile crack extension or at the onset of ductile crack instability or unstable crack extension. In cases where cracks grow in a stable manner under ductile tearing conditions, a resistance curve describing fracture toughness as a function of crack extension is measured. In some cases in the testing of ferritic materials, unstable crack extension can occur by cleavage or ductile crack initiation and growth, interrupted by cleavage extension. The fracture toughness at crack arrest is not covered by this document. Special testing requirements and analysis procedures are necessary when testing weldments, and these are described in ISO 15653 which is complementary to this document.Statistical variability of the results strongly depends on the fracture type, for instance, fracture toughness associated with cleavage fracture in ferritic steels can show large variation. For applications that require high reliability, a statistical approach can be used to quantify the variability in fracture toughness in the ductile-to-brittle transition region, such as that given in ASTM E1921. However, it is not the purpose of this document to specify the number of tests to be carried out nor how the results of the tests are to be applied or interpreted.

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