1.1 本规程涵盖了轴向力控制疲劳试验的执行程序，以获得金属材料在疲劳状态下的疲劳强度，其中应变在初始加载和整个试验过程中主要是弹性的。本规程仅限于在室温下在空气中承受恒定振幅、周期性力函数的轴向无缺口和缺口试样的疲劳试验。 1.2 本试验方法的使用仅限于试样，不包括全尺寸部件、结构或消费品的试验。 1.3 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.4 本标准的文本引用了提供解释材料的注释和脚注。这些注释和脚注（不包括表和图中的注释和脚注）不应视为本标准的要求。 注1: 以下文件虽然未在本文中直接引用，但被认为足够重要，可以在本实践中列出: E739 线性或线性化应力寿命（S-N）和应变寿命（ε-N）疲劳数据的统计分析实施规程 STP 566疲劳试验手册 2. STP 588疲劳试验统计规划和分析手册 3. STP 731估算中值疲劳极限的表格 4. 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 轴向力疲劳试验用于确定材料、几何形状、表面条件、应力等变化对金属材料在相对大量循环中承受直接应力的疲劳抗力的影响。 结果也可作为选择在重复直接应力条件下使用的金属材料的指南。 4.2 为了验证使用本规程生成的此类基本疲劳数据在实验室之间具有可比性、可再现性和相关性，从统计学家的角度来看，进行循环式测试程序可能是有利的。要做到这一点，需要控制或平衡通常被视为有害变量的因素；例如，硬度、清洁度、晶粒度、成分、方向性、表面残余应力、表面光洁度等。因此，当开始执行这种性质的计划时，必须先验地定义和保持一致性，尽可能合理地定义和保持尽可能多的变量，并尽可能地节约成本。应报告使用的所有材料变量、测试信息和程序，以便以当前良好测试实践的方式尝试结果的相关性和再现性。 4.3 只有当试样试验条件真实地模拟了使用条件或某些计算使用条件的方法可用且定义明确时，轴向力疲劳试验的结果才适用于设计。

1.1 This practice covers the procedure for the performance of axial force controlled fatigue tests to obtain the fatigue strength of metallic materials in the fatigue regime where the strains are predominately elastic, both upon initial loading and throughout the test. This practice is limited to the fatigue testing of axial unnotched and notched specimens subjected to a constant amplitude, periodic forcing function in air at room temperature. 1.2 The use of this test method is limited to specimens and does not cover testing of full-scale components, structures, or consumer products. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. Note 1: The following documents, although not directly referenced in the text, are considered important enough to be listed in this practice: E739 Practice for Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (ε-N) Fatigue Data STP 566 Handbook of Fatigue Testing 2 STP 588 Manual on Statistical Planning and Analysis for Fatigue Experiments 3 STP 731 Tables for Estimating Median Fatigue Limits 4 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The axial force fatigue test is used to determine the effect of variations in material, geometry, surface condition, stress, and so forth, on the fatigue resistance of metallic materials subjected to direct stress for relatively large numbers of cycles. The results may also be used as a guide for the selection of metallic materials for service under conditions of repeated direct stress. 4.2 In order to verify that such basic fatigue data generated using this practice is comparable, reproducible, and correlated among laboratories, it may be advantageous to conduct a round-robin-type test program from a statistician's point of view. To do so would require the control or balance of what are often deemed nuisance variables; for example, hardness, cleanliness, grain size, composition, directionality, surface residual stress, surface finish, and so forth. Thus, when embarking on a program of this nature it is essential to define and maintain consistency a priori, as many variables as reasonably possible, with as much economy as prudent. All material variables, testing information, and procedures used should be reported so that correlation and reproducibility of results may be attempted in a fashion that is considered reasonably good current test practice. 4.3 The results of the axial force fatigue test are suitable for application to design only when the specimen test conditions realistically simulate service conditions or some methodology of accounting for service conditions is available and clearly defined.