1.1 本试验方法旨在作为对实心圆细钢丝进行旋转弯曲疲劳试验的程序，以获得在应变（应力）主要为线弹性的疲劳状态下，金属材料在规定寿命下的疲劳强度。本试验方法仅限于承受恒定振幅周期应变（应力）的小直径实心圆钢丝的疲劳试验。该方法可用于评估内部材料结构（如夹杂物）对熔体技术和冷加工研究的影响。然而，有一个警告。由于试验方法施加的径向应变梯度，应变在表面处最大，在中心线处为零。因此，试验方法可能无法找到控制单轴高周疲劳寿命的“最薄弱环节”，即最大夹杂物，其中应变在横截面上是均匀的，并且疲劳损伤开始于次表面位置 ( 1- 5. ) . 2. 此外，本试验方法中不包括可能影响疲劳寿命的预应变。 注1: 以下文件虽然未特别提及，但被认为足够重要，可以在本试验方法中列出: ASTM STP 566疲劳试验手册 ASTM STP 588疲劳试验统计规划和分析手册 ASTM STP 731估算中值疲劳极限的表格 ( 6- 8. ) 1.2 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。 1.3 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====== 5.1 获得特定寿命下疲劳应变（应力）的方法是电线制造商、设计师和消费者感兴趣的。该方法可用于生产控制、材料验收和确定特定疲劳寿命（即疲劳强度）下钢丝的疲劳应变（应力）。通过将预定长度的试样在90°至180°的弧度内循环，可以对小直径实心圆导线进行旋转弯曲疲劳试验。弯曲应变（应力）由由此形成的环的几何形状确定。该方法能够进行高频测试，前提是供试品的温度恒定，并且导线没有绝热加热。将试样浸入恒温液浴或测试介质中，可以保持恒定温度。 这使得快速测试足够数量的样本变得切实可行，以提供给定应变（应力）下疲劳寿命的统计频率分布或生存概率分布。疲劳寿命信息有助于确定导线的使用耐久性，并评估熔体实践和冷加工处理的影响。

1.1 This test method is intended as a procedure for the performance of rotating bending fatigue tests of solid round fine wire to obtain the fatigue strength of metallic materials at a specified life in the fatigue regime where the strains (stresses) are predominately and nominally linear elastic. This test method is limited to the fatigue testing of small diameter solid round wire subjected to a constant amplitude periodic strain (stress). The methodology can be useful in assessing the effects of internal material structure, such as inclusions, in melt technique and cold work processing studies. However, there is a caveat. The strain, due to the radial strain gradient imposed by the test methodology, is a maximum at the surface and zero at the centerline. Thus the test method may not seek out the “weakest link,” largest inclusions, that govern uniaxial high cycle fatigue life where the strain is uniform across the cross section and where fatigue damage initiates at a subsurface location ( 1- 5 ) . 2 Also, pre-strain, which can influence fatigue life, is not included in this test method. Note 1: The following documents, although not specifically mentioned, are considered sufficiently important to be listed in this test method: ASTM STP 566 Handbook of Fatigue Testing ASTM STP 588 Manual on Statistical Planning and Analysis for Fatigue Experiments ASTM STP 731 Tables for Estimating Median Fatigue Limits ( 6- 8 ) 1.2 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. 1.3 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 ====== 5.1 A method for obtaining fatigue strain (stress) at a specific life is of interest to the wire manufacturer, designer and consumer. The method is useful in production control, material acceptance and determination of the fatigue strain (stress) of the wire at a specific fatigue life, that is, fatigue strength. Rotating bending fatigue testing of small diameter solid round wire is possible by looping a specimen of predetermined length through an arc of 90° to 180°. The bending strain (stress) is determined from the geometry of the loop thusly formed. The methodology is capable of high frequency testing provided the temperature of the test article is constant and there is no adiabatic heating of the wire. A constant temperature can be maintained by immersing the specimen in a constant temperature fluid bath or test media. This makes it practical to quickly test a sufficient number of specimens to provide a statistical frequency distribution or survival probability distribution of fatigue life at a given strain (stress). Fatigue life information is useful to ascertain wire in-service durability and to assess, for example, the effects of melt practice and cold work processing.