1.1 本试验方法旨在作为实心圆细钢丝旋转弯曲疲劳试验的一种程序，以获得金属材料在疲劳状态下的特定寿命下的疲劳强度，其中应变（应力）主要是名义线性弹性的。该试验方法仅限于承受恒定振幅周期应变（应力）的小直径实心圆线的疲劳试验。该方法可用于评估熔体技术和冷加工研究中夹杂物等内部材料结构的影响。然而，有一个警告。由于试验方法施加的径向应变梯度，应变在表面为最大值，在中心线为零。 因此，试验方法可能不会找出“最弱的环节”，即最大的夹杂物，这些夹杂物控制着单轴高周疲劳寿命，其中应变在横截面上是均匀的，并且疲劳损伤在地下位置开始 ( 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: 以下文件虽然没有特别提及，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疲劳实验统计规划和分析手册 ASTM STP 731中位疲劳极限估算表 ( 6. 8. ) 1.2 以英寸磅为单位的数值应视为标准。括号中给出的值是国际单位制的数学转换，仅供参考，不被视为标准。 1.3 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 电线制造商、设计者和消费者感兴趣的是获得特定寿命下的疲劳应变（应力）的方法。 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）下线材的疲劳应变（应力）。小直径实心圆钢丝的旋转弯曲疲劳试验可以通过将预定长度的试样在90°至180°的弧中循环进行。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是恒定的，并且导线没有绝热加热。可以通过将试样浸入恒温流体浴或测试介质中来保持恒定的温度。 这使得快速测试足够数量的试样以提供给定应变（应力）下疲劳寿命的统计频率分布或生存概率分布变得可行。疲劳寿命信息有助于确定电线的使用寿命，并评估例如熔化实践和冷加工的影响。

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.