1.1 本试验方法包括测定硫化橡胶在反复弯曲应变或弯曲时的裂纹扩展。它特别适用于合成橡胶化合物的试验，当用试验方法的方法B进行试验时，合成橡胶化合物能够抵抗由于弯曲而引发的开裂 D430 . 这些材料在使用过程中因小切口或撕裂而产生的裂纹，可能会迅速增大尺寸，并发展到完全失效，即使材料对最初的弯曲具有极高的抵抗力- 疲劳开裂。由于合成化合物的这一特性，尤其是SBR型化合物的这一特性，在评估此类材料的疲劳开裂性能时，应使用这种试验方法，即首先在弯曲区域人为刺穿试样。 1.2 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 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 该试验估计了硫化橡胶在受到弯曲或弯曲时抵抗穿孔试样裂纹扩展的能力。 4.2 由于服务条件的不同性质，这些测试结果与服务之间没有确切的相关性。

1.1 This test method covers the determination of crack growth of vulcanized rubber when subjected to repeated bending strain or flexing. It is particularly applicable to tests of synthetic rubber compounds which resist the initiation of cracking due to flexing when tested by Method B of Test Methods D430 . Cracking initiated in these materials by small cuts or tears in service, may rapidly increase in size and progress to complete failure even though the material is extremely resistant to the original flexing-fatigue cracking. Because of this characteristic of synthetic compounds, particularly those of the SBR type, this test method in which the specimens are first artificially punctured in the flex area should be used in evaluating the fatigue-cracking properties of this class of material. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 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 test gives an estimate of the ability of a rubber vulcanizate to resist crack growth of a pierced specimen when subjected to bending or flexing. 4.2 No exact correlation between these test results and service is implied due to the varied nature of service conditions.