1.1 本试验方法包括测定绞纱形式纱线的断裂强度。观察到的断裂强度用力单位表示，并提供了将断裂强度转换为骨架断裂韧性和骨架断裂因子的方程式。 注1: 关于用单股法测定纱线的断裂强度和伸长率，请参阅试验方法 D2256 . 1.2 本试验方法适用于由任何纤维或纤维混合物组成的单股或合股纺纱，但不适用于拉伸超过5 % 当张力从2.5增加到7.5 mN/tex或0.03增加到0.08 gf/denier时。 1.3 该测试方法根据卷筒周长、绞纱中的包裹数和机器速度或断裂时间提供三种选择。 1.3.1 选项1- 在1.50米或1.5码卷轴上旋转80、40或20圈，以300毫米/分钟或12英寸的速度断裂。 /最小。 1.3.2 选项2- 在1.00米或1码卷轴上旋转50圈，以300毫米/分钟或12英寸的速度断裂/最小。 1.3.3 选项3- 在一个1米长的卷轴上旋转50圈，在20秒内断裂。 注2: 选项1在美国普遍使用，选项2用于毛纱，选项3已在国际标准组织（ISO）中提出供国际使用。 注3: 公制卷筒的周长为1米和1.125米。来自两个卷盘的数据约为1 % 不同（参见 5.6 ). ISO使用1米圆周卷筒。 1.4 该试验方法经常与在相同骨架上进行的线密度测定相结合。注意了卷绕此类绞纱的特殊注意事项。 1.5 在适当情况下，本试验方法以国际单位制表示所有要求。传统的单位是英寸-磅，是精确的数值。 1.6 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。 1.7 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 试验方法 D1578 对于任何细纱的断裂强度测试，都被认为是商业运输验收测试的满意方法，因为该方法已在贸易中广泛使用。 5.1.1 如果因使用测试方法时报告的测试结果的差异而产生争议 D1578 对于商业装运的验收测试，买方和供应商应进行比较测试，以确定其实验室之间是否存在统计偏差。 建议为调查偏差提供称职的统计协助。作为最低要求，双方应尽可能均匀地从大量相关类型的材料中选取一组试样。然后，应将试样以相同数量随机分配给每个实验室进行测试。两个实验室的平均结果应使用学生的 t -测试未配对数据和双方在测试开始前选择的可接受概率水平。如果发现偏差，必须找到并纠正其原因，或者买方和供应商必须同意根据已知偏差解释未来的测试结果。 5.2 本试验方法不适用于拉伸超过5 % 当力从2.5增加到7.5 mN/tex或0.03增加到0.08 gf/denier时，因为( 一 )它们需要采取特殊预防措施，以防卷取过程中的张力，以及( b )这种纱线的用户更感兴趣的是其在低作用力下的弹性行为，而不是其极限断裂强度。 5.3 对于方案1，建议使用适当容量的拉伸试验机，将绞链断裂80圈。如果需要打断只有40或20圈的骨架，则分别乘以2或4的因子，将观察结果转换为80圈。（现有文献未表明使用这些因素会导致任何重大误差。） 5.4 用于确定断裂载荷的骨架周长不是临界值，因此，无需密切控制骨架缠绕时的张力。然而，如果出于任何目的使用相同的骨架来确定纱线数量，则必须在符合试验方法中给出的要求的卷轴上，在受控张力下卷绕骨架 D1907 . 5.5 出于某些目的，建议将观察到的一个纱线的骨架断裂强度转换为不同纱线编号的估计骨架断裂强度。棉纱进行这种转换的因素见 11.2 . 对于由其他纤维纺制的纱线，还没有制定相应的因素。 5.6 从不同方案获得的结果不具有完全可比性，因为每次包裹的破断力随着骨架周长的减小而略有增加。观察到的1米绞纱的绞纱断裂韧性可能高达4 % 更高，1码skeins 5码 % 高于1.5码绞纱的观察值。这些关系可能因纱线类型或纱线不匀度而异，不应用作换算系数。通过合理数量的试样，该方法提供了一个结合不均匀性和单链强度影响的有用指标。 5.7 这种方法很少（如果有的话）用于长丝纱，因为其均匀性使单股法能够经济地获得可靠的结果。

1.1 This test method covers the determination of the breaking strength of yarn in skein form. The observed breaking strength is expressed in units of force, and equations are provided to convert breaking strength to skein breaking tenacity and to skein break factor. Note 1: For the determination of the breaking strength and elongation of yarn by the single strand method, refer to Test Method D2256 . 1.2 This test method is applicable to spun yarns, either single or plied, composed of any fiber or blend of fibers, but is not suitable for yarns which stretch more than 5 % when the tension is increased from 2.5 to 7.5 mN/tex or 0.03 to 0.08 gf/denier. 1.3 This test method provides three options based on the perimeter of the reel, the number of wraps in the skein, and the machine speed or time-to-break. 1.3.1 Option 1— Eighty, forty, or twenty turns on a 1.50 m or 1.5-yd reel, broken at 300 mm/min or 12 in./min. 1.3.2 Option 2— Fifty turns on a 1.00 m or 1-yd reel, broken at 300 mm/min or 12 in./min. 1.3.3 Option 3— Fifty turns on a 1 m reel, broken in 20 s. Note 2: Option 1 is in general use in the United States, Option 2 is used for woolen yarns, and Option 3 has been proposed in the International Standards Organization (ISO) for international use. Note 3: Metric reels are available with 1 and 1.125 m circumferences. Data from the two reels will be about 1 % different (see 5.6 ). ISO uses a 1 m circumference reel. 1.4 This test method is frequently combined with the determination of linear density carried out on the same skeins. Special precautions for reeling such skeins are noted. 1.5 Where appropriate, this test method states all requirements in SI units. The traditional units are inch-pound and are exact values. 1.6 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. 1.7 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 Test Method D1578 for testing any spun yarn for breaking strength is considered satisfactory for acceptance testing of commercial shipments since the method has been used extensively in the trade. 5.1.1 In case of a dispute arising from differences in reported test results when using Test Method D1578 for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of the type in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student's t -test for unpaired data and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results in the light of the known bias. 5.2 This test method is not suitable for yarns that stretch more than 5 % when the force is increased from 2.5 to 7.5 mN/tex or 0.03 to 0.08 gf/denier, because ( a ) they require special precautions as to tension in reeling, and ( b ) users of such yarns are more interested in their elastic behavior at low forces than in their ultimate breaking strength. 5.3 For Option 1, it is advisable to use a tensile testing machine of the proper capacity to break skeins with 80 turns. If it is necessary to break skeins having only 40 or 20 turns, convert the observed results to an 80-turn basis by multiplying by factors of 2 or 4, respectively. (The available literature does not show that any significant error is introduced by the use of these factors.) 5.4 The circumference of the skeins used to determine the breaking load is not critical, and as a consequence, close control of the tension at which the skeins are wound is not necessary. If, however, the same skeins are to be used to determine yarn number for any purpose, the skeins must be reeled under controlled tension on a reel meeting the requirements given in Test Method D1907 . 5.5 For some purposes it may be advisable to convert the skein breaking strength observed for yarn of one number to the estimated skein breaking strength of a different yarn number. Factors for making such a conversion for cotton yarns are given in 11.2 . No corresponding factors have been developed for yarns spun from other fibers. 5.6 The results obtained from different options are not fully comparable because the breaking force per wrap increases slightly as the perimeter of the skein is reduced. The skein breaking tenacity observed for 1 m skeins may be as much as 4 % higher, and from 1-yd skeins 5 % higher, than that observed for 1.5-yd skeins. These relationships may vary with the type of yarn or with yarn unevenness and should not be used as conversion factors. With a reasonable number of specimens, this method provides a useful index that combines the effects of unevenness and single strand strength. 5.7 This method is rarely, if ever, used for filament yarns because their uniformity makes it possible to obtain reliable results economically by the single-strand method.