1.1 本试验方法包括测定单丝、复丝和纺纱的拉伸性能，单丝、合股或缆绳纱线，但拉伸超过5.0的纱线除外 % 当张力从0.05增加到1.0 cN/tex[0.5到1.0 gf/tex]时。 1.2 本试验方法涵盖了纱线断裂力和伸长率的测量，包括断裂韧性、初始模量、弦模量和断裂韧性的计算方向。 1.2.1 试验样本的选项包括: （A） 直的 （B） 打结，以及 （C） 循环形式。 1.2.2 试验条件包括以下试样的试验: (1) 调节空气， (2) 潮湿，未浸没， (3) 潮湿、浸没、， (4) 烤箱干燥， (5) 暴露于高温，或 (6) 暴露于低温。 注1: 测试由特定纤维制成的纱线的特殊方法； 即玻璃、亚麻、大麻、苎麻和牛皮纸等为特定产品；也就是说，已经出版了轮胎帘线和绳索:试验方法 D885 ，和规格 D578 . 注2: 有关用绞纱法测定纱线断裂力的说明，请参阅试验方法 D1578 . 1.3 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.4 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。 1.5 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====== 5.1 验收测试- 试验方法选项A1 D2256 被认为是令人满意的商业货运验收测试，因为该测试方法已在验收测试行业中广泛使用。然而，本声明不适用于结和环断裂力测试、湿试件测试、烘干试件测试或暴露于低温或高温下的试件测试，在进行验收测试时应谨慎使用，因为以下各项之间的事实信息- 实验室精度和偏差不可用。 5.1.1 如果两个实验室（或更多实验室）的报告测试结果之间存在实际意义上的差异，则应进行比较测试，以确定它们之间是否存在统计偏差，并使用适当的统计协助。作为最低要求，使用尽可能同质的样品进行比较试验，从与初始试验期间产生不同结果的样品相同批次的材料中提取，并随机等份分配给每个实验室。应使用未配对数据的统计测试对相关实验室的测试结果进行比较，这是在测试系列之前选择的概率水平。如果发现偏差，必须找到并纠正其原因，或者考虑到已知偏差，必须调整该材料的未来测试结果。 5.2 基本特性- 根据断裂力和线密度计算的断裂强度和伸长率是基本特性，广泛用于限制纱线加工或转换及其最终用途。初始模量是衡量纱线在屈服点以下的力下拉伸的阻力。弦模量用于估计施加应变的阻力。断裂韧性是衡量纱线断裂所需功的一种指标。 5.3 与绞纱试验的比较- 与绞纱法相比，单链法可以更准确地测量材料中的断裂力，并且使用的材料更少。绞纱断裂力始终低于单独断裂相同数量端部的断裂力总和。 5.4 适用性- 大多数纱线都可以用这种测试方法进行测试。根据纱线的结构和成分，可能需要对其夹紧技术进行一些修改。为了防止夹钳滑动或因夹钳夹住而损坏，可能需要对由玻璃或长链聚烯烃等纤维制成的高模量纱线进行特殊的夹紧调整。如果获得了具有代表性的力-伸长曲线，则可根据个人实验室的要求修改试样夹持。在任何情况下，必须保持本试验方法中所述的获得拉伸性能的程序。 5.5 断裂强度- 纱线的断裂强度影响由纱线制成的织物的断裂强度，尽管织物的断裂强度也取决于其结构，并可能受到制造操作的影响。 5.5.1 由于任何纤维类型的断裂强度大致与线密度成正比，因此可以通过将观察到的断裂强度转换为断裂强度（厘米牛顿/特、克力/特或克力/旦）来比较不同尺寸的股线。 5.6 伸长率- 纱线的伸长率对制造过程和所生产的产品有影响。它提供了服装区域（如膝盖、肘部或其他应力点）可能拉伸行为的指示。它还提供了用于增强塑料制品、软管和轮胎等物品的纱线或绳索拉伸性能的设计标准。 5.7 力伸长曲线- 力-伸长曲线允许计算各种值，本试验方法中未讨论所有值，例如断裂伸长率、规定力下伸长率、规定伸长率下的力、抗拉伸的初始弹性模量、在应力下屈服的柔度，以及弹性模量的倒数和曲线下面积，韧性的度量，与所做的功成比例。 注3: 如果将力转换为单位应力，如厘牛顿/tex、磅/平方英寸、帕斯卡、克力/tex或克力/丹尼尔，则力-伸长曲线可以转换为应力-应变曲线，并且伸长率基于单位长度的变化。 5.8 结和环断裂力- 由于打结或线圈的存在，断裂力的降低被认为是纱线脆性的一种度量。已知结或环试验中的伸长率没有任何意义，通常也没有报告。 5.9 运行速度- 一般来说，断裂力随着断裂时间的增加而略有下降。 5.9.1 在恒定的断裂时间下运行CRT、CRE和CRL张力试验机可以最大限度地减少三种类型张力试验机之间的试验结果差异。 当在固定的断裂时间进行拉伸试验时，通常发现CRT和CRE拉伸试验机之间在断裂力方面存在合理的一致性。 4. 当CRL张力试验机的不同制造商同时进行断裂操作时，也获得了一致的结果。然而，CRE或CRT张力试验机与CRL张力试验机之间的协议并不一定是好的，即使它们同时运行以破坏。CRE型测试仪是首选的张力测试机。 5.9.2 本试验方法规定了规范建议的平均断裂时间为20±3 s D76/D76M . 它还提供了备用速度，例如300±10 mm[12±0.5 in]/使用250毫米[10英寸]时的最小值标距长度。 看见 9.2 . 5.9.3 断裂时间±3 s的公差足够宽，可以方便地调整张力试验机的运行速度，并且足够窄，可以确保试验之间的良好一致性。17秒和23秒的试验之间的破断拉力差通常不超过1.5 % 具有更高的值。 5.9.4 如果张力试验机不能在20秒的时间内进行断裂操作，则本试验方法中应包括其他操作速率。这些替代费率只能在有关各方之间达成协议或适用材料规范要求时使用。 5.10 湿试样试验- 湿试件的测试通常仅针对在潮湿或暴露于高湿度下时表现出断裂力损失的纱线，例如，由动物纤维和人造纤维制成的纱线- 由再生和改性纤维素制成的纤维。对亚麻纱线进行了湿法测试，以检测掺假，但未显示断裂力增加。 5.11 烘干试样和高温试样的试验- 在标准或高温下对烘箱干燥试样进行的测试通常仅针对将在高温下使用或将在影响观察到的断裂力的非常干燥的条件下使用的纱线，例如，针对拟用于轮胎帘线的人造丝纱线和用于其他工业目的的纱线。注意，在标准温度下测试烘干试样时获得的结果不一定与在高温下测试烘干纱线时获得的结果一致。 5.12 低温下的试样试验- 暴露在低温下的试样测试通常仅在将在低温下使用的纱线上进行，例如，用于寒冷气候或户外设计的外套中的纱线- 空间情况。对用于制造室外应用材料（如筛网织物）的涂层纱线进行低温测试。

1.1 This test method covers the determination of tensile properties of monofilament, multifilament, and spun yarns, either single, plied, or cabled with the exception of yarns that stretch more than 5.0 % when tension is increased from 0.05 to 1.0 cN/tex [0.5 to 1.0 gf/tex]. 1.2 This test method covers the measurement of breaking force and elongation of yarns and includes directions for the calculation of breaking tenacity, initial modulus, chord modulus, and breaking toughness. 1.2.1 Options are included for the testing of specimens in: (A) straight, (B) knotted, and (C) looped form. 1.2.2 Conditions of test are included for the testing of specimens that are: (1) conditioned air, (2) wet, not immersed, (3) wet, immersed, (4) oven-dried, (5) exposed to elevated temperature, or (6) exposed to low temperature. Note 1: Special methods for testing yarns made from specific fibers; namely, glass, flax, hemp, ramie, and kraft paper and for specific products; namely, tire cords and rope, have been published: Test Methods D885 , and Specification D578 . Note 2: For directions covering the determination of breaking force of yarn by the skein method refer to Test Method D1578 . 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.4 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. 1.5 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 ====== 5.1 Acceptance Testing— Option A1 of Test Method D2256 is considered satisfactory for acceptance testing of commercial shipments because the test method has been used extensively in the trade for acceptance testing. However, this statement is not applicable to knot and loop breaking force tests, tests on wet specimens, tests on oven-dried specimens, or tests on specimens exposed to low or high temperatures and should be used with caution for acceptance testing because factual information on between-laboratory precision and bias is not available. 5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, use the samples for such a comparative tests that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in disparate results during initial testing and randomly assigned in equal numbers to each laboratory. The test results from the laboratories involved should be compared using a statistical test for unpaired data, a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias. 5.2 Fundamental Properties— The breaking tenacity, calculated from the breaking force and the linear density, and the elongation are fundamental properties that are widely used to establish limitations on yarn processing or conversion and on their end-use applications. Initial modulus is a measure of the resistance of the yarn to extension at forces below the yield point. The chord modulus is used to estimate the resistance to imposed strain. The breaking toughness is a measure of the work necessary to break the yarn. 5.3 Comparison to Skein Testing— The single-strand method gives a more accurate measure of breaking force present in the material than does the skein method and uses less material. The skein-breaking force is always lower than the sum of the breaking forces of the same number of ends broken individually. 5.4 Applicability— Most yarns can be tested by this test method. Some modification of clamping techniques may be necessary for a given yarn depending upon its structure and composition. To prevent slippage in the clamps or damage as a result of being gripped in the clamps, special clamping adaptations may be necessary with high modulus yarns made from fibers such as glass or extended chain polyolefin. Specimen clamping may be modified as required at the discretion of the individual laboratory providing a representative force-elongation curve is obtained. In any event, the procedure described in this test method for obtaining tensile properties must be maintained. 5.5 Breaking Strength— The breaking strength of a yarn influences the breaking strength of fabrics made from the yarn, although the breaking strength of a fabric also depends on its construction and may be affected by manufacturing operations. 5.5.1 Because breaking strength for any fiber-type is approximately proportional to linear density, strands of different sizes can be compared by converting the observed breaking strength to breaking tenacity (centinewtons per tex, grams-force per tex, or grams-force per denier). 5.6 Elongation— The elongation of a yarn has an influence on the manufacturing process and the products made. It provides an indication of the likely stretch behavior of garment areas such as knees, elbows, or other points of stress. It also provides design criteria for stretch behavior of yarns or cords used as reinforcement for items such as plastic products, hose, and tires. 5.7 Force-Elongation Curve— Force-elongation curves permit the calculation of various values, not all of which are discussed in this test method, such as elongation at break, elongation at specified force, force at specified elongation, initial elastic modulus which is resistance to stretching, compliance which is ability to yield under stress, and is the reciprocal of the elastic modulus, and area under the curve, a measure of toughness, which is proportional to the work done. Note 3: Force-elongation curves can be converted to stress-strain curves if the force is converted to unit stress, such as to centinewtons per tex, or pounds per square inch, or pascals, or grams-force per tex, or grams-force per denier, and the elongation is based on change per unit length. 5.8 Knot and Loop Breaking Force— The reduction in breaking force due to the presence of a knot or loop is considered a measure of the brittleness of the yarn. Elongation in knot or loop tests is not known to have any significance and is not usually reported. 5.9 Rate of Operation— In general, the breaking force decreases slightly as time-to-break increases. 5.9.1 Operation of CRT, CRE, and CRL tension testing machines at a constant time-to-break has been found to minimize differences in test results between the three types of tension testing machines. When tensile tests are performed at a fixed time-to-break, then reasonable agreement in breaking force has generally been found to exist between CRT and CRE tension testing machines. 4 Consistent results are also obtained between different manufacturers of CRL tension testing machines when they are operated at the same time-to-break. The agreement is not necessarily good, however, between CRE or CRT tension testing machines on the one hand and CRL tension testing machines on the other even when they are all operated at the same time-to-break. The CRE-type tester is the preferred tension testing machine. 5.9.2 This test method specifies an average time-to-break of 20 ± 3 s as recommended by Specification D76/D76M . It also provides for alternate speeds, such as 300 ± 10 mm [12 ± 0.5 in.]/min when using a 250-mm [10-in.] gauge length. See 9.2 . 5.9.3 The tolerance of ±3 s for the time-to-break is wide enough to permit convenient adjustment of the tension testing machine's rate of operation, and it is narrow enough to ensure good agreement between tests. The difference in breaking force between tests at 17 and 23 s will usually not exceed 1.5 % of the higher value. 5.9.4 In case a tension testing machine is not capable of being operated at 20-s time-to-break, alternative rates of operation are included in this test method. These alternative rates may be used only by agreement between the parties concerned or when required in an applicable material specification. 5.10 Tests on Wet Specimens— Tests on wet specimens are usually made only on yarns which show a loss of breaking force when wet or when exposed to high humidity, for example, yarns made from animal fibers and man-made fibers based on regenerated and modified cellulose. Wet tests are made on flax yarns to detect adulteration by failure to show a gain in breaking force. 5.11 Tests on Oven-Dried Specimens and Specimens at High Temperatures— Tests on oven-dried specimens at standard or high temperatures are usually made only on yarns that will be used at high temperatures or will be used under very dry conditions which will affect the observed breaking force, for example, on rayon yarns intended for use in tire cords and yarns for other industrial purposes. Note that results obtained when testing oven-dried specimens at standard temperature will not necessarily agree with the results obtained when testing oven-dried yarns at high temperatures. 5.12 Tests on Specimens at Low Temperatures— Tests on specimens exposed to low temperatures are usually made only on yarns that will be used at low temperatures, for example, yarns used in outerwear designed for cold climates or outer-space situations. Low-temperature tests are made on coated yarns used in the manufacture of materials used in outdoor applications, such as screening fabrics.