1.1 本试验方法 2. 涵盖了硬质合金横向断裂强度的测定。 1.2 以英寸-磅为单位的数值应视为标准值。括号中的SI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====== 3.1 本试验方法用于通过测量硬质合金级粉末的烧结强度来确定其质量。 在按规定形状、尺寸和表面光洁度制备的试样上进行；如果尺寸允许，可以从成品零件制备试样。本试验方法没有已知的标准材料。硬质合金的横向断裂强度不是设计值。 3.1.1 大多数商用硬质合金的机械性能最好归类为脆性（可忽略延展性）。断裂强度取决于内部或表面缺陷。非相干内部缺陷的示例为大孔、B型孔隙率（见试验方法 B276页 )和杂质颗粒的夹杂。此类缺陷在烧结材料内的空间和尺寸上随机分布。这赋予了任何横向断裂强度测量的统计性质。 3.1.2 梁在三点载荷下的应力分布是不均匀的。它沿跨度线性增加，在中心达到最大值，并在从顶部压缩到底部拉伸的任何截面上线性变化。 因此，最大拉伸应力出现在样品最底部纤维的中心跨距处，定义为破坏时的横向断裂强度。失效发生在随机缺陷部位，这很可能与最大应力不一致。这为横向断裂强度测量提供了额外的统计特性。

1.1 This test method 2 covers the determination of the transverse rupture strength of cemented carbides. 1.2 The values stated in inch-pound units are to be regarded as the standard. The SI values in parentheses are provided 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 ====== 3.1 This test method is used as a means of determining the quality of cemented carbide grade powders by measuring their sintered strength. It is performed on test specimens prepared to specified shape, dimensions, and surface finish; test specimens may be prepared from finished parts if size permits. There is no known standard material for this test method. The transverse rupture strength of cemented carbides is not a design value. 3.1.1 Most commercial cemented carbides have mechanical behavior that is best classified as brittle (negligible ductility). Fracture strengths are dependent on internal or surface flaws. Examples of incoherent internal flaws are macropores, Type B porosity (see Test Method B276 ), and inclusions of foreign particles. Such flaws are randomly distributed spatially and in size within the sintered material. This imparts a statistical nature to any transverse rupture strength measurement. 3.1.2 The stress distribution in a beam in three-point loading is non-uniform. It increases linearly along the span to a maximum at the center, and varies linearly through any section from compression on the top to tension on the bottom. The maximum tensile stress therefore occurs at center span in the bottom most fibers of the sample, and is defined as the transverse rupture strength at failure. Failure is initiated at a random flaw site, which is most probably not coincident with the maximum stress. This imparts an additional statistical nature to transverse rupture strength measurements.