1.1 本试验方法涵盖了测量硫化橡胶或热塑性橡胶硬度的程序。在与橡胶接触的两种条件下，通过指定尺寸球的穿透深度差获得硬度:( 1. )以较小的初始力和( 2. )具有更大的最终力。在指定时间进行差异渗透，并将其转换为硬度标度值。 1.2 该试验方法在技术上与ISO 48相似。 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 国际硬度试验基于在规定条件下测量刚性球对橡胶试样的渗透。将测得的贯入度转换为IRHD，选择的度标度为0表示弹性模量为零的材料，100表示无限弹性模量的材料。 4.1.1 在大多数正常硬度范围内，标尺还满足以下条件: 一个IRHD范围代表杨氏模量的近似相同比例差，对于通常弹性范围内的硫化橡胶，IRHD中的读数与a型硬度计（试验方法）给出的读数相当 D2240 )测试标准试样时。 4.1.1.1 术语“通常弹性范围”用于排除具有异常高应力松弛率或变形滞后率的化合物。对于此类化合物，两种硬度试验（试验方法）中停留时间的差异 D2240 和 D1415 )导致硬度值差异。在测试弯曲或不规则形状的试样时，读数可能不具有可比性。 4.1.2 对于基本上具有弹性的各向同性材料，如硫化良好的天然橡胶，IRHD中的硬度与杨氏模量具有已知关系，但对于明显塑性或各向异性的橡胶，这种关系将不太精确。 4.1.3 以IRHD表示的渗透差和硬度之间的关系基于以下内容: 4.1.3.1 关系 4. 在理想弹性各向同性材料的贯入度和杨氏模量之间: 哪里: D = 理想弹性各向同性材料的已知关系，压痕， R = 球的半径，mm， F = 总压入力， E = 杨氏模量以兆帕表示，以及 f = 接触力 4.1.3.2 使用probit（综合正态误差）曲线关联日志 10 M IRHD中的硬度，如所示 图1 . 该曲线定义如下: 图1 点曲线与对数相关 10 M和IRHD中的硬度 4.1.3.3 log的值 10 M 对应于曲线中点等于0.364，即， M = 2.31 MPa或335 psi。 4.1.3.4 最大斜率等于每单位对数增加57 IRHD 10 M .

1.1 This test method covers a procedure for measuring the hardness of vulcanized or thermoplastic rubber. The hardness is obtained by the difference in penetration depth of a specified dimension ball under two conditions of contact with the rubber: ( 1 ) with a small initial force and ( 2 ) with a much larger final force. The differential penetration is taken at a specified time and converted to a hardness scale value. 1.2 This test method is technically similar to ISO 48. 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 International Hardness test is based on measurement of the penetration of a rigid ball into the rubber specimen under specified conditions. The measured penetration is converted into IRHD, the scale of degrees being so chosen that 0 represents a material having an elastic modulus of zero, and 100 represents a material of infinite elastic modulus. 4.1.1 The scale also fulfills the following conditions over most of the normal range of hardness: one IRHD range represents approximately the same proportionate difference in Young's modulus, and for rubber vulcanizates in the usual range of resilience, readings in IRHD are comparable with those given by a Type A durometer (Test Method D2240 ) when testing standard specimens. 4.1.1.1 The term “usual range of resilience” is used to exclude those compounds that have unusually high rates of stress relaxation or deformational hysteresis. For such compounds, differences in the dwell time in the two hardness tests (Test Methods D2240 and D1415 ) result in differences in hardness values. Readings may not be comparable when testing curved or irregularly shaped test specimens. 4.1.2 For substantially elastic isotropic materials like well-vulcanized natural rubbers, the hardness in IRHD bears a known relation to Young's modulus, although for markedly plastic or anisotropic rubbers the relationship will be less precisely known. 4.1.3 The relation between the difference of penetration and the hardness expressed in IRHD is based on the following: 4.1.3.1 The relation 4 between penetration and Young's modulus for a perfectly elastic isotropic material: where: D = known relationship for a perfectly elastic isotropic material, between indentation, R = radium of the ball, mm, F = total indenting force, E = Young's modulus expressed in megapascals, and f = contact force 4.1.3.2 Use of a probit (integrated normal error) curve to relate log 10 M and hardness in IRHD, as shown in Fig. 1 . This curve is defined as follows: FIG. 1 Point Curve to Relate Log 10 M and the Hardness in IRHD 4.1.3.3 The value of log 10 M corresponding to the midpoint of the curve is equal to 0.364, that is, M = 2.31 MPa or 335 psi. 4.1.3.4 The maximum slope is equal to 57 IRHD per unit increase in log 10 M .