1.1 本试验方法涵盖浸没在液体中时在高频振动的试样表面上产生的空化损伤。振动会导致液体中空腔的形成和坍塌，坍塌的空腔会对试样造成损坏和侵蚀（材料损失）。 1.2 尽管这种方法中产生流体空化的机制不同于流动系统和液压机器中的机制（参见 5.1 )材料损伤机制的性质基本相似。因此，该方法提供了一种小规模、相对简单和可控的测试，可用于比较不同材料的抗空蚀性，详细研究给定材料中损伤的性质和过程，或通过改变一些测试条件来研究测试变量对产生的损伤的影响。 1.3 本试验方法规定了标准试验条件，包括试样的直径、振幅和频率，以及试验液体及其容器。如果适当记录，它允许偏离其中一些条件，这可能适用于某些目的。它为设置合适的仪器提供了指导，并涵盖了测试和报告程序以及要采取的预防措施。它还规定了必须使用的标准参考材料，以验证设施的运行，并定义其他试验材料的标准化抗侵蚀性。 1.4 本试验方法的历史记录如所示 附录X4 ，然后是一个全面的参考书目。 1.5 以国际单位制表示的数值应视为标准值。括号中的英寸-磅单位仅供参考。 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和健康实践，并确定监管限制的适用性。 有关具体的安全警告信息，请参阅 6.1 , 10.3 和 10.6.1 . ====意义和用途====== 5.1 本试验方法可用于估计材料对气蚀的相对阻力，例如在泵、水轮机、液压测功机、阀门、轴承、柴油机缸套、船舶螺旋桨、水翼船和有障碍物的内部流道中可能遇到的气蚀。 出于类似目的，另一种方法是试验方法 G134页 ，它利用空化液体射流在静止试样上产生侵蚀。后者可能更适用于不容易形成精确形状试样的材料。或的结果 任何 应谨慎使用气蚀试验；看见 5.8 . 5.2 一些研究人员还使用这种试验方法作为筛选试验，以筛选在低压蒸汽涡轮机和在暴雨中飞行的飞机、导弹或航天器中遇到的受到液体冲击侵蚀的材料。试验方法 G73 描述了另一种专门针对该类型环境的测试方法。 5.3 本试验方法不推荐用于评估弹性或顺应性涂层，其中一些已成功用于防止中等强度的气蚀或液体冲击。这是因为试样上涂层的顺应性可能会降低其振动运动引起的液体空化的严重程度。结果不代表现场应用，其中空化的流体动力产生与涂层无关。 注1: 另一种方法是“固定试样”法，该方法使用相同的基本仪器，并被视为适用于顺应性涂层。在该方法中，将试样固定在液体容器内，并将喇叭的振动尖端放置在其附近。 喇叭（通常配有高阻力可更换尖端）引起的空化“气泡”作用于试样。虽然一些研究人员使用了这种方法（参见 X4.2.3 )他们在防区外距离和其他安排方面有所不同。根据本试验方法的要求，固定试样法也可用于不能形成螺纹试样或不能形成可粘接到螺纹试样上的圆盘的脆性材料（见 7.6 ). 5.4 对于电化学腐蚀或固体颗粒冲击起主要作用的应用，不应直接使用该试验方法对材料进行分级。然而，基本方法和装置的修改已用于此类目的（参见 9.2.5 , 9.2.6 和 X4.2 ). 指导 G119页 为了确定机械效应和电化学效应之间的协同作用，可以遵循。 5.5 那些从事基础研究或关注非常专业应用的人可能需要改变一些测试参数以适应其目的。然而，在所有其他方面遵守该测试方法将允许更好地理解和关联不同研究者的结果。 5.6 由于空化和液体冲击侵蚀中侵蚀-时间曲线的非线性性质，在进行比较和得出结论时必须考虑该曲线的形状。 参见第节 11 . 5.7 该试验的结果可能会受到试样表面处理的显著影响。在规划、执行和报告测试计划时必须考虑到这一点。另请参见 7.4 和 12.2 . 5.8 空化侵蚀和液体冲击侵蚀的机制尚未完全理解，可能会有所不同，具体取决于液/固相互作用的详细性质、规模和强度。因此，“抗侵蚀性”可能代表多种性能而非单一性能，尚未成功与其他可独立测量的材料性能相关联。因此，不同测试方法或不同现场条件下的结果一致性不是很好。 两种材料之间的微小差异可能并不显著，它们的相对排名很可能在另一个测试中逆转。 5.9 如果测试程序必须偏离仪器、试样或测试条件的标准规范，则应解释原因，并将结果描述为“修改了ASTM G32测试方法”另请参见 5.4 , 5.5 和 12.1 .

1.1 This test method covers the production of cavitation damage on the face of a specimen vibrated at high frequency while immersed in a liquid. The vibration induces the formation and collapse of cavities in the liquid, and the collapsing cavities produce the damage to and erosion (material loss) of the specimen. 1.2 Although the mechanism for generating fluid cavitation in this method differs from that occurring in flowing systems and hydraulic machines (see 5.1 ), the nature of the material damage mechanism is believed to be basically similar. The method therefore offers a small-scale, relatively simple and controllable test that can be used to compare the cavitation erosion resistance of different materials, to study in detail the nature and progress of damage in a given material, or—by varying some of the test conditions—to study the effect of test variables on the damage produced. 1.3 This test method specifies standard test conditions covering the diameter, vibratory amplitude and frequency of the specimen, as well as the test liquid and its container. It permits deviations from some of these conditions if properly documented, that may be appropriate for some purposes. It gives guidance on setting up a suitable apparatus and covers test and reporting procedures and precautions to be taken. It also specifies standard reference materials that must be used to verify the operation of the facility and to define the normalized erosion resistance of other test materials. 1.4 A history of this test method is given in Appendix X4 , followed by a comprehensive bibliography. 1.5 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are for information only. 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific safety warning information, see 6.1 , 10.3 , and 10.6.1 . ====== Significance And Use ====== 5.1 This test method may be used to estimate the relative resistance of materials to cavitation erosion as may be encountered, for instance, in pumps, hydraulic turbines, hydraulic dynamometers, valves, bearings, diesel engine cylinder liners, ship propellers, hydrofoils, and in internal flow passages with obstructions. An alternative method for similar purposes is Test Method G134 , which employs a cavitating liquid jet to produce erosion on a stationary specimen. The latter may be more suitable for materials not readily formed into a precisely shaped specimen. The results of either, or any , cavitation erosion test should be used with caution; see 5.8 . 5.2 Some investigators have also used this test method as a screening test for materials subjected to liquid impingement erosion as encountered, for instance, in low-pressure steam turbines and in aircraft, missiles or spacecraft flying through rainstorms. Test Method G73 describes another testing approach specifically intended for that type of environment. 5.3 This test method is not recommended for evaluating elastomeric or compliant coatings, some of which have been successfully used for protection against cavitation or liquid impingement of moderate intensity. This is because the compliance of the coating on the specimen may reduce the severity of the liquid cavitation induced by its vibratory motion. The result would not be representative of a field application, where the hydrodynamic generation of cavitation is independent of the coating. Note 1: An alternative approach that uses the same basic apparatus, and is deemed suitable for compliant coatings, is the “stationary specimen” method. In that method, the specimen is fixed within the liquid container, and the vibrating tip of the horn is placed in close proximity to it. The cavitation “bubbles” induced by the horn (usually fitted with a highly resistant replaceable tip) act on the specimen. While several investigators have used this approach (see X4.2.3 ), they have differed with regard to standoff distances and other arrangements. The stationary specimen approach can also be used for brittle materials which can not be formed into a threaded specimen nor into a disc that can be cemented to a threaded specimen, as required for this test method (see 7.6 ). 5.4 This test method should not be directly used to rank materials for applications where electrochemical corrosion or solid particle impingement plays a major role. However, adaptations of the basic method and apparatus have been used for such purposes (see 9.2.5 , 9.2.6 , and X4.2 ). Guide G119 may be followed in order to determine the synergism between the mechanical and electrochemical effects. 5.5 Those who are engaged in basic research, or concerned with very specialized applications, may need to vary some of the test parameters to suit their purposes. However, adherence to this test method in all other respects will permit a better understanding and correlation between the results of different investigators. 5.6 Because of the nonlinear nature of the erosion-versus-time curve in cavitation and liquid impingement erosion, the shape of that curve must be considered in making comparisons and drawing conclusions. See Section 11 . 5.7 The results of this test may be significantly affected by the specimen’s surface preparation. This must be considered in planning, conducting and reporting a test program. See also 7.4 and 12.2 . 5.8 The mechanisms of cavitation erosion and liquid impingement erosion are not fully understood and may differ, depending on the detailed nature, scale, and intensity of the liquid/solid interactions. “Erosion resistance” may, therefore, represent a mix of properties rather than a single property, and has not yet been successfully correlated with other independently measurable material properties. For this reason, the consistency of results between different test methods or under different field conditions is not very good. Small differences between two materials are probably not significant, and their relative ranking could well be reversed in another test. 5.9 If a test program must deviate from the standard specifications for apparatus, test specimens, or test conditions, the reasons shall be explained, and the results characterized as obtained by “ASTM Test Method G32 modified.” See also 5.4 , 5.5 , and 12.1 .