1.1 本规程涵盖了弯曲梁应力腐蚀试样的设计、制备和使用程序。 1.2 针对不同的产品形式（如薄板或平板），给出了不同的试样配置。本规程适用于应力水平低于材料弹性极限的任何金属试样，因此，可以准确计算或测量施加的应力（见 注1 ). 本规程中的应力计算不适用于塑性应力试样。 注1: 这些实践的本质是，只能计算施加的应力。由于应力腐蚀开裂是总应力的函数，为了关键应用和正确解释结果，应通过适当的无损方法（例如X射线衍射法）确定残余应力（施加外部应力之前）或总弹性应力（施加外部应力之后）- 射线衍射( 1. ). 2. 1.3 给出了暴露在气体和液体环境中进行应力腐蚀试验的试验程序。 1.4 弯曲梁测试最适用于扁平产品形状，如薄板、带材和板材。对于板材，弯曲梁试样更难使用，因为必须建造更坚固的试样支架来容纳试样。中描述了四点加载试样的双梁修改，以利用较重的材料 10.5 . 1.5 由于其他实践（例如实践）涉及这一方面，因此仅对试样在腐蚀环境中的暴露进行了简要处理 D1141 , G30 , G36 , G44集团 , G50 和 G85 . 实验者参考ASTM特别技术出版物425 ( 2. ). 1.6 弯曲梁试验通常构成恒定应变（挠度）试验。 一旦开始开裂，裂纹尖端以及未开裂区域的应力状态已经改变，因此，本实践中讨论的已知或计算的应力或应变值仅适用于裂纹开始之前存在的应力状态。 1.7 以国际单位制表示的数值应视为标准值。国际单位制后括号中给出的值仅供参考，不被视为标准值。 1.8 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。 （有关更具体的安全隐患信息，请参阅第节。） 7. 和 12.1 .) 1.9 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 弯曲梁试样用于测定合金板材和板材在各种环境中的应力腐蚀行为。弯曲梁试样设计用于在低于合金弹性极限的应力水平下进行测试。对于塑性范围内的测试，应使用U形弯曲试样（见实践 G30 ). 虽然可以将弯曲梁试样应力至塑性范围，但无法计算塑性应力三点和四点加载试样以及双梁试样的应力水平。因此，一般情况下不建议使用塑性范围内的弯曲梁试样。

1.1 This practice covers procedures for designing, preparing, and using bent-beam stress-corrosion specimens. 1.2 Different specimen configurations are given for use with different product forms, such as sheet or plate. This practice is applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured (see Note 1 ). Stress calculations by this practice are not applicable to plastically stressed specimens. Note 1: It is the nature of these practices that only the applied stress can be calculated. Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress (before applying external stress) or the total elastic stress (after applying external stress) should be determined by appropriate nondestructive methods, such as X-ray diffraction ( 1 ). 2 1.3 Test procedures are given for stress-corrosion testing by exposure to gaseous and liquid environments. 1.4 The bent-beam test is best suited for flat product forms, such as sheet, strip, and plate. For plate material the bent-beam specimen is more difficult to use because more rugged specimen holders must be built to accommodate the specimens. A double-beam modification of a four-point loaded specimen to utilize heavier materials is described in 10.5 . 1.5 The exposure of specimens in a corrosive environment is treated only briefly since other practices deal with this aspect, for example, Practices D1141 , G30 , G36 , G44 , G50 , and G85 . The experimenter is referred to ASTM Special Technical Publication 425 ( 2 ). 1.6 The bent-beam practice generally constitutes a constant strain (deflection) test. Once cracking has initiated, the state of stress at the tip of the crack as well as in uncracked areas has changed, and therefore, the known or calculated stress or strain values discussed in this practice apply only to the state of stress existing before initiation of cracks. 1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.8 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. (For more specific safety hazard information see Section 7 and 12.1 .) 1.9 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 The bent-beam specimen is designed for determining the stress-corrosion behavior of alloy sheets and plates in a variety of environments. The bent-beam specimens are designed for testing at stress levels below the elastic limit of the alloy. For testing in the plastic range, U-bend specimens should be employed (see Practice G30 ). Although it is possible to stress bent-beam specimens into the plastic range, the stress level cannot be calculated for plastically-stressed three- and four-point loaded specimens as well as the double-beam specimens. Therefore, the use of bent-beam specimens in the plastic range is not recommended for general use.