This test method provides a means of verifying instrument alignment in order to quantify and minimize systematic experimental error in X-ray diffraction residual stress measurement. This method is suitable for application to conventional diffractometers or to X-ray diffraction instrumentation of either the diverging or parallel beam types.3 , 4
Application of this test method requires the use of a flat specimen of stress-free material that produces diffraction in the angular region of the diffraction peak to be used for stress measurement. The specimen must be sufficiently fine-grained so that large numbers of individual crystals contribute to the diffraction peak produced. The crystals must provide intense diffraction at all angles of tilt, x03C8;, which will be employed (see Note 1).
Note 18212;Complete freedom from preferred orientation in the stressfree specimen is, however, not critical in the application of the technique.
1.1 This test method covers the preparation and use of a flat stress-free test specimen for the purpose of checking the systematic error caused by instrument misalignment or sample positioning in X-ray diffraction residual stress measurement, or both.
1.2 This test method is applicable to apparatus intended for X-ray diffraction macroscopic residual stress measurement in polycrystalline samples employing measurement of a diffraction peak position in the high-back reflection region, and in which the , 2, and rotation axes can be made to coincide (see ).
1.3 This test method describes the use of iron powder which has been investigated in round-robin studies for the purpose of verifying the alignment of instrumentation intended for stress measurement in ferritic or martensitic steels. To verify instrument alignment prior to stress measurement in other alloys, base metal powder having the same crystal structure as the alloy should be prepared in similar fashion and used to check instrument alignment at the appropriate diffraction angle.
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 and health practices and determine the applicability of regulatory limitations prior to use.
X射线衍射法的残余应力测试仪应力的测试方法中以X射线衍射法的应用最为普遍,因为其理论推导严格成熟,测量结果准确可靠,并且在测量表面残余应力时该方法完全是无损的。X射线衍射法可以测量应力沿层深的分布,测试光斑一般为ϕ(1~5)mm,所测深度根据靶材和被测试材料的变化而有所不同。...
ARE X 残余奥氏体分析仪■ 可测奥氏体220/311、铁素体200/211的衍射峰值强度,符合ASTM E975-03国际标准;■ 多衍射峰测量方式能够减少晶体优化取向带来的影响;■ 使用精密的自动反馈控制电路获得极高的X射线发生器稳定性;■ 自动调整高电压与电流输出脉动值;■ 配备大功率、优质的玻璃(陶瓷)X 射线管;■ 高聚焦单毛细管准直器,高分辨率CCD探测器。...
有些情况下用侧倾法测量垂直于齿面方向的残余应力时,也不需要切除齿尖,只是测量结果没有同倾法精确。使用限制主要取决于两个相邻的齿尖到齿根的角度。图8:测定齿轮根部应力时测角仪的摆动角度范围 中国标准GB/T 7704和国际标准SAE J784a、ASTM E915-10和EN 15305-2008要求在测量残余应力采用多次曝光技术(MET),仪器设备要满足这些标准并按照这些标准进行校准。...
精确测量残余奥氏体的含量,对于热处理过程的控制是意义重大的,能够在钢铁热处理过程中控制产品的特性和质量。X 射线衍射法是目前为止测量钢体中残余奥氏体含量最准确的方法,而且是唯一可以测量残余奥氏体百分比含量低至 0.5%的方法。根据 ASTM E975 的 X 射线测量近无规结晶取向钢中残余奥氏体的标准方法,ARE X残余奥氏体分析仪能够很轻松检测出钢体中残余奥氏体的含量。...
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