1.1 本规程涵盖了通过扫频正弦输入法使用过程补偿谐振测试（PCRT）对新制造和在用零件总体进行零件到自身（PTI）检查的一般程序。PCRT检测金属和非金属零件中的共振模式差异。实践 E2534 用于PCRT缺陷检测和实践 E3081 对于PCRT异常值筛选，涵盖PCRT排序模块的开发和应用，该模块在单个时间点检查零件。这些方法使用从测试零件记录的共振频谱，并执行不同的统计分析，以将测试零件与参考总体进行比较。 这些比较包括并必须补偿任何零件群中存在的正常几何、材料和加工变化。然而，在许多应用中，用户可能需要评估单个处理步骤或服务负载的影响，与其他变化源隔离。例如，制造商可能希望对热处理或硬化过程进行过程监控。维修人员可能希望评估发动机中服务周期的影响。PCRT PTI检查测量零件在两个时间点的共振频谱，例如制造工艺步骤之前和之后，并计算共振频率的变化，以评估干预工艺的效果。 可以在频率变化上设置控制限值，以实现PTI通过/失败检查能力。这些限制可能基于具有可接受和不可接受变化水平的零件的训练总体、零件变化影响的模型预测，或来自过程控制实践的标准。可通过PCRT PTI检查评估的制造过程和在役载荷包括但不限于热处理、热等静压（HIP）、喷丸、感应硬化、渗碳、涂层、热历史变化、残余应力变化、蠕变、塑性变形、腐蚀和疲劳。本规程适用于能够在声学或超声波频率范围内或两者中激励、测量、记录和分析多个全身机械振动共振频率的仪器。 1.2 单位- 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 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====== 5.1 PCRT应用程序和功能- PCRT PTI检测已成功应用于制造和维护环境中的广泛零件。中讨论了使用PTI评估的制造过程、维修过程和在役损伤机制的示例 1.1 . PCRT已被证明能够在许多行业（包括汽车、航空航天和发电）提供基于PTI的成本效益高、准确的无损检测、过程监测和寿命监测。目前用于商业用途的成功应用示例包括但不限于: (1) 热处理操作: （a） 航空航天燃气涡轮发动机部件（叶片、叶片、盘） （b） 额外制造的部件 （c） 钢制机械部件 （d） 工业燃气轮机叶片 (2) 感应淬火和渗碳（表面硬化和穿透硬化零件）: （a） 齿轮 （b） 球形螺母 (3) 热等静压（HIP）: （a） 燃气轮机发动机部件（叶片、叶片、盘） （b） 额外制造的部件 (4) 喷丸处理: （a） 钢制机械部件 (5) 在役热历史、老化、蠕变损伤、疲劳: （a） 燃气轮机发动机部件（叶片、叶片、盘） （b） 工业燃气轮机叶片 （c） 飞机起落架齿轮 (6) 维护维修/恢复过程: （a） 燃气轮机发动机部件（叶片、叶片、盘） （b） 工业燃气轮机叶片 （c） 飞机起落架齿轮。 5.2 通过扫频正弦输入进行PCRT的一般方法和设备要求: 5.2.1 PCRT系统包括能够诱导振动、记录部件对诱导振动的响应以及分析收集的数据的硬件和软件。将扫频正弦波输入零件已被证明是引入机械振动的有效方法，并且可以通过与零件物理接触的适当有源传感器耦合的高质量信号发生器来实现。通过记录适当的被动振动传感器接收到的信号来收集零件的共振响应。 分析可用数据所需的软件可能包括各种合适的统计分析和模式识别工具。测量精度和重复性对PCRT的应用至关重要。 5.2.2 硬件要求- 要求扫描正弦波信号发生器和响应测量系统在测试零件的期望频率范围内工作，精度高于0.002 %. 信号发生器应按照适用的行业标准进行校准。传感器必须在相同的频率范围内工作。通常使用三个传感器；一 驾驶 传感器和两个 接收 传感器。传感器通常在干燥环境中工作，为被检零件提供直接接触耦合。 然而，当零件潮湿或涂有油时，非接触响应方法可以适用。除了夹具和传感器接触之外，不允许与零件有其他接触，因为这些机械力会抑制某些振动。为了进行最佳检查，应将零件精确放置在传感器上（通常，每个轴上±0.062 in.（1.6 mm）可提供可接受的结果）。检查槽和电缆应隔离 驾驶 从…起 接收 信号和接地回路，以免产生（机械或电气） 相声 在通道之间。过大的外部振动或可听见的噪音或两者都会影响测量。 5.3 约束和限制: 5.3.1 PCRT不能基于不影响零件结构完整性的视觉可检测异常来分离零件。可能需要对零件进行额外的目视检查，以识别这些迹象。 5.3.2 零件几何形状或基材特性的过度变化可能会限制PCRT PTI检查的灵敏度。 5.3.3 PCRT PTI通常不可能直接测量经历材料状态变化的区域的单个几何尺寸，例如感应硬化区域的表面深度（厘米或英寸）。频率变化取决于导致材料状态变化的过程的总体积效应。 然而，通过精确训练的可接受极限，PCRT PTI在筛选可接受和不可接受加工的组件群体方面非常有效。 5.3.4 PCRT仅适用于提供峰值质量因子（Q）值大于500的共振的刚性物体。非刚性材料或薄壁零件不会产生有用的Q值。 5.3.5 虽然PCRT在许多情况下可以应用于涂漆和涂层零件，但一些表面涂层（如吸振材料和重油层）的存在可能会限制或排除PCRT的应用。 5.3.6 虽然PCRT PTI检测可适用于温度范围广泛的零件，但不能适用于温度快速变化的零件。 在收集共振数据之前，应稳定零件温度。 5.3.7 教学集中的错误分类部分，以及教学集中存在的未知异常，可以显著降低PCRT的准确性和灵敏度。

1.1 This practice covers a general procedure for using the Process Compensated Resonance Testing (PCRT) via swept sine input method to perform Part-to-Itself (PTI) examination on populations of newly manufactured and in-service parts. PCRT detects resonance pattern differences in metallic and non-metallic parts. Practice E2534 for Defect Detection with PCRT and Practice E3081 for Outlier Screening with PCRT cover the development and application of PCRT sorting modules that inspect a part at a single point in time. These methods use the resonance frequency spectra recorded from test parts and perform different statistical analyses to compare test parts to reference populations. These comparisons include, and must compensate for, the normal geometric, material, and processing variations present in any population of parts. In many applications, however, the user may need to evaluate the effects of a single processing step or in-service load in isolation from other sources of variation. For example, a manufacturer may want to perform process monitoring and control on a heat treatment or hardening process. A maintainer may want to evaluate the effect of service cycles in an engine. A PCRT PTI examination measures the resonance frequency spectrum of a part at two points in time, such as before and after a manufacturing process step, and calculates the change in resonance frequencies to evaluate the effect of the intervening process. Control limits can be set on the frequency change to field a PTI PASS/FAIL inspection capability. The limits may be based on training populations of parts with acceptable and unacceptable levels of change, model predictions of the effects of part changes, or criteria derived from process control practices. Manufacturing processes and in-service loads that can be evaluated with a PCRT PTI inspection include, but are not limited to heat treatment, hot isostatic pressing (HIP), shot peening, induction hardening, carburization, coating, thermal history changes, residual stress changes, creep, plastic deformation, corrosion, and fatigue. This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple, whole body, mechanical vibration resonance frequencies in acoustic or ultrasonic frequency ranges, or both. 1.2 Units— The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 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 ====== 5.1 PCRT Applications and Capabilities— PCRT PTI examination has been applied successfully to a wide range of parts in manufacturing and maintenance environments. Examples of manufacturing processes, repair processes, and in-service damage mechanisms evaluated with PTI are discussed in 1.1 . PCRT has been shown to provide cost effective and accurate PTI-based NDT, process monitoring, and life monitoring in many industries including automotive, aerospace, and power generation. Examples of successful applications currently employed in commercial use include, but are not limited to: (1) Heat treatment operations: (a) Aerospace gas turbine engine components (blades, vanes, disks) (b) Additively manufactured components (c) Steel mechanical components (d) Industrial gas turbine blades (2) Induction hardening and carburization (both case-hardened and through-hardened parts): (a) Gears (b) Ballnuts (3) Hot Isostatic Pressing (HIP): (a) Gas turbine engine components (blades, vanes, disks) (b) Additively manufactured components (4) Shot peening: (a) Steel mechanical components (5) In-service thermal history, aging, creep damage, fatigue: (a) Gas turbine engine components (blades, vanes, disks) (b) Industrial gas turbine blades (c) Aircraft landing gear wheels (6) Maintenance repair/rejuvenation processes: (a) Gas turbine engine components (blades, vanes, disks) (b) Industrial gas turbine blades (c) Aircraft landing gear wheels. 5.2 General Approach and Equipment Requirements for PCRT via Swept Sine Input: 5.2.1 PCRT systems comprise hardware and software capable of inducing vibrations, recording the component response to the induced vibrations, and analyzing the data collected. Inputting a swept sine wave into the part has proven to be an effective means of introducing mechanical vibration and can be achieved with a high-quality signal generator coupled with an appropriate active transducer in physical contact with the part. Collection of the part’s resonance response is achieved by recording the signal received by an appropriate passive vibration transducer. The software required to analyze the available data may include a variety of suitable statistical analysis and pattern recognition tools. Measurement accuracy and repeatability are extremely important to the application of PCRT. 5.2.2 Hardware Requirements— A swept sine wave signal generator and response measurement system operating over the desired frequency range of the test part are required with accuracy better than 0.002 %. The signal generator should be calibrated to applicable industry standards. Transducers must be operable over same frequency range. Three transducers are typically used; one Drive transducer and two Receive transducers. Transducers typically operate in a dry environment, providing direct contact coupling to the part under examination. However, noncontacting response methods can operate suitably when parts are wet or oil-coated. Other than fixturing and transducer contact, no other contact with the part is allowed as these mechanical forces dampen certain vibrations. For optimal examination, parts should be placed precisely on the transducers (generally, ±0.062 in. (1.6 mm) in each axis provides acceptable results). The examination nest and cabling shall isolate the Drive from Receive signals and ground returns, so as to not produce (mechanical or electrical) cross talk between channels. Excessive external vibration or audible noise, or both, will compromise the measurements. 5.3 Constraints and Limitations: 5.3.1 PCRT cannot separate parts based on visually detectable anomalies that do not affect the structural integrity of the part. It may be necessary to provide additional visual inspection of parts to identify these indications. 5.3.2 Excessive variation in part geometry or base material properties may limit the sensitivity of PCRT PTI examination. 5.3.3 A direct measurement of a single geometric dimension of a region undergoing a material state change, such as the case depth (in centimeters or inches) of an induction hardened region, is generally not possible with PCRT PTI. The frequency changes are dependent on the total volumetric effect of the process that causes the material state change. With accurately trained acceptability limits, however, PCRT PTI is very effective at screening populations of components for acceptable and unacceptable processing. 5.3.4 PCRT will only work with stiff objects that provide resonances whose peak quality factor (Q) values are greater than 500. Non-rigid materials or very thin-walled parts will not yield useful Q values. 5.3.5 While PCRT can be applied to painted and coated parts in many cases, the presence of some surface coatings such as vibration absorbing materials and heavy oil layers may limit or preclude the application of PCRT. 5.3.6 While PCRT PTI examination can be applied to parts over a wide range of temperatures, it cannot be applied to parts that are rapidly changing temperature. The part temperature should be stabilized before collecting resonance data. 5.3.7 Misclassified parts in the teaching set, along with the presence of unknown anomalies in the teaching set, can significantly reduce the accuracy and sensitivity of PCRT.