Standard Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without the Use of Electronic Measurement Instruments
不使用电子测量仪器的超声脉冲回波测试仪器和系统的性能特性评估标准实践
1.1
本规程描述了评估超声脉冲回波检测仪器和系统以下性能特征的程序:水平极限和线性;垂直极限和线性;分辨率-入口表面和远表面;灵敏度和噪声;校准增益控制的准确性。这些特性的评估旨在用于比较仪器和系统,或通过定期重复,用于检测可能指示即将发生故障的给定仪器或系统特性的长期变化,如果超过某些限制,则需要进行纠正性维护。
根据本规程测量的仪器特性表示为与超声波检测潜在用途相关的术语。用纯电子术语表示的仪器特性可以按照指南中的描述进行测量
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1.2
可以评估使用脉冲波列和A扫描呈现(rf或视频)的超声波检测系统。
1.3
该程序适用于车间或现场条件;不需要额外的电子测量仪器。
1.4
本规程未规定考试系统的性能限制;
如果需要此类验收标准,则必须由使用方指定。在此处暗示验收标准的情况下,这些标准仅为示例,或多或少受到客户和最终用户控制文件施加的限制。
1.5
待评估的具体参数、测试条件和频率以及所需的报告数据也必须由用户确定。
1.6
本规程可用于评估完整的检查系统,包括搜索单元、仪器、互连、固定装置和连接的报警和辅助装置,主要用于重复使用此类系统而不进行更改或替换的情况。
本规程不用于替代检验任何给定材料的仪器或系统的校准或标准化。为此目的使用标准参考试块存在局限性。
2.
1.7
除待评估的仪器或系统外,所需的测试仪器还包括选定的试块和精密外部衰减器(如有规定)。
1.8
包括与程序适用性和结果解释相关的预防措施。
1.9
替代程序,如本文件中所述的示例或其他程序,只能在客户批准的情况下使用。
1.10
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。
1.11
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。
1.12
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
本规程描述了适用于车间和现场条件的程序。对完整系统及其组件的特性进行更全面或更精确的测量通常需要实验室技术和电子设备,如示波器和信号发生器。
在适当情况下,不排除替代这些方法;然而,它们的使用不在本实践的范围内。
5.2
本文件不确定系统验收极限,也不打算作为全面的设备规范。
5.3
虽然包括了几个重要的特征,但在某些应用中可能具有重要意义的其他特征没有涵盖。
5.4
由于必须规定待评估的参数和适用的测试条件,因此本规程只能由熟悉超声波无损检测技术的人员规定,并且所需的测试应由此类合格人员或在其监督下进行。
5.5
实施可能需要使用设施格式的更详细的程序说明。
5.6
在评估完整系统的情况下,应谨慎选择要进行的特定测试;如果相关参数在预期应用中不重要,则其包含可能是不合理的。例如,垂直线性可能与带缺陷门警报的通过/不通过测试无关,而水平线性可能仅用于从显示屏上准确测量缺陷深度或厚度。
5.7
不建议或暗示系统评估或校准的频率。这是使用方的特权,取决于设备的应用、环境和稳定性。
5.8
某些章节仅适用于接收器增益控制以分贝(dB)校准的仪器。虽然这些有时可能在各种仪器上被指定为“增益”、“衰减器”或“灵敏度”,但在本实践中,术语“增益控制”将用于指那些专门控制仪器接收器增益但不包括拒绝、电子距离的控制-
振幅补偿或自动增益控制。
5.9
这些程序通常可应用于任何常用类型和频率的仪器和搜索装置的组合,以及大多数接触式或浸入式直射束检查。某些部分还与角波束、车轮、延迟线和双搜索单元技术兼容。然而,它们的使用应相互商定,并在测试报告中确定。
5.10
所得结果的有效性将取决于仪表显示读数的精度。
假设为±0.04英寸。(±1 mm),屈服于1 % 和2 % 具有适当屏幕分划和显示清晰度的可用仪器的全刻度(fs)可读性。
1.1
This practice describes procedures for evaluating the following performance characteristics of ultrasonic pulse-echo examination instruments and systems: Horizontal Limit and Linearity; Vertical Limit and Linearity; Resolution - Entry Surface and Far Surface; Sensitivity and Noise; Accuracy of Calibrated Gain Controls. Evaluation of these characteristics is intended to be used for comparing instruments and systems or, by periodic repetition, for detecting long-term changes in the characteristics of a given instrument or system that may be indicative of impending failure, and which, if beyond certain limits, will require corrective maintenance. Instrument characteristics measured in accordance with this practice are expressed in terms that relate to their potential usefulness for ultrasonic testing. Instrument characteristics expressed in purely electronic terms may be measured as described in Guide
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1.2
Ultrasonic examination systems using pulsed-wave trains and A-scan presentation (rf or video) may be evaluated.
1.3
The procedures are applicable to shop or field conditions; additional electronic measurement instrumentation is not required.
1.4
This practice establishes no performance limits for examination systems; if such acceptance criteria are required, these must be specified by the using parties. Where acceptance criteria are implied herein, they are for example only and are subject to more or less restrictive limits imposed by customer's and end user's controlling documents.
1.5
The specific parameters to be evaluated, conditions and frequency of test, and report data required must also be determined by the user.
1.6
This practice may be used for the evaluation of a complete examination system, including search unit, instrument, interconnections, fixtures and connected alarm and auxiliary devices, primarily in cases where such a system is used repetitively without change or substitution. This practice is not intended to be used as a substitute for calibration or standardization of an instrument or system to inspect any given material. There are limitations to the use of standard reference blocks for that purpose.
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1.7
Required test apparatus includes selected test blocks and a precision external attenuator (where specified) in addition to the instrument or system to be evaluated.
1.8
Precautions relating to the applicability of the procedures and interpretation of the results are included.
1.9
Alternate procedures, such as examples described in this document, or others, may only be used with customer approval.
1.10
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.
1.11
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.
1.12
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
This practice describes procedures applicable to both shop and field conditions. More comprehensive or precise measurements of the characteristics of complete systems and their components will generally require laboratory techniques and electronic equipment such as oscilloscopes and signal generators. Substitution of these methods is not precluded where appropriate; however, their usage is not within the scope of this practice.
5.2
This document does not establish system acceptance limits, nor is it intended as a comprehensive equipment specification.
5.3
While several important characteristics are included, others of possible significance in some applications are not covered.
5.4
Since the parameters to be evaluated and the applicable test conditions must be specified, this practice shall be prescribed only by those familiar with ultrasonic NDT technology and the required tests shall be performed either by such a qualified person or under his supervision.
5.5
Implementation may require more detailed procedural instructions in the format of the using facility.
5.6
In the case of evaluation of a complete system, selection of the specific tests to be made should be done cautiously; if the related parameters are not critical in the intended application, then their inclusion may be unjustified. For example, vertical linearity may be irrelevant for a go/no-go test with a flaw gate alarm, while horizontal linearity might be required only for accurate flaw-depth or thickness measurement from the display screen.
5.7
No frequency of system evaluation or calibration is recommended or implied. This is the prerogative of the using parties and is dependent on application, environment, and stability of equipment.
5.8
Certain sections are applicable only to instruments having receiver gain controls calibrated in decibels (dB). While these may sometimes be designated “gain,” “attenuator,” or “sensitivity” on various instruments, the term “gain controls” will be used in this practice in referring to those which specifically control instrument receiver gain but not including reject, electronic distance-amplitude compensation, or automatic gain control.
5.9
These procedures can generally be applied to any combination of instrument and search unit of the commonly used types and frequencies, and to most straight-beam examination, either contact or immersed. Certain sections are also compatible with angle-beam, wheel, delay-line, and dual-search unit techniques. Their use, however, should be mutually agreed upon and so identified in the test report.
5.10
The validity of the results obtained will depend on the precision of the instrument display readings. This is assumed to be ±0.04 in. (±1 mm), yielding between 1 % and 2 % of full scale (fs) readability for available instrumentation having suitable screen graticules and display sharpness.