ASTM E1816-12
应用电磁声传感器 (EMAT) 技术进行超声检测的标准方法

Standard Practice for Ultrasonic Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques

被代替

ASTM E1816-12 发布历史

ASTM E1816-12由美国材料与试验协会 US-ASTM 发布于 2012。

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ASTM E1816-12 应用电磁声传感器 (EMAT) 技术进行超声检测的标准方法的最新版本是哪一版？

最新版本是 ASTM E1816-18(2022) 。

ASTM E1816-12 发布之时，引用了标准

• ASTM E114 用接触法做超声脉冲回波纵波检验
• ASTM E1316 <？的标准术语？Pub Dtl？>无损检测
• ASTM E1774 电磁声学传感器用标准指南
• ASTM E494 测量超声波在材料中传播速度的标准实施规范
• ASTM E543 无损检测机构的标准实施规程
• ASTM E587 超声波角度接触测试标准实践
• ASTM E797 用人工超声脉冲回波接触法测量厚度的标准实施规程

ASTM E1816-12的历代版本如下：

• 2022年 ASTM E1816-18(2022) 用脉冲回波电磁声换能器（EMAT）方法测量厚度的标准实施规程
• 2018年 ASTM E1816-18 用脉冲回波电磁声换能器（EMAT）方法测量厚度的标准实施规程
• 2012年 ASTM E1816-12 应用电磁声传感器 (EMAT) 技术进行超声检测的标准方法
• 2007年 ASTM E1816-07 用电磁声换能器(EMAT)技术的超声波测试用标准实用规程
• 1996年 ASTM E1816-96(2002) 用电磁声传导(EMAT)技术的超声波检验用标准实用规程
• 1996年 ASTM E1816-96 用电磁声换能器（EMAT）技术进行超声波检验的标准实施规程

 

5. Significance and UseTop Bottom

5.1 Since EMAT techniques are noncontacting, they should be considered for ultrasonic examinations in which applications involve automation, high-speed examinations, moving objects, applications in remote or hazardous locations, and applications to objects at elevated temperatures or objects with rough surfaces. This practice describes procedures for using EMAT techniques as associated with the ultrasonic method to detect flaws for both surface and volumetric examinations as well as to measure thickness.

5.2 The uniqueness of the electromagnetic acoustic transducer technique for ultrasonic examination basically lies in the generation and reception of the ultrasonic waves. Otherwise, conventional ultrasonic techniques and methodologies generally apply.

5.3 An EMAT generates and receives acoustic waves in a material by electromagnetic means; electrically conductive or ferromagnetic materials can be examined. In its simplest form, an EMAT as a generator of ultrasonic waves is basically a coil of wire, excited by an alternating current, and placed in a uniform magnetic field near the surface of a material. For conductive materials, eddy currents are induced as a result of the alternating current. Due to the magnetic field, these eddy currents experience Lorentz forces that in turn are transmitted to the solid by collisions with the lattice or other microscopic processes. These forces are alternating at the frequency of the driving current and act as a source of ultrasonic waves. If the material is ferromagnetic, additional coupling mechanisms play a part in the generation of ultrasonic waves. Interactions between the dynamic magnetic field generated by the alternating currents and the magnetization associated with the material offer a source of coupling, as do the associated magnetostrictive influences. Reciprocal processes exist whereby all of these mechanisms lead to detection. Fig. 3 depicts the mechanisms (forces), along with associated direction, for electromagnetic ultrasound generation.

Note 1???j8201;=8201;current in a single conductor, Bo8201;=8201;magnetization from external magnet, Fm8201;=8201;magnetic force (ferromagnetic material), Fms8201;=8201;magnetostrictive force (ferromagnetic material), and FL8201;=8201;Lorentz force (conductive material).FIG. 3 Mechanisms of Electromagnetic Ultrasound Generation

5.4 The EMAT can be used to generate all ultrasonic modes of vibration. As with conventional ultrasonic techniques, material types, probable flaw locations, and flaw orientations determine the selection of beam directions and modes of vibration. The use of EMATs and selection of the proper wave mode presuppose a knowledge of the geometry of the object; the probable location, size, orientation, and reflectivity of the expected flaws; the allowable range of EMAT lift-off; and the laws of physics governing the propagation of ......

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标准号

ASTM E1816-12

发布

2012年

发布单位

美国材料与试验协会

替代标准

ASTM E1816-18

当前最新

ASTM E1816-18(2022)

 

 

引用标准

ANSI/ASNT CP-189 ASTM E114 ASTM E1316 ASTM E1774 ASTM E494 ASTM E543 ASTM E587 ASTM E797

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