Ultrasonic methods penetrant inspection

Liquid penetrant examination or magnetic particle methods and 100% volumetric examination by ultrasonic methods will be conducted at about ten-year intervals during the plant shutdown coinciding with the in-service inspection schedule as required by the ASME Code, Section XI. 

ASTM G 46 also includes procedures for the nondestructive evaluation of pitied specimens. These include radiographic, electromagnetic, ultrasonic, and dye-penetrant inspection. These methods can be used to locate pits and to provide some information on thdr size, but they generally cannot detea small pits or differentiate bOween pits and other types of surface defects. 

In this paper, we have exposed a solution to improve the resolution in Low Frequency Ultrasonic Tomography. Since the basic principle of ultrasonic reflection tomography prohibits the inspection of objects with strong contrast and large extension, we turn down the frequency of the transducer, in order to increase the penetration length of the wave and the validity of the method. But this is done at the expense of resolution. 

NDE shall be performed as required by the material specification. If additional radiographic, ultrasonic, magnetic particle or liquid penetrant examinations of the welds or materials are specified by the purchaser, the methods and acceptance criteria shall be in accordance with the standards shown in Table 13. Alternative standards may be proposed by the vendor or specified by the purchaser. The welding and material inspection data sheet in Annex N may be used for this purpose. 

Preliminary testing is done next to uncover flaws in joining, and sometimes in the metal itself. Nondestructive test methods, such as ultrasonics and X- or gamma-ray inspection, are used on main welding seams Dye penetration, hydrostatic, or air-soap tests are also used to locals leaks and cracks. Helium or Freon leak detectors are necessary fok more critical leak testing, particularly on high-vacuum equipment. 

In order to reduce the occurrence of rail-defect-related failures, various methods are used to detect rail defects. These methods include visual inspection by the track maintenance staff, ultrasonic defect detection, eddy-current testing, ground-penetrating radar, impedance spectroscopy, and electromagnetic acoustic transducers [16,17]. 

However, it appears that none of the non-destructive tests currently employed directly correlate with any critical failure property. Most industrial test techniques such as through-transmission and pulse-echo ultrasonics, sonic vibration techniques. X-ray radiography, thermal inspection methods, holography, liquid penetrants, etc. basically attempt to find defects in the joint. Such defects may arise from several sources. Some defects arise from porosity, cracks or voids in the adhesive layer or at the interface and are typically filled with air they will simply be referred to as voids in the present discussions. However, during the service life of the joint such voids may fill with water which makes them far more difficult to detect since, for example, water has a much higher acoustic, impedance than air. Also, zero-volume voids, or debonds, may occur when the adhesive and substrate are in contact but no... 

Nondestructive testing. An ultrasonic inspection technique is available for the detection of flaws in plate, piping, and tubing. The water-immersed pulse-echo ultrasound equipment has been adapted to highspeed use. Eddy-current, dye-penetrant, and radiogr.aphic inspection methods are also used as required. The inspected materials have included Inconel, austenitic stainless steel, INOR-8, and the Hastelloy and other nickel-molybdenum-ba.se alloys. 

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