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JP-7856466-B2 - Flaw detection device and flaw detection method

JP7856466B2JP 7856466 B2JP7856466 B2JP 7856466B2JP-7856466-B2

Inventors

  • 長濱 大輔
  • 奥野 元貴
  • 谷村 康行

Assignees

  • 本田技研工業株式会社

Dates

Publication Date
20260511
Application Date
20220331
Priority Date
20210331

Claims (8)

  1. A flaw detection inspection apparatus comprising a storage tank for storing a solvent and an immersion probe for emitting ultrasonic waves towards an object to be inspected immersed in the solvent, The immersion probe comprises a transducer that emits ultrasonic waves with a frequency of 10 MHz or higher to the object under inspection, a casing that houses the transducer and has an opening at the end facing the object under inspection, and a front plate that is circular in plan view, and whose surface facing the object under inspection is formed as a concave surface that curves so as to gradually indent towards the center, and which closes the opening of the casing. When the radii of curvature of the first and second virtual tangents, which are mutually perpendicular at the center of the concave and curve along the concave, are denoted as the first radius of curvature and the second radius of curvature, the first radius of curvature and the second radius of curvature are different, A flaw detection inspection device wherein the ultrasonic waves emitted from the transducer and output from the front plate into the solvent are focused at two locations in the solvent, in which the object to be inspected is not immersed, based on the difference between the first radius of curvature and the second radius of curvature, while the ultrasonic waves that pass through the solvent and enter the object to be inspected are focused at one location inside the object to be inspected.
  2. A flaw detection inspection apparatus according to claim 1 , further comprising: a rotating table provided in the storage tank for holding the object to be inspected; and a movable part for moving the immersion probe at least along the height direction of the object to be inspected held on the rotating table.
  3. A flaw detection inspection apparatus according to claim 1 or 2 , comprising at least two immersion probes, wherein the at least two immersion probes each emit ultrasonic waves, and the focal points of these ultrasonic waves within the object under inspection are different from those of the other.
  4. In a flaw detection inspection method in which an object to be inspected is immersed in a solvent, and ultrasonic waves with a frequency of 10 MHz or higher are emitted from a transducer constituting a liquid immersion probe, and the presence or absence of defects in the object to be inspected is inspected using the ultrasonic waves, A method for inspecting defects using a liquid immersion probe comprising: a casing that houses the transducer and has an opening at the end facing the object to be inspected; a front plate that is circular in plan view, with the surface facing the object to be inspected being formed as a concave surface that curves gradually toward the center to close the opening of the casing; and having a first virtual tangent and a second virtual tangent that are mutually orthogonal at the center of the concave surface and curve along the concave surface, wherein the radius of curvature of the first and second virtual tangents are different, and the ultrasonic waves emitted from the transducer and output from the front plate into the solvent are focused at two locations in the solvent where the object to be inspected is not immersed, based on the difference between the first and second radii of curvature, while the first and second radii of curvature are set to the radius of curvature at which the ultrasonic waves that have passed through the solvent and entered the object to be inspected are focused at one location inside the object to be inspected.
  5. A flaw detection inspection method according to claim 4 , wherein the object to be inspected is a cylindrical body with a diameter of 8 inches.
  6. A method for inspecting defects according to claim 4 or 5 , wherein the object to be inspected is made of a nickel-based alloy.
  7. A flaw detection inspection method according to any one of claims 4 to 6 , wherein at least two immersion probes are used, each having different focal points for the ultrasonic waves it emits within the object under inspection.
  8. A method for inspecting defects according to any one of claims 4 to 7 , wherein water is used as the solvent.

Description

This invention relates to an immersion probe that emits ultrasonic waves, a flaw detection inspection apparatus including the same, and a flaw detection inspection method using the same. For example, a turbine engine has numerous components that rotate at high speeds. These types of components are generally manufactured by forging billets. Here, components used in harsh environments, such as those in a turbine engine, must exhibit sufficient durability. To obtain such components, it is desirable to use billets free of major internal defects. From this perspective, flaw detection testing is performed on the billets prior to forging. One specific method for this is water immersion testing. In water immersion testing, ultrasonic waves are emitted from a transducer towards a billet immersed in water. When the billet has a large diameter, multiple transducers emitting ultrasonic waves with different focal points may be used to inspect deep inside the billet, as described in Patent Document 1. This is because ultrasonic waves with longer focal lengths can penetrate deeper into the billet. Furthermore, Patent Document 2 proposes a probe configuration that enables oscillation in two modes: an electron focusing mode and a time reversal mode. In this case, by selecting the electron focusing mode for detecting relatively shallow areas of the billet and the time reversal mode for detecting deeper areas, it is possible to detect defects from the inside to the surface of the billet with a single probe. U.S. Patent No. 5,533,401U.S. Patent No. 6,202,489 This is a schematic perspective view of a flaw detection inspection device according to an embodiment of the present invention.Figure 1 is a schematic perspective view of the immersion probe that constitutes the flaw detection inspection device.Figure 3A is a cross-sectional view of the main part of the immersion probe in Figure 2 along the Y direction, and Figure 3B is a cross-sectional view of the main part along the Z direction.Figure 2 is a schematic diagram illustrating the focus point of the ultrasonic waves emitted from the immersion probe.Figure 4 shows ultrasonic beam profile data indicating the focusing range of the ultrasonic waves on a planar incident object at F1 and F2.This is a schematic diagram illustrating the situation where the focal length is extended when the first wave enters the billet.Figures 7A and 7B are schematic diagrams illustrating the situation when the second wave is incident on the billet.Figure 8A shows a liquid immersion probe, different from the one in Figure 2, facing the billet, and Figure 8B is a schematic diagram illustrating the state in which reflected waves are generated by a defect.This diagram shows the relationship between the distance from the second transducer (underwater equivalent distance) when ultrasound is incident on the billet and the ultrasound beam profile data focused inside the billet.This diagram shows the relationship between comparative FBH (circular planar defects) and the diameter of FBH that can be used to determine whether or not they exist.This diagram shows the evaluation of the characteristics of a dual-focus probe using immersion probes with varying first and second curvature radii. The following describes a preferred embodiment of the flaw detection inspection method according to the present invention, relating the immersion probe and the flaw detection inspection apparatus comprising it, with reference to the attached drawings. In the following, "front" refers to the side facing the object under inspection, and "rear" refers to the opposite direction. For example, "front end of the immersion probe" means "the end of the immersion probe facing the object under inspection." First, a brief description of the billet 10 shown in Figure 1 will be provided. The billet 10, the object under inspection, is cylindrical, and in this case, its diameter D is set to 8 inches (203.2 mm). Furthermore, the billet 10 is manufactured by so-called powder metallurgy, which involves sintering powder of a heat-resistant nickel-based alloy. That is, this billet 10 is made of a heat-resistant nickel-based alloy. On the other hand, the flaw detection inspection device 20 is equipped with a storage tank 22. Water 24 is stored in the storage tank 22 as a solvent. As will be described later, ultrasonic waves propagate through the water 24 to reach the billet 10. Displacement guide rails 26a and 26b are laid on the upper surface of the storage tank 22. A rotary table 28 for positioning and fixing the billet 10 is installed at the bottom of the storage tank 22. The rotary table 28 is rotatable under the action of a rotary motor (not shown) or the like, provided on its underside. Furthermore, gripping guide rails 30a to 30c are laid on the upper surface of the rotary table 28, extending radially from its center of rotation and spaced approximately 120° apart from each other. Each of the gripping guide rails 30a to 30c is slidably prov