JP2009053151A - X-ray inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray inspection method capable of detecting ceramic core remaining in the turbine blade by utilizing X-ray inspecting technique. <P>SOLUTION: The X-ray inspection method of this invention for inspecting existing ceramic foreign matter remaining in the inspection object from an X-ray image is characterized in that an inspection object W is irradiated with the X-ray using an X-ray inspection device 1, the X-ray transmission image 3 is focused on the x-ray detector 2 having ≥16 bit contrast range, an X-ray transmission image is focused on the X-ray detector and developed by a digital developer 4 for obtaining the X-ray image 5 for inspecting the existing ceramic foreign matter remaining in the inspection object. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray inspection method for inspecting whether or not a ceramic foreign matter remains in an inspection object with a high-resolution X-ray inspection apparatus having a dynamic range of 16 bits or more.

  In order to reduce the weight and suppress the temperature rise due to high speed rotation, the jet engine turbine blade has a structure in which a large number of small chambers are formed inside and a large number of pores communicating between the small chambers are formed to circulate the coolant. have. Such turbine blades are manufactured by casting, but in order to form the chambers and pores, a ceramic core is inserted into the corresponding part of the mold and dissolved during casting. Like to do.

  This manufacturing method enables casting of turbine blades having a complex internal structure, but in some cases, the ceramic core may remain without completely removing the ceramic core. When such a turbine blade with the ceramic core remaining is used in an actual machine, there is a problem that the residual ceramic core blocks the pores and obstructs the circulation of the coolant, and the turbine blade cannot be sufficiently cooled. Therefore, conventionally, it is examined whether or not a ceramic core remains in the turbine blade, and when a residual piece is confirmed, a solution is further introduced to dissolve it.

  Conventionally, neutron radiography technology has been used to inspect the presence or absence of ceramic cores in turbine blades. This is because in the X-ray inspection apparatus, X-rays are transmitted through the ceramic core and the X-ray image is not contrasted, which makes inspection difficult.

  However, in order to use neutron radiography technology, it is necessary to go to a place where a cyclotron capable of obtaining a large amount of powerful neutron beams is installed, which leads to a large inspection facility and extremely high inspection costs. There was a point.

For this reason, conventionally, it has been desired to be able to use an X-ray inspection technique that is relatively small in scale and low in cost for the inspection of the residual ceramic core in the turbine blade.
JP-A-5-196745 US Patent Publication No. 20040251420

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an X-ray inspection method that enables detection of a residual ceramic core in a turbine blade using an X-ray inspection technique. .

  The present invention irradiates an inspection object with X-rays using an X-ray inspection apparatus, forms an X-ray transmission image of the inspection object on an X-ray detector having a contrast range of 16 bits or more, and The X-ray transmission image of the inspection object formed by the X-ray detector is developed by a digital developing device to obtain an X-ray image, and the ceramic foreign matter remaining in the inspection object from the X-ray image It is characterized by an X-ray inspection method for inspecting for the presence or absence.

  In the X-ray inspection method of the above invention, an X-ray flat panel detector can be used as the X-ray detector.

  In the X-ray inspection method of the above invention, an X-ray CT apparatus can be used as the X inspection apparatus.

  Furthermore, in the X-ray inspection method of the above invention, an X-ray CT apparatus can be used for the X inspection apparatus, and an X-ray flat panel detector can be used for the X-ray detector.

  In the X-ray inspection method of the present invention, an X-ray inspection apparatus is used to irradiate an inspection object with X-rays, and an X-ray transmission image is formed on an X-ray detector having a contrast range of 16 bits or more. By developing an X-ray transmission image of the object to be inspected, which is imaged by the detector, with a digital developing device, the residual ceramic core in the turbine blade that has not been able to develop a shadow image due to the transmission of X-rays is ensured. Can be developed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) An X-ray inspection method according to a first embodiment of the present invention is applied to a turbine blade W as an object to be inspected using an X-ray inspection apparatus 1 as shown in FIG. The X-ray transmission image 3 of the turbine blade W is formed on the X-ray flat panel detector 2 having a contrast range of 16 bits or more (that is, a gradation of 65536 steps or more). Then, as shown in FIG. 2, an X-ray transmission image 3 of the turbine blade formed by the X-ray flat panel detector 2 is scanned by a laser beam scanner 4 as a digital developing device to obtain an X-ray image 5. The X-ray image 5 is inspected for the presence of a ceramic core remaining in the turbine blade W.

  In the laser beam scanner 4 shown in FIG. 2, 41 is a laser light source, 42 is an optical scanner, 43 is a photomultiplier tube, 44 is an electric signal amplifier, 45 is an AD converter, and the digital output of the AD converter 45 is displayed. The X-ray image 5 of the turbine blade W is obtained by printing the image and printing it out.

  As the X-ray inspection apparatus 1, for example, Y.OL of German company YXOLN, IMAGE3500-DD can be used. The X-ray flat panel detector 2 may be a product having a pixel size of 200 μm, a size of 300 mm × 300 mm, and a contrast range of 16 bits or more, such as an X-ray flat panel detector manufactured by Perkin Elmer.

  In the X-ray inspection method of the present embodiment, an X-ray transmission image of the turbine blade W is formed by the X-ray flat panel detector 2 having a contrast range of 16 bits or more, so that the contrast range is small and the X-ray image is obtained. The residual ceramic core in the turbine blade W that did not appear in can also be formed in the X-ray transmission image. As a result, it is possible to inspect a minute residual ceramic core of 0.5 mm × 0.5 mm or less in the turbine blade W, which has been conventionally performed by neutron radiography technology, using an X-ray inspection apparatus, The inspection can be performed at a low cost with a relatively small equipment scale.

  (Second Embodiment) An X-ray inspection method according to a second embodiment of the present invention uses an X-ray CT inspection apparatus 1A as an X-ray inspection apparatus as shown in FIG. Are irradiated with X-rays, and an X-ray transmission image 3 of the turbine blades W is formed on an X-ray line detector 2A having a contrast range of 16 bits or more. Then, the X-ray transmission image 3 of the turbine blade formed by the X-ray line detector 2A is image-processed by a computer system 4A that also serves as a digital developing device to obtain an X-ray image 5 from the X-ray image 5. It is characterized in that the presence or absence of ceramic residue remaining in the blade W is inspected.

  In the X-ray CT inspection apparatus 1A shown in FIG. 3, reference numeral 11 denotes an X-ray source, and 12 denotes an inspection object manipulator, and the inspection object manipulator 12 relatively rotates the inspection object X while rotating the inspection object. A digital tomographic image of the turbine blade W is formed by irradiating the X-ray transmission transmission image 3 on the X-ray line detector 2 </ b> A by irradiating the X-ray from the radiation source 11 to the turbine blade W which is the inspection object. obtain.

  The computer system 4A includes an X-ray control unit 4A1 that controls the X-ray source 11, a manipulator control unit 4A2 that controls the inspection target manipulator 12, a data acquisition unit 4A3 that captures X-ray image data of the X-ray line detector 2A, A data storage unit 4A4 that stores image data, an image reconstruction processing unit 4A5 that performs noise removal processing on the image data and reconstructs the image data as a two-dimensional image or a three-dimensional image, and a reconstructed X-ray image An image processing unit 4A6 that performs image processing and displays the X-ray image 5 on the display 4A8, and an operation console 4A7 are provided.

  Also by the X-ray CT inspection apparatus 1A of the present embodiment, an image of the residual ceramic core remaining in the turbine blade W appears by adopting an X-ray line detector 2A having a contrast range of 16 bits or more. The residual ceramic core in the turbine blade can be inspected using an X-ray inspection apparatus.

  (Third Embodiment) An X-ray inspection method according to a third embodiment of the present invention uses an X-ray CT inspection apparatus having an X-ray flat panel detector as a detector as the X-ray inspection apparatus, and the second embodiment. In the same manner as in the embodiment, the turbine blade W as the inspection object is irradiated with X-rays, and an X-ray transmission image 3 of the turbine blade W is formed on an X-ray flat panel detector having a contrast range of 16 bits or more. Then, the X-ray transmission image of the turbine blade imaged by the X-ray flat panel detector is digitally processed by the laser beam scanner 4 shown in FIG. 2, displayed on the display, and printed out. The presence or absence of a ceramic core remaining in the turbine blade W is inspected from the image.

  Also by the X-ray CT inspection apparatus of the present embodiment, an image of the ceramic core remaining in the turbine blade W can be displayed by adopting an X-ray flat panel detector having a contrast range of 16 bits or more. The residual ceramic core in the turbine blade can be inspected using an X-ray inspection apparatus.

  As shown in the photograph in Fig. 4, an X-ray inspection is performed by setting a ceramic core with a minimum dimension of 0.3 mm thickness and 0.3 mm x 0.3 mm square on a test piece that simulates a turbine blade. did.

  The X-ray inspection system is a Y.L. The IMAGE 3500-DD, X-ray flat panel detector was a 16-bit contrast range manufactured by Perkin Elmer.

X-ray flat panel detector specifications:
・ Size: 300mmx300mm
・ Pixel size: 200μm
-Contrast range: 16 bits (65536 gradations)
・ Image composition time: 0.14 seconds / screen X-ray inspection equipment specifications:
X-ray source: MG225
・ Focus size: 0.4mm
・ Maximum tube voltage: 225Kvp
・ Maximum tube current: 4 mA
Magnification: 3 times ・ FSD: 260mm
・ FFD: 800mm
Image processing ・ Integration processing: 300 sheets (processing time 42 seconds)
The test results are as shown in the photographs of FIGS. 5 and 6, and it was possible to detect a 0.3 mm ceramic core through a 4 mm-thick test piece.

  The reason why the flat panel detector with a pixel size of 200 μm was selected was to focus on the noise that is the problem for image evaluation, not the resolution, and the highest SN ratio in the current product is obtained with the pixel size of 200 μm. Because it was a thing.

  Using an X-ray CT apparatus, a ceramic core was inspected with respect to a test piece simulating a turbine blade similar to the above in an X-ray inspection apparatus using an X-ray flat panel detector as an X-ray image detector.

X-ray CT apparatus used: Y.L. CT Precision
Flat panel detector: X-ray flat panel detector manufactured by Perkin Elmer, similar to Example 1.

X-ray source: 225 microfocus ・ Focal size: 3 μmm
・ Maximum tube voltage: 225Kvp
・ Maximum tube current: 1 mA
Enlargement ratio: 4 times-FSD: 250mm
-FFD: 1000mm
Scanning method:
・ 3rd generation (rotation)
・ 0.3 degrees / 900ms
As shown in FIGS. 7 and 8, the inspection result is transmitted through a 4 mm-thick test piece and can detect a 0.3 mm × 0.3 mm square ceramic core as in the case of the planar image. It was.

  Using the same X-ray CT apparatus as in Example 2, an X-ray inspection apparatus using an X-ray flat panel detector as an X-ray image detector, using an actual turbine blade as a test piece, various sizes as shown in FIG. X-ray inspection was performed on the ceramic cores placed in various places in the turbine blade. The ceramic core was 9 pieces of various sizes shown in Table 1 of FIG.

X-ray source: 225 microfocus ・ Focal size: 3 μmm
・ Maximum tube voltage: 200Kv
・ Maximum tube current: 0.1 mA
Magnification ratio: 8x Scanning method:
・ 3rd generation (rotation)
・ 0.3 degrees / 900ms
As a result of the inspection, as shown in the photographs of FIGS. 11 to 15, the ceramic core Nos. Of various sizes set on the turbine blade test piece were used. 1-No. Clear X-ray images of all nine of the nine pieces could be obtained. From this, it was verified that the residual ceramic core in the turbine blade could be confirmed by X-ray inspection.

Explanatory drawing of the X-ray inspection apparatus used for the X-ray inspection method of the 1st Embodiment of this invention. Explanatory drawing of the laser beam scanner used for the image visualization of the X-ray image obtained with the said X-ray inspection apparatus. Explanatory drawing of the X-ray CT inspection apparatus used for the X-ray inspection method of the 2nd Embodiment of this invention. The photograph of the test piece made into the test object by the X-ray inspection method of Example 1 of this invention. Photo 1 of an X-ray image of a test piece obtained by the X-ray inspection method of Example 1 above. Photo 2 of the X-ray image of the test piece obtained by the X-ray inspection method of Example 1 above. Photograph 1 of an X-ray CT image obtained by the X-ray inspection method of Example 2 of the present invention. Photograph 2 of an X-ray CT image obtained by the X-ray inspection method of Example 2 of the present invention. The front view of the test piece made into the test object by the X-ray inspection method of Example 3 of this invention. The size table | surface of the residual ceramic core set to the test piece made into the test object by the X-ray inspection method of Example 3 of this invention. Residual ceramic core No. in the X-ray CT image obtained by the X-ray inspection method of Example 3 of the present invention. 1 is a photograph showing an X-ray image of 1. Residual ceramic core No. in the X-ray CT image obtained by the X-ray inspection method of Example 3 of the present invention. 2 is a photograph showing an X-ray image of 2; Residual ceramic core No. in the X-ray CT image obtained by the X-ray inspection method of Example 3 of the present invention. The photograph which shows the X-ray image of 4,5,6. Residual ceramic core No. in the X-ray CT image obtained by the X-ray inspection method of Example 3 of the present invention. 8 is a photograph showing an X-ray image of 8; Residual ceramic core No. in the X-ray CT image obtained by the X-ray inspection method of Example 3 of the present invention. 9 is a photograph showing 9 X-ray images.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray inspection apparatus 1A X-ray CT apparatus 2 X-ray flat panel detector 3 X-ray transmission image 4 Laser beam scanner 5 X-ray image

Claims (4)

X-ray inspection equipment is used to irradiate the object to be inspected with X-rays,
Forming an X-ray transmission image of the inspection object on an X-ray detector having a contrast range of 16 bits or more;
An X-ray transmission image of the inspection object formed by the X-ray detector is developed with a digital developing device to obtain an X-ray image.
An X-ray inspection method for inspecting the presence or absence of ceramic foreign matter remaining in the inspection object from the X-ray image.   The X-ray inspection method according to claim 1, wherein the X-ray detector is an X-ray flat panel detector.   The X-ray inspection method according to claim 1, wherein the X-inspection apparatus is an X-ray CT apparatus.   The X-ray inspection method according to claim 1, wherein the X-inspection apparatus is an X-ray CT apparatus, and the X-ray detector is an X-ray flat panel detector.