CN217605759U - Reference test block for ultrasonic detection of water turbine runner blade - Google Patents

Abstract

The present application relates to a reference test block for ultrasonic testing of turbine runner blades. The reference test block (5) is in the shape of a strip as a whole, with a vertical surface (1) on the left side and two semicircular arc surfaces (1) on the right side. 8, 9) Symmetrical arrangement; the reference test block (5) is provided with a small transverse hole (2) in the middle of the side close to the vertical surface (1), and the first large transverse hole is provided on the side close to the bottom surface group (4) and the second largest cross-hole group (7). The reference test block can be used to calibrate the speed of sound, make a DAC curve, calibrate the probe delay, calibrate the detection sensitivity and verify the effectiveness of the detection process, and can solve the problem of low signal-to-noise ratio and defect signal in ultrasonic detection of runner blades and blade welds in hydropower plants. It is easy to be confused, and the detection accuracy is low. In addition, the reference test block of the present application further integrates settings for ultrasonic testing of the blade and the weld between the blade and the upper crown.

Description

A reference test block for ultrasonic testing of turbine runner blades

technical field

The application relates to the technical field of non-destructive testing, and in particular, to a reference test block for ultrasonic testing of turbine runner blades.

Background technique

In hydropower plants, the blade profile of the turbine runner blade is a curved shape with a spatially variable cross-section, and the thickness of the interface varies greatly. It is usually formed by casting, and then the blade, the upper crown and the lower crown are connected into one body by welding. Due to the unstable water flow and complex operating conditions, the blades vibrate, and then regular and irregular cracks are prone to occur near the welding area between the upper crown, lower crown and blade of the runner, resulting in unit operation failure and causing large economic losses and safe operation of equipment.

The non-destructive testing technology of turbine runner blades is used in all stages of manufacturing, installation and maintenance, which is conducive to early detection and treatment of defects, and is of great significance for improving the safe operation and work efficiency of hydropower stations.

Because the blades and blade welds are typical coarse-grained structures, the grains are coarse and the structure noise is strong. Using the traditional ultrasonic testing reference block, the signal-to-noise ratio is low, and the defect signal is easily confused with the noise, resulting in inability to identify, which seriously affects the defect detection rate and accuracy.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present application is to provide a reference test block for ultrasonic testing of turbine runner blades that improves the defect detection rate and accuracy.

In order to solve the above problems, the present application provides a reference test block for ultrasonic testing of turbine runner blades, the reference test block is in the shape of a strip as a whole, the left side is a vertical plane, and the right side is two semicircular arcs facing each other. Scale arrangement, the radius is 1/2h, h is the height of the reference test block; the reference test block is provided with a small transverse hole for simulating defects in the middle of the side close to the vertical surface, and the side close to the bottom surface is provided with a small transverse hole. There are a first large transverse through hole group and a second large transverse through hole group, the first large transverse through hole group is evenly distributed with different burial depths in the vertical direction from the bottom surface, and the second large transverse through hole group The groups are uniformly distributed along a 45° line from the bottom surface.

Preferably, the reference test block further includes a third large transverse hole group and a fourth large transverse hole group provided on one side of the top surface, which are respectively connected with the first large transverse hole group and the fourth large transverse hole group. The second large transverse hole group is arranged in an axial symmetry.

Preferably, the diameter of the small transverse hole is 1 mm, and the diameter of the first large transverse hole group and the second large transverse hole group is 2 mm.

The reference test block is integrally formed, and the material is martensitic stainless steel.

Compared with the prior art, the present application has the following advantages:

Aiming at ultrasonic testing of turbine runner blades, the present application provides a reference test block, which can be used to calibrate sound velocity, make DAC curve, calibrate probe delay, calibrate detection sensitivity and verify the validity of the detection process. Solve the problems of low signal-to-noise ratio of ultrasonic detection of runner blades and blade welds in hydropower plants, easy confusion of defect signals, and low detection accuracy.

In addition, the reference test block of the present application further integrates the settings for ultrasonic testing of the weld between the blade and the upper crown.

Description of drawings

The specific embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

FIG. 1 is a front view of a reference test block for ultrasonic testing of a turbine runner blade provided by an embodiment of the present application.

FIG. 2 is a side view of a reference test block for ultrasonic testing of a turbine runner blade provided by an embodiment of the present application.

FIG. 3 is a top view of a reference test block for ultrasonic testing of a turbine runner blade provided by an embodiment of the present application.

In the figure: 1—vertical plane, 2—small transverse hole, 3—third largest transverse hole group, 4—first large transverse hole group, 5—reference test block, 6—fourth largest transverse hole Group, 7—the second largest transverse hole group, 8, 9—semi-circular arc surface.

Detailed ways

Referring to FIGS. 1 to 3 , an embodiment of the present application provides a reference test block for ultrasonic testing of turbine runner blades. The reference test block 5 is in the shape of a strip as a whole, made of martensitic stainless steel, preferably ZG0Cr13Ni5Mo, and a height h of 100 mm. , the width w is 30mm, and the length L is 300mm.

Among them, the reason why the reference test block material is set to martensitic stainless steel: martensitic steel welded joints have cold cracking and embrittlement phenomena, in addition, martensitic steel has poor thermal conductivity, large welding residual stress, coarse grains, and relatively structural noise. powerful. Using the traditional ultrasonic testing reference block, the signal-to-noise ratio is low, and the defect signal is easily confused with the noise, resulting in inability to identify, which seriously affects the defect detection rate and accuracy.

The reference test block 5 is integrally formed, the left side is the vertical surface 1, the right side is two semi-circular arc surfaces 8 and 9 symmetrically arranged, the radius is 1/2h, the arc surfaces are opposite, the bottom surface is a horizontal surface, and the top surface is 150 °Inner concave.

The reference test block 5 is provided with a small transverse hole 2 for simulating defects in the middle position of the side close to the vertical surface 1, and a first large transverse hole group 4 and a second large transverse hole group 7 are provided on the side close to the bottom surface. The diameter of the small transverse holes 2 is 1 mm, and the diameters of the first large transverse hole group 4 and the second large transverse hole group 7 are both 2 mm. "Transverse" means penetrating through the front and rear walls of the reference block 5 .

The number of through holes in the first large horizontal through hole group 4 is 4, which are evenly distributed at different burial depths in the vertical direction from the bottom surface, such as 10mm, 20mm, 30mm, and 40mm from the bottom surface, and the second largest horizontal through hole group The number of through holes of 7 is 6, which are evenly distributed along a 45° line from the bottom surface, such as 5mm, 10mm, 15mm, 20mm, 25mm, and 30mm from the lowest point of the bottom surface. In actual production, on the premise that the length meets the requirements, the first large transverse hole group 4 and the second large transverse hole group 7 are staggered as much as possible.

In use, the small transverse hole 2 is used for the positioning and quantitative calibration of the simulated defect between the upper inner concave surface and the lower plane after the instrument calibration is completed. The semicircular arc surfaces 8 and 9 are used for ultrasonic detection probe time delay and sound velocity calibration, and are also used for probe front edge measurement. The first large transverse hole group 4 and the second large transverse hole group 7 refer to the design of the turbine blades, and are used to meet the sensitivity simulation and calibration of detecting the smallest defects; in application, conventional small-sized inclined probes are used for calibration.

For ultrasonic testing of the weld between the blade and the upper crown, the reference block 5 of the present application further includes the third largest transverse hole group 3 and the fourth largest transverse hole group 6 designed with reference to the structure of the weld between the turbine blade and the upper crown. Sensitivity simulation and calibration to meet the detection and detection of the smallest defects. The third large transverse hole group 3 and the fourth large transverse hole group 6 are arranged on the side close to the top surface, and are axially symmetrical with the first large transverse hole group 4 and the second large transverse hole group 7 respectively.

When in use, the probe should be adapted to the curvature of the top surface. The third largest transverse hole group 3 can be used to test the ultrasonic angle resolution; the fourth largest transverse hole group 6 is used for the production of the TCG/DAC curve.

The technical solutions provided by the present application have been introduced in detail above. Specific examples are used herein to illustrate the principles and implementations of the present application, and the descriptions of the above embodiments are only used to help understand the structure and core ideas of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the present application, several improvements and modifications can also be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims (4)

1. A reference test block for ultrasonic detection of water turbine runner blades is characterized in that the whole reference test block (5) is strip-shaped, the left side surface is a vertical surface (1), the right side surface is formed by symmetrically arranging two semi-circular arc surfaces (8, 9), the radius is 1/2h, and h is the height of the reference test block (5); the reference test block (5) is close to the middle position of one side of the vertical surface (1) is provided with a small transverse through hole (2) for simulating defects, one side of the reference test block close to the bottom surface is provided with a first large transverse through hole group (4) and a second large transverse through hole group (7), the first large transverse through hole group (4) is uniformly distributed along the vertical direction along different burial depths from the bottom surface, and the second large transverse through hole group (7) is uniformly distributed along a 45-degree linear form from the bottom surface.

2. The reference block according to claim 1, further comprising a third large transverse through hole group (3) and a fourth large transverse through hole group (6) disposed near one side of the top surface, and disposed axially symmetrically with the first large transverse through hole group (4) and the second large transverse through hole group (7), respectively.

3. The reference block according to claim 1 or 2, wherein the small transverse through hole (2) has a diameter of 1mm and the first and second large transverse through hole groups (4, 7) have a diameter of 2mm.

4. The reference block of claim 1 or 2, wherein the reference block is integrally formed and is made of martensitic stainless steel.

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