Wedge block for ultrasonic testing of low-sound-velocity materials, and manufacturing method for wedge block

Abstract

The present invention relates to the technical field of ultrasonic testing, and in particular to a wedge block for ultrasonic testing of low-sound-velocity materials, and a manufacturing method for a wedge block. The present invention employs the following technical solution: the wedge block comprises a wedge block main body, wherein the wedge block main body is made of a hydrogel material or a rubber mixed mineral oil material, and the sound velocity of the wedge block main body is lower than 2000 m / s; the hydrogel material is prepared by using a water-soluble polymer and a cross-linking agent as main components in a cross-linking mode; and the rubber mixed mineral oil material is prepared by extruding thermoplastic elastic rubber and mineral oil as main components by means of a screw extruder. The wedge block has the beneficial effects that the wedge block has the characteristic of low sound velocity and can be suitable for ultrasonic testing of low-sound-velocity materials; the integrally formed structure is simple, prevents liquid leakage, avoids contamination on the surface of a material under test, and eliminates bubble formation which interferes with a testing result; and the material itself has certain elasticity, which enables good coupling even when the surface of the material under test is uneven, thereby effectively improving the effect of ultrasonic flaw detection.

Description

A wedge for ultrasonic testing of low-velocity materials and its preparation method Technical Field

[0001] This invention relates to the field of ultrasonic testing technology, and in particular to a wedge for ultrasonic testing of low-velocity materials and its preparation method. Background Technology

[0002] In ultrasonic flaw detection, in order to change the angle at which the sound beam enters the material being tested, a wedge is used to refract the sound beam. In order for the sound beam to enter the material being tested at a wider range of incident angles, the sound velocity of the wedge needs to be designed to be smaller than that of the material being tested. The greater the difference between the sound velocity of the wedge and the sound velocity of the material being tested, the wider the incident angle that it can cover. Conventional wedges are made of various resin materials with sound velocities exceeding 2000 m / s. When the material being tested is a metal or other material with a high sound velocity, these wedges can meet the testing requirements. However, when the material being tested is also a resin material or another material with a low sound velocity, conventional wedges cannot meet the testing requirements. The current solution is to use liquid-filled wedges, which are wedge-shaped containers filled with low-velocity liquid, so that the sound velocity of the wedge can meet the testing requirements. However, liquid-filled wedges have problems such as the need to fill and replenish the liquid during use, leakage, and contamination. In addition, after the wedge is filled with liquid, it is easy for bubbles to be generated due to shaking, which can interfere with the ultrasonic testing. Summary of the Invention

[0003] The purpose of this invention is to provide a wedge for ultrasonic testing of low-velocity materials and its preparation method. Specifically, it provides a wedge that is easy to use, has a low sound velocity close to that of pure water, and is suitable for ultrasonic testing of various low-velocity materials, as well as its preparation method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a wedge for ultrasonic testing of low-velocity materials, comprising a wedge body, wherein the wedge body is made of hydrogel material or rubber mixed with mineral oil material, and the sound velocity of the wedge body is less than 2000m / s.

[0005] Specifically, the aforementioned hydrogel material is made by cross-linking, with water-soluble polymers and cross-linking agents as the main components.

[0006] Specifically, the aforementioned rubber-mineral oil blend material is made by extruding thermoplastic elastic rubber and mineral oil as the main components using a screw extruder.

[0007] A method for preparing a wedge for ultrasonic testing of low-velocity materials, wherein the wedge is made of hydrogel material, specifically including the following steps: First, a certain amount of purified water is weighed, and sodium chloride, a water-soluble polymer, a crosslinking agent, and a preservative are added sequentially to the purified water. The mixture is stirred with a magnetic stirrer until completely dissolved to obtain a hydrogel solution. Then, the hydrogel solution is stirred a second time and defoamed using a vacuum stirrer. Finally, the defoamed solution is poured into a molding mold using a vacuum injection method, and placed under an ultraviolet lamp for 30 minutes to carry out a crosslinking reaction, so that the hydrogel solution solidifies and forms a shape. After removing the mold, a wedge for ultrasonic testing of low-velocity materials is obtained.

[0008] A method for preparing a wedge for ultrasonic testing of low-velocity materials, wherein the wedge is made of a rubber-mineral oil mixture, specifically including the following steps: First, a certain amount of thermoplastic elastic rubber and mineral oil are weighed, and then processed using a twin-screw extruder with a liquid metering pump: The thermoplastic elastic rubber is added from the main feed port of the twin-screw extruder, and the mineral oil is added from the fifth zone of the twin-screw extruder using a liquid metering pump. After extrusion molding by the twin-screw extruder, it is cut into granules by underwater pelletizing and dried to obtain granular raw material; Finally, the granular raw material is heated to complete melting using temperature-controlled hot melt adhesive, poured into a mold and cooled to form a wedge for ultrasonic testing of low-velocity materials.

[0009] The beneficial effects of this invention are as follows: the wedge body is made of hydrogel material or rubber mixed with mineral oil material, so that the sound velocity of the wedge body can be close to the sound velocity of water, and the sound velocity value can be controlled below 2000m / s, which is suitable for ultrasonic testing of low sound velocity materials; at the same time, compared with liquid-filled wedges, it has the advantages of simple integrated molding structure, no liquid leakage, no contamination of the surface of the tested material, no air bubbles interfering with the test results, and the material itself has a certain degree of elasticity, which can achieve good coupling even when the surface of the tested material is uneven, effectively improving the effect of ultrasonic flaw detection. Detailed Implementation

[0010] This application provides a wedge for ultrasonic testing of low-velocity materials, comprising a wedge body made of hydrogel material or rubber-mineral oil mixture, wherein the velocity of sound in the wedge body is below 2000 m / s. The wedge body of this application, made of hydrogel material or rubber-mineral oil mixture, possesses the advantage of low velocity of sound. Furthermore, the wedge body is integrally molded, offering advantages over liquid-filled wedges such as simple structure, no liquid leakage, no contamination of the tested material surface, and no air bubbles interfering with the test results. Simultaneously, the aforementioned hydrogel material or rubber-mineral oil mixture itself has a certain degree of elasticity, enabling good coupling even when the tested material surface is uneven, effectively improving the ultrasonic flaw detection effect. The specific process for testing with this wedge is as follows:

[0011] 1. Assemble the wedge block and the matching ultrasonic probe together.

[0012] 2. Connect the probe to a flaw detector or other testing system that can provide similar functionality.

[0013] 3. Confirm that the probe is working properly and that the probe and wedge are well coupled.

[0014] 4. Directly couple the probe and wedge to the workpiece being inspected.

[0015] 5. Start the testing process according to the testing requirements.

[0016] 6. After the inspection is completed, remove the probe and wedge from the workpiece to complete the inspection.

[0017] Specifically, the hydrogel material used in the wedge of this application is made by cross-linking, with water-soluble polymers and cross-linking agents as the main components.

[0018] Specifically, the rubber-mineral oil mixture used in the wedge of this application is made by extruding thermoplastic elastic rubber and mineral oil as the main components through a screw extruder.

[0019] In this regard, this application provides the following two embodiments, which specifically describe the preparation methods of the wedge body made of hydrogel material and the wedge body made of rubber mixed with mineral oil material.

[0020] Example 1: A method for preparing a wedge for ultrasonic testing of low-velocity materials, wherein the wedge is made of hydrogel material, specifically including the following steps: First, weigh 100 parts of purified water, then add 5 parts of sodium chloride, 30 parts of water-soluble polymer, 0.2 parts of crosslinking agent, and 0.5 parts of preservative to the purified water in sequence. Stir the mixture with a magnetic stirrer until completely dissolved to obtain a hydrogel solution. Next, use a vacuum stirrer to perform secondary stirring and defoaming treatment on the hydrogel solution. Finally, pour the defoamed solution into a molding mold using a vacuum injection method, and place it under an ultraviolet lamp for 30 minutes to carry out a crosslinking reaction, so that the hydrogel solution solidifies and forms a shape. After removing the mold, a wedge for ultrasonic testing of low-velocity materials is obtained.

[0021] Example 2: A method for preparing a wedge for ultrasonic testing of low-velocity materials. The wedge is made of a rubber-mineral oil mixture and includes the following steps: First, weigh 10 parts of thermoplastic elastic rubber and 90 parts of mineral oil. Then, process the mixture using a twin-screw extruder with a liquid metering pump: add the thermoplastic elastic rubber from the main feed port of the twin-screw extruder, and add the mineral oil from the fifth zone of the twin-screw extruder using the liquid metering pump. After extrusion molding by the twin-screw extruder, cut the mixture into granules using underwater pelletizing and dry it to obtain granular raw material. Finally, heat the granular raw material to complete melting using temperature-controlled hot melt adhesive, pour it into a mold, and cool and solidify it to obtain a wedge for ultrasonic testing of low-velocity materials.

[0022] In addition, this application also measures and compares the sound velocity, acoustic impedance, and sound attenuation coefficient of the hydrogel material wedge prepared in Example 1, the rubber-mineral oil mixture wedge prepared in Example 2, the existing polystyrene plastic wedge, and the liquid-filled wedge filled with pure water. The test results are shown in the table below:

[0023] Sample acoustic characteristic impedance ×10 6 Pa·s / m Sound velocity m / s Sound attenuation coefficient dB / cm / MHz Example 1 - Hydrogel 1.70 160 30.10 Example 2 - Rubber Mineral oil 1.53 1560 0.07 Polystyrene 2.45 2360 0.38 Water-filled wedge 1.52 15000 0.01

[0024] The comparison results above show that the wedges of Embodiments 1 and 2 of this application have significantly lower sound velocities compared to conventional low-sound-velocity polystyrene wedges. Both exhibit sound velocities close to those of water-filled wedges, and their acoustic impedance and sound attenuation coefficients are also closer to those of water-filled wedges, demonstrating good performance in ultrasonic testing. Compared to water-filled wedges, the wedges of Embodiments 1 and 2 of this application, being integrally molded, do not suffer from structural complexity or the need for liquid filling, internal liquid replacement, liquid leakage, or air bubbles interfering with test results. This facilitates operation during ultrasonic testing and provides better and more stable ultrasonic testing performance.

[0025] Of course, the above are only preferred embodiments of the present invention and are not intended to limit the scope of application of the present invention. Therefore, any equivalent changes made to the principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A wedge for ultrasonic testing of low-velocity materials, characterized in that: It includes a wedge body, which is made of hydrogel material or rubber mixed with mineral oil material, and the sound velocity of the wedge body is less than 2000m / s.

2. A wedge block for ultrasonic testing of low-velocity materials according to claim 1, characterized in that: The hydrogel material is made by cross-linking, with water-soluble polymers and cross-linking agents as the main components.

3. A wedge block for ultrasonic testing of low-velocity materials according to claim 1, characterized in that: The rubber-mineral oil blend material is made by extruding thermoplastic elastic rubber and mineral oil as the main components using a screw extruder.

4. A method for preparing a wedge for ultrasonic testing of low-velocity materials, characterized in that: The wedge is made of a rubber-mineral oil mixture, and the specific steps include: first, weighing a certain amount of thermoplastic elastic rubber and mineral oil, and then processing it using a twin-screw extruder with a liquid metering pump: adding the thermoplastic elastic rubber from the main feed port of the twin-screw extruder, and adding the mineral oil from the fifth zone of the twin-screw extruder using the liquid metering pump, extruding it into shape by the twin-screw extruder, cutting it into granules by underwater pelletizing, and drying it to obtain granular raw material; finally, heating the granular raw material to complete melting using temperature-controlled hot melt adhesive, pouring it into a mold and cooling it to form a wedge for ultrasonic testing of low-velocity materials.