Non-magnetic cemented carbide material standard test block and manufacturing method thereof, and method for detecting nickel pool in non-magnetic cemented carbide material

Abstract

The present application relates to a method for manufacturing a non-magnetic cemented carbide material standard block, comprising the following steps: determining the size of the cylindrical standard block to be prepared and the diameter and depth of the internal nickel pool, measuring the shrinkage coefficient c of the non-magnetic cemented carbide material, calculating the diameter φ3 and height h2 of the cylindrical compact, the diameter φ4 and depth H2 relative to the pressing surface of the paraffin wax ball according to the shrinkage coefficient c of the non-magnetic cemented carbide material, over-pressing the compact obtained in the mold to obtain a blank, and performing precision machining to obtain the non-magnetic cemented carbide material standard block. The method for manufacturing a non-magnetic cemented carbide material standard block provided by the present application utilizes the migration of metallic nickel to the position of the specifically designed paraffin wax ball during the sintering process to form a nickel pool with a specific diameter and / or depth in the standard block. The present application also relates to a non-magnetic cemented carbide material standard block manufactured by the above method and a rapid detection method for the nickel pool in the non-magnetic cemented carbide material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-magnetic hard alloy defect detection, in particular to a non-magnetic hard alloy material standard test block, a manufacturing method thereof and a non-magnetic hard alloy nickel pool detection method. BACKGROUND

[0002] The non-magnetic hard alloy takes nickel as a binder phase, has the characteristics of non-magnetic, high hardness, wear resistance, heat resistance and corrosion resistance, is mainly used for device accessories working in a corrosive environment, and is widely used in civilian products and military industry, such as a sealing ring. The sealing ring has high quality requirements and good physical and mechanical properties and chemical stability. These requirements make it difficult to control the production process of the non-magnetic hard alloy, and the producer needs to have a high process control level.

[0003] In particular, in the actual production process of the sealing ring, since nickel is a binder phase, the carbon range is relatively wide and is difficult to control, and in addition, due to the need for corrosion resistance, the required chromium content is high, and the performance is more difficult to control, and there are more nickel pools and the third phase. The nickel pool not only affects the performance of the alloy, but also causes the product to have a primary cell, thereby reducing the corrosion resistance of the product. Therefore, in the production process of the sealing ring, the appearance of the nickel pool must be strictly controlled.

[0004] In addition, the size of the nickel pool in the non-magnetic hard alloy is very small, most of which is below 20 um. Its reflected wave is similar to the dirty hole wave, and the two must be distinguished, otherwise the process control direction will be misled, the internal quality of the product will be a problem, and great economic losses will be caused.

[0005] Therefore, it is urgent to develop a rapid detection method for the nickel pool in the non-magnetic hard alloy material. SUMMARY

[0006] Based on the above, the main purpose of the present application is to provide a non-magnetic hard alloy material standard test block, a manufacturing method thereof and a rapid detection method for the nickel pool in the non-magnetic hard alloy material.

[0007] To this end, in a first aspect, the present application provides a manufacturing method of a non-magnetic hard alloy material standard test block, comprising the following steps:

[0008] S100, determining the diameter φ1 and height h1 of the cylindrical standard test block to be prepared and the diameter φ2 and depth H1 of the nickel pool in the standard test block, wherein φ1> φ2, h1> H, 0.02 mm≤ φ2≤ 0.10 mm;

[0009] S200, measuring the shrinkage coefficient c of the non-magnetic hard alloy material, calculating the diameter φ3 and height h2 of the cylindrical green compact, the diameter φ4 and depth H2 of the paraffin ball with the pressing surface as the reference according to the shrinkage coefficient c of the non-magnetic hard alloy material,

[0010] Wherein, φ3=φ1*c, h2=h1*c, φ4=φ2*c, H2=H1*c;

[0011] S300, after loading part of the non-magnetic alloy material powder into the mold, a paraffin wax ball with a diameter of φ4 is put in, to ensure that the depth of the paraffin wax ball based on the pressing surface is H2, and then the non-magnetic alloy material powder is continuously loaded, and after the loading is completed, the pressing is carried out to obtain a green body;

[0012] S400, the green body obtained in step S300 is over-pressed and burned to obtain a cylindrical blank with a diameter of φ1 and a height of h1, and the blank has a nickel pool with a diameter of φ2 and a depth of H1;

[0013] S600, the blank obtained in step S500 is precision machined.

[0014] In the present application, the shape of the nickel pool is ideally spherical, but some deformation may occur during the pressing process. Here, the depth H1 refers to the depth at the center of the nickel pool.

[0015] In step S500 of the present application, during the pressing and burning process, the paraffin wax ball is sintered and decomposed into gas and volatilized. The molten nickel in the non-magnetic alloy material powder migrates to the position originally occupied by the paraffin wax to form a nickel pool. The metallographic sectioning technology is used for verification. The error of the diameter of the nickel pool in the blank and the set value φ2 is within ±0.01mm, preferably within ±0.002mm. The error of the depth of the nickel pool in the blank and the set value H1 is within ±0.3mm. The perpendicularity tolerance of the nickel pool in the blank is within 0.1mm.

[0016] In the present application, the paraffin wax ball can be gasified into gas at a temperature of about 1000℃ and volatilized, without affecting the overall physical and chemical properties of the non-magnetic hard alloy material.

[0017] In the present application, the rapid detection of the nickel pool in the non-magnetic hard alloy material relies on the non-magnetic hard alloy material standard test block. Since the size of the nickel pool in the standard test block is very small, in the order of microns, and its performance needs to be ensured, the production of the nickel pool in the standard test block is a difficulty. The production method of the non-magnetic hard alloy material standard test block provided in the present application utilizes the migration of metallic nickel to the position of a specially designed paraffin wax ball during the sintering process to form a nickel pool with a specific diameter and / or depth in the standard test block. Thus, a series of ultrasonic detection test blocks with the same diameter and different depths of the nickel pool, or a series of ultrasonic detection test blocks with the same depth and different diameters of the nickel pool are realized.

[0018] As a specific embodiment of the present application, the non-magnetic hard alloy material comprises:

[0019] Tungsten carbide WC, 75.4%-84.4%,

[0020] Nickel Ni, 8%-23%,

[0021] Chromium Cr, 0.5%-0.9%,

[0022] Molybdenum Mo, 0.7%-1.1%.

[0023] As a specific embodiment of the present application, in step S200, the shrinkage coefficient c of the non-magnetic hard alloy material is measured by the following steps: adding the non-magnetic hard alloy material into the mold for pressing, sintering under the condition that no cracks or delamination occurs in the green body, and calculating the ratio of the size of the non-magnetic hard alloy material before and after sintering as the shrinkage coefficient.

[0024] As a specific embodiment of the present application, in step 400, the overpressure sintering conditions include: degreasing temperature 300-800℃, degreasing time 1-3h, sintering temperature 1340-1400℃, and sintering time 10-15h.

[0025] As a specific embodiment of the present application, in step S400, the step of selecting paraffin wax balls with a diameter of φ4 includes: sieving the paraffin wax balls on a sieve, and then sieving through a sieve with a specific mesh size.

[0026] As a specific embodiment of the present application, in step 500, the precision machining includes the following steps: machining the roughness Ra of the upper and lower surfaces of the blank to 3.0-4.0μm.

[0027] To this end, in a second aspect, the present application provides a non-magnetic alloy material standard test block containing a nickel pool, which is made by using the above manufacturing method.

[0028] To this end, in a third aspect, the present application provides a rapid detection method for a nickel pool in a non-magnetic alloy material, which includes the following steps:

[0029] S10, a series of cylindrical non-magnetic hard alloy material standard test blocks with the same diameter φ1 and height h1 are made by using the above manufacturing method, and the nickel pools in each non-magnetic hard alloy material standard test block have the same diameter φ2 and different depths;

[0030] S20, the nickel pools in each non-magnetic hard alloy material standard test block are tested by using ultrasonic waves, and a DAC curve graph is established by reading the nickel pool attenuator readings at the same diameter and different depths.

[0031] S30, the nickel pool in the test sample is tested by using ultrasonic waves, and the depth H of the nickel pool in the test sample is calculated from the DAC curve graph by reading the nickel pool attenuator readings at the same diameter φ2.

[0032] As a specific embodiment of the present application, preferably, in step S20, the ultrasonic testing uses an ultrasonic flaw detector with RF mode, and a 2-15MHz straight probe is selected.

[0033] To this end, the fourth aspect, the present application provides a kind of quick detection method of nickel pool in non-magnetic alloy material, comprising the following steps:

[0034] S1, using the preparation method described above to prepare a series of cylindrical non-magnetic hard alloy material standard test blocks with the same diameter φ1 and height h1, the nickel pool in each non-magnetic hard alloy material standard test block has the same depth H1 and different diameters;

[0035] S2, test the nickel pool in each non-magnetic alloy material standard test block using ultrasonic wave, establish DAC curve graph by the attenuation of nickel pool at the same depth and different diameters;

[0036] S3, test the nickel pool in the sample to be tested using ultrasonic wave, calculate the diameter φ of the nickel pool in the sample to be tested from DAC curve graph by the attenuation of nickel pool at the same depth H1.

[0037] As a specific embodiment of the present application, preferably, in step S2, the ultrasonic testing uses an ultrasonic flaw detector with RF mode, and a 2MHz-15MHz straight probe is selected.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] 1. The preparation method of non-magnetic hard alloy material standard test block provided by the present application uses the migration of metallic nickel to the position of the original paraffin ball during sintering to form a nickel pool with a specific diameter and / or depth. Thus, a series of nickel pool ultrasonic test blocks with the same diameter and different depths, or a series of nickel pool ultrasonic test blocks with the same depth and different diameters can be prepared. A set of ultrasonic test blocks are developed to prepare a nickel pool DAC curve graph, which can be used to quickly determine the size of the nickel pool found in detection.

[0040] 2. The preparation method of non-magnetic hard alloy material standard test block provided by the present application is simple, efficient and economical.

[0041] 3. The preparation method of non-magnetic hard alloy material standard test block provided by the present application can promote the development of non-destructive ultrasonic testing technology and the development of non-magnetic hard alloy production technology. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a physical diagram of paraffin ball with a specific diameter.

[0043] Figure 2 It is a physical diagram of non-magnetic hard alloy material standard test block prepared in Example 1.

[0044] Figure 3The metallographic picture of the nickel pool found by the metallographic section technique for Example 1 is shown in Figure 1, and the diameter of the nickel pool is 52 μm.

[0045] Figure 4 The metallographic picture of the nickel pool found by the metallographic section technique for Example 2 is shown in Figure 2, and the diameter of the nickel pool is 41.2 μm.

[0046] Figure 5 is a DAC curve graph established by using a series of non-magnetic hard alloy material standard blocks (each standard block has a nickel pool with the same diameter and different depths).

[0047] Figure 6a is a detection graph of the nickel pool of the sample to be tested 1 detected by ultrasonic detection.

[0048] Figure 6b is the size of the nickel pool of the sample to be tested 1 determined by using the DAC curve graph.

[0049] Figure 7a is a detection graph of the nickel pool of the sample to be tested 2 detected by ultrasonic detection.

[0050] Figure 7b is the size of the nickel pool of the sample to be tested 2 determined by using the DAC curve graph. DETAILED DESCRIPTION

[0051] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations of the present application. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not marked with the manufacturer, and are all conventional products that can be obtained by purchase.

[0052] Example 1

[0053] The present embodiment provides a method for manufacturing a non-magnetic hard alloy material standard block, and the specific steps are as follows:

[0054] (1) The non-magnetic hard alloy material standard block prepared in the present embodiment is a cylinder, and the diameter φ1 (50 mm) and the height h1 (100 mm) of the standard block; the diameter φ2 (0.05 mm) and the depth H1 (50 mm) of the nickel pool in the standard block;

[0055] (2) Select a non-magnetic alloy material, and the composition of the non-magnetic alloy material is:

[0056] Tungsten carbide WC, 84.4%,

[0057] Nickel Ni, 14.1%,

[0058] Chromium Cr, 0.7%,

[0059] Molybdenum Mo, 0.8%.

[0060] (3) The shrinkage coefficient c of the non-magnetic alloy material is measured: 1 kg of the non-magnetic mixture is pressed, and the diameter of the compact is 20 mm and the height is 50 mm without cracks and delamination; after sintering (debinding temperature 500°C, debinding time 1.5 hours, sintering temperature 1400°C, sintering time 13.5 hours), the diameter is 16 mm and the height is 40 mm, and c = 1.25 is calculated;

[0061] (4) The diameter φ3 and the height h2 of the cylindrical compact, the diameter φ4 and the depth H2 of the paraffin ball based on the pressing surface are calculated according to the shrinkage coefficient c of the preferred non-magnetic alloy material,

[0062] φ3 = φ1 * c = 62.5 mm, h2 = h1 * c = 125 mm,

[0063] φ4 = φ2 * c = 0.0625 mm, H2 = H1 * c = 50 * 1.25 = 62.5 mm;

[0064] (5) 1 kg of spherical paraffin particles is sieved for 0.5 hours, first through a 230 mesh sieve, and then through a 200 mesh sieve, and spherical paraffin particles with a diameter of 0.0625 mm are selected (see Figure 1 );

[0065] (6) The non-magnetic cemented carbide material powder is loaded into the inner cavity of the mold, and when half is loaded, the spherical paraffin particles selected in step (5) are loaded into the inner cavity of the mold, and the depth H2 based on the pressing surface is 62.5 mm. Continue to load the non-magnetic cemented carbide material, and after the non-magnetic cemented carbide material is fully loaded, press the compact, and the compact after pressing is cylindrical with a diameter φ3 = 62.5 mm and a height h2 = 125 mm;

[0066] (7) The compact after pressing in step (6) is over-pressed and sintered (first debinding and then sintering, debinding temperature 500°C, debinding time 1.5 hours, sintering temperature 1400°C, sintering time 13.5 hours) to obtain a cylindrical blank with a diameter φ1 and a height h1;

[0067] (8) The blank is processed so that the roughness Ra of the upper and lower surfaces (two circular surfaces of the cylindrical shape) is 3.2 μm, which is convenient for subsequent flaw detection, and a non-magnetic cemented carbide material standard test block is obtained (see Figure 2 );

[0068] (9) The diameter of the nickel pool in the standard test block is verified by metallographic sectioning technology to be 52 μm (see Figure 3The difference between the diameter of the nickel pool in the standard test block and the set value is 0.002 mm, the difference between the depth of the nickel pool in the standard test block and the set value is 0.1 mm, and the perpendicularity tolerance of the nickel pool in the standard test block is 0.1 mm.

[0069] Example 2

[0070] The present example provides a method for manufacturing a non-magnetic cemented carbide material standard test block, and the specific steps are as follows:

[0071] (1) The non-magnetic cemented carbide material standard test block prepared in the present example is a cylinder, and the diameter φ1' (50 mm) and height h1' (100 mm) of the standard test block; the diameter φ2' (0.04 mm) and depth H1' (50 mm) of the nickel pool in the standard test block;

[0072] (2) and (3) are the same as in Example 1;

[0073] (4) The diameter φ3' and height h2' of the cylindrical compact, the diameter φ4' and depth H2' of the paraffin wax ball with respect to the pressing surface are calculated according to the shrinkage coefficient c of the preferred non-magnetic alloy material,

[0074] φ3' = φ1' * c = 62.5 mm, h2' = h1' * c = 125 mm,

[0075] φ4' = φ2' * c = 0.05 mm, H2' = H1' * c = 50 * 1.25 = 62.5 mm;

[0076] (5) Select 1 kg of spherical paraffin particles and sieve for 0.5 hours, first through a 270 mesh sieve, then through a 230 mesh sieve, and select spherical paraffin with a diameter of 0.05 mm;

[0077] (6) The above non-magnetic cemented carbide material and spherical paraffin particles are placed in the mold for pressing (the same as in Example 1);

[0078] (7) The pressed compact is over-pressed and burned (first degreasing at 500°C for 1.5 hours, then sintering at 1400°C for 13.5 hours) to obtain a cylindrical blank with a diameter φ1' and a height h1';

[0079] (8) The blank is precision machined (the machining requirements are the same as in Example 1) to obtain a non-magnetic cemented carbide material standard test block;

[0080] (9) Verified by metallographic sectioning technology, see Figure 4The diameter of the nickel pool in the standard test block is 41.2 μm. The difference between the diameter of the nickel pool in the standard test block and the set value is 0.0012 mm, the difference between the depth of the nickel pool in the standard test block and the set value is 0.3 mm, and the perpendicularity tolerance of the nickel pool in the standard test block is 0.1 mm.

[0081] Example 3

[0082] The present example provides a method for manufacturing a standard test block of non-magnetic cemented carbide material, and the specific steps are as follows

[0083] (1) The standard test block of non-magnetic cemented carbide material prepared in the present example is a cylinder, and the diameter φ1" (50 mm) and height h1" (100 mm) of the standard test block; the diameter φ2" (0.03 mm) and depth H" (50 mm) of the nickel pool in the standard test block;

[0084] (2) and (3) are the same as in Example 1;

[0085] (4) The diameter φ3" and height h2" of the cylindrical compact, the diameter φ4" and depth H2" of the paraffin wax ball with respect to the pressing surface are calculated according to the shrinkage coefficient c of the preferred non-magnetic alloy material,

[0086] φ3" = φ1" * c = 62.5 mm, h2" = h1" * c = 125 mm,

[0087] φ4" = φ2" * c = 0.0375 mm, H2" = H1' * c = 50 * 1.25 = 62.5 mm;

[0088] (5) Select 1 kg of specific paraffin wax particles and sieve for 0.5 hours, first through a 400 mesh sieve, then through a 325 mesh sieve, and select spherical paraffin wax with a diameter of 0.0375 mm;

[0089] (6) The above non-magnetic cemented carbide material and spherical paraffin wax particles are placed in the mold for pressing (the same as in Example 1);

[0090] (7) The pressed compact is subjected to overpressure sintering (the conditions for overpressure sintering are the same as in Example 1) to obtain a blank with a diameter φ1" and a height h1";

[0091] (8) The blank is subjected to precision machining (the machining requirements are the same as in Example 1) to obtain a standard test block of non-magnetic cemented carbide material.

[0092] Test Example 1

[0093] A series of non-magnetic alloy material standard test blocks (cylindrical, diameter φ 150 mm, height hi 100 mm) were prepared by the method of Example 1, with the internal nickel pool having the same diameter of 0.05 mm and different depths of 15 mm, 25 mm, 35 mm, 45 mm, 55 mm, 65 mm, and 75 mm.

[0094] The series of non-magnetic alloy material standard test blocks were tested by an ultrasonic 5 MHz probe and a 10 MHz probe, respectively, to obtain Figure 5 the φ 0.05 mm curve (solid line corresponding to the 5 MHz probe and dotted line corresponding to the 10 MHz probe). Figure 5 The abscissa distance represents the depth, and the ordinate amplitude (unit: db) represents the reading of the instrument attenuator.

[0095] The same method as above was used to obtain Figure 5 the φ 0.04 mm curve, the φ 0.03 mm curve, and the φ 0.02 mm curve.

[0096] During the detection of the product to be tested 1, ultrasonic detection found that the product to be tested 1 had an internal nickel pool as shown in FIG. (6a). According to the waveform diagram, the depth H of the nickel pool was measured to be 66 mm, and the attenuator reading was 53 dB. Referring to Figure 5 , it can be known that the diameter of the nickel pool was 33 μm (see Figure 6b ).

[0097] During the detection of the product to be tested 2, ultrasonic detection found that the product to be tested 2 had an internal nickel pool as shown in FIG. (7a). Using the curve Figure 5 , it was determined that the diameter of the nickel pool was 40 μm (see Figure 7b ).

[0098] The above description of the embodiments is for the purpose of facilitating understanding and application of the present application by those of ordinary skill in the art. Those skilled in the art can easily make various modifications to the embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A method for preparing standard test blocks of non-magnetic cemented carbide materials, characterized in that, Includes the following steps: S100. Determine the diameter φ1 and height h1 of the cylindrical standard test block to be prepared, as well as the diameter φ2 and depth H1 of the nickel pool inside the standard test block, wherein φ1 > φ2, h1 > H1, and 0.02 mm ≤ φ2 ≤ 0.10 mm. S200. Determine the shrinkage coefficient c of the non-magnetic cemented carbide material. Based on the shrinkage coefficient c, calculate the diameter φ3 and height h2 of the cylindrical blank, the diameter φ4 of the paraffin ball, and the depth H2 based on the pressing surface. Wherein, φ3=φ1*c, h2=h1*c, φ4=φ2*c, H2=H1*c; S300. After loading some non-magnetic alloy material powder into the mold, put in a paraffin ball with a diameter of φ4, ensuring that the depth of the paraffin ball relative to the pressing surface is H2, and continue to load non-magnetic alloy material powder. After loading, press to obtain a compact. S400, The pressed blank obtained in step S300 is subjected to over-pressing to obtain a cylindrical blank with a diameter of φ1 and a height of h1, and the blank has a nickel pool with a diameter of φ2 and a depth of H1. S600, Perform precision machining on the blank obtained in step S500.

2. The manufacturing method according to claim 1, characterized in that, The non-magnetic cemented carbide material includes: Tungsten carbide (WC), 75.4%-84.4%, Nickel Ni, 8%-23%, Chromium (Cr), 0.5%-0.9%, Molybdenum, 0.7%-1.1%.

3. The manufacturing method according to claim 1 or 2, characterized in that, In step S200, the determination of the shrinkage coefficient c of the non-magnetic hard alloy material includes the following steps: adding non-magnetic hard alloy material into a mold and pressing it, sintering it without cracking or delamination of the pressed blank, and calculating the ratio of the size of the non-magnetic hard alloy material before and after sintering, which is the shrinkage coefficient.

4. The manufacturing method according to claim 1 or 2, characterized in that, In step 400, the conditions for overpressure sintering include: degumming temperature of 300℃-800℃, degumming time of 1h-3h, sintering temperature of 1340℃-1400℃, and sintering time of 10h-15h.

5. The manufacturing method according to claim 1 or 2, characterized in that, Step S400, the step of selecting paraffin balls with a diameter of φ4 includes: wiping the paraffin balls on a sieve and then sieving them through a sieve with a specific mesh size.

6. The manufacturing method according to claim 1 or 2, characterized in that, In step 500, the precision machining includes the following steps: machining the surface roughness Ra of the upper and lower surfaces of the blank to 3.0μm-4.0μm.

7. A standard test block of non-magnetic hard alloy material containing a nickel pool, prepared using the method described in any one of claims 1-6.

8. A rapid detection method for nickel pools in non-magnetic hard alloy materials, characterized in that, Includes the following steps: S10. Using the manufacturing method of any one of claims 1-6, a series of cylindrical non-magnetic hard alloy material standard test blocks with the same diameter φ1 and height h1 are manufactured, and the nickel pools in each non-magnetic hard alloy material standard test block have the same diameter φ2 and different depths; S20. Using ultrasonic testing, standard test blocks of various non-magnetic hard alloy materials are tested, and DAC curves are established by reading the nickel pool attenuator at different depths with the same diameter. S30. Use ultrasonic testing to test the nickel pool inside the test sample. Calculate the nickel pool depth H of the test sample from the DAC curve by using the nickel pool attenuator readings under the same diameter φ2.

9. A rapid detection method for nickel pools in non-magnetic hard alloy materials, characterized in that, Includes the following steps: S1. A series of cylindrical non-magnetic hard alloy material standard test blocks with the same diameter φ1 and height h1 are produced by the manufacturing method of any one of claims 1-6, wherein the nickel pool in each non-magnetic hard alloy material standard test block has the same depth H1 and different diameters; S2. Use ultrasonic testing to test the nickel pool inside the standard test blocks of various non-magnetic alloy materials, and establish a DAC curve by reading the nickel pool attenuator at the same depth but different diameters. S3. Use ultrasonic testing to test the nickel cell inside the sample. Calculate the nickel cell diameter φ of the sample from the DAC curve by using the nickel cell attenuator reading at the same depth H1.

10. The detection method according to claim 8 or 9, characterized in that, In steps S20 and S2, the ultrasonic tests may be the same or different, and each uses an ultrasonic flaw detector with RF mode independently, with a 2MHz-15MHz straight probe selected.

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