CN115356403A - Method for preparing nondestructive testing simulation test block by diffusion bonding metallurgy technology - Google Patents

Abstract

The invention relates to a method for preparing a nondestructive simulation test block by hot-pressing diffusion bonding, which realizes three axial deformation limit conditions of the test block with gradient of 3-1 mm by using a graphite limiting device and implements a hot-pressing diffusion bonding test. The nondestructive testing test block has excellent quality, and the testing result shows that the boundary of the prefabricated rectangular defect of the test block under each condition is clear; the microstructure shows that the tissues in the area of the connecting interface are fully diffused and fused without generating harmful defects obviously influencing the prefabricated defects; the connecting interface area and the matrix metallographic structure are not obviously different, and the chemical elements are uniformly distributed; the hot-pressing diffusion bonding metallurgy method can be applied to the development of nondestructive testing simulation test blocks.

Description

Method for preparing nondestructive testing simulation test block by diffusion bonding metallurgy technology

Technical Field

The invention belongs to the field of nondestructive testing, and relates to a method for preparing a nondestructive testing simulation test block by using a diffusion bonding metallurgy technology.

Background

In a nondestructive testing system, a nondestructive testing test block plays an important detection quality guarantee role, wherein the quality of the nondestructive testing test block has a crucial influence on the efficiency and precision of nondestructive testing, particularly, in a nondestructive testing simulation test block, the real existing state of defects is reflected, and the nondestructive testing simulation test block plays an irreplaceable role in the fields of equipment and device operation guarantee, laboratory capability verification, scientific research personnel training and the like. The preparation of non-destructive test specimens in the prior art typically involves the following studies:

CN110132665A relates to a manufacturing method of a circular defect test piece, which comprises the following steps: assembling two test plates with 30-degree grooves, reserving a gap of 2mm, and performing backing welding by manual argon tungsten-arc welding; continuing welding to the thickness required to have the circular defect, stopping welding, covering heat preservation cotton on the surface of the welding line of the workpiece, and naturally cooling the test piece to room temperature; drilling by using a drill bit with the same diameter of the required circular defect on the thickness of the circular defect to be generated, and finishing drilling when the hole depth reaches the diameter value of the required circular defect; determining the number of drilled holes according to the requirement; putting corresponding zirconia ceramic particles into the corresponding drilled holes obtained in the step S3, wherein the diameters of the zirconia ceramic particles are the same as the pore diameters of the drilled holes; and continuing to perform cover surface welding until the test piece is welded.

CN106404921A relates to a preparation method of a sample for ultrasonic nondestructive testing capability verification, and belongs to the technical field of ultrasonic nondestructive testing. The invention takes the characteristics of ultrasonic nondestructive testing capability verification and the requirement on a sample as starting points, and takes the principle that the defect based on ultrasonic testing and a matrix have different acoustic characteristic impedances as a basis, and proposes that a method of embedding foreign matters in the sample preparation and processing process is adopted to form artificial defects in the sample matrix, so as to obtain the sample with the artificial defects. The foreign bodies in which the artificial defects are made are suitably solids, liquids or gases having a significant difference in acoustic characteristic impedance from the substrate. According to the design and preparation method provided by the invention, a sample for verifying the ultrasonic nondestructive testing capability can be obtained.

CN113049331A provides a preparation method of a nondestructive testing simulation test block and a simulation test block, the method includes: hot pressing: setting the surface to be connected of one test block and the surface to be connected of the other test block to be in contact with each other, carrying out hot pressing on the two test blocks at the temperature of 0.5-0.8T and under a preset pressure, and setting the heat preservation time to be 40-100 min, wherein T is the melting point of the test block; at least one of the surface to be connected of one test block and the surface to be connected of the other test block is formed with a simulated defect; the predetermined pressure is adapted to the temperature and the holding time. The method provided by the invention can better control the test block and the deformation inside the test block by controlling the preparation process parameters (temperature, heat preservation time and pressure), and avoids the condition that the quality of the simulated test block is reduced due to the deformation of the test block and the internal defects in the prior art.

Although the prior art has the preparation and research of samples required by nondestructive testing, the prior art still has some defects, for example, the preparation of the prior nondestructive testing simulation test block is mostly formed by the process of 'material reduction manufacturing' from outside to inside such as mechanical drilling holes, grooves and the like, and the problems brought by the preparation that the shape and the size of the prepared defect are limited by the shape and the size of the edge of a machining tool and the defect is single in type; meanwhile, the prepared defects penetrate from the inside to the outside of the test block, and meanwhile, the chemical components are uneven, so that the prepared defects are not suitable for being used as real blind samples. Other simulation test block preparation methods which rely on traditional manual welding techniques or cut and process natural defects in past detection by embedding have low efficiency and great difficulty, and are difficult to ensure the consistency of the internal defects of the test blocks. The defects of the existing preparation method of the simulation test block cause that the simulation test block cannot fully meet various application requirements of quality evaluation. Therefore, there is a need to develop a method for preparing a simulation test block for nondestructive testing of a complete preform defect state without significantly affecting the preform defect.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a preparation method for applying a hot-pressing diffusion bonding metallurgy method to an ultrasonic simulation test block, and aims to solve the problems of non-uniform chemical elements, inconsistent defects and the like of a nondestructive test block in the prior art.

The inventor takes the actual application requirement of the nondestructive testing simulation test block as the starting point, and innovatively applies the diffusion bonding metallurgy technology to the preparation of the nondestructive testing simulation test block. The essence of the hot-pressing diffusion bonding method is that the atomic scale close contact is realized by means of macroscopic/microscopic plastic deformation, and a firm metallurgical bonding is formed by element diffusion across an interface. However, the deformation of the member caused by the preparation process can affect the nondestructive testing of the simulation test block and the internal prefabricated defect, and finally the application effectiveness of the test block is affected. In the application research of the existing diffusion connection, macroscopic deformation, microscopic deformation and rules thereof generated by the process are not reported, and especially for the preparation application with higher requirements on plastic deformation control, the effective control of the deformation is realized on the premise of ensuring the connection quality, so that the practical significance is realized. The invention takes the test blocks prepared under different deformation limit conditions as research objects, and through the analysis of macroscopic deformation of the test blocks, microscopic deformation of prefabricated defects, tissue change and the like, the application of the hot-pressing diffusion preparation method in the preparation of nondestructive testing simulation test blocks is met, and the actual application requirements are met.

Specifically, the first aspect of the invention provides a method for preparing a nondestructive testing simulation test block by using a diffusion bonding metallurgy technology, which comprises the following steps:

1) Selecting experimental materials: in the experiment, hot-rolled carbon structural steel No. 20 round steel is used as a base material;

2) Sample treatment: machining 20 # round steel of a test base material into a plurality of cylindrical test blocks, performing surface plane grinding on the test blocks until the roughness Ra is within the range of 0.1-0.3 mu m, and connecting the test blocks into a pre-connection test block by combining two test blocks with one defect-free test block, wherein the parallelism of the upper surface and the lower surface of the test block is 0.01 mm;

3) Diffusion bonding test: placing the pre-connected test block into a device furnace, heating to a test temperature, preserving heat, applying pressure, maintaining the vacuum degree in the furnace, performing axial hot-pressing diffusion connection test to prepare a nondestructive test simulation test block,

the method is characterized in that: during diffusion connection, the graphite limiting blocks with different thicknesses are simultaneously diffusion-connected with the test block to control the limit displacement of the pressure head of the device, so that different deformation limit control conditions of the test block in the axial direction are realized.

In a preferred embodiment, the chemical composition of the matrix material is:

in a preferred embodiment, in step 1), the test block is cylindrical

Cube (20-30 × 20-30 × 20-30 mm) or cuboid (20-30 × 20-30 × 40-50 mm).

In a preferred embodiment, in step 2), one selected from each group is designed into a rectangular defect array on one side surface, and is processed and prepared by adopting an electric spark etching process.

In a preferred embodiment, in step 2), the pre-joint block is formed by electron beam seal welding.

In a preferred embodiment, in step 2), the pre-connecting block is cylindrical

Cube (50-60X 50-60 mm) or cuboid (50-60X 70-80 mm).

In a preferable embodiment, in the step 3), the test temperature is 1000-1200 ℃, the temperature is uniformly increased from the room temperature to the test temperature, and after the temperature is kept for 40-60min, the temperature is cooled to the room temperature along with the furnace.

In a preferable embodiment, in the step 3), the axial pressure applied to the test block is controlled to be 10-30MPa, and the pressure is kept constant in the temperature keeping time.

In a preferred embodiment, in step 3), the vacuum degree is less than 10Pa.

In a preferred embodiment, the matrix structure of the resulting test piece on both sides of the diffusion interface is recrystallized and new grains are formed.

In a preferred embodiment, the radial deformation of the resulting test block increases with increasing axial deformation limit, and each exhibits a profile that is high in the middle and low in the ends.

In a preferred embodiment, further, as the axial deformation limit of the test block is gradually increased, the radial maximum deformation part is gradually shifted upwards from the bottom of the test block, and the two sides of the axial deformation gradually tend to be symmetrical.

The second aspect of the invention provides an application of a nondestructive testing simulation test block prepared by a diffusion bonding metallurgy technology in nondestructive testing.

In a preferred embodiment, the method comprises the following steps:

1) Performing three-dimensional scanning measurement on the prepared test blocks under different deformation limit conditions by using a laser three-dimensional scanner, comparing the scanning data with the results of a theoretical digital analogy, and analyzing radial and axial deformation rules of the test blocks;

2) Performing at least one of the following tests:

detecting the quality and defect state of a diffusion connection interface of the test block by using an ultrasonic scanning detection system; carrying out nondestructive testing on the horizontal shape and position of the defect in the test block by using an X-ray machine; metallographic analysis is carried out on the structure, the diffusion fusion state and the structure change condition of each test block diffusion connection area by using a metallographic microscope, and the actual deformation of the prefabricated defect is measured; or analyzing the chemical components of the welding seam connection region by using a thermal field emission scanning electron microscope and an energy spectrometer.

The invention has the beneficial effects that:

(1) Compared with the traditional preparation methods such as manual welding and the like, the hot-pressing diffusion connection method has the advantages that the preparation efficiency is low, the rejection rate is high, and defects cannot be copied and prepared.

(2) The matrix tissues on two sides of the diffusion interface of the test block prepared by the diffusion connection method are recrystallized to form new crystal grains, so that the tissue morphology is more controllable, and the subsequent nondestructive testing is facilitated; the tissue of the diffusion connection region is not obviously different from the tissue of the base material, and the extrinsic influence on the detection result caused by the non-uniform components is avoided. The strength of the ultrasonic feedback information of the defect after actual deformation is in positive correlation with the width/depth ratio of the prefabricated defect of the test block, namely, the actual state of the defect can be truly reflected by ultrasonic detection.

(3) The test block prepared by the hot-pressing diffusion bonding method not only can be used for preparing and researching the simulated cracks and the layered defects, but also can be used for nondestructively detecting the simulated test block and has other typical defects, and the defects brought by the failure processes of material production, processing and application can be reproduced in the simulated test block, so that the simulated test block has more significance in nondestructive detection and product quality control evaluation in various application fields.

Drawings

FIG. 1 is a schematic diagram of a rectangular defect array design pattern on one side surface of each group of test blocks of No. 20 round steel of hot-rolled carbon structural steel adopted in the experiment of the invention;

FIG. 2 is a schematic view of the hot-pressing diffusion apparatus and the manufacturing principle of the present invention;

FIG. 3 is a schematic diagram of a data point cloud obtained after a test block is scanned by a laser in three dimensions according to the present invention;

FIG. 4 is a diagram of the distribution of the amount of deformation of the curved surface of FIG. 3 resulting from the development of the dimensional deviation of the curved surface in the circumferential direction according to the present invention;

FIG. 5 shows the axial plastic deformation variation trend of the test block under three deformation limit conditions of the present invention;

FIG. 6 shows the texture of the connecting interface under different deformation limit conditions according to the embodiment of the present invention;

FIG. 7 is a diagram of elemental analysis of the interface region of the connection under different deformation limits of the examples;

FIG. 8 is an X-ray detection spectrum under different deformation limit conditions of the example;

FIG. 9 is the variation rule of the width and depth of the defect under different deformation limit conditions of the embodiment;

FIG. 10 is a diagram of an ultrasonic C-scan under different deformation limit conditions of an embodiment;

FIG. 11 shows the defect profiles at different deformation limits of the examples: (a) defect morphology under 3mm deformation limit condition; (b) defect morphology under 2mm deformation limit condition; (c) defect morphology under the deformation limit condition of 1 mm.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar modules or modules having the same or similar functionality throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention and are not to be construed as limiting the present invention.

In the description herein, references to the description of "one embodiment," "another embodiment," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

The diffusion bonding metallurgy technology applied by the invention is a precise bonding method, and can be used for preparing and bonding new materials such as dissimilar metals, heat-resistant alloys, intermetallic compounds, ceramics, composite materials and the like. At present, researchers and engineers have studied the practical application of superplastic forming and diffusion bonding technology in the manufacturing of engine blades, and conducted a dissimilar alloy vacuum diffusion welding test on TA2 pure titanium of a drill rod material of an oil well pipe and 14MnMoVN steel of a drill bit material, and analyzed the law of the effect of temperature and heat preservation time on the mechanical property of a joint.

The invention provides a method for preparing a nondestructive testing simulation test block by using a diffusion bonding metallurgy technology.

The physical and mechanical properties of the hot-rolled carbon structural steel No. 20 round steel adopted in the experiment are as follows:

Chemical composition of matrix material(wt.％)

machining the 20 # round steel of the test base material into a plurality of cylindrical test blocks, and performing surface plane grinding and fine grinding on the test blocks until the roughness Ra is within the range of 0.1-0.3 mu m, and the parallelism of the upper surface and the lower surface is 0.01mm, wherein the two test blocks are in a group. Each group selects a rectangular defect array with one side surface designed as shown in figure 1, and is processed and prepared by adopting an electric spark etching process. Wherein the rectangular defect lengths are all 5mm, the design values of the defect widths of the A-D columns are 1.5, 1.0, 0.75 and 0.5 (mm), respectively, and the design values of the defect depths of the 1-6 rows are 0.01, 0.05, 0.1, 0.5,1.0 and 2.0 (mm), respectively. And connecting the test block with another defect-free test block by electron beam seal welding to form a pre-connection test block.

A schematic diagram of a hot-pressing diffusion device and a preparation principle thereof is shown in fig. 2. And (3) placing the cylindrical pre-connection test block with the external dimension into the device, and carrying out an axial hot-pressing diffusion connection test. The test temperature is selected from a proper range, is uniformly increased from the room temperature to the test temperature, and is cooled to the room temperature along with the furnace after heat preservation. When the test temperature is reached in the furnace, the axial pressure applied to the test block is increased to about a certain range, and the pressure is kept unchanged in the heat preservation time. The vacuum degree in the furnace is less than 10Pa in the diffusion bonding stage.

On the basis of the test samples and the test conditions, the graphite limit blocks (57 mm, 58mm and 59 mm) with different thicknesses are simultaneously connected with the test block in a diffusion mode to control the limit displacement of the pressure head of the device, so that the control conditions of different deformation limits (3 mm, 2mm and 1 mm) in the axial direction of the test block are realized.

Performing three-dimensional scanning measurement on the prepared test block under different deformation limit conditions by using a KSCAN20 laser three-dimensional scanner, comparing the scanning data with the result of a theoretical digital analog through GOM (generic object model) expert software, and analyzing radial and axial deformation rules of the test block; and detecting the quality and defect state of the diffusion bonding interface of the test block by using a UPK-T1800HS water immersion ultrasonic C scanning detection system. And carrying out nondestructive testing on the horizontal shape and position of the defect in the test block by using an XRS-420 type X-ray machine. And (3) carrying out metallographic analysis on the structure, the diffusion fusion state and the structure change condition of the diffusion connection area of each test block by using a Zeiss Axio Vert. A1 metallographic microscope, and measuring the actual deformation of the prefabricated defect. And (3) analyzing the chemical components of the welding seam connection region by using an FEI Quanta 650FEG thermal field emission scanning electron microscope and an Oxford X-Max50 spectrometer.

Fig. 3 is a schematic diagram of a data point cloud obtained after a test block is scanned by laser in three dimensions, and the deviation of the curved surface dimension (the difference between the scanned data and the theoretical data) is represented by using a color difference. Fig. 4 is a distribution diagram of the amount of deformation formed by spreading the dimensional deviation of the curved surface of fig. 3 in the circumferential direction. As shown in the figure, the radial deformation amount of the test piece increases with the increase of the axial deformation limit, and both ends are distributed to be high in the middle. Along with the gradual increase of the axial deformation limit of the test block, the radial maximum deformation part is gradually transferred upwards from the bottom of the test block, and the two sides of the axial deformation gradually tend to be symmetrical.

FIG. 5 shows the axial plastic deformation of the test block under three deformation limit conditions. Under the condition of the deformation limit of a test block of 3 mm-1 mm, the axial plastic deformation of the test block is reduced along with the reduction of the axial deformation limit, the axial plastic deformation is sequentially 3.4mm,2.4mm and 1.7mm, and the actual axial plastic deformation of the test block is slightly larger than the theoretical deformation.

Specifically, the following sets forth a description of specific embodiments of a method for making a nondestructive testing mock block by diffusion bonded metallurgy techniques.

Example (b): method for preparing nondestructive testing simulation test block by diffusion bonding metallurgy technology

1. In the experiment, hot-rolled carbon structural steel No. 20 round steel is used as a base material;

2. a test base material No. 20 round steel is mechanically processed into a plurality of cylindrical test blocks with phi 68 multiplied by 30mm, the surface of each test block is finely ground until the roughness Ra is within the range of 0.1-0.3 mu m, the parallelism of the upper surface and the lower surface is 0.01mm, and the two test blocks form a group. Each group is prepared by selecting a rectangular defect array with one side surface designed as shown in figure 1 and adopting an electric spark etching process. Wherein the rectangular defect lengths are all 5mm, the design values of the defect widths of the A-D columns are 1.5, 1.0, 0.75 and 0.5 (mm), respectively, and the design values of the defect depths of the 1-6 rows are 0.01, 0.05, 0.1, 0.5,1.0 and 2.0 (mm), respectively. And connecting the test block with another defect-free test block by electron beam seal welding to form a phi 68 multiplied by 60mm pre-connection test block.

3. When the hot-pressing diffusion bonding is prepared, the test temperature is 1100 ℃, the temperature is uniformly raised from the room temperature to the test temperature, and after the temperature is kept for 45min, the temperature is cooled to the room temperature along with the furnace. When the test temperature in the furnace is reached, the axial pressure applied to the test block is increased to about 20MPa, and the pressure is kept constant during the holding time. The vacuum degree in the furnace is less than 10Pa in the diffusion bonding stage.

Then, a KSCAN20 laser three-dimensional scanner is used for carrying out three-dimensional scanning measurement on the prepared test blocks under different deformation limit conditions (3-1 mm), the scanning data and a theoretical digital analog are compared through GOM (goal Professional) instruction Professional software, and radial and axial deformation rules are analyzed on the test blocks; and detecting the quality and defect state of the diffusion bonding interface of the test block by using a UPK-T1800HS water immersion ultrasonic C scanning detection system. And carrying out nondestructive testing on the horizontal shape and position of the defect in the test block by using an XRS-420 type X-ray machine. And (3) carrying out metallographic analysis on the structure, the diffusion fusion state and the structure change condition of the diffusion connection area of each test block by using a Zeiss Axio Vert.A1 metallographic microscope, and measuring the actual deformation of the prefabricated defect. The chemical components of the welding seam connection area are analyzed by using an FEI Quanta 650FEG thermal field emission scanning electron microscope and an Oxford X-Max50 energy spectrometer.

Analysis of test block structure and composition

As shown in FIG. 6, the test results of the height of the vertical cross section of the diffusion bonded area of the test piece are shown in FIGS. 6 (a) to 6 (c), which are the surface texture profiles under the deformation limit conditions of 3mm to 1mm in examples. At the 3mm deformation limit, very small holes remain on the interface, and almost disappear. Under the 2mm deformation limit, the interface is straight and micro holes are distributed along the interface. When the deformation limit is reduced to 1mm, discontinuous strip-shaped holes remain at the interface, and the length of the holes is about 15-20 μm. Under the above deformation limit conditions, the matrix structures on both sides of the diffusion interface are recrystallized and form new crystal grains. The structure of the diffusion bonding region is not obviously different from the structure of the base material, and is ferrite and pearlite structures.

FIG. 7 is an energy spectrum line scanning analysis of the diffusion bonding area of the test block under the deformation limit condition of 3 mm-1 mm in the example, which shows that the elements of the interface and the two sides of the substrate are uniformly distributed, and the signal intensities of the elements are basically consistent under different conditions.

Defect analysis

Table 1 shows the actual width, depth and width/depth ratio of the prepared rectangular defect array before hot pressing. The processing precision is better within the range of the design value of the defect width of 1.5-0.5 mm, and the tolerance is 0.01-0.13 mm. The defect depth is within the range of 2.0-0.1 mm design value, and the tolerance is 0.02-0.04 mm; the defect depth is within 0.05-0.01 mm, the corresponding actual depth is 0.09-0.03 mm, and the difference with the design value is larger.

TABLE 1

X-ray transmission and ultrasonic C-scan detection are carried out on the prepared test blocks under different deformation limit conditions of the embodiment so as to analyze the prefabricated defect condition of the test blocks. The test block has the defect X-ray detection results shown in FIGS. 8 (a) to 8 (c) under the deformation limit of 3mm to 1mm, the test block only presents 1 to 3 rows of defect arrays with the design depths of 2.0, 1.0 and 0.5mm under different deformation limit conditions, the defect widths are consistent, and the defect volume state is not obviously changed. The three rows of defects with different depths are subjected to metallographic sample preparation, and the change rules of the defect width and the depth under different deformation limits are analyzed, as shown in fig. 9 (a) to 9 (c), the three rows of defects with the designed depth are respectively corresponding to 2.0, 1.0 and 0.5 mm. Under the deformation limit of 3 mm-1 mm, the deformation in the depth direction of the defect is reduced along with the reduction of the deformation limit; under the same design depth, the deformation amount of the defect depth tends to be reduced along with the reduction of the width, namely, the deformation in the depth direction of the defect is favorably reduced by a narrower defect. When the depth is the same, the width change of different defects is small under different deformation limit conditions, and the width deformation is mostly in the range of 0.02 mm.

Example defect array ultrasonic C-scan results fig. 10 shows that the first three rows of the defect array are consistent with the ray casting inspection results and the defect equivalent size decreases as the width of the preformed defect decreases. Under the deformation limit condition that 1mm is larger than 2mm and 3mm, the 4 th row of defects still present complete and strong defect information, and the equivalent size change of the defects is consistent with that of the first three rows.

Wherein, under the 3mm deformation limit, the 4 th row has stronger D-4 defect information, the rest 3 prefabricated wider defect information is weaker, and both the 5 th row and the 6 th row have no defect information; under the 2mm deformation limit, the C-4 and D-4 defect information in 4 rows is more clearly visible than the rest defect information, and the D-5 defect information in 5 rows appears; at the 1mm deformation limit, 5 rows of defect information all appear. The prefabricated defects are all at the same depth, and the equivalent size reflected by the ultrasonic information of the defects is increased along with the reduction of the width of the prefabricated rectangular groove.

In order to analyze the change of the defect width after the hot pressing treatment, the defects of the test block are subjected to metallographic sample preparation analysis. FIGS. 11 (a) to 11 (c) show the cross sections of the defects in line 4 at the strain limit of 3mm to 1mm, respectively, corresponding to the designed defect depth of 0.1 mm. The defect appearance under the condition of 3mm deformation limit is shown in fig. 11, partial diffusion fusion occurs at the defect part caused by deformation, and the defect width becomes small. When the deformation limit is reduced to 2mm, the defect depth gradually becomes smaller along with the increase of the defect width, and the matrix tissue parts on the two sides of the defect are in diffusion connection, so that the defect is discontinuous and reflected that the reflection information of the ultrasonic defect is weakened and partially disappears. Compared with other conditions, the 1mm deformation limit is smaller in defect depth along with the increase of defect width, defects are continuous, incident waves can be better reflected, and the result is consistent with the ultrasonic detection result.

The ultrasonic detection information, the defect diffusion fusion degree and the like of the rectangular defect array are combined to present a certain relation with the width/depth ratio (table 2) of the defects. Defects with a width/depth ratio of less than 3.6 at the deformation limit of 3mm and 2 mm; under the condition of 1mm deformation limit, the width/depth ratio of the defect is less than 5.4, the intensity of the ultrasonic feedback information of the defect after actual deformation is positively correlated with the width/depth ratio of the prefabricated defect of the test block, namely, the actual state of the defect can be truly reflected by ultrasonic detection.

Analysis shows that the method for preparing the nondestructive testing simulation test block by using the diffusion bonding metallurgy technology can effectively control the deformation of the test block and the internal prefabricated defects under the condition that the deformation of the component is not completely avoidable. The test carries out quantitative control to the test block axial deformation limit through designing graphite stop device, and the deflection of test block all directions obtains the effective control of different degrees under the prerequisite that keeps connection quality. Under the deformation limit of 3 mm-1 mm, three prefabricated defects of 2.0, 1.0 and 0.5mm in design depth series can be well reserved; designing the defects with the depth of 0.1mm or below, and realizing the preparation of the defects in different states by controlling different deformation limits. The most complete pre-defect state can be obtained under the control of the deformation limit of 1 mm.

It should be understood that the above examples are only for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And such obvious changes and modifications as fall within the spirit of the invention are deemed to be within the scope of the invention.

Claims (10)

1. A method for preparing a nondestructive testing simulation test block by using a diffusion bonding metallurgy technology comprises the following steps:

1) Selecting experimental materials: in the experiment, hot-rolled carbon structural steel No. 20 round steel is used as a base material;

2) Sample treatment: machining 20 # round steel of a test base material into a plurality of block-shaped test blocks, grinding the surface planes of the test blocks to be accurate to the extent that the roughness Ra is within the range of 0.1-0.3 mu m, and connecting the test blocks into a pre-connection test block by combining the test blocks with a defect-free test block, wherein the parallelism of the upper surface and the lower surface is 0.01 mm;

3) Diffusion bonding test: placing the pre-connected test block into a device furnace, heating to a test temperature, preserving heat, applying pressure, maintaining the vacuum degree in the furnace, performing axial hot-pressing diffusion connection test to prepare a nondestructive test simulation test block,

the method is characterized in that: during diffusion connection, the graphite limiting blocks with different thicknesses are simultaneously diffusion-connected with the test block to control the extreme displacement of the pressure head of the device, so that different axial deformation limit control conditions of the test block are realized.

2. The method for preparing a nondestructive testing analog test block by using the diffusion bonding metallurgy technology according to claim 1, wherein in the step 1), the block-shaped test block is cylindrical, cubic or cuboid.

3. The method for preparing a nondestructive testing simulation test block according to the diffusion bonding metallurgy technology of claim 1, wherein in the step 2), one selected block in each group is designed into a rectangular defect array on one side surface and is processed and prepared by adopting an electric spark etching process.

4. The method for preparing a nondestructive testing analog test block by using the diffusion bonding metallurgy technology according to claim 1, wherein in the step 2), the pre-connection block is cylindrical, square or rectangular.

5. The method for preparing a nondestructive testing simulation test block according to the diffusion bonding metallurgy technology of claim 1, wherein in the step 3), the testing temperature is selected to be 1000-1200 ℃, the temperature is uniformly increased from the room temperature to the testing temperature, and the temperature is kept for 40-60min and then cooled to the room temperature along with the furnace.

6. The method for preparing a nondestructive testing simulation test block by using the diffusion bonding metallurgy technology as claimed in claim 1, wherein in the step 3), the axial pressure applied to the test block is controlled to be 10-30MPa, and the pressure is kept constant in the temperature keeping time.

7. The method for preparing a nondestructive testing analog test block by using the diffusion bonding metallurgy technology according to claim 1, wherein in the step 3), the vacuum degree is less than 10Pa.

8. The method for preparing a nondestructive testing simulation test block by using the diffusion bonding metallurgy technology as claimed in claim 1, further comprising the step of gradually shifting the radial maximum deformation part from the bottom of the test block upwards as the axial deformation limit of the test block is gradually increased, and gradually making the two sides of the axial deformation symmetrical.

9. The use of the diffusion bonded metallurgy in the form of diffusion bonded metallurgy for the manufacture of non-destructive test coupons for the non-destructive testing of ceramic parts in a non-destructive testing environment.

10. The use according to claim 9, comprising:

1) Performing three-dimensional scanning measurement on the prepared test blocks under different deformation limit conditions by using a laser three-dimensional scanner, comparing the scanning data with a theoretical digital analog, and analyzing radial and axial deformation rules of the test blocks;

2) Performing at least one of the following tests:

detecting the quality and defect state of the diffusion bonding interface of the test block by using an ultrasonic scanning detection system; carrying out nondestructive testing on the horizontal shape and position of the defect in the test block by using an X-ray machine; metallographic analysis is carried out on the structure, the diffusion fusion state and the structure change condition of each test block diffusion connection area by using a metallographic microscope, and the actual deformation of the prefabricated defect is measured; or analyzing the chemical components of the welding seam connection region by using a thermal field emission scanning electron microscope and an energy spectrometer.

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