A method for manufacturing a test block for ultrasonic detection of unwelded defects at diffusion welding interfaces

Abstract

The present invention discloses a method for making a test block for ultrasonic detection of unwelded defects at a diffusion welding interface, including a method for making a rotor plunger hole comparison test block and a method for making a rotor end face comparison test block; the method for making a rotor plunger hole comparison test block includes the following steps: a. First, multiple horizontal holes of different diameters are drilled on the side of a steel substrate to obtain product A; b. Product A is connected to a copper tube as a whole by diffusion welding to obtain a finished product of the rotor plunger hole comparison test block; the method for making a rotor end face comparison test block includes the following steps: c. First, multiple vertical holes of different diameters are drilled on the end face of another steel substrate to obtain product C; d. Product C is connected to a copper plate as a whole by diffusion welding to obtain a finished product of the rotor end face comparison test block. The test block made by the present invention is used for ultrasonic detection and quality evaluation of rotors, and has the advantage of not causing serious misjudgment when evaluating the equivalent size of defects.

Description

Technical Field

[0001] The invention belongs to the field of ultrasonic detection of unwelded defects at diffusion welding interfaces, and in particular relates to a method for manufacturing a test block for ultrasonic detection of unwelded defects at diffusion welding interfaces. Background Art

[0002] Diffusion welding is a welding method that welds two metal parts with different properties together. For example, the core component (rotor) of the hydraulic pump in the aerospace hydraulic system includes a cylindrical steel substrate with a plunger hole on the top surface of the steel substrate. A copper tube with a thickness of about 0.6 mm is diffusion welded in the plunger hole, and a copper plate with a thickness of about 0.6 mm is diffusion welded on the bottom surface of the steel substrate. The resulting rotor combines the excellent properties of the two materials, giving full play to their respective performance advantages and making the rotor perform better.

[0003] With the rapid development of the aerospace industry, more stringent requirements have been put forward for the reliability and performance of hydraulic pumps, and the corresponding rotor performance requirements are higher, which requires that the copper and steel in the rotor are well welded and the unwelded defects in the rotor must be strictly controlled. Therefore, it is of great significance to detect the unwelded defects at the copper-steel joint in order to make a reliable quality evaluation. At present, ultrasonic waves are mainly used to detect and evaluate the copper-steel joint of the rotor.

[0004] When ultrasonic waves are used to detect and evaluate the quality of the copper-steel joint of the rotor, two test blocks are used, namely the rotor plunger hole comparison test block and the rotor end face comparison test block. The existing method for making a rotor plunger hole comparison test block is to first obtain a sample formed by diffusion welding of a steel substrate and a copper tube, and then drill a plurality of horizontal holes of different diameters on the side wall of the steel substrate, and the horizontal holes reach the surface of the copper tube to obtain a rotor plunger hole comparison test block. The existing method for making a rotor end face comparison test block is to first obtain another sample formed by diffusion welding of a steel substrate and a copper plate, and then drill vertical holes on the steel substrate, and the vertical holes reach the surface of the copper plate to obtain a rotor end face comparison test block. The holes in the test block are used to form artificial defects, and the test block is used to calibrate ultrasonic testing equipment and evaluate the equivalent size of actual defects in the product.

[0005] Since the joint surface between the steel matrix and the copper tube in the rotor plunger hole comparison test block is a cylindrical surface, and the current drilling method can only drill out artificial defects of flat-bottom holes, but cannot drill out artificial defects of cylindrical surfaces, resulting in insufficient simulation of the welding interface of the rotor plunger hole comparison test block and the actual welding interface at the rotor plunger hole. In addition, the thickness of the copper tube is very thin (0.6mm), and the drill bit can easily drill through the copper-steel interface and damage the copper tube, resulting in the collected artificial defect ultrasonic reflection wave and the initial wave being mixed together and difficult to identify, resulting in serious misjudgment or inability to evaluate the defect equivalent size of the measured rotor. Although the welding interface in the rotor end face comparison test block and the welding interface at the rotor end face can be fully simulated, there is still the problem that the drill bit can easily drill through the copper-steel interface and damage the copper plate, resulting in inaccurate collected artificial defect ultrasonic reflection waves. When the copper layer is very thin, the artificial defect reflection wave will also be mixed with the initial wave and difficult to identify, resulting in serious misjudgment or inability to evaluate the defect equivalent size of the measured rotor.

[0006] Therefore, when the test blocks made by the existing test block making method are used for rotor ultrasonic testing and quality evaluation, there is a defect that may cause serious misjudgment when evaluating the defect equivalent size. Summary of the invention

[0007] The purpose of the present invention is to provide a method for manufacturing a test block for ultrasonic detection of unwelded defects at diffusion welding interfaces. The test block manufactured by the present invention is used for ultrasonic detection and quality evaluation of rotors, and has the advantage of not causing serious misjudgment when evaluating the equivalent size of defects.

[0008] The technical solution of the present invention is: a method for manufacturing a test block for ultrasonic detection of unwelded defects at a diffusion welding interface, including a method for manufacturing a rotor plunger hole comparison test block and a method for manufacturing a rotor end surface comparison test block;

[0009] The method for making a rotor plunger hole comparison test block comprises the following steps:

[0010] a. First, drill multiple horizontal holes of different diameters on the side of a steel substrate to obtain grade A.

[0011] b. Use diffusion welding to connect product A and the copper tube into a whole to obtain the finished product of the rotor plunger hole comparison test block;

[0012] The method for manufacturing a rotor end surface comparison test block comprises the following steps:

[0013] c. First, drill multiple vertical holes of different diameters on the end face of another steel substrate to obtain product C.

[0014] d. Use diffusion welding to connect product C and the copper plate into a whole, and obtain the finished product with the rotor end facing the test block.

[0015] In the aforementioned method for making a test block for ultrasonic detection of unwelded defects at diffusion welding interfaces, in step a, there are five types of transverse holes, and the diameters of the five types of transverse holes are 0.6 mm, 0.8 mm, 1.2 mm, 2 mm and 3.2 mm respectively.

[0016] In the aforementioned method for making a test block for ultrasonic detection of unwelded defects at diffusion welding interfaces, in step c, there are five types of vertical holes, and the diameters of the five types of vertical holes are 0.6 mm, 0.8 mm, 1.2 mm, 2 mm and 3.2 mm respectively.

[0017] Compared with the prior art, the present invention actually swaps the two processes of drilling and diffusion welding, drilling first and then diffusion welding to form a test block. The rotor plunger hole comparison test block thus obtained has a cylindrical surface artificial defect that can truly simulate the actual welding interface at the rotor plunger hole, and will not damage the copper layer, so that the collected artificial defect ultrasonic reflection wave is accurate and reliable and will not be mixed with the initial wave, easy to identify, and will not cause misjudgment of the equivalent size of the defect in the measured rotor; the rotor end face comparison test block thus obtained has a cylindrical surface artificial defect that can truly simulate the actual welding interface at the rotor end face, and will not damage the copper layer, so that the collected artificial defect ultrasonic reflection wave is accurate and reliable and will not be mixed with the initial wave, easy to identify, and will not cause misjudgment of the equivalent size of the defect in the measured rotor (can be seen from Figure 6 , Figure 7 , Figure 8 and Fig. 9 This conclusion can be seen in Figure 2. Therefore, the test block made by the present invention is used for rotor ultrasonic testing and quality evaluation, and has the advantage of not causing serious misjudgment when evaluating the equivalent size of defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of product A.

[0019] Figure 2 It is a structural schematic diagram of a rotor plunger hole comparison test block of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of product C.

[0021] Figure 4 It is a schematic structural diagram of the rotor end surface of the present invention against a comparison test block.

[0022] Figure 5 The ultrasonic echo amplitude characteristic images are collected under the same testing conditions using a 15 MHz point focusing probe for a rotor end face comparison test block made by an existing manufacturing method and a rotor end face comparison test block made by the present invention.

[0023] Figure 6 yes Figure 5Waveform diagram of the φ0.6mm artificial defect in area A.

[0024] Figure 7 yes Figure 5 Waveform diagram of the φ1.2mm artificial defect in the middle B area.

[0025] Figure 8 yes Figure 5 Waveform diagram of the φ2mm artificial defect in the middle B area (the hole was drilled through the steel-copper bonding surface and damaged the copper layer).

[0026] Fig. 9 yes Figure 5 The waveform of the black part in the middle (i.e. the qualified welding interface part).

[0027] The marks in the accompanying drawings are: 1- horizontal hole, 2- copper tube, 3- vertical hole, 4- copper plate. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0029] Embodiment. A method for making a test block for ultrasonic detection of unwelded defects at a diffusion welding interface, including a method for making a rotor plunger hole comparison test block and a method for making a rotor end surface comparison test block;

[0030] The method for making a rotor plunger hole comparison test block comprises the following steps:

[0031] a. Figure 1 As shown, a plurality of transverse holes 1 of different diameters are firstly drilled on the side of a steel substrate (with a plunger hole in the axial direction), and the transverse holes 1 penetrate to the plunger hole or pass through the plunger hole to obtain A grade.

[0032] b. Figure 2 As shown, product A and copper tube 2 are connected into a whole by diffusion welding to obtain a finished product of a rotor plunger hole comparison test block;

[0033] The method for manufacturing a rotor end surface comparison test block comprises the following steps:

[0034] c. Figure 3 As shown, a plurality of vertical holes 3 with different diameters are firstly drilled on the end surface of another steel substrate to obtain a C product.

[0035] d. Figure 4 As shown, product C is connected to a 0.6 mm thick copper plate 4 by diffusion welding to form a whole, and a finished product with the rotor end facing the comparison test block is obtained.

[0036] In step a, there are five types of transverse holes 1, and the diameters of the five types of transverse holes 1 are 0.6 mm, 0.8 mm, 1.2 mm, 2 mm and 3.2 mm respectively.

[0037] In step c, there are five types of vertical holes 3 arranged in two rows, each type of vertical holes 3 has two vertical holes, and the diameters of the five types of vertical holes 3 are 0.6 mm, 0.8 mm, 1.2 mm, 2 mm and 3.2 mm respectively.

[0038] Comparative test. The rotor end face comparison test block made by the existing production method and the rotor end face comparison test block made by the present invention were subjected to ultrasonic feature scanning imaging test under the same test conditions using a 15MHz point focusing probe. The test results are as follows: Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, area B corresponds to the artificial defect image of the rotor end surface produced by the existing production method, and area A corresponds to the artificial defect image of the rotor end surface comparison block produced by the present invention. The number and size of the artificial defects in areas A and B are the same, with 2 artificial defects of diameters of 0.6 mm, 0.8 mm, 1.2 mm, 2 mm, and 3.2 mm respectively. Figure 5 In the figure, four colors are used to represent different amplitude ranges, the blue amplitude is 40-55 (normalized amplitude, the same below); the green amplitude is 55-70; the yellow amplitude is 70-85; the red amplitude is greater than 85. It can be seen that only three artificial defects with diameters of 1.2mm, 2mm and 3.2mm can be detected in area B, and artificial defects with diameters of 0.6mm and 0.8mm cannot be detected. Moreover, the displayed sizes of the three artificial defects detected are not proportional to the actual sizes of the artificial defects. The minimum diameter of the detectable artificial defect is 1.2mm, and its echo height is only 53, and there is only one defect reflection wave. In area A, all artificial defects (5 in each row, 10 in total for two rows) can be detected, and the diameters of artificial defects in each row are 0.6mm, 0.8mm, 1.2mm, 2mm, and 3.2mm, respectively, and the display of each artificial defect is proportional to the actual size of the artificial defect. The relative position, relative size, echo amplitude, and phase characteristics of the defect wave of each artificial defect can be clearly seen in the figure. Artificial defects with a minimum diameter of 0.6mm can be detected, and their echo height is 77. The phase characteristics of the secondary defect reflection wave can also be clearly seen. The following conclusions can be drawn from the above comparison: the test block produced by the present invention of drilling first and then welding is significantly higher than the test block obtained by the existing method (welding first and then drilling) in terms of accuracy, repeatability, detection sensitivity, defect authenticity, defect quantification, defect qualitativeness, and defect positioning.

[0039] The test block manufactured by the present invention is used for ultrasonic detection and quality evaluation of rotors and has the advantage of not causing serious misjudgment when evaluating the equivalent size of defects.

Claims

1. A method for manufacturing a test block for ultrasonic detection of unwelded defects at diffusion welding interfaces, characterized in that: It includes a method for making a rotor plunger hole comparison test block and a method for making a rotor end surface comparison test block; The method for making a rotor plunger hole comparison test block comprises the following steps: a. First, drill multiple horizontal holes of different diameters on the side of a steel substrate to obtain grade A. b. Use diffusion welding to connect product A and the copper tube into a whole to obtain the finished product of the rotor plunger hole comparison test block; The method for manufacturing a rotor end surface comparison test block comprises the following steps: c. First, drill multiple vertical holes of different diameters on the end face of another steel substrate to obtain product C. d. Use diffusion welding to connect product C and the copper plate into a whole, and obtain a finished product with the rotor end facing the test block; In step a, the diameters of the transverse holes are five, and the diameters of the five transverse holes are 0.6 mm, 0.8 mm, 1.2 mm, 2 mm and 3.2 mm respectively; In step c, there are five types of vertical holes, and the diameters of the five types of vertical holes are 0.6 mm, 0.8 mm, 1.2 mm, 2 mm and 3.2 mm respectively; The transverse hole penetrates to the plunger hole or passes through the plunger hole.

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