Processing method for fracture toughness compact tension specimen

Abstract

The present invention discloses a processing method for a fracture toughness compact tension specimen. The specimen is a compact tension specimen (CTS), and the implementation steps are as follows: S1. Blanking: Prepare the blank of the specimen and mark the position of the notch surface of the specimen; S2. Rough machining: Milling the blank on the basis of leaving a margin on one side of the machining surface, and machining the side surfaces connected to the machining surface to the standard size requirements of the compact tension specimen (CTS); S3. Finish machining: Grinding the machining surface of the specimen to machine the thickness of the specimen to the standard size requirements of the compact tension specimen (CTS); then, determine the drilling position according to the standard of the compact tension specimen (CTS), and drill the specimen through a milling machine; S4. Heat treatment: Perform heat treatment on the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent processing; S5. Notch machining: Determine the cutting position of the notch according to the standard of the compact tension specimen (CTS), and machine the heat-treated specimen by wire cutting to finally obtain a standard specimen that meets the requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material processing, and relates to a processing method for a fracture toughness compact tension specimen. Background Art

[0002] Fracture toughness refers to the ability of a material to prevent the propagation of macroscopic cracks, and is a quantitative index for measuring the toughness of a material. A compact tension specimen (CTS) is one of the specimen types for measuring fracture toughness, and is also recommended by the test method. When measuring the fracture toughness of a metal material with a compact tension specimen, the size and precision of the specimen have a quite significant influence on the test results. Only after the parameters such as the thickness, width, and hole spacing of the specimen meet the requirements of the standard specimen can the fracture toughness test be carried out. Therefore, ensuring the size and precision of the specimen is crucial for obtaining normal test results.

[0003] In the prior art, the method of manufacturing a CTS by mechanical cutting has problems such as an overly complex processing technology, low precision of the processed surface of the specimen, and difficulty in ensuring the dimensional precision of the specimen. Therefore, how to improve the processing precision of the CTS and reduce the process complexity has become the main problem to be solved in the current field of CTS manufacturing. Summary of the Invention

[0004] The purpose of the present invention is to provide a processing method for a fracture toughness compact tension specimen, which solves the problem of low dimensional precision of the specimen caused by the complex processing technology in the prior art.

[0005] The technical solution adopted by the present invention is a processing method for a fracture toughness compact tension specimen. The specimen is a compact tension specimen (CTS), and is implemented according to the following steps:

[0006] S1. Blanking: Prepare the blank of the specimen and mark the position of the notch surface of the specimen.

[0007] S2. Rough machining: Milling the blank on the basis of leaving a margin on one side of the processed surface, and processing the processed surface and its connected side surfaces to the standard size requirements of a compact tension specimen (CTS).

[0008] S3. Finish machining: Grinding the processed surface of the specimen to process the thickness of the specimen to the standard size requirements of a compact tension specimen (CTS); then, determine the drilling position according to the standard of a compact tension specimen (CTS), and drill the specimen through a milling machine.

[0009] S4. Heat treatment: Perform heat treatment on the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent processing.

[0010] S5. Notch processing: According to the standard of compact tensile specimen (CTS), determine the cutting position of the notch, and use wire cutting to process the heat-treated specimen to finally obtain a standard specimen that meets the requirements.

[0011] The present invention is also characterized in that:

[0012] In S1, the blank of the sample is produced by sawing or wire cutting.

[0013] When cutting by sawing, the sample size is B + +2 5 mm*1.25W + +2 5 mm*1.25W + +2 5 mm, the allowance on the processed surface should be no less than 2mm when cutting.

[0014] When cutting by wire cutting, the sample size is B + +1 2 mm*1.25W + +1 2 mm*1.25W + +1 2 mm, the allowance on the processed surface should be no less than 1mm when cutting.

[0015] During S2 rough machining, leave a margin of 0.25mm to 0.5mm on one side of the machined surface.

[0016] When processing the S5 notch, the specimen is fixed and clamped by a fixture that is suitable for the specimen.

[0017] The clamp includes a first fixing plate, a second fixing plate, a third fixing plate, and a fourth fixing plate which are vertically and fixedly connected in sequence. The first fixing plate and the fourth fixing plate are not connected and both have threaded holes on them, and the threaded holes are equipped with positioning screws; the end faces of the first fixing plate, the second fixing plate, the third fixing plate, and the fourth fixing plate are provided with inward positioning ridges.

[0018] Avoidance holes are provided at the connections between the first fixing plate and the second fixing plate, the second fixing plate and the third fixing plate, and the fourth fixing plate and the first fixing plate. The avoidance holes are provided along the height direction of the fixing plates.

[0019] The first fixing plate and the fourth fixing plate are provided with more than two threaded holes along the height direction thereof, and the threaded holes are evenly spaced.

[0020] The technical solution of the present invention has achieved the following beneficial technical effects:

[0021] 1. By controlling the processes of blanking, rough machining, finish machining, and notch machining, it is ensured that during the machining process of batch samples, time waste is reduced, work efficiency is improved, and at the same time, errors can be reduced and the yield rate is increased.

[0022] 2. By means of rough machining and finish machining, the control of machining dimensions and grinding accuracy is realized, ensuring the shape dimensions and roughness requirements of the compact tension specimens for fracture toughness.

[0023] 3. During the notch machining process, through the positioning of the notch machining fixture, multiple specimens can be machined simultaneously, improving the machining efficiency and ensuring the machining accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic flow chart of the machining method for compact tension specimens for fracture toughness of the present invention;

[0025] Figure 2 is a schematic structural diagram of the fixture used in the notch machining of the machining method for compact tension specimens for fracture toughness of the present invention;

[0026] Figure 3 is a schematic diagram of a compact tension specimen (CTS).

[0027] In the figure, 1, the first fixing plate; 2, the second fixing plate; 3, the third fixing plate; 4, the fourth fixing plate; 5, threaded holes; 6, positioning screws; 7, clearance holes; 8, positioning ribs. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0029] As Figure 1 shown, for the machining method of compact tension specimens for fracture toughness of the present invention, blanking is carried out by wire cutting. After making the blank of the specimen, rough machining, finish machining, heat treatment, and notch machining are carried out. During the rough machining process, the side surface of the specimen connection surface is machined to the standard dimension requirements by milling. During the finish machining process, the thickness of the machining surface of the specimen is machined to the standard dimension requirements by a grinding machine, and then drilling is carried out by a milling machine. Finally, notch machining is carried out by wire cutting to produce CTS specimens that meet the standard requirements.

[0030] Specifically, it includes the following steps:

[0031] S1. Blanking: Select appropriate blanking methods according to different materials and shapes, such as sawing or wire cutting, to ensure that the depth of the surface where the material is not distorted or the product is not affected is greater than the amount removed by the final processing. During blanking, avoid deformation of the test sample or the generation of a surface effect layer that affects the final dimensions. Then, prepare the blank of the test sample and mark the position of the notch surface of the test sample.

[0032] S2. Rough machining: Milling the blank, leaving a margin of 0.25 mm to 0.5 mm on each side of the machined surface, and machining the side surfaces connected to the machined surface to the standard size requirements of the CTS test sample.

[0033] S3. Finish machining: Grinding the machined surface of the test sample to machine the thickness of the test sample to the standard size requirements of the CTS test sample. After that, determine the drilling position according to the CTS standard and drill the test sample through a milling machine.

[0034] S4. Heat treatment: Perform heat treatment on the drilled test sample to eliminate the internal stress of the test sample and facilitate subsequent processing.

[0035] S5. Notch machining: Determine the cutting position of the notch according to the CTS standard, and machine the heat-treated test sample by wire cutting to finally obtain a standard test sample that meets the requirements.

[0036] During the S5 notch machining process, a fixture adapted to the test sample is used to fix the test sample to prevent the test sample from shifting or deflecting during the machining process.

[0037] As Figure 2 shown, the fixture includes a first fixing plate 1, a second fixing plate 2, a third fixing plate 3, and a fourth fixing plate 4 that are vertically and fixedly connected in sequence. The first fixing plate 1 and the fourth fixing plate 4 are not connected and are both provided with threaded holes 5, and positioning screws 6 are arranged on the threaded holes 5; positioning ribs 8 are arranged inwardly on the end faces of the first fixing plate 1, the second fixing plate 2, the third fixing plate 3, and the fourth fixing plate 4.

[0038] Among them, clearance holes 7 are provided at the joints of the first fixing plate 1 and the second fixing plate 2, the second fixing plate 2 and the third fixing plate 3, and the fourth fixing plate 4 and the first fixing plate 1. The opening direction of the clearance holes 7 is along the height direction of the fixing plate. The clearance holes 7 can ensure that the test sample fits with the fixing plate, so as to better perform positioning and fixing.

[0039] Two or more threaded holes 5 are provided on the first fixing plate 1 and the fourth fixing plate 4 along their height directions, and the threaded holes 5 are evenly arranged at equal intervals for clamping and fixing the test sample.

[0040] This fixture processes at least five specimens each time. After the fixture is positioned, the specimens can be directly placed in it, and the positioning plate is used to position the specimens in the length and width directions. The positioning rib 8 can position the bottom surface of the specimen, thereby improving the clamping speed and positioning accuracy of the specimens, reducing the waste of time in batch specimen processing, improving work efficiency, and at the same time reducing errors and increasing the yield rate. By installing positioning screws 6 on the side of the fixed plate, the workpiece can be locked, thus avoiding loosening during processing and being applicable to the processing of specimens of different sizes within a certain range.

[0041] To further illustrate the technical solution of the present invention, the following specific embodiments are provided. Among them, Embodiments 1-3 are specimens made of titanium alloy, and Embodiments 4-6 are specimens made of superalloy.

[0042] Embodiment 1

[0043] This embodiment is a processing method for a fracture toughness compact tension specimen of titanium alloy. The processing dimensions and requirements of the specimen are as shown in Figure 3 shown.

[0044] S1. Blanking: Cut the material according to the drawing and the sampling application location (or according to the marking). The sawing method is used for blanking, and a 2-mm allowance is left on the processing surface. The dimensions are B + +2 5 mm * 1.25W + +2 5 mm * 1.25W + +2 5 mm. Ensure that the depth of the surface where the material is not distorted or the product is not affected is greater than the removal amount of the final processing. In addition, avoid deformation of the test piece or the generation of a surface effect layer that affects the final dimensions.

[0045] S2. Rough machining: The rough machining method is milling. Mill the surface of the specimen; mill the outer shape surface, leaving a 0.25-mm allowance on the processing surface unilaterally, and machine the side surface to the dimensional requirements.

[0046] S3. Finish machining: The finish machining methods are grinding on a grinding machine and drilling on a milling machine. The specimen is finish-machined to meet the requirements of the attached Figure 2 drawing. Grind the upper and lower surfaces of the specimen in the thickness direction on a grinding machine to the final dimensions specified in the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on a milling machine.

[0047] S4. Heat treatment: Heat-treat the specimen after drilling to eliminate the internal stress of the specimen and facilitate subsequent processing.

[0048] S5. Notch machining: Place the specimen in the fixture and fix the fixture to the specimen with the positioning screws. Then, after positioning the fixture, determine the cutting position of the notch according to the CTS standard and perform notch machining by wire cutting to finally obtain a standard specimen that meets the requirements of the fracture toughness compact tension test.

[0049] Example 2

[0050] This example is a processing method for a fracture toughness compact tension specimen of a titanium alloy. The processing dimensions and requirements of the specimen are shown as follows Figure 3 as follows.

[0051] S1. Blanking: Cut the material according to the drawing and the sampling application location (or according to the scribed line). The blanking method is sawing, leaving a machining allowance of 2.8 mm on the machining surface, with dimensions of B + +2 5 mm * 1.25W + +2 5 mm * 1.25W + +2 5 mm. Ensure that the surface depth of the material without distortion or the product without being affected is greater than the removal amount of the final machining. In addition, avoid deformation of the test material or the generation of a surface effect layer that affects the final dimensions.

[0052] S2. Rough machining: The rough machining method is milling. Mill the surface of the specimen; mill the outer shape surface, leaving a unilateral machining allowance of 0.4 mm on the machining surface, and machine the side surface to the dimensional requirements.

[0053] S3. Finish machining: The methods are grinding on a grinding machine and drilling on a milling machine. Finish machine the specimen to meet the requirements of the attached Figure 2 drawing. Grind the upper and lower surfaces of the specimen in the thickness direction on a grinding machine to the final dimensions specified in the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on a milling machine.

[0054] S4. Heat treatment: Perform heat treatment on the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent machining.

[0055] S5. Notch machining: Place the specimen in the fixture and fix the fixture to the specimen with the positioning screws. Then, after positioning the fixture, determine the cutting position of the notch according to the CTS standard and perform notch machining by wire cutting to finally obtain a standard specimen that meets the requirements of the fracture toughness compact tension test.

[0056] Example 3

[0057] This example is a processing method for a fracture toughness compact tension specimen of a titanium alloy. The processing dimensions and requirements of the specimen are shown as follows Figure 3 as follows.

[0058] S1. Blanking: Blank the material according to the parts shown on the drawing and the sampling application (or according to the marking). The blanking method is wire cutting, and the size of the cut specimen is When blanking, the machining allowance on the machined surface is 1 mm. It is ensured that the depth of the surface where the material is not distorted or the product is not affected is greater than the removal amount of the final machining. In addition, the test piece should be prevented from being deformed or a surface effect layer that affects the final dimensions should not be generated.

[0059] S2. Rough machining: The rough machining method is milling. Mill the surface of the specimen; mill the outer shape surface, leaving a unilateral allowance of 0.5 mm on the machined surface, and machine the side surface to the dimensional requirements.

[0060] S3. Finish machining: The methods are grinding on a grinding machine and drilling on a milling machine. Finish machine the specimen to meet the requirements of the attached Figure 2 drawing. Grind the upper and lower surfaces of the specimen in the thickness direction on the grinding machine to the final dimensions specified on the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on the milling machine.

[0061] S4. Heat treatment: Heat-treat the specimen after drilling to eliminate the internal stress of the specimen and facilitate subsequent machining.

[0062] S5. Notch machining: Place the specimen in the fixture and fix the fixture and the specimen with the positioning screws; then, after positioning the fixture, determine the cutting position of the notch according to the CTS standard and perform notch machining by wire cutting to finally obtain a standard specimen that meets the requirements of the fracture toughness compact tension test.

[0063] Example 4

[0064] This example is a processing method for a fracture toughness compact tension specimen of a superalloy. The processing dimensions and requirements of the specimen are as shown Figure 3 below.

[0065] S1. Blanking: Blank the material according to the parts shown on the drawing and the sampling application (or according to the marking). The blanking method is sawing, leaving a machining allowance of 2 mm on the machined surface, and the dimensions are B + +2 5 mm * 1.25W + +2 5 mm * 1.25W + +2 5 mm. It is ensured that the depth of the surface where the material is not distorted or the product is not affected is greater than the removal amount of the final machining. In addition, the test piece should be prevented from being deformed or a surface effect layer that affects the final dimensions should not be generated.

[0066] S2. Rough machining: The rough machining method is milling. Mill the surface of the specimen; mill the outer shape surface, leaving a unilateral allowance of 0.25 mm on the machined surface, and machine the side surface to the dimensional requirements.

[0067] S3. Finish machining: The methods are grinding on a grinding machine and drilling on a milling machine. The specimen is finish-machined to meet the requirements of the attached Figure 2 drawing. Grind the upper and lower surfaces of the specimen in the thickness direction on the grinding machine to the final dimensions specified in the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on the milling machine.

[0068] S4. Heat treatment: Heat-treat the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent processing.

[0069] S5. Notch machining: Place the specimen in the fixture and fix the fixture to the specimen through the positioning screws; then, after positioning the fixture, determine the cutting position of the notch according to the CTS standard and perform notch machining by wire cutting to finally obtain a standard specimen that meets the requirements of the fracture toughness compact tension test.

[0070] Example 5

[0071] This example is a processing method for a fracture toughness compact tension specimen of a superalloy. The processing dimensions and requirements of the specimen are as shown Figure 3 as follows.

[0072] S1. Blanking: Cut the material according to the drawing and the sampling application location (or according to the scribed line). The blanking method is sawing. Leave a machining allowance of 2.8 mm on the machined surface, and the dimensions are B + +2 5 mm * 1.25W + +2 5 mm * 1.25W + +2 5 mm. Ensure that the surface depth where the material is not distorted or the product is not affected is greater than the removal amount of the final machining. In addition, avoid deformation of the test material or the generation of a surface effect layer that affects the final dimensions.

[0073] S2. Rough machining: The rough machining method is milling. Mill the surface of the specimen; mill the outer profile surface, leaving a machining allowance of 0.4 mm on each side of the machined surface, and machine the side surfaces to the dimensional requirements.

[0074] S3. Finish machining: The methods are grinding on a grinding machine and drilling on a milling machine. The specimen is finish-machined to meet the requirements of the attached Figure 2 drawing. Grind the upper and lower surfaces of the specimen in the thickness direction on the grinding machine to the final dimensions specified in the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on the milling machine.

[0075] S4. Heat treatment: Heat-treat the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent processing.

[0076] S5. Notch machining: Place the specimen in the fixture and fix the fixture to the specimen through the positioning screws. Then, after positioning the fixture, determine the cutting position of the notch according to the CTS standard and perform notch machining by wire cutting to finally obtain a standard specimen that meets the requirements of the fracture toughness compact tension test.

[0077] Example 6

[0078] This example is a processing method for a fracture toughness compact tension specimen of a superalloy. The processing dimensions and requirements of the specimen are shown as follows. Figure 3 as shown.

[0079] S1. Blanking: Cut the material according to the drawing and the sampling application location (or according to the marking). The blanking method uses wire cutting, and the cut specimen size is B + +1 2 mm * 1.25W + +1 2 mm * 1.25W + +1 2 mm, and the allowance for the machining surface during blanking is 1 mm. Ensure that the depth of the surface where the material is not distorted or the product is not affected is greater than the removal amount of the final machining. In addition, avoid deformation of the test material or the generation of a surface effect layer that affects the final dimensions.

[0080] S2. Rough machining: The rough machining method is milling. Mill the surface of the specimen; mill the outer profile surface, leaving a 0.5 mm allowance on each side of the machining surface, and machine the side surface to the required dimensions.

[0081] S3. Finish machining: The methods are grinding on a grinding machine and drilling on a milling machine. Finish machine the specimen to meet the requirements of the attached drawing. Grind the upper and lower surfaces of the specimen in the thickness direction to the final dimensions specified in the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on the milling machine. Figure 2 The upper and lower surfaces of the specimen in the thickness direction are ground to the final dimensions specified in the drawing; determine the drilling positions on the specimen according to the drawing requirements and drill holes on the milling machine.

[0082] S4. Heat treatment: Perform heat treatment on the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent processing.

[0083] S5. Notch machining: Place the specimen in the fixture and fix the fixture to the specimen through the positioning screws. Then, after positioning the fixture, determine the cutting position of the notch according to the CTS standard and perform notch machining by wire cutting to finally obtain a standard specimen that meets the requirements of the fracture toughness compact tension test.

[0084] The processing method provided by the present invention can not only reduce the processing difficulty of the CTS specimen, improve the processing efficiency, but also ensure the dimensional accuracy of the specimen and improve the accuracy of the test results. At the same time, using a fixture adapted to the specimen to clamp and fix the specimen can effectively prevent the displacement or deflection of the specimen and ensure the normal progress of the test.

Claims

1. A processing method for a fracture toughness compact tension specimen, characterized in that, The specimen is a compact tension specimen (CTS), and the implementation steps are as follows: S1. Blanking: Prepare the blank of the specimen and mark the position of the notch surface of the specimen; S2. Rough machining: Milling the blank on the basis of leaving a margin on one side of the machining surface, and machining the machining surface and its connected side surfaces to the standard size requirements of the compact tension specimen (CTS); S3. Finish machining: Grinding the machining surface of the specimen to machine the thickness of the specimen to the standard size requirements of the compact tension specimen (CTS); then, determine the drilling position according to the standard of the compact tension specimen (CTS), and drill the specimen through a milling machine; S4. Heat treatment: Perform heat treatment on the drilled specimen to eliminate the internal stress of the specimen and facilitate subsequent machining; S5. Notch machining: Determine the cutting position of the notch according to the standard of the compact tension specimen (CTS), and machine the heat-treated specimen by wire cutting to finally obtain a standard specimen that meets the requirements; In S1, the blank of the specimen is prepared by a machining method of sawing or wire cutting; When blanking by sawing, the size of the cut specimen is , and the allowance left on the machined surface during blanking is not less than 2 mm; When blanking by wire cutting, the size of the cut specimen is , and the allowance left on the machined surface during blanking is not less than 1 mm; When performing rough machining in S2, leave a margin of 0.25 mm to 0.5 mm on one side of the machining surface.

2. The processing method for a fracture toughness compact tension specimen according to claim 1, characterized in that, When performing notch machining in S5, fix and clamp the specimen through a fixture adapted to the specimen.

3. The processing method for a fracture toughness compact tension specimen according to claim 2, characterized in that, The fixture includes a first fixing plate (1), a second fixing plate (2), a third fixing plate (3), and a fourth fixing plate (4) that are vertically and fixedly connected in sequence. The first fixing plate (1) and the fourth fixing plate (4) are not connected and are both provided with threaded holes (5), and positioning screws (6) are arranged on the threaded holes (5); positioning ridges (8) facing inward are provided on the end faces of the first fixing plate (1), the second fixing plate (2), the third fixing plate (3), and the fourth fixing plate (4).

4. The processing method for a fracture toughness compact tension specimen according to claim 3, characterized in that, Avoidance holes (7) are provided at the joints of the first fixing plate (1) and the second fixing plate (2), the second fixing plate (2) and the third fixing plate (3), and the fourth fixing plate (4) and the first fixing plate (1), and the opening direction of the avoidance holes (7) is along the height direction of the fixing plate.

5. The processing method for a fracture toughness compact tension specimen according to claim 3, characterized in that, Two or more threaded holes (5) are provided on the first fixing plate (1) and the fourth fixing plate (4) along their height directions, and the threaded holes (5) are evenly arranged at equal intervals.

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