Method and device for preparing high-hardness impact toughness sample notch

Abstract

The invention provides a method and a device for preparing a notch of a high-hardness impact toughness sample. The preparation method of the high-hardness impact toughness sample notch comprises the steps of sampling, grinding, opening and accurate grinding. The high-hardness impact toughness sample notch preparation device comprises a two-dimensional moving mechanism for controlling a sample to move in a plane and a lifting mechanism for controlling a grinding head to move. According to the preparation method and device for the high-hardness impact toughness sample notch, the defects that an existing preparation method for the sample notch is low in efficiency and high in cost are overcome.

Description

Technical Field

[0001] The invention relates to the field of metal material impact toughness test specimens, and in particular to a method and a device for preparing a notch of a high-hardness impact toughness test specimen. Background Art

[0002] According to the GB / T 229-2020 "Metallic Materials Charpy Pendulum Impact Test Method" standard, U-shaped impact specimens need to have specific shapes and sizes. For metal material impact toughness specimens with a surface hardness of more than 47HRC and a U-shaped notch depth of 5mm, the existing specimen processing technology has defects such as low cutting efficiency and high specimen preparation cost.

[0003] The existing application number is "202210196730.8", the applicant is "AVIC Metal Material Physical and Chemical Testing Technology Co., Ltd.", and the name is "Processing method of U-shaped notch of specimen for Charpy impact test", and the application number is "201810627095.8", the applicant is "AVIC Aircraft Landing Gear Co., Ltd.", and the name is "A U-shaped notch processing system for impact specimens". The notch processing method adopts an ordinary surface grinder, and a special tooling is made for processing, which has the defect of low processing efficiency. The notch processing method does not specify the applicability of high-hardness metal material specimens, the special tooling is easy to wear, and there is a defect of high preparation cost.

[0004] In addition, there is also a solution to use wire cutting technology to achieve notch processing. However, in order to ensure the geometric dimensions and ensure that the roughness of the notch surface is controlled within the range, only slow wire cutting can be used to process the U-shaped notch. The processing efficiency is low and the sample preparation cost is high. Summary of the invention

[0005] In order to solve the defects of low efficiency and high cost in the existing sample notch preparation method, the present invention provides a method and device for preparing a high hardness impact toughness sample notch to solve the above problems.

[0006] A method for preparing a notch of a high-hardness impact toughness specimen comprises the following steps: Step 1, taking out a sample without a notch from a metal sample; Step 2, grinding the surface of the sample; Step 3, performing wire cutting notch processing on the sample; Step 4: fine grinding the notched surface.

[0007] In a preferred embodiment of the method for preparing a notched high hardness impact toughness specimen provided by the present invention, after step 2, the specimen has a length of 55 mm, a width of 10 mm, a thickness of 10 mm, an angle of 90° between adjacent longitudinal faces of the specimen, and a surface roughness of less than 5 μm.

[0008] After step 3, the width of the sample ligament is 5 mm, the root radius of the sample notch is 1 mm, and the distance from the symmetric surface of the sample notch to the end is 27.5 mm.

[0009] After step 4, the surface roughness of the notch is less than 1.6 μm.

[0010] In a preferred embodiment of the method for preparing a notch of a high-hardness impact toughness specimen provided by the present invention, the specimen length processing deviation is ±0.60mm, the width processing deviation is ±0.11mm, the thickness processing deviation is ±0.11mm, the angle processing deviation between adjacent longitudinal surfaces of the specimen is ±1°, the ligament width processing deviation of the specimen is ±0.09mm, the notch root radius processing deviation is ±0.07mm, and the notch symmetry plane to end distance processing deviation is ±0.42mm.

[0011] In a preferred embodiment of the method for preparing a notch of a high-hardness impact toughness specimen provided by the present invention, high-speed wire cutting is used in step 3.

[0012] In a preferred embodiment of the method for preparing a notch of a high-hardness impact toughness specimen provided by the present invention, a disc-shaped rotating grinding head is used in step 4. The edge size of the grinding head is consistent with the size of the notch.

[0013] A notch preparation device for a high-hardness impact toughness specimen comprises a longitudinal adjustment mechanism, a transverse adjustment structure, an up-and-down adjustment mechanism and a grinding mechanism, wherein the longitudinal adjustment mechanism and the up-and-down adjustment mechanism are arranged on the same platform, and the movable ends of the longitudinal adjustment mechanism and the up-and-down adjustment mechanism are respectively provided with the transverse adjustment structure and the grinding mechanism, and the movable end of the transverse adjustment mechanism is provided with a chuck, which clamps one or more notched specimens.

[0014] In a preferred embodiment of the high hardness impact toughness specimen notch preparation device provided by the present invention, a disc-shaped rotating grinding head is provided at the output end of the grinding mechanism, and the plane where the grinding head is located is a vertical plane and is parallel to the longitudinal adjustment mechanism.

[0015] Compared with the prior art, the high-hardness impact toughness specimen notch preparation method and device provided by the present invention optimize the preparation process of high-hardness U-notch impact toughness specimens, quickly form them through high-speed wire cutting, and use a fine grinder to polish the notch surface to ensure the preparation quality of the specimens, thereby achieving high-quality and rapid preparation of high-hardness impact toughness specimens, improving processing efficiency, reducing processing costs, avoiding the influence of specimen preparation quality on test results, and improving the one-time success rate of impact toughness tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the specimen; Figure 2 It is a front view of a notch preparation device for a high hardness impact toughness specimen; Figure 3 It is a side view of the notch preparation device for high hardness impact toughness specimens.

[0017] Numbers in the figure: length L, width W, thickness B, ligament width 2, root radius 3, distance from symmetry plane to end 4, angle between adjacent longitudinal planes 5, specimen 15, longitudinal adjustment mechanism 11, longitudinal handwheel 111, transverse adjustment structure 12, transverse handwheel 121, up and down adjustment mechanism 13, up and down knobs 131, grinding mechanism 14, grinding head 141. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] See also Figure 1 , is a schematic diagram of the sample structure, including Figure 1 -a and Figure 1 -b, respectively refer to the main view and cross-sectional view of the specimen.

[0020] A method for preparing a notch of a high-hardness impact toughness specimen, comprising: Step 1: Take out a sample without a notch from the metal sample.

[0021] Step 2: Grind the sample surface to achieve a specific shape and size. Specifically, the sample length L is required to be 55 mm, the width W is 10 mm, the thickness B is 10 mm, the angle 5 between adjacent longitudinal surfaces of the sample is 90°, and the surface roughness of the sample is less than 5 μm.

[0022] The processing deviation of length L is ±0.60mm, the processing deviation of width W is ±0.11mm, the processing deviation of thickness B is ±0.11mm, and the processing deviation of angle 5 between adjacent longitudinal surfaces of the specimen is ±1°.

[0023] Step 3, perform wire cutting notch processing on the sample. Specifically, a fast wire cutting process is used to cut an arch-shaped notch from the midpoint of the wide surface of the sample. Specifically, the width from the root of the notch to the other side of the sample after cutting, that is, the ligament width 2 is 5mm, the notch root radius 3 is 1mm, and the distance 4 from the notch symmetry surface to the end is 27.5mm.

[0024] The processing deviation of the specimen ligament width 2 is ±0.09mm, the processing deviation of the notch root radius 3 is ±0.07mm, and the processing deviation of the distance from the notch symmetry plane to the end 4 is ±0.42mm.

[0025] Step 4: polish the notch position of the sample using a high hardness impact toughness sample notch preparation device so that the notch surface roughness is less than 1.6 μm.

[0026] Please also see Figure 2 and Figure 3 , are respectively the front view and side view of the notch preparation device for high hardness impact toughness specimens provided by the present invention.

[0027] The high hardness impact toughness specimen notch preparation device comprises a longitudinal adjustment mechanism 11 , a transverse adjustment structure 12 , an up and down adjustment mechanism 13 and a grinding mechanism 14 .

[0028] The longitudinal adjustment mechanism 11 and the up-down adjustment mechanism 13 are arranged on the same platform, and the up-down adjustment mechanism 13 is located on the extension line of the longitudinal adjustment mechanism 11 .

[0029] The longitudinal adjustment mechanism 11 includes a slide rail, a hand wheel and a slider. The slider is driven to move left and right along the slide rail by rotating the hand wheel (depending on the Figure 2 The hand wheel is recorded as the longitudinal hand wheel 111. The structure of the up-down adjustment mechanism 13 is similar to the longitudinal adjustment mechanism 11. The slider is driven to move up and down along the slide rail by turning the knob at the top. The knob is recorded as the up-down knob 131.

[0030] The movable ends of the longitudinal adjustment mechanism 11 and the up-and-down adjustment mechanism 13 are provided with a transverse adjustment mechanism 12 and a grinding mechanism 14 respectively.

[0031] The structure of the transverse adjustment mechanism 12 is similar to that of the longitudinal adjustment mechanism 11, but the direction is perpendicular. The handwheel at the end thereof is turned to drive the slider to move forward and backward along the slide rail. The handwheel is denoted as the transverse handwheel 121. The slider of the transverse adjustment mechanism 12 is provided with a notch and a locking nut to form a chuck structure for clamping three specimens 15. The grinding mechanism 14 is set at an angle parallel to the longitudinal adjustment mechanism 11, and a disc-shaped rotating grinding head 141 is provided at one end thereof close to the transverse adjustment mechanism 12, and the edge size of the grinding head 141 is consistent with the size of the notch.

[0032] When in use, place three samples 15 at the chuck of the transverse adjustment mechanism 12, align the notches of the three, and lock them. Use the longitudinal handwheel 111 and the transverse handwheel 121 to adjust the position of the notches of the three samples to be directly below the grinding head 141. Move the grinding head 141 into the notch by the up and down knobs 131. After confirming that the position is accurate, start the grinding mechanism 14 to polish the surface of the notched sample for 2 to 3 minutes. After polishing is completed, reversely operate the up and down knobs 131, the longitudinal handwheel 111 and the transverse handwheel 121, and finally remove the processed sample 15.

[0033] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a notch of a high hardness impact toughness specimen, characterized in that: The following steps are involved: Step 1, taking out a sample without a notch from a metal sample; Step 2, grinding the surface of the sample; Step 3, performing wire cutting notch processing on the sample; Step 4: fine grinding the notched surface.

2. The method for preparing a notch of a high hardness impact toughness specimen according to claim 1, characterized in that: After step 2, the sample has a length of 55 mm, a width of 10 mm, and a thickness of 10 mm. The angle between adjacent longitudinal faces of the sample is 90°, and the surface roughness of the sample is less than 5 μm.

3. The method for preparing a notch of a high hardness impact toughness specimen according to claim 2, characterized in that: After step 3, the width of the sample ligament is 5 mm, the root radius of the sample notch is 1 mm, and the distance from the symmetric surface of the sample notch to the end is 27.5 mm.

4. The method for preparing a notch of a high hardness impact toughness specimen according to claim 3, characterized in that: After step 4, the surface roughness of the notch is less than 1.6 μm.

5. The method for preparing a notch of a high hardness impact toughness specimen according to claim 4, characterized in that: The processing deviation of the specimen length is ±0.60mm, the processing deviation of the width is ±0.11mm, the processing deviation of the thickness is ±0.11mm, the processing deviation of the angle between adjacent longitudinal surfaces of the specimen is ±1°, the processing deviation of the ligament width of the specimen is ±0.09mm, the processing deviation of the notch root radius is ±0.07mm, and the processing deviation of the distance from the notch symmetry plane to the end is ±0.42mm.

6. The method for preparing a notched high hardness impact toughness specimen according to any one of claims 1 to 5, characterized in that: In the step 3, fast wire cutting is used.

7. The method for preparing a notched high hardness impact toughness specimen according to any one of claims 1 to 5, characterized in that: In step 4, a disc-shaped rotating grinding head is used.

8. The method for preparing a notch of a high hardness impact toughness specimen according to claim 7, characterized in that: The edge size of the grinding head is consistent with the size of the notch.

9. A notch preparation device used in the notch preparation method for a high hardness impact toughness specimen according to any one of claims 1 to 8, characterized in that: It includes a longitudinal adjustment mechanism, a transverse adjustment structure, an up-and-down adjustment mechanism and a grinding mechanism. The longitudinal adjustment mechanism and the up-and-down adjustment mechanism are arranged on the same platform. The movable ends of the longitudinal adjustment mechanism and the up-and-down adjustment mechanism are respectively provided with the transverse adjustment structure and the grinding mechanism. The movable end of the transverse adjustment mechanism is provided with a chuck, and the chuck clamps one or more notched samples.

10. The high hardness impact toughness specimen notch preparation device according to claim 9, characterized in that: A disc-shaped rotating grinding head is provided at the output end of the grinding mechanism, and the plane where the grinding head is located is a vertical plane and is parallel to the longitudinal adjustment mechanism.

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