CN110579382A - A kind of press knife for pressing the notch of DWTT sample and its application method - Google Patents

Abstract

The invention discloses a press knife for pressing the notch of a DWTT sample, comprising a base (11) and a blade (12) of the press knife (1), the base (11) is a cuboid, and the upper side of the base (11) The edge is provided with chamfering (11b); the bottom surface (11c) of the base body (11) is provided with a groove (11a), and the middle part of the groove (11a) is provided with a protruding blade (12), and the blade (12) It is V-shaped and protrudes from the bottom surface (11c) of the substrate (11). The vertical distance between the knife tip (12a) and the bottom surface (11c) is basically consistent with the depth of the sample notch, and the angle of the knife edge (12) is consistent with the sample notch. angles are basically the same. The invention has the advantages of meeting the requirements of the angle and depth of the notch, ensuring the quality of the notch, improving the quality and test efficiency of the pressing knife, reducing the phenomenon of warping and cracking of the pressing knife, and saving costs.

Description

A kind of press knife for pressing the notch of DWTT sample and its application method

technical field

The invention relates to the technical field of DWTT testing equipment, in particular to a pressing knife for pressing a notch of a DWTT sample and an application method thereof.

Background technique

The drop weight tear test (DWTT) is a test item that characterizes the toughness and brittleness of materials. It is mainly used for the low temperature brittleness test and research of metal materials. Because the results obtained by this test method are consistent with the results of the actual pipeline blasting test, it is widely used. It is used in the toughness evaluation of pipeline steel and is used as one of the quality acceptance indicators of steel pipes.

According to the test standard, the notch of the sample must meet the standard requirements. In order to press out the notch of the sample that meets the requirements, a pressing knife that meets the requirements in shape and strength is required. The quality of the sample notch depends on the surface roughness, precision, hardness and other properties of the press knife. The currently used pressing knives often cause the angle and depth of the notch to fail to meet the requirements due to their own performance defects, and even often tilt. The quality of the notch is guaranteed, and the test efficiency is also reduced.

Contents of the invention

The purpose of the present invention is to solve the problem of low efficiency of the existing press knife test and the inability to guarantee the quality of the notch, and provides a press knife for pressing the notch of the DWTT sample and its use method. The material, roughness, and hardness of the press knife Make adjustments so that the pressed notch can meet the angle and depth requirements, ensure the quality of the notch, and improve the quality of the pressing knife and the test efficiency.

In order to achieve the above object, the present invention adopts the following technical solutions:

A kind of pressing knife for pressing the notch of DWTT sample, comprising the substrate and blade of pressing knife, is characterized in that:

The base body is a cuboid, and the upper side of the base body is provided with a chamfer, and the chamfer is 45°, so that the pressing knife fits better with the testing machine and makes the pressing knife evenly stressed;

The bottom surface of the substrate is provided with a groove, and a protruding blade is provided in the middle of the groove. Basically the same to ensure the depth requirements of the pressing gap;

The angle of the blade is 45°±2°, so as to meet the angle requirement of pressing the notch;

The surface roughness of the blade is Ra0.8, and the material hardness is required to be 58-65HRC, so as to improve the smoothness and wear resistance of the pressing knife.

The press knife is integrally formed.

In order to further realize the object of the present invention, also provide a kind of use method for pressing the use method of the press knife of DWTT sample breach, it is characterized in that comprising the following steps:

a. Manufacture according to the performance size and structure of the press knife provided above to ensure the blade angle, depth, smoothness and hardness requirements;

b. The pressing knife is directly installed on the testing machine that presses the notch of the sample, and fixed with bolts;

c. Place the sample directly under the press knife according to the test requirements, and the placement position should be accurate;

d. Start the testing machine, and the gap is pressed and formed at one time;

e. Take out the pressed notched sample, put it in the designated position, carry out the next round of DWTT test, put in the next sample and continue the test until the test is all over.

Compared with the prior art, the beneficial effects of the present invention are: through the integrally formed pressing knife, it is more convenient to assemble, disassemble and replace, the angle and height of the knife edge ensure the angle and depth of the sample notch, and the smoothness of the knife edge prevents the The phenomenon of knife sticking occurs to ensure the integrity and validity of the sample notch, thereby ensuring the validity and accuracy of the DWTT drop weight tear test. At the same time, this device does not need to change other test equipment, which saves costs.

Description of drawings

Fig. 1 is the front view of a kind of press knife that is used for pressing DWTT sample gap of the present invention;

Fig. 2 is the side view of a kind of pressing knife that is used for pressing DWTT sample gap of the present invention;

Fig. 3 is the bottom view of a kind of press knife that is used for pressing DWTT sample gap of the present invention;

Fig. 4 is an enlarged view of the blade structure of the pressing knife of the present invention.

Detailed ways

Example 1

In order to make the present invention clearer, a kind of pressing knife for pressing the DWTT sample gap and its application method of the present invention will be further described below in conjunction with the accompanying drawings. The specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

Referring to Fig. 1 and Fig. 2, a press knife for pressing the notch of a DWTT sample includes a base body 11 and a blade 12 of the press knife 1, and is characterized in that:

The base 11 is a cuboid, and the upper side of the base 11 is provided with a chamfer 11b, and the angle α of the chamfer 11b is 45°, so that the pressing knife fits better with the testing machine and makes the pressing knife evenly stressed;

Referring to Fig. 1, Fig. 2, Fig. 3, the bottom surface 11c of the substrate 11 is provided with a groove 11a, and the middle part of the groove 11a is provided with a protruding blade 12, and the blade 12 is set as a V shape, and the blade 12 protrudes from the substrate 11 The bottom surface 11c of the bottom surface 11c, and the vertical distance between the tip 12 and the bottom surface 11c is basically consistent with the depth of the sample notch, so as to ensure the depth requirement of the pressed notch;

Referring to Fig. 4, the angle β of the blade 12 is 45°, so as to meet the angle requirement of pressing the notch;

The surface roughness of the blade 12 is Ra0.8, and the material hardness is required to be 62HRC, so as to improve the smoothness and wear resistance of the pressing knife.

The pressing knife 1 is integrally formed.

The present invention also provides a kind of method that uses above-mentioned pressing knife to carry out DWTT pressing sample gap, it is characterized in that comprising the following steps:

a. Manufacture according to the performance size and structure of the press knife provided above to ensure the blade angle, depth, smoothness and hardness requirements;

b. The pressing knife is directly installed on the testing machine that presses the notch of the sample, and fixed with bolts;

c. Place the sample directly under the press knife according to the test requirements, and the placement position should be accurate;

d. Start the testing machine, and the gap is pressed and formed at one time;

e. Take out the pressed notched sample, put it in the designated position, carry out the next round of DWTT test, put in the next sample and continue the test until the test is all over.

In the present invention, the total length of the pressing knife 1 is 60mm, the width is 29.5±0.2mm, the thickness of the base 11 is 20mm, the height of the blade 12 is 5.1±0.5mm, the notch angle of the pressed sample is 45°, and the depth is 5mm. The formed pressing knife is more convenient for loading, unloading and replacement. The angle and height of the knife edge ensure the angle and depth of the sample notch. The smoothness of the knife edge prevents sticking of the knife during the notch pressing process, ensuring the integrity and effectiveness of the sample notch. , so as to ensure the effectiveness and accuracy of the DWTT drop weight tear test, and at the same time, this device does not need to change other test equipment, saving costs.

In addition to the above-mentioned embodiments, the present invention can also have other implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims (7)

1. A pressing knife for pressing DWTT sample notches comprises a base body (11) and a knife edge (12) of the pressing knife (1), and is characterized in that:

the base body (11) is a cuboid, and the side edge of the upper part of the base body (11) is provided with a chamfer (11 b);

The bottom surface (11 c) of the base body (11) is provided with a groove (11 a), the middle part of the groove (11 a) is provided with a convex blade (12), the blade (12) is V-shaped and extends out of the bottom surface (11 c) of the base body (11), the vertical distance between the blade tip (12 a) and the bottom surface (11 c) is basically consistent with the depth of a sample gap, and the angle of the blade (12) is basically consistent with the angle of the sample gap.

2. a pressing knife for pressing DWTT specimen notches according to claim 1, characterized in that:

the angle of the cutting edge (12) is 45 degrees +/-2 degrees.

3. A pressing knife for pressing DWTT specimen notches according to claim 1, characterized in that: the surface roughness Ra0.8 of the blade (12).

4. The pressing knife for pressing DWTT test piece notches according to claim 1 is characterized in that the hardness requirement of the material of the cutting edge (12) is 58 ~ 65 HRC.

5. A pressing knife for pressing DWTT specimen notches according to claim 1, characterized in that: the pressing knife (1) is integrally formed.

6. a pressing blade for pressing DWTT specimen notches according to claim 1 ~ 5, characterized in that the chamfer (11 b) is 45 °.

7. a method of using a spatula for pressing DWTT specimen notches as recited in any one of claims 1 ~ 5, comprising the steps of:

a. The pressing cutter is manufactured according to the performance size and the structure of the pressing cutter, so that the requirements on the angle, the depth, the finish and the hardness of the cutting edge are met;

b. the pressing cutter is directly arranged on a testing machine for pressing a sample notch and is fixed by a bolt;

c. Placing the sample under the pressing knife according to the test requirements, wherein the placing position is accurate;

d. starting the testing machine, and performing one-step compression molding on the notch;

e. and taking out the pressed notch sample, placing the notch sample to a specified position, carrying out the next DWTT test, and placing the next sample for continuing the test until the test is completely finished.