JPH0339715Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a press notching jig, and particularly to a press notching jig suitable for press notching a test piece.

[Prior Art] A DWTT (Drop Weight Tear Test) test piece is a test method often applied to steel materials for gas line pipes. This DWTT is used as an industrial test because there is a good correspondence between the ductile fracture surface ratio of the fracture surface after the test and the brittle crack propagation speed obtained in the actual pipe test. This DWTT test is conducted using API (American Petroleum) as shown in Figure 3A and B.
Conducted using methods recommended by the Institute.
1 is a test piece, 2 is a fulcrum, and 3 is a hammer. A crack is generated and propagated by impact bending, and the ductile fracture surface ratio is measured at a portion where no crack is generated or is not affected by impact.

Fig. 3C shows an enlarged view of the press notch 4, which has a 45 degree angle and a tip radius.
Introduced by press-fitting a 0.025mm sharp knife edge. The present invention is used for processing this press notch.

FIG. 4 is a front view showing a conventional press notching apparatus 10. The press notch processing device 10 is configured using a compression testing machine or a universal testing machine,
The DWTT test piece 12 is placed on the top of the crosshead 11.
The knife edge 14 attached to the lower end of the compression member 13 is press-fitted into the test piece 12 via the column 15, the testing machine frame 16, the load cell 17, and the compression member 13.

[Problems to be Solved by the Invention] However, the conventional press notching apparatus 10 has the following problems.

a After the knife edge 14 is press-fitted into the test piece 12, the knife edge 14 bites into the test piece 12, and it takes a considerable amount of time to remove the knife edge 14, reducing test efficiency.

b. When removing the knife edge 14 that has become wedged, an excessive force is applied to the knife edge 14, damaging the blade portion at the tip of the knife edge 14.

The purpose of the present invention is to prevent the knife edge from digging into the test piece after press-fitting, and to separate the test piece and the knife edge immediately after the press notch processing is completed, thereby improving testing efficiency and extending the life of the knife edge.

[Means for Solving the Problems] The present invention provides a press notch processing jig for introducing a press notch into a test piece under the compressive force of a compression member that moves up and down with respect to the crosshead. The test piece has a knife edge attached thereto, and an elastic member attached to the processing bed to hold the test piece near both longitudinal ends thereof.

[Function] According to the present invention, when the press notch processing of the test piece with the knife edge is completed, the elastic member that has been compressed by the bending of the processing bed and the test piece elastically restores its elastic force. It easily separates from the knife edge attached to the processing bed. That is, the knife edge reliably separates from the test piece after being press-fitted without biting into it, improving test efficiency and extending the life of the knife edge.

[Example] Fig. 1A is a front view schematically showing a press notching device to which the present invention is applied, Fig. 1B is a side view of Fig. 1A, and Fig. 2A is a main view of Fig. 1A. Figure 2B is a plan view of Figure 2A;
FIG. 2C is a side view of FIG. 2A.

The press notch processing apparatus 20 is constructed using a compression testing machine or a universal testing machine, and includes a crosshead 21, a column 22, a testing machine frame 23, a load cell 24, and a compression member 25. 26 is a test piece. The crosshead 21 is the processing bed 2
Equipped with 7.

Thus, a knife edge 28 is attached to the processing bed 27. Further, a pair of elastic members 29 are attached to the processing bed 27 to hold the DWTT test piece 26 near both longitudinal ends thereof.
The height of the elastic member 29 is set to be several mm higher than the height of the knife edge 28, and the heights of both elastic members 29 relative to the processing bed 27 are set to be exactly equal. The material of the elastic member 29 is preferably urethane rubber, for example, in terms of durability and ease of use.

Note that the press notch introduction position with respect to the test piece 26 was kept constant for each test, and the knife edge 28
The direction of the blade and the longitudinal direction of the test piece 26 are arranged perpendicularly when viewed from above, and in order to further increase the test efficiency,
A positioning jig for setting the test piece 26 at a certain position on the elastic member 29 is attached to the processing bed 27.
It is desirable to install it in

Next, the operation of the press notching device 20 will be explained.

The jig constituting the present invention is set in a compression testing machine, and the test piece 26 is set on the elastic member 29 using the appropriate positioning jig. The crosshead 21 is raised to begin compression work. After the upper holding plate 30 contacts the test piece 26, when the crosshead 21 is further raised, both elastic members 29
are uniformly compressed and deformed, the knife edge 28 comes into contact with the test piece 26, and press notching is started. When the crosshead 21 is further raised to continue processing, the test piece 26 and the processing bed 27 come into contact with each other at the end of the press notch processing, and the load detected by the load cell 24 increases. When the load detected by the load cell 24 increases, the crosshead 21 stops rising and starts lowering. As the crosshead 21 descends, the test piece 26 is given an upward force by the elastic force of the compressed elastic member 29, and the knife edge 28 and the test piece 26 are easily separated, allowing safe and reliable press notching. can.

According to the above embodiment, a) the knife edge and the test piece are immediately separated from each other even after the press notch processing, so that the test efficiency can be improved.

b. When removing the knife edge, no excessive force is applied to the knife edge, so the blade portion at the tip of the knife edge is not damaged.

The present invention is applicable not only to press notch processing on DWTT test specimens, but also to other fracture toughness tests such as Shapey impact test specimens, ESSO test specimens, and DT test specimens.
It can also be applied to press notch processing such as (Dynamic Tear) testing.

[Effects of the invention] As described above, the present invention is a press notch processing jig that introduces a press notch into a test piece under the compressive force of a compression member that moves up and down with respect to the crosshead. and an elastic member that is attached to the processing bed and holds the test piece near both longitudinal ends thereof. Therefore, the knife edge does not dig into the test piece after press-fitting, and the test piece and knife edge can be separated immediately after the press notch process is completed, thereby improving testing efficiency and extending the life of the knife edge.

[Brief explanation of drawings]

Fig. 1A is a front view schematically showing a press notch processing device to which the present invention is applied, Fig. 1B is a side view of Fig. 1A, and Fig. 2A is a main part of Fig. 1A. FIG. 2B is a plan view of FIG. 2A,
Figure 2C is a side view of Figure 2A, Figure 3A is a side view of Figure 2A.
A front view showing the DWTT test piece, Figure 3B is a sectional view taken along line B-B of Figure 3A, Figure 3C is Figure 3A
FIG. 4 is a front view showing a conventional press notching device. 20... Press notch processing device, 21... Crosshead, 25... Compression member, 26... Test piece,
27... Processing bed, 28... Knife edge,
29...Elastic member.

Claims (1)

[Scope of utility model registration request] In a press notch processing jig for introducing a press notch into a test piece under the compressive force of a compression member that moves up and down with respect to the crosshead, a knife edge attached to a processing bed on the crosshead;
A jig for press notch processing, comprising: an elastic member that is attached to the processing bed and holds the test piece near both longitudinal ends thereof.