JPS6359098B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a material tensile testing device for testing by installing a plate-shaped test piece between a stationary chuck and a movable chuck.

When tensile testing a plate material such as a steel plate, the relationship between load and elongation from the start of tension to breakage is as follows:
It can be easily determined as a numerical value or a diagram using a conventionally well-known tensile test device.

However, in the case of steel plates, etc., it is necessary to evaluate the deep drawability for press formability, etc., and to evaluate the quality of the material by accurately understanding the state at break, and the parameters used to evaluate the former are r value, n Values are often used.

The r value is called the plastic strain ratio, and is defined as r=εw/εt. Using the condition of constant volume during plastic deformation, r=-εw/εl+εw εw: Volumetric strain εl: Plate Long strain εt: Can be expressed as plate thickness strain, and the r value can be determined from the plate width and gauge length without depending on the plate thickness, which makes it difficult to improve measurement accuracy.

As shown in FIG. 1, it is normal for the plate-shaped test piece A to break approximately at the center, and if it breaks unevenly, it is determined that the material is defective.

Conventional material tensile testing equipment does not have a device to measure the dimensions of the plate-shaped test piece A, which is necessary to calculate various characteristic values such as the r value, so the plate-shaped test piece A is removed during the test. The width was measured using a micrometer, or by manually setting the plate-shaped test piece A between the contacts 11 of the contact width meter 1 as shown in FIG.

Moreover, the appearance of the plate-shaped test piece A at the time of breakage was determined visually by a person.

However, with such conventional material testing equipment, various measurements are extremely complicated, and when a large number of plate-shaped test pieces A have to be processed, testing time and man-hours increase, resulting in poor efficiency.
The problem was that the cost was also high.

The present invention was made by focusing on such conventional problems, and it automatically scans a light beam onto a plate-shaped test piece during a test to measure various dimensions and automatically detect various tensile property values. The purpose is to provide a material testing device that enables

In order to achieve such an objective, the present invention includes an extensometer that measures the elongation of a plate-shaped test piece based on changes in the gauge interval of the plate-shaped test piece, and a test in which a tensile load is applied to the plate-shaped test piece. A device main body is provided, and an entrance mirror and a light receiving mirror are opposed to each other in the direction of the plate surface of the plate-shaped test piece with a plate-shaped test piece in between, and are supported so as to be able to move up and down in a controlled manner;
a scanning unit that makes a light beam incident on the incident mirror and irradiates the plate surface of the plate-shaped test piece with the light beam reflected by the incident mirror, and displaces the plate-shaped test piece in the longitudinal direction while swinging back and forth in the width direction; When the test device main body applies a load to the plate-shaped test piece and the plate-shaped test piece is not broken, the light beam is reflected by the light-receiving mirror after passing through the position of , and is scanned by the scanning unit. In the normal measurement mode, only the width of the plate is detected by the interruption time of the light beam, and when the plate-shaped test piece breaks and it is no longer possible to apply a tensile load, the scanned light beam detects the width of the plate on both sides of the fracture groove. However, by passing through the fracture groove, the width of the plate is detected by adding the width of the fracture groove, and the fracture measurement mode detects the fracture position based on the displacement position of the light beam in the longitudinal direction of the plate-shaped specimen. A material tensile testing device is characterized in that it is equipped with a board width measuring device consisting of a light-receiving section, and the board width measuring device automatically measures the board width, thereby quickly detecting various characteristic values. , the fracture state can also be automatically determined.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

3 to 5 show a material tensile testing apparatus according to an embodiment of the present invention, with some parts omitted.

The test device main body 2 that applies a load to and pulls the plate-shaped test piece A is connected from a main body base 21 that has a built-in drive mechanism and drive control mechanism for applying a load to struts 22, 2.
A fixed chuck 23 is fixedly supported on the upper part of the pillars 22, 22, a driving threaded rod 24 is provided inside each pillar 22, and a movable chuck 25 moves up and down by the rotation of the driving threaded rod 24. The chuck 23 is provided below the fixed chuck 23, and the fixed chuck 23 is provided with a fixed chuck blade 26, and the movable chuck 25 is provided with a movable chuck blade 27.

The board width measuring device support base 3 is arranged so that the support legs 31 straddle the main body base 21 of the testing device main body 2, and the board width measuring device 4 is mounted on the support beam 32 of the board width measuring device support base 3. It is provided.

The board width measuring device 4 is provided adjacent to the movable chuck 25 of its movable base 5, and the movable base 5 is supported via guide cylinders 51, 51 on the support beam 32 of the board width measuring device support base 3 so as to be movable up and down. and a vertical drive cylinder 5 fixed to the support beam 32.
The tip end 54 of the second drive rod 53 is connected to the movable base 5.

A scanning section 6 is fixed to one end of the movable base 5, and a light receiving section 7 is fixed to the other end. extended between 25 and
An entrance mirror 61 is extended at the tip of the scanning unit 6.
A light-receiving mirror 71 extends from the tip of the light-receiving section 7 .

The scanning unit 6 inputs a laser beam L, which is a type of light beam, into an input mirror 61 and
The laser beam L reflected by the plate-shaped test piece A is irradiated onto the plate surface of the plate-shaped test piece A, and the plate-shaped test piece A is moved back and forth in the width direction and displaced in the longitudinal direction. Passing through the position of piece A, the light receiving mirror 7
The laser beam L reflected by the laser beam L is received and analyzed.

The entrance mirror 61 and the light receiving mirror 71 are sandwiched between the fixed chuck blade 26 of the fixed chuck 23 and the movable chuck blade 27 of the movable chuck 25, and face each other with the plate-shaped test piece A to be attached between them. The incident mirror 61 is provided at a predetermined angle at a position where the laser beam L incident from the scanning section 6 is reflected onto the plate surface of the plate-shaped test piece A.
is the position where the laser beam L reflected by the incident mirror 61 reaches after passing through the position of the plate-shaped test piece A,
It is provided at an angle to receive the laser beam L and reflect it to the light receiving section 7.

In addition, the test device main body 2 is equipped with an extensometer 8 for measuring the elongation of the plate-shaped test piece A, and a pair of clamps are placed at the top and bottom of the tip of a reciprocating bar 81 that advances and retreats toward the plate-shaped test piece A. Arms 82, 82 are provided, and grippers 83, 83 are provided at the tip of each clamping arm 82.
is attached, and there are a pair of grippers 8 on the upper and lower sides.
3 and 83 are adapted to grip the upper and lower gauge points, and when the plate-shaped test piece A is replaced, the grippers 83 and 83 are opened and the clamping arm 82 is retracted so as not to get in the way.

As shown in FIG. 6, the plate-shaped test piece A, which is held between the fixed chuck blade 26 and the movable chuck blade 27 at both ends and is installed between the fixed chuck 23 and the movable chuck 25, is subjected to a tensile load. is added to the initial state (a), 10% elongated state (b), 15% elongated state (c),
It is stretched to 20% elongation state (d) and fractured state (e). In this example, in the initial state (a), the width of the gripping ends A1 at both ends is 35 mm, the width of the middle measurement part A2 is 25 mm,
The length is set to approximately 90 mm, and the measurement section is a 50 mm section divided by 25 mm on both sides from the center line A3, which equally divides the length of the measurement section A2, and the extensometer 8 is used at both ends of the measurement section to measure the extension. It is gripped by grippers 83, 83, and together with the grippers 83, 83, it forms gauge points A4, A4 with a widening interval.

As shown in Figure 7, when the plate-shaped test piece A breaks, the break groove A5 is within 1/4 of the measurement section distributed from the center line A3 (12.5 mm on each side, 25 mm in total).
(within), the fracture is determined to be A fracture, which is a normal fracture, and otherwise, it is determined to be a B fracture, which is an abnormal fracture. In addition, the laser beam L of the plate width measuring device 4 is irradiated onto the plate surface of the plate-shaped specimen A and scanned in the width direction as shown by the dashed line, and the laser beam L that has hit the plate surface cannot pass through the plate. The width of the plate-shaped specimen A can be measured by receiving the laser beam L that has passed through both ends of the plate-shaped specimen A by the light receiving section 7. The presence or absence of breakage of the plate-shaped test piece A is determined by the testing device main body 2.
It can be determined from the load condition of board width measuring device 4.
When the plate-shaped test piece A is not broken, the light-receiving unit 7 operates in the normal width measurement mode that detects only the plate width w, and when the plate-shaped test piece A is broken, it operates in the normal width measurement mode that detects the width w of the plate, and when the plate-shaped test piece A is broken, it detects the fracture groove through which the light beam passes. It operates in a fracture measurement mode that detects the sum of the width s and the widths w1 and w2 appearing on both sides of the fracture groove width s that does not allow light to pass through.

Next, the effect will be explained.

First, a plate-shaped test piece A is set. The plate-shaped test piece A is automatically supplied between the fixed chuck 23 and the movable chuck 25 using, for example, a manipulator,
The gripping ends A1 at both ends thereof are clamped by the fixed chuck blade 26 and the movable chuck blade 27, respectively, and the gripper 83 of the extensometer 8,
83 are held together to determine the initial state. At this time, the board width measuring device 4 is in the normal measurement mode.

When the testing device main body 2 is driven to rotate the driving threaded rod 24 and the movable chuck 25 is lowered, the plate-shaped test piece A gradually stretches, and the test device main body 2 records the change in load.

The operation of the plate width measuring device 4 until the plate-like test piece A breaks is explained with reference to FIG. For example, the growth rate is set to 10%, 15%, and 20% as mentioned above. The plate-shaped test piece A is elongated by 10% and the drive rod 53 of the vertical drive cylinder 52 is
is activated, the plate width measuring device 4 is lowered, and reaches a position where the laser beam L is irradiated approximately at the center of the measurement portion A2 of the plate-shaped test piece A.

Therefore, a laser beam L is emitted from the scanning unit 6 of the plate width measuring device 4, and the laser beam L is swung in the width direction of the plate-shaped test piece A through the incident mirror 61.
When the width measuring device 4 is lowered at the same time, the laser beam L scans along the surface of the plate-shaped test piece A as shown in FIG. After passing through the position of the plate-shaped test piece A, the laser beam L enters the light-receiving section 7 where it is reflected by the light-receiving mirror 71, where it is analyzed and the plate width is automatically determined.

As shown in steps 3 to 5, the board width measuring device 4 measures 25 mm around the center line A3 of the measuring portion A2 of the plate-shaped test piece A, calculates the average value, and uses the measured value as the board width w. Thereafter, the board width measuring device 4 is raised and returned to its original position in steps 6 to 8. Furthermore, as shown in step 9, the above-mentioned r
Calculate the value. Note that in step 9, it is possible to calculate parameters such as the n value in addition to the r value.

As mentioned above, the plate width measuring device 4 operates in the normal width measurement mode until the plate-shaped specimen A breaks, and further measures the plate width w and various parameters in the same way even in the elongated state of 15% and 20%. calculate.

The operation of the plate width measuring device 4 when the plate-shaped test piece A breaks will be explained with reference to FIG.

Step 1 in FIG. 9 corresponds to step 1 in FIG. 8, and when a break in the plate-shaped test piece A is detected, the board width measuring device 4 switches to the break measurement mode in step 2. Then, in step 3, the plate width measuring device 4 is lowered, and the laser beam L scans the plate surface of the plate-shaped test piece A in the same manner as shown in FIG. As mentioned above, if the fracture does not occur within a predetermined section from the center line A3 of the measurement portion A2 of the plate-shaped test piece A, it must be determined as a B fracture.

Therefore, the board width measuring device 4 is moved downward so that the laser beam L scans within the predetermined section, and the presence or absence of the fracture groove A5 is detected by the pattern of the laser beam L received by the light receiving section 7. That is, in the normal width measurement mode, the minute fracture groove width s does not occur, so the pattern of the laser beam L is simple, but in the fracture measurement mode, the fracture groove width s and the board width W
1 and W2 occur alternately, so by planning this pattern in advance, it is possible to know the fracture groove width s and the board widths W1 and W2 after fracture. Moreover, if this pattern is unexpected, it will be an abnormal breakage. This is step 4 in Figure 9, and further step 5.
7 is added, and the board width w is represented by board width w1+rupture groove A5+board width w2, and the lowest value within the measurement section is registered as width data.

When the measurement within the measurement section is completed, the board width measuring device 4 is stopped in step 8, switched to the normal width measurement mode in step 9, and returned to the standby position in steps 10 to 12.

After that, in step 13, it is determined whether the width data has been registered in step 6, and if it has been registered, in step 14, the width data is recognized as final data and used for calculating various parameters, and it is determined that the A fracture has occurred. do. If it is not registered, it means that the fracture groove A5 of the plate-shaped test piece A has not been formed within the measurement area, and therefore, in step 15, it is determined that the fracture is B.

At this point, the test on one plate-shaped test piece A is completed, and after removing the set plate-shaped test piece A, the next plate-shaped test piece A is set as described above and the next test is performed.

According to the material tensile testing device according to the present invention, the width of the plate-shaped test piece can be automatically obtained without requiring any manual labor, and by adding the functions of the test device main body, when testing the plate-shaped test piece, It is now possible to obtain various characteristic values extremely easily, significantly improving testing efficiency, and is especially effective when processing a large number of plate-shaped test pieces.

[Brief explanation of drawings]

Figure 1 is a front view showing the fractured state of a plate-shaped test piece;
Fig. 2 is a front view of a plate-shaped test piece showing a conventional measurement state of plate width, and Figs. 3 to 5 show a material tensile test device according to an embodiment of the present invention with some parts omitted. Figure 3 is a front view, Figure 4 is a front view of the board width measuring device enlarged from Figure 3, Figure 5 is a plan view, and Figure 6 shows the state of elongation of the plate-shaped test piece. 7 is a front view showing the fracture position of the plate-shaped test piece enlarged from FIG. 6, and FIGS. 8 and 9 are flowcharts for explaining the operation. The figure shows the plate-shaped test piece until it breaks, and FIG. 9 shows the time at which it breaks. A...Plate test piece, L...Laser light, 2...
Test device main body, 23... fixed chuck, 25...
Movable chuck, 3... Board width measuring device support base,
32... Support beam, 4... Board width measuring device, 5... Moving base, 6... Scanning section, 61... Incoming mirror,
7... Light receiving section, 71... Light receiving mirror, 8... Extensometer.

Claims (1)

[Scope of Claims] 1. In a material tensile testing device in which a plate-shaped test piece is installed between a fixed side crosshead and a movable side crosshead for testing, the plate-shaped test piece is In addition to being equipped with an extensometer to measure elongation, the main body of the test device applies a tensile load to the plate-shaped test piece. An incident mirror and a light receiving mirror are supported so as to be movable up and down, and a beam is incident on the incident mirror, and the beam reflected by the incident mirror is irradiated onto the plate surface of a plate-shaped specimen and reciprocated in the width direction. a scanning unit that displaces the plate-shaped test piece in the longitudinal direction while shaking it; There is a normal measurement mode in which only the plate width is detected by the interruption time of the light beam scanned by the scanning section when the plate-shaped specimen is not broken, and a normal measurement mode in which only the plate width is detected when the plate-shaped specimen is broken and a tensile load is applied. When this happens, the scanned light beam is blocked on both sides of the fracture groove, but passes through the fracture groove, and the width of the plate is detected by adding the fracture groove width. What is claimed is: 1. A material tensile testing device comprising a board width measuring device having a light receiving section having a break measurement mode for detecting a break position based on the displacement position of a light beam.