JPS62245137A - Hardness tester - Google Patents

Abstract

PURPOSE:To increase the measuring speed of hardness by shortening the time required in measurement, by simultaneously measuring the hardness of an article to be measured in such a state that a diamond pressure element is penetrated under pressure. CONSTITUTION:An inner cylinder 16 is received in an outer cylinder 15 through a spring 17 and the diamond pressure element 18 fixed to the leading end of the inner cylinder 16 is pressed to a specimen 20. If the leading end of the outer cylinder 15 is pushed in the specimen 20 until it is brought into contact with the measuring surface thereof, the pressure element 18 is pressed to the specimen 20 by the constant spring force due to the spring 17. Measuring light is reflected from the light source part 22 arranged to the upper part of the inner cylinder 16 to be incident to the pressure element 18 through a half mirror 25. The reflected light from the pressure element 18 is inputted to an image converting device 29 through an impression trace image detecting optical system 23. The device 29 photoelectrically converts the impression trace image detected by the reflected light from the pressure element 18 to an electric signal which is, in turn, sent to an image processing unit 31. Herein, the length of the diagonal of the impression is automatically operated from the impression image converted to the electric signal and the hardness of the measuring surface of the specimen is calculated to be displayed on a display part 32. As mentioned above, by simultaneously measuring hardness in such a state that the pressure element is penetrated under pressure, a measuring speed can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a hardness testing machine suitable for measuring the hardness of objects to be measured such as gold-Iil manufactured products.

(Prior Art) Generally, the hardness of a metal is a measure of the resistance that the material exhibits when deformed by an indenter or hammer, and by measuring this hardness, the mechanical strength of the material can be easily measured. To measure the hardness of metals, etc., standard hardness testers such as Brinell, Vickers, Rockwell, and Shore hardness testers specified by JIS are used.

These standard hardness testers require a standard sample of a certain size, so in order to measure the hardness of the part that is actually used, it is necessary to take a standard sample from this part. It's inconvenient.

For this reason, recent hardness testers (1J, below, referred to as hardness meters) have a small, lightweight, portable hardness meter that allows the hardness meter to be brought into contact with the object to be measured. method is adopted. As this kind of hardness tester, there is an ultrasonic portaple minute Vickers hardness tester (see, for example, the monthly magazine "Machine Research", Vol. 37, No. 11, p. 1245, 1985). This ultrasonic hardness meter has a structure shown in FIG. 3, and a vibrating rod 3 biased by a spring 2 is housed in a housing 1 so as to be movable forward and backward. The vibrating rod 3 is mechanically reinforced by a sleeve 4 having a spring receiver, and a Vickers diamond indenter 5 is fixed to the tip thereof.
It protrudes outside the housing 1.

In addition, a piezoelectric cord 6 is attached to the middle of the vibrating rod 3.
The vibration rod 3 is made to vibrate ultrasonically by energizing the piezoelectric element 6, and the vibration state of the vibration rod 3 is detected by the detection unit 7.
It is detected more accurately.

In this ultrasonic hardness tester, a Vickers diamond indenter 5 fixed to a vibrating rod 3 vibrated by a piezoelectric element 6 is pressed against an object to be measured 8 such as a sample with a predetermined spring force of a spring 2, thereby creating a Pickers indentation. form. The diamond indenter 5 is press-fitted by forming a Vickers indentation, and the vibration frequency of the vibrating rod 3 changes depending on the amount of press-fitting. The change in vibration frequency is accurately detected by the detection section 7, and this detection signal is amplified by the amplification section 9 and then sent to the frequency discrimination section 10.
It is then sent to the display section 11, where the Vickers hardness is displayed.

Because the ultrasonic hardness tester has a lightweight structure, it is effective for measuring the hardness of large structures that have already been installed. It is necessary to calibrate with known materials. Further, the ultrasonic hardness meter has a problem in that the measured value varies greatly depending on the surface condition of the object to be measured.

Furthermore, in the ultrasonic hardness tester, a vibrating rod 3 equipped with a piezoelectric element 6 and a detecting section 7 is biased by a spring 2, and a load bearing section and a hardness detecting section are arranged on the same axis of the vibrating rod 3. and are placed. For this reason, the ultrasonic hardness tester has a length of a, which increases the length in the axial direction, making it unsuitable for measuring the inner surface of a tube or the center hole of a rotating body.

By the way, in the JIS standard hardness tester, the test method and the test piece as the object to be measured are standardized. The basic idea of conventional standardization is to obtain highly accurate hardness values with good repeatability of hardness tests, but recently hardness tests have been widely used for product quality evaluation, management, and assurance. As it has become more widely used, it has become important to consider automating hardness testing, speeding it up, and expanding its applicability.

For example, in a conventional Vickers hardness tester, there is a step in which the diagonal length of the Vickers indentation made by the indenter is measured using a microscope. Therefore, automation of measurement is strongly desired. For this reason, the microscopic field of view is captured using a TV camera! Attempts have been made to measure the diagonal length of the Vickers indentation on the screen of a TV monitor.

In addition, in order to speed up the hardness test, for example, in a conventional Vickers hardness tester, it is necessary to shorten the steps of press-fitting the Gockers indenter, removing the load, and measuring the Vickers indentation. In conventional hardness testing machines, after introducing a Vickers indentation, it is necessary to remove the Vickers indenter and measure the indented area using a microscope. Therefore, in order to speed up the measurement during a hardness test, it is necessary to measure the size of the indentation at the same time as the indenter is inserted, like an ultrasonic hardness meter.

Furthermore, with regard to expanding the applicability of hardness testing, conventional hardness testing machines create a standardized sample as the object to be measured and conduct hardness tests on this standardized sample, whereas In order to enable hardness testing, it is necessary to make the hardness testing machine smaller, lighter, and more compact. When detecting the hardness of an actual product to be measured, it becomes possible to measure the smallest part of the hardness tester, especially the hardness detection part. In particular, when measuring the hardness of the inner surface of a tube, the center hole of a rotor, etc., it is necessary to further downsize the hardness detection section of the hardness tester.

(Problem to be solved by the invention) Hardness testing using a hardness testing machine is useful for product quality evaluation and management.
As it has become widely used for warranty purposes, consideration has been given to automating hardness testing, speeding it up, and expanding its applicability. It has become highly desired.

The present invention was made in consideration of the above-mentioned circumstances, and it not only automates and speeds up the hardness measurement of the object to be measured, but also expands its applicability and makes it possible to measure the hardness of actual products as the object to be measured. The purpose is to provide a hardness testing machine.

[Structure of the invention]

(Means for Solving the Problems) The hardness tester according to the present invention has a slidable inner station in an outer cylinder and is biased by a spring to form a load bearing part,
A diamond indenter that presses the object to be measured is fixed to the tip of the inner cylinder so as to be able to protrude from the outside, and a light source unit that irradiates the diamond indenter with measurement light is provided. The reflected light is guided to an image conversion processing device via an indentation image detection optical system, and this image conversion processing device is connected to a display section.

(Function) The hardness tester of the present invention presses the diamond indenter against the sample with a constant load by pressing the outer cylinder against the sample to be measured. At this time, when the diamond indenter is irradiated with the measurement light in the contact area that does not come into contact with the part where the diamond indenter is in contact with the sample (indentation part), the reflectance of the measurement light changes optically. When the diamond indenter is observed from the load axis direction through an indentation image detection optical system, the difference in reflectance is recognized as the size of the indentation.

Therefore, the Vickers hardness is automatically measured by image processing the size of the indentation and measuring it as the diagonal quality of the indentation.

At this time, if the reflected light is scanned by the indentation image detection optical system and the image conversion processing device is installed on the side of the outer cylinder, the height of the hardness detection section can be suppressed to make it smaller and more compact. This makes it possible to measure the hardness of the inner surface of holes in small-diameter tubes, rotors, etc.

(Example) Hereinafter, an example of the hardness tester according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 15 indicates a cylindrical outer cylinder of the hardness tester, and a slidable inner cylinder 16 is accommodated in the outer cylinder 15 in a spring-biased state by a spring 17 to serve as a load bearing part. is forming. A Vickers diamond indenter 18 is fixed to the tip of the inner cylinder 16 so as to be able to protrude from the outer cylinder 15.
The protrusion of the diamond indenter 18 is regulated by an inward flange-shaped stopper 19 formed on the outer cylinder 15. The diamond indenter 18 is pressed against a sample 20 such as a metal product as an object to be measured, and a Vickers indentation image is formed on the measurement surface of the sample 20 by the pressure.

On the other hand, a light source unit 22 that irradiates measurement light onto the diamond indenter 18 is housed at the rear end of the inner cylinder 16, and an indentation image detection optical system that scans the reflected light of the measurement light irradiated onto the diamond indenter 18. 23 is provided within the inner cylinder 16. The indentation image detection optical system 23 is located inside fi! It is formed from an L-shaped transparent body 24 made of quartz glass, plastic, etc. housed in a mirror 16, and a half mirror 25 formed by applying a vapor-deposited film to the inclined surface of this transparent body 24. The transparent body 24 is bonded with a diamond tipped indenter 18 to strengthen the inner tube 16, and the inclined surface of the transparent body 24 is preferably formed at an angle of 45 degrees with respect to the axis of the inner tube 16.

As a result, the reflected light from the diamond indenter 18 along the axial direction of the cart is scanned by the half mirror 25, and the outer cylinder 15 is scanned by the half mirror 25.
The image is input through the window hole 26 to an image conversion processing device 28 attached to the side of the outer cylinder 15.

The image conversion processing device 28 includes an image conversion device 29 that converts an indentation image detected from the light reflected by the diamond indenter 18 into an electrical signal, and an image processing device 31 connected to the image conversion device 29 by a cable 30. The image processing device 31 performs image processing to calculate the hardness value of the sample measurement surface by calculating the diagonal length of the indentation from the electric signal of the indentation image converted by the image conversion device 29. Image processing device 3
1 is connected to a display section 32, and is configured to display an image of the hardness of the sample measurement surface that has been image-processed by the image conversion processing device 28.

Next, hardness measurement using a hardness tester will be explained.

An inner cylinder 1G of the hardness tester is housed in an outer cylinder 15 via a spring 17, and a diamond indenter 18 fixed to the tip of the inner cylinder 16 is pressed against a sample 20 as an object to be measured. When pushing the outer cylinder 15 until the tip of the sample 20 comes into contact with the measurement surface of the sample 20, the die 17 and the indenter 18 are pressed against the spring 1.
7 is pressed against the sample with a constant spring force.

On the other hand, the light source part 2 disposed at the rear end (upper part) of the inner cylinder 16
The measurement light is reflected from the half mirror 25.
The light is then incident on the diamond indenter 18. The reflected light from the diamond indenter 18 passes through an indentation image detection optical system 23 and is input to an image conversion device 29 provided on the side of the outer cylinder 15. The image conversion device 29 photoelectrically converts the indentation image detected by the reflected light from the die 17 and the indenter 1B into an electric signal and sends it to the image processing device 31. Here, the diagonal length of the indentation is calculated from the indentation image converted into an electric signal. The hardness value of the sample measurement surface is calculated automatically by ωj, and the hardness value is displayed on the display unit 32.

Conventional Vickers hardness testers measure the Vickers hardness value from the size of the indentation after removing the load of the Vickers indenter that is press-fitted into the sample measurement surface. It is necessary to compare and calibrate the size of the indentation during press-in and unloading.

On the other hand, in the hardness tester shown in FIG. 1, the diamond indenter 18 can be pressed against the sample measurement surface and the hardness can be measured simultaneously while the diamond indenter 18 is press-fitted.

FIG. 2 t shows an indentation image subjected to image flI processing by the image conversion processing device 28. From the processed image, the indentation area A where the diamond indenter 18 is in contact with the sample measurement surface and the non-contact area B where the diamond indenter 18 is not in contact are determined by changes in the reflectance of light at the interface area of the diamond indenter 18 that is in contact with the sample 20. , because they are optically clearly distinguished, it becomes possible to easily convert the size of the indentation image into an rli value.

In this way, by simultaneously measuring the size of the indentation with the Vickers diamond indenter 18 pressed in, it is possible to speed up hardness measurement. The indented area (
The hardness can be determined optically from the difference in the reflectance of the measurement light between the contact area) and the non-contact area, and image processing is performed to automatically measure the hardness. Furthermore, by providing the image conversion processing device 28 on the side of the outer cylinder 15, the load applying part to the diamond indenter and the hardness detection part can be arranged almost at right angles.・It can be made into a portaple, making it possible to measure the hardness inside the tube or rotor hole. In particular, since the size and height of the hardness tester is determined only by the size of the load-carrying part, the hardness tester can be made smaller and lighter, and the inner surface of the tube, which cannot be measured with conventional hardness meters, can be It becomes possible to measure actual metal products such as the inner peripheral surface of the rotor hole.

In addition, in one embodiment of the present invention, an example was explained in which the light source section was provided at the rear end of the inner cylinder, but it is also possible to install the light source section at the tip of the outer cylinder and irradiate the measurement light from the side surface of the indentation. It's okay. In this case, since it is not necessary to install the light source section in the inner office, the height of the entire hardness tester is reduced, and it is possible to achieve further miniaturization.

Further, the indentation image detection optical system housed in the inner cylinder may be installed simply by tilting the half mirror with respect to the axis of the inner cylinder. In this case, a transparent body is not required.

Further, a transparent body may be interposed above the half mirror to strengthen the inner cylinder.

[Effects of the Invention] As described above, in the hardness testing machine according to the present invention, the hardness of the object to be measured that is damaged by the gold Fd manufactured product can be measured simultaneously with the diamond indenter inserted. , the time required for hardness measurement is shortened, and hardness measurement can be performed at high speed.

In addition, the hardness of the object to be measured is measured by optically detecting the indentation image made by the diamond indenter, and automatically processing the image by an image conversion processing device via an indentation image detection optical system. Since the information is displayed on the display section, there are no individual differences in accuracy measurement, which reduces labor and can also be expected to improve measurement accuracy.

Furthermore, the reflected light from the diamond indenter can be freely scanned by the indentation image detection optical system, increasing the degree of freedom in setting the position of the hardness detection unit, making the hardness testing machine smaller and more compact. This makes it possible to measure the hardness of mounted products such as the inner surface of tubes and the inner surface of holes such as turbine rotors.

[Brief explanation of drawings]

Fig. 1 is a diagram schematically showing an embodiment of the hardness tester according to the present invention, Fig. 2 is a schematic diagram of an indentation image observed by the above-mentioned hardness tester, and Fig. 3 is a diagram showing a conventional small-sized hardness tester. FIG. 2 is a schematic diagram without showing an ultrasonic hardness meter as a gauge. DESCRIPTION OF SYMBOLS 15... Outer tube, 16... Inner tube, 17... Spring, 18... Diamond indenter, 20... Sample (object to be measured), 22... Light source part, 23... Indentation Image detection optical system, 24... Transparent body, 25... Half mirror, 28
...Image conversion processing 5AV3.29...Image conversion device, 31...Image processing device, 32...Display section.

Claims (1)

[Scope of Claims] 1. A load-bearing portion is formed by urging an inner cylinder that is freely slidable inside the outer cylinder with a spring, and a diamond indenter that presses the object to be measured is attached to the tip of the inner cylinder. A light source unit is provided which is fixed to protrude freely from the outer cylinder and irradiates measurement light onto the diamond indenter, and the reflected light of the measurement light irradiated onto the diamond indenter is sent to an image conversion processing device via an indentation image detection optical system. A hardness testing machine characterized in that the image conversion processing device is connected to a display section. 2. The indentation image detection optical system is equipped with a half mirror installed in the inner cylinder obliquely with respect to the axis, and this half mirror guides the reflected light from the diamond indenter to the image conversion processing device installed on the side of the outer cylinder. A hardness testing machine according to claim 1. 3. The indentation image detection optical system houses a transparent material such as quartz glass or plastic in an inner cylinder, forms an inclined surface of approximately 45 degrees with respect to the axis of the inner cylinder in the transparent material, and deposits vapor on this inclined surface. Claim 1, wherein a film is applied to form a half mirror, and a diamond indenter is bonded to the tip of the transparent body.
The hardness tester described in section. 4. The hardness testing machine according to claim 1, wherein the light source is provided at the rear end of the inner cylinder or around the diamond indenter in the outer cylinder. 5. The image conversion processing device includes an image conversion device that converts an indentation image detected from the reflected light from the diamond indenter into an electrical signal, and a hardness value by calculating the diagonal length of the indentation from the electrical signal of this indentation image. The hardness tester according to claim 1, further comprising an image processing device for calculating the hardness.