JPS6382341A - Indentation hardness test method and apparatus - Google Patents

Abstract

PURPOSE:To prevent errors in measured values otherwise caused by the deformation of a tester, by a method wherein displacement detected with an obtuse-angle correcting indenter adapted to allow little indentation into a test piece is subtracted from that by the same load detected with a normal indenter to determine a indentation depth. CONSTITUTION:A test piece 7 is set, an eccentric cam 16 is turned to lower an indenter 2 (or a correcting indenter 2') to the test piece 7 and when the indenter 2 or 2' abuts the test piece 7, with the energization of a load generating section 5 a specified test load is applied to detect displacement with a displacement detector 20. Displacement A caused with the normal indenter 2 and displacement as caused B with the correcting indenter 2' when the same load is applied are measured and displacement C obtained by subtraction of B from A is identified as indentation depth to determine the hardness of the test piece 7 from the load and the depth. This can eliminate the deformation of a tester thereby enabling the performing of a highly accurate test.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for measuring indentation hardness in which an indenter is pushed into a test piece and the indentation hardness of the test piece is determined from the indentation depth.

[Prior art] The indentation hardness test method, in which an indenter with a sharp tip such as a triangular forceps is pushed into the surface of a test piece, and the surface hardness is determined from the indentation depth and load, has been adopted as one of the hardness measurement methods. has been done.

[Problems to be Solved by the Invention] In the conventional testing method described above, the measured displacement includes the amount of deformation such as elastic deformation of the testing device, so as the load increases, the amount of deformation of the testing device increases. As a result, there is a problem in that the obtained hardness value becomes lower, which causes an error in the measured value.

The present invention aims to solve the above-mentioned problems, and provides a method and apparatus for testing indentation hardness with a high particle size in which deformation of the testing device does not affect measured values.

[Means for Solving the Problems] In order to solve the above problems, the present invention employs the following configuration.

That is, in the indentation hardness measuring method (first invention) according to the present invention, a load of a loading mechanism is applied to an indenter, the indenter is pushed into a test piece, and the displacement at that time is detected by a displacement detection means to determine the indentation depth. In the indentation hardness test method, which determines the hardness from the indentation, the amount of displacement detected using an obtuse-angled correction indenter that is hardly pushed into the test piece instead of the indenter is the same as that detected using the regular indenter. The feature is that the indentation depth is subtracted from the amount of displacement with respect to the load, and the indentation hardness is determined based on this value.

Moreover, the indentation hardness testing device according to the present invention (second invention)
It is possible to selectively attach an indenter with a sharp tip that is pushed into the test piece and a correction indenter with an obtuse angle that is hardly pushed into the test piece, and it is possible to apply a test load to these indenters or the correction indenter. A loading mechanism that can be loaded, a detection means for detecting the displacement of the loading mechanism during loading, and a displacement detected in a preliminary test in which the correction indenter is attached to the loading mechanism, in a regular test using the indenter. and calculation means for calculating the indentation depth by subtracting the detected displacement.

[Function] The amount of displacement (A) when a load is applied using a regular hardness measurement indenter, and the amount of displacement (A) when the same load is applied using a correction indenter that is hardly pressed into the test piece. B) is measured, and the displacement amount (C) obtained by subtracting (B) from (A) is set as the indentation depth, and the hardness is determined from the load and this indentation depth. The deformation of the test device can be expressed as the displacement ffi (B), but the total displacement ff1 (B) during measurement using an indenter is
Since this value is subtracted from A), the amount of deformation of the testing device can be removed, and therefore a highly accurate test can be performed.

[Embodiment] FIG. 1 is a schematic diagram showing an embodiment of the present invention. This indentation hardness testing device 1 includes a guide section 3 that supports an indenter 2 so as to be movable up and down, a load lever 6 that transmits the load of a load generating section 5 to the indenter, and a test piece 7 positioned directly below the indenter 2. A loading mechanism 10 is provided with a lifting lever 9 for lifting the indenter 2 when the indenter 2 is moved.

A vertical indenter attachment rod 4 is provided at the end of the guide portion 3, and an indenter 2 or a correction indenter 2' is selectively attached to the tip thereof. The load lever 6 has an intermediate portion supported by a fulcrum member 8 in a scale-like manner, and a distal end portion connected to the guide portion 3.

As shown in FIG. 2(a), the indenter 2 has, for example, a triangular pyramid-shaped sharp tip, and is used for regular hardness tests. In addition, as shown in FIG. 2(b), the tip of the correction indenter 2' is formed into an obtuse shape, such as a spherical surface with a large curvature, so that it is hardly pressed into the test piece, so that the test device itself is deformed. (for example, the deformation of the load lever 6).

The other end of the load lever 6 is connected to the force coil 5a of the load generator 5, and this portion receives an upward force in proportion to the current flowing through the load generator. Therefore, when a current is applied to the load generating section 5, the indenter 2 is pressed downward.

The lifting lever 9 has an indenter mounting rod 4 having a guide portion 3 at its front end.
The other end is supported by a fulcrum 11 so as to be vertically rotatable. A convex portion 12 is provided on the lower side of the lifting lever 9.
A support member 13 having a support member 13 is supported by a fulcrum 14 so as to be rotatable up and down. An eccentric cam 16 that is rotated by a motor 15 and supports the support member 13 is provided below the support member 13 . By rotating the eccentric cam 16, the support member 13 is rotated up and down. When the support member 13 is lifted to the upper position by the eccentric cam 16, the convex portion 12 pushes up the lifting lever 9 and supports it, so that the indenter 2 is supported lifted from the test position, and the eccentric cam 16 and support member 1
When the indenter 3 is moved downward, the lifting lever 9 is also moved downward, and the indenter 2 is lowered onto the test piece 7.

A differential transformer type displacement detector 20 is installed at a position close to the indenter 2 in the middle of the indenter mounting rod 4 to which the indenter 2 is attached.
is provided.

Figure 'fJ3 is a block diagram showing the electrical configuration of this indentation hardness testing device 1. When a load is set in the load setting section 30, a current corresponding to the set load is supplied to the load generating section 5 by a signal output from the CPU 31 to the drive circuit 32. Therefore, the indenter 2 is pressed downward and pushed into the surface of the test piece. The load at this time is displayed on the load display section 33.

On the other hand, the displacement signal detected by the displacement detector 20 is
C
It is arithmetic processed by the PU 31 and displayed on the push-in depth display section 35. Note that the displacement detected by the displacement detector 20 is stored in the RAM 36.

When using this indentation hardness testing device 1, the test piece 7 is set at a predetermined test position, and the eccentric cam 16 is rotated to lower the indenter 7-2 (or correction indenter 2') onto the test piece 7. let When the indenter 2 (correction indenter 2') comes into contact with the test piece 7, the load generator 5 is energized to apply a predetermined test load,
A displacement detector 20 detects displacement.

In this indentation hardness testing device 1, in addition to the test using the regular test indenter 2, a load test is performed using a correction indenter 2' according to the same procedure, and calculations are performed to determine the true indentation depth. That is, the displacement B when a load is applied using the correction indenter 2' that is hardly pressed into the test piece 7 is stored in the RAM 36, and the displacement B when the test is performed using the regular test indenter 2 is stored in the RAM 36. subtracted from A (A-B=
C＞. Since the correction indenter 2' is not pressed into the test piece,
The displacement B represents the amount of deformation of the testing device itself in response to the load, and the value C obtained by subtracting this from the displacement A represents the true indentation depth of the indenter 2. The indentation hardness H is determined from this value C and the load (P).

H=KP/(A-B) 2=KP/C2 Here, K is a constant determined by the shape of the test indenter 2.

This indentation hardness H is displayed on the indentation hardness display section 37.

Figure 4 is a graph showing the relationship between load and displacement. Figure (a) is a load-displacement diagram for the regular hardness measurement indenter 2, and Figure (b) is a compensation indenter, i.e. Load-displacement diagram of the indenter for measuring the deformation of the testing machine body, (C) is A
It is a load-displacement diagram when B is subtracted from . The graph in FIG. 4(c) shows the true indentation hardness.

Note that it is convenient to perform the test using the correction indenter 2' before the test using the indenter 2, but conversely, it is convenient to perform the test using the correction indenter 2' after the test using the indenter 2. You may do so. In this case, the displacement due to the indenter 2 (A1
．． A2...) will be stored in RAM and B will be subtracted later. In some cases, both tests may be performed alternately.

Note that the displacement amount can be displayed in three ways on the indentation depth display section 35: the actual detected value (A), the deformation amount of the device itself (B), and the corrected value (C). It's convenient.

[Effects of the Invention] As explained above, according to the present invention, the indentation hardness is determined based on the true indentation depth after subtracting the amount of deformation of the testing device itself during loading, so that the test results for high particle sizes are Now you can get it.

This testing device is extremely effective when applied to, for example, an ultra-micro hardness tester that performs tests with an accuracy of I/I (to microns or higher).

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing one embodiment of the indentation hardness testing device according to the present invention, and FIG. (b) is an explanatory diagram of an indenter and a correction indenter, FIG. 3 is a block diagram showing the electrical configuration, and FIG. 4(a). (b) and (c) are graphs showing the relationship between load and displacement amount. 1... Indentation hardness test device 2... Indenter 2'... Correction indenter 3... Guide section 5... Load generation section
6...Load lever 10...Load mechanism
20...Displacement detector 31-CP U Patent applicant Shimadzu Corporation Representative Patent attorney Hiroshi Sugawara Figure 2 (a) (C) Change position l () Lm) Figure 4 (b) Quickly] "Kabuto m)

Claims (2)

[Claims] (1) In an indentation hardness test method in which a load from a loading mechanism is applied to an indenter, the indenter is pushed into a test piece, the displacement at that time is detected by a displacement detection means, and the hardness is determined from the indentation depth.
The amount of displacement detected using an obtuse-angled correction indenter that is hardly pressed into the test piece instead of the indenter is subtracted from the amount of displacement for the same load detected using the regular indenter, and this is determined as the indentation depth. An indentation hardness test method characterized by determining indentation hardness based on the value. (2) It is possible to selectively attach an indenter with a sharp tip that is pushed into the test piece and a correction indenter with an obtuse angle that is hardly pushed into the test piece, and the test load is applied to these indenters or the correction indenter. a load mechanism capable of loading the
Detection means for detecting displacement of the load mechanism under load;
an indentation hardness comprising: calculation means for calculating the indentation depth by subtracting the displacement detected in a preliminary test performed by attaching the correction indenter to a loading mechanism from the displacement detected in a regular test using the indenter; Test equipment.