JPS62245135A - Method and apparatus for measuring hardness - Google Patents

Abstract

PURPOSE:To measure the hardness of the peripheral wall of a center hole having a small inner diameter with high reliability, by inclining a hardness meter with respect to a measuring surface. CONSTITUTION:A hardness meter fixing apparatus 1 is arranged to the center hole 3 of a turbine rotor 4 in a manner movable to the longitudinal direction thereof. The apparatus 1 has wheels 5 and can be held so that the horizontal surface 1a thereof is inclined and the angle theta of inclination of the horizontal surface 1a is detected. The angle theta is displayed on an angle display device 7a through a cable 6a and inputted to an operation apparatus 9 by a cable 8a. Further, a hardness meter 2 is provided to the horizontal surface 1a and a pressure element is pressed to the peripheral wall 3 of the center hole under the constant pressure of a spring to form a cavity. When the pressure element is not brought into contact with the peripheral wall, vibration frequency is constant but changes during the penetration of the pressure element under pressure. If the peripheral wall 3 is soft, the cavity is large and the change in the frequency becomes large. The hardness meter 2 accurately detects the change in the frequency to display the same on a hardness display device 7b through a cable 6b. The apparatus 9 corrects the hardness of the angle theta on the basis of preliminarily calculated function to display true hardness on a digital hardness display device 10.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a hardness measuring method for measuring the hardness of a peripheral wall of a center hole of a rotor such as a turbine rotor or a generator, and a hardness measuring method thereof. Regarding equipment.

(Prior technology) Turbine rotors have a center hole that extends in the axial direction, and during rotor manufacturing, flaw detection from the center hole is performed to check the quality of the product. As for the rotor.

Creep damage and thermal fatigue damage that accumulate over long periods of use can cause material deterioration and cracks, so flaw detection should be performed on the outer surface of the rotor and the surrounding wall of the center hole on a regular basis even after turbine operation. At the same time, the hardness of the rotor surface is measured to determine material deterioration. However, the stress acting on the turbine rotor is the largest;
The area where the material deterioration is large is the peripheral wall of the center hole, and in order to judge the material deterioration of the rotor and confirm the safety against destruction, it is required to measure the hardness of the peripheral wall of the center hole.

(Problem to be solved by the invention) The length of the center hole of a turbine rotor is as much as 5 m, and many rotors have an inner diameter of 8011I11 or less. Even a small hardness tester such as an ultrasonic porta-pull micro Vickers hardness tester cannot be inserted into the center hole and cannot measure the hardness of the peripheral wall of the center hole of the turbine rotor.

An object of the present invention is to provide a hardness measuring method and device that can measure the hardness of the peripheral wall of a central hole even if the inner diameter of the central hole is 80 mm or less, and that can obtain highly reliable hardness values. There is.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides hardness obtained by a porta-pull minute Vickers hardness meter fixed at a certain angle on the horizontal plane of the hardness needle fixing device shown in FIG. The hardness value (Hv) and the angle (θ) between the peripheral wall of the center hole and the hardness meter obtained from the hardness needle fixing device are both input into the calculation device, and the hardness obtained from the above is A calculation device that can correct the hardness based on the value (Hv) and angle (θ), that is, the relationship f (Hv, fJ) shown in the graph shown in Figure 2 must be input into the calculation device in advance. The basic content is
This device implements a hardness measurement method that performs hardness correction using this function and outputs true hardness.

The horizontal plane of the hardness needle fixing device is held at a variable angle.

Additionally, wheels are attached to the rotor so that it can move in the axial direction of the rotor. Further, the hardness meter is equipped with a Vickers diamond indenter, which makes an indentation on the peripheral wall of the center hole, and furthermore, the indenter is automatically moved up and down to perform automatic measurement.

(Function) In the case of the center hole of a turbine rotor, the length is as much as 5 m, and the inner diameter of the center hole is often as small as 801 mm or less. For such central holes where the hardness cannot be measured, the hardness can be measured by tilting the hardness meter with respect to the measurement surface, and from the relationship between the value obtained at this time and the angle of inclination, the hardness can be measured. .

FIG. 2 shows the relationship of hardness to this angle of inclination.

Therefore, the present invention focuses on the characteristics with respect to the gradient of hardness,
Insert the hardness meter into the center hole at a certain angle, measure the hardness, and use the hardness needle fixing device to measure the angle between the peripheral wall of the center hole and the hardness meter (
by detecting θ).

The above problem is solved by correcting the hardness.

In the present invention, the horizontal plane of the hardness needle fixing device can be freely tilted, and the characteristics of the hardness inclination can be input into the calculation device in advance so that the hardness can be easily corrected. desirable.

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which a hardness needle fixing device 1 is installed in a center hole 3 of a turbine rotor 4 so as to be movable in the longitudinal direction. The hardness meter fixed above! i! 1 is
It has wheels 5 and a horizontal surface 1alA←→A′←→A
It has a structure that allows it to be held at a variably tilted position as shown in the figure. That is, the angle θ can be freely adjusted. Further, the hardness needle fixing device 1 detects the inclination angle θ of the horizontal plane 1a, and this angle θ is displayed on the angle indicator 7a installed outside the rotor 4 via the connected cable 6a, and The data is input to the arithmetic unit 9 by the following. Also, the horizontal 1 of the hardness needle fixing device 1
A porta-pull minute Vickers hardness tester 2 is mounted on a. The hardness meter 2 is equipped with a Vickers diamond indenter at one end of a vibrating rod vibrated by a piezoelectric element, and the indenter is slowly pressed against the peripheral wall 3 of the center hole with a constant pressure of a spring to create a Vickers depression. The vibration frequency is constant when the indenter is not in contact with the peripheral wall 3 of the center hole, but the frequency changes while the indenter is being press-fitted. If the peripheral wall 3 of the center hole is soft, the depression will be large and the change in frequency will be large.

The hardness meter 2 has a mechanism to accurately detect this frequency change and digitally display the Vickers hardness on the hardness display 7b via the cable 6b. On the other hand, the above-mentioned hardness value is input to the arithmetic unit 9 via a cable 8b. However, the arithmetic device 9 has a cable 8a,
The hardness (Hv) obtained at the angle θ input via 8b is corrected using a predetermined function f (Hv, e), and the true hardness is digitally displayed 10. FIG. 2 shows a correction curve for hardness (Hv) and angle (θ). This correction curve is input into the calculation device 9 in advance.

In such a configuration, a hardness meter 2 is attached to the hardness needle fixing device 1.
The horizontal surface 1a of the hardness needle fixing device 1 is tilted according to the inner diameter of the center hole 3 of the turbine rotor 4 to be measured, and the hardness needle is inserted into the center hole 3.

The angle θ is sequentially input from the hardness needle fixing device 1 to the calculation device 9 via the cable 8a. Then, the hardness meter 2 inserted into the center hole 3 at the same time automatically activates the diamond indenter to detect the frequency change at that time, and the hardness obtained via the cable 6b is displayed on the hardness indicator 7b. The digitally displayed six-dimensional hardness is input to the calculation device 9 via the cable 8b, and is corrected by the function of the correction curve f(Hv, θ) shown in FIG. 2 that has been input in advance. The hardness will be digitally displayed as 10.

〔Effect of the invention〕

As described above, according to the present invention, a hardness needle fixing device equipped with a hardness meter is inserted into the center hole of the rotor, and the hardness needle fixing device is used to measure the hardness (Hv) of the peripheral wall of the center hole and the center Since the system detects the angle (θ) with the circumferential wall of the rotor and can correct the hardness using a calculation device, the present invention allows the hardness of the circumferential wall of the rotor center hole, which was previously impossible, to be measured by adjusting the inner diameter of the center hole. It is possible to more accurately determine the value by measuring the value according to the value and correcting it using the correction curve input to the arithmetic unit. Therefore, it is possible to determine the deterioration of the rotor's material and to check its safety against destruction, and it is possible to efficiently control the quality of the rotor.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a hardness measuring device for the center hole of a turbine rotor according to an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the hardness of the hardness meter and the angle between the measuring surface. . 1...Hardness needle fixing device 1a...Horizontal surface of hardness needle fixing device 2...Hardness meter 3...Central hole peripheral wall 4...Turbine rotor 6a, 6b...Cable 7a...・Angle indicator 7b...Hardness indicator 8a, 8b...Cable 9...Arithmetic unit 10...Hardness indicator board agent Patent attorney Noriyuki Chika Yudo Hirofumi Mitsumata No. 1 in Figure 1 (θn Figure 2

Claims (3)

[Claims] (1) A hardness measuring method characterized by tilting a hardness meter with respect to a measurement surface when measuring the hardness of a peripheral wall of a hole drilled in a test object. (2) The hardness according to claim 1, characterized in that the relationship between the angle θ between the hardness meter and the measurement surface and the hardness Hv is determined in advance, and the true hardness is determined from this relationship. Measuring method. (3) A hardness meter fixing device that is inserted into a hole drilled in a test subject and includes a means for movably holding the inclination angle of the horizontal plane and a means for detecting the inclination angle, and the hardness meter fixing device A hardness measuring device comprising: a hardness meter mounted on a hardness meter and held so as to be movable integrally with the horizontal surface.