JPS60202357A - Method and apparatus for measuring hardened depth of roll - Google Patents

Abstract

PURPOSE:To rapidly perform non-destructive measurement, by providing a transmitter and a reciver to the side and front surfaces of a roll and calculating the max. position of sensitivity of the receiving ultrasonic wave of the receiver to measure the hardened depth of the roll on the basis of the calculated position. CONSTITUTION:An ultrasonic wave is incident on a roll at an incident angle theta1 from a transmitter 3 and transmitted therethrough at sound velocity v1 over the radius direction distance l1 of the roll usual part and refracted at the interface to be transmitted through a part having a hardened depth l2 at a refracted angle theta' and sound velocity v2 to be allowed to reach a receiver 4. After the position of the transmitter 3 and the incident angle theta1 were determined, the receiver 4 is measured from the reference position P1 of the roll side surface in the roll axis direction and, by detecting the max. sensitivity position P2 at this time, operation is performed according to a predetermined calculation formula and the depth thickness l2 of a hardened layer can be determined.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for reducing the depth of a hardened layer in rolls (rolling rolls, etc.) when induction hardening is applied to minimize wear with materials, etc. Concerning a method and device for non-destructive measurement.

[Technical background of the invention and its problems]

Controlling the depth of the hardened layer created by induction hardening of rolls is extremely important from the standpoint of quality assurance.

Conventionally, this type of depth measurement has been carried out by cutting the core itself in the radial direction, polishing the cut surface, etching it, and performing macroscopic observation.

However, this requires a lot of time and effort for measurement, and it is also difficult to perform a complete inspection. Therefore, a method for quickly and non-destructively measuring the roll hardening depth has been desired.

On the other hand, at the 10th World Congress on Non-destructive Testing, BASATSKAYA et al. under the title "Ultrasonic testing of hardened layers in cold rolls" transmitted longitudinally spaced signals on the surface of hardened layers. with a child and a receiver,
We propose a method to measure the curing depth using total reflection of ultrasonic waves that occurs at a critical angle.

However, according to studies conducted by the present inventor, the measurement accuracy is not very high, and it is difficult to use it for quality control specified for rolling rolls, for example, or life estimation in in-service inspections.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a method and apparatus for measuring the hardening depth of a roll, which can be measured non-destructively and quickly, and which has high measurement accuracy.

[Summary of the invention]

The method of the present invention to achieve this objective includes providing a transmitter and a receiver on the side and surface of the roll in a positional relationship that allows the ultrasonic beam to pass through both the hardened layer and the normal part of the roll.
Find the maximum sensitivity of the ultrasound received by the receiver,
This method is characterized by measuring the hardening depth of the roll based on that position.

Furthermore, the device of the present invention relatively moves the ultrasonic transmitter provided at a normal position on the side surface of the roll, the receiver provided on the surface of the hardened roll layer, and the roll and the receiver in the roll axis direction. The vehicle is characterized by being equipped with a means of transportation.

That is, the main points of the present invention are as follows.

(1) Non-destructive measurement using ultrasonic waves is performed by taking advantage of the fact that the sound speed of ultrasonic waves is different between the normal part and the hardened layer, and refraction occurs at the interface between them.

(2) In the measurement method using the above-mentioned ultrasonic critical phenomenon, the angle of incidence is large (70° or more in the case of a roll), and if the angle of incidence deviates slightly, the measurement accuracy deteriorates.

Furthermore, since the rate of change in sound velocity is not constant between the two layers, 100q6 ultrasonic waves are not reflected even at the critical angle, and it is thought that the receiving sensitivity is often insufficient for practical use. Furthermore, it is difficult to clearly calculate scattering at the interface. In contrast, in the present invention, by utilizing the refraction phenomenon at the interface between the normal part and the hardened layer, a transmitter and a receiver are provided on the side surface of the roll and the surface of the hardened layer to transmit the hardened layer. be. This makes it possible to measure the hardening depth with extremely high accuracy.

[Specific examples of the invention]

The present invention will be explained in detail below with reference to the drawings.

First, the measurement principle of the present invention will be explained with reference to FIG.

1 is a normal part, 2 is a hardened layer, a transmitter 3 is provided in the normal part on the side surface of the roll, and a receiver 4 is arranged on the surface of the hardened layer 2.

Ultrasonic waves are incident from the transmitter 3 at an incident angle θ, transmitted through the radial distance 11 of the normal part at the sonic speed v1, refracted at the interface, transmitted at the hardening depth 12 at the refraction angle θ' at the sonic speed v2, and transmitted to the receiver. 4
Assuming that , the missing equations (1) and (2) hold true.

bz−(nl+#2)/lanθ −−−−−−
--(1) hl = 11/lanθ+l! 2/1an
(90-θ') ・−・・−・・−(2) Also, position P
If the maximum sensitivity is shown at 2, then Snell's law (3)
The formula holds true.

Pulling power l--pulling μ V V2 ・,・ θ'=s stone-'si++(90-θl)1=str+'-cosθ1・Bunku (3)1 Furthermore, there is no hardened layer, and the incident angle When the ultrasonic wave reaches the roll surface with θ1 unchanged, the length to the roll side reference position P1 is hl, and the length to the maximum sensitivity position P2 is h2, the deviation amount Δh==hi-h2 is ( 4)
It is given by Eq.

Δh=h1 h2=j+2/1an(71J2/1an
(90-θ') (4) Then, once the position of the transmitter 3 and the angle of incidence θ are determined, the set position P,
By measuring the receiver 4 in the roll axis direction and detecting the maximum sensitivity position P2 at that time, the amount of deviation Δh can be determined, the incident angle θ1 is already known, and the refraction angle θ′
Since is given by equation (3), it is possible to know the depth and thickness 12 of the hardened layer.

On the other hand, dl=300mm, 12=50mm, V
When 2'/Vl=0.96 and θ1=45 degrees, the amount of deviation Δ
h is approximately 5 words. Therefore, it is clear that the hardening depth can be measured with sufficient accuracy by measuring this deviation amount Δh.

FIGS. 2(a) to 2(d) show the received waveforms of ultrasonic waves at each position. Then, the maximum receiving sensitivity position P2 is determined by scanning the receiver along the surface of the hardened layer in the axial direction, and moving the rail 5 having the groove 5a to the ground so as to find the position showing the maximum sensitivity (received wave level). A guide 6 is fitted into the groove 5a, a receiver 4 is provided on the guide 6, a feed screw rod 7 is screwed onto the guide 6, and the feed screw rod 7 is connected to the rotation motor 8. For example, a configuration may be adopted in which the receiving element 4 is moved along the surface of the hardened layer 2 via the guide 6 by rotating it forward and backward.

Note that, if necessary, the roll may be moved together with the transmitter 3 and the receiver 4 may be fixed to determine the position of maximum sensitivity. Further, contrary to the above example, an example in which a transmitter is provided on the roll surface and a receiver is provided on the side surface is also included in the present invention.

The system of the device of the present invention is the same as that of a normal flaw detection device, so it will not be described in detail, but the operating procedure is shown in FIG. 4.

On the other hand, on the transmitter 3, so that it comes out smoothly on the side of the roll,
As shown in FIG. 5, it is preferable to provide a shoe 3a on the front surface that matches the side surface of the roll. It's a trench, the side of the roll has a slight inclination α, and that part is wedged (velocity of sound V)
Acts as. The angle of incidence β on the wedge is preferably determined by equation (6).

Here, VIVl, α can be measured by other methods and β Therefore, the angle of incidence β can be easily determined.

〔Effect of the invention〕

In summary, according to the present invention, the roll hardening depth can be measured non-destructively and quickly, and the measurement accuracy is greatly improved compared to conventional methods.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the measurement principle of the present invention, Figure 2 (a)
-(d) are waveform diagrams obtained at each reception position, and FIG. 3 is a schematic diagram and an explanatory diagram showing an example of a means for moving the receiver. DESCRIPTION OF SYMBOLS 1... Normal part, 2... Hardened layer, 3... Transmitter, 4
...Receiver, 5...Rail, 7...Transmission threaded rod,
8...Rotation motor. Figure 1 Figure 2 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A transmitter and a receiver are provided on the side and surface of the roll in a positional relationship that allows the ultrasonic beam to pass through both the hardened layer and the normal part of the roll, and the position of maximum sensitivity of the ultrasonic waves received by the receiver is determined. A method for measuring the hardening depth of a roll, characterized in that the hardening depth of the roll is measured based on the position of the roll. (2) An ultrasonic transmitter provided at a normal position on the side surface of the roll, a receiver placed on the surface of the hardened roll layer, and a moving means for relatively moving the roll and the receiver in the roll axis direction. A roll hardening depth measuring device characterized by: