JPH08145965A - Ultrasonic cured layer measuring apparatus by electronic scanning - Google Patents

Abstract

PURPOSE: To improve the measuring time, distance and accuracy in the measurement of the cured layer of a columnar specimen having the layer by an ultrasonic wave. CONSTITUTION: The ultrasonic cured layer measuring apparatus can so linearly move an electronic scanning type transmitter group in which incident points are electronically aligned on the circumference by an electronic scanning array type transmitter 2 that an ultrasonic beam transmitted by the transmitter 2 is received by a focusing type receiver 3 via the position of a desired depth in a specimen 1. The propagating speeds of the layers are obtained, and the depth of a cured layer is finally measured from the relationship between the speed and the hardness. The depth of the layer can be more rapidly and accurately measured in the wide range from the surface layer to the interior of the specimen without entirely damaging the specimen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic hardening layer measuring method and apparatus for ultrasonically measuring the hardness of a sample and its internal distribution.

In particular, it relates to an ultrasonic wave transmitter and receiver.

[0003]

2. Description of the Related Art In forged steel rolls for rolling, the state of the quench-hardened layer in the surface layer is an important condition that influences the life of the roll, and it is important to measure this hardened layer nondestructively. It is important for quality assurance.

In all of the conventional hardened layer measuring devices, only the surface of the subject or a relatively shallow position of the surface layer portion (1 from the surface) is used.
Only a hardened layer of 0 to 20 mm) can be measured.

According to the patent No. JP-B-63-26340 "Non-destructive method and apparatus for measuring hardened layer", the hardened layer distribution can be accurately measured, but the measurement accuracy is largely dependent on the installation accuracy of the wave transmitter and the wave receiver. It was affected, and it took time to install it accurately. Further, the positions of the transmitter and the receiver on the circumference of the cylindrical object are moved semi-mechanically, so the measurement interval cannot be made very small. To measure more accurately,
It is necessary to improve the positioning accuracy of the transmitter and receiver. The measurement accuracy of the distribution of the hardened layer largely depends on the installation accuracy of the wave transmitter and the wave receiver on the subject, and it took time to accurately install the wave transmitter and the wave receiver. Further, since the installation positions of the wave transmitter and the wave receiver on the circumference of the subject are mechanically moved, there is a minimum limit on the moving distance. In order to further improve the measurement accuracy, it has been desired to reduce the moving distance, that is, the measurement interval.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks and to accurately and nondestructively cure a hardened layer in a relatively deep range from the surface of a subject to the inside thereof by using ultrasonic waves. It is to provide a method and an apparatus for measuring in a short time.

[0007]

[Means for Solving the Problems] As a result of investigating ultrasonic characteristics using various forged steel roll pieces having different hardness as test pieces by using ultrasonic waves penetrating into a subject, hardness Hs (Shore hardness It has been confirmed that there is a good correspondence between the ultrasonic wave velocity and the ultrasonic wave propagation velocity as shown in FIG.

Focusing on the above relationship, the ultrasonic wave propagation velocity in the subject is determined, and the hardness of the subject is measured from the magnitude of the velocity.

By the way, in a subject having a cylindrical surface such as a body roll, the hardened layer (hatched portion) is distributed substantially symmetrically with respect to the axis O of the subject 1 as shown in FIG. In the vicinity, the hardness is the highest and the hardness decreases as the inner layer is formed.

On the other hand, the roll has a considerable length in the axial direction, and the depth of the hardened layer is often different between the center part of the body and the end face of the body. It is difficult to find the speed. Therefore, in the case of such a cylindrical multi-layered object, the ultrasonic beam emitted from the transmitter hypothesizes multiple layers that are symmetrical with respect to the axis and that are spaced at arbitrary intervals, so that the position of the desired depth of the object is detected. In order to allow the wave to be received by the wave receiver, the distance between the wave transmitter and the wave receiver can be changed by electronic scanning, and the wave is placed between two points on the circumference of the object to be measured in the chord direction at the desired depth. Determine the ultrasonic wave propagation velocity of.

That is, in order to achieve the above-mentioned object, an electronic scanning array type probe is used for at least one of the transmitter and the receiver, and the transmitter and the receiver are used for each measurement from the first layer to the n-th layer. Try not to place Hamiko.

[0012]

In the measurement of the hardened layer of the body roll, the first layer at the shallowest position on the surface, the second layer, the third layer, ...
The ultrasonic wave propagation velocity that propagates along the chordal path length of the depth corresponding to the layer is set by setting the positions of the transmitter and the receiver so that the maximum depth of the path length is in the layer where the propagation velocity is obtained. Then, the propagation time at this time can be obtained by the geometrically obtained path length in each layer and the already-obtained propagation velocity from the first layer to the previous layer.

At this time, the transmitter and the receiver are (1) a transmitter: an electronic scanning array type probe, a receiver: a single point incident type probe, (2) a transmitter: a single point incident type probe, Receiving device: There are three combinations of electronic scanning array type probe, (3) electronic scanning array type probe for both transmitter and receiving device, and any one of them is used.

Therefore, the positions of the transmitter and the receiver are set to 1
The ultrasonic wave propagation velocity for propagating along the chordal path length of the depth corresponding to the second layer, the third layer, ... It will be possible. Also, by the combination of the transmitter and the receiver,
The measurement interval can be reduced, and the measurement accuracy can be improved.

[0015]

【Example】

Example 1 An example of the present invention will be described. FIG. 3 is characterized in that a focusing type transducer 3 in which a concave transducer having a focusing point of an ultrasonic beam is incorporated on one surface of a subject 1 and an electronic scanning array type transmitting element 2 is used on the other side. I am trying.

According to the present method, the ultrasonic wave can be electronically focused in the same manner as the focusing type transducer by using the electronic scanning type transducer as the transmitting element, and the electronic scanning type transmitting element can be used. By using a plurality of wave elements sequentially from the wave receiver of the subject 1 on the circumference, it becomes possible to electronically move the incident point linearly. In addition, the measurement interval is set to 1 mm, that is, the chord length measurement pitch is set to 1 mm, and an accurate hardened layer measurement result is obtained. As a result, the hardened layer distribution measurement from the surface layer portion to the inside can be accurately measured in a short time by setting the position once, without installing a wave transmitter and a wave receiver for each measurement. (Embodiment 2) On the contrary to Embodiment 1 described above, the same effect can be obtained by changing the incident direction of ultrasonic waves by switching the wave transmitter to the focusing type and the wave receiver to the electronic array scanning type. Furthermore, by making both the wave transmitter and the wave receiver an electronic array scanning type, it is possible to measure the hardened layer from both directions.

By using the electronic array scanning probe for either one or both of the transmitter and the receiver, and by using the electronic array scanning probe in combination with the electronic sector scanning and the electronic linear scanning, By installing the wave transmitter and wave receiver once, it is possible to measure the hardened layer from the surface layer to the inside of the object in a short time and with high accuracy.

[0018]

The ultrasonic hardening layer measuring method and apparatus using the wave transmitter and the wave receiver according to the present invention has a large depth of the hardening layer from the surface layer to the inside of the object without damaging the object at all. Can be measured accurately in a short time.

[Brief description of drawings]

FIG. 1 Hardness distribution of roll test material (Hs: Shore hardness)
It is a relationship diagram which experimentally calculated | required the relationship between and ultrasonic wave propagation velocity.

FIG. 2 is a reference diagram showing a distribution state of a hardened layer of a subject having a cylindrical surface.

FIG. 3 is a reference diagram for carrying out the method for measuring an ultrasonically cured layer according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Subject, 2 ... Electronic scanning array type | formula transmitter, 3 ... Focusing type | formula receiver.

Front Page Continuation (72) Inventor Hirotoshi Kino 2-6-2 Otemachi, Chiyoda-ku, Tokyo Inside Nitto Construction Machinery Co., Ltd.

Claims (2)

[Claims] 1. A first outermost layer of the subject, assuming that the hardened layer of a cylindrical subject having a hardened layer formed on an outer shell portion having a circular cross section is a multilayer having an arbitrary interval symmetrical about an axis. Part 1
The propagation velocity of the ultrasonic beam in the first layer is obtained from the propagation time and the path length of the ultrasonic beam passing through only the layer, and then the first
The propagation velocity in the second layer is calculated from the propagation time of the ultrasonic beam passing through only the first layer and the second layer, the path lengths in the first layer and the second layer, and the propagation velocity of the first layer which has already been obtained. , The propagation velocity up to the n-th layer is obtained by the same method, and finally the hardness of each layer is obtained from the correlation between the propagation velocity and the hardness which is previously obtained based on the propagation velocity of each layer. In the ultrasonic hardening layer measuring device, an electronic scanning array type probe is used for the transmitter by combining the transmitter and receiver to determine the propagation time of the ultrasonic beam passing through the outer shell of the cylindrical object in the chord direction. When a single-incidence probe is used for the receiver and a single-incidence probe is used for the transmitter and an electronic scanning array type probe is used for the receiver, both the transmitter and the receiver are Hardened layer by any combination when using a scanning array type probe A device for measuring an ultrasonically cured layer by electronic scanning, which is characterized by measuring a cloth. 2. An ultrasonic wave transmitting / receiving unit for transmitting / receiving ultrasonic waves,
A transmitter for transmitting an ultrasonic beam into the subject by a transmission pulse from the ultrasonic transmitter / receiver, a receiver for receiving the ultrasonic beam that has passed through the subject, and a desired ultrasonic beam in the subject. And a setting holder for setting and holding the wave transmitter and the wave receiver so that the wave is received through a layer having a depth of, and an ultrasonic beam is sent to the inside of the subject and then received by the wave receiver. The propagation time measuring unit for measuring the propagation time until the end of the ultrasonic wave, and the path through which the ultrasonic beam entering the subject reaches the receiver based on the relative positional relationship between the transmitter and the receiver. A path length calculation unit for calculating the length, a propagation velocity calculation for calculating the propagation velocity in the layer under measurement based on the output of the propagation time measurement unit and the output of the path length calculation unit, and the propagation velocity of each layer already obtained. And the transmission of each layer for which the propagation velocity is calculated. Item 1. In an ultrasonic hardening layer measuring device, comprising: a memory unit capable of storing a velocity and reading it out as necessary, and a hardness calculation unit for converting a propagation velocity into hardness and displaying an output, An ultrasonic hardening layer measuring device by electronic scanning characterized by using the above-mentioned wave transmitter and wave receiver.