JPH0464010A - Nondestructive measuring apparatus for casehardened layer - Google Patents

Abstract

PURPOSE:To achieve continuous measurement by measuring the distance of a wave sender which sends ultrasonic beams and a wave receiver which receives the ultrasonic beans, with use of the surface wave of the ultrasonic beams. CONSTITUTION:The distance between a wave sender 2 and a wave receiver 3 provided on two points on a circumference of a body 1 to be detected can be changed. The propagating speed of the ultrasonic beams at each position of the wave receiver 2 is obtained as the position is changed sequentially from A to C, whereby the thickness of a layer which is set through hardening is measured. When the surface wave of the ultrasonic beams is propagated via a ultrasonic wave transmitting/receiving part 6 between the wave sender 2 and wave receiver 3 provided on the surface of the body, and the propagating time is measured by a propagating time measuring part 7, the distance L of the propagating path of the transverse wave of the ultrasonic beams between the sender 2 and receiver 3 can be measured.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for non-destructively measuring the thickness of a hardened layer of a forged steel roll for rolling, and in particular, it relates to a device for non-destructively measuring the thickness of a hardened layer of a forged steel roll for rolling. The present invention relates to a device that accurately measures the thickness of a hardened layer by accurately and quickly measuring the thickness of the hardened layer.

[Conventional technology]

Japanese Patent Application No. 55-90628 discloses measuring the hardened layer of a forged steel roll using ultrasonic waves.

Japanese Patent Application No. 62-319220 discloses a method for measuring the hardening depth of a cylindrical machine.

[Problem to be solved by the invention]

When measuring the thickness of the hardened layer of a forged steel roll by measuring the sound velocity of ultrasonic waves, an ultrasonic transmitter and a receiver are installed at a fixed interval, and the propagation time between them is measured. It is necessary to measure the spacing between receivers. The transmitter and receiver are installed on the same circumference of a cylinder, and the propagation time of the ultrasonic waves is measured while moving the receiver sequentially, so the spacing between the transmitter and receiver is also continuous. need to be measured.

The present invention measures the distance between a transmitter and a receiver using ultrasonic surface waves, and the configuration of the measuring device is simplified, making it possible to quickly measure the distance.

[Means to solve the problem]

1) Since the structure of the forged steel roll surface is stable and the sound speed of the ultrasonic surface wave is constant, it was decided to measure the interval by measuring the propagation time.

2) The structure of the ultrasonic wave transmitter and wave receiver is designed so that surface waves and transverse waves are generated simultaneously, so that the internal and surface propagation times can be measured simultaneously.

[Effect]

1) The transmitter and receiver have a structure in which a transverse wave for measuring the internal sound speed and a surface wave for measuring the surface propagation time are generated simultaneously.

2) Since the distance can be measured using ultrasonic waves, there is no need to employ other measuring means, which simplifies the device and makes it easier to handle on site.

〔Example〕

As a result of investigating the ultrasonic properties using forged steel roll pieces with different hardness as test specimens using ultrasonic transverse waves that can be delivered into the test object, we found that the relationship between hardness (Shore hardness) and ultrasonic propagation speed was There is a good correspondence as shown in FIG. In the case of a forged steel roll, the hardened layer due to quenching is distributed symmetrically with respect to the axis, being hardest near the surface and becoming softer toward the inner layer. As shown in FIG. 1, the transmitter 2 and the receiver 3 are arranged between two points on the circumference of the subject 1 so that the distance between them can be changed, and the receiver is positioned at A.

By determining the propagation velocity of the ultrasonic beam at each position while changing the position sequentially like B and C, the thickness of the hardened layer due to quenching can be measured.

In this case, it is necessary to find the propagation velocity at each position from the propagation path and propagation time of the ultrasonic beam.

The present invention measures the propagation path length of the ultrasonic beam by propagating an ultrasonic surface wave between a transmitter and a receiver placed on the surface of the object and measuring the propagation time. It is characterized by measuring the propagation path length of transverse waves.

It is known that the propagation speed of ultrasonic waves varies depending on the metal structure of the specimen, but since the surface structure of the 5 forged steel roll is stable, the propagation speed of ultrasonic surface waves is also constant. Therefore, by measuring the propagation time of ultrasonic surface waves,
Propagation path length can be measured.

FIG. 2 is an example of calculation for determining the ultrasonic transverse wave propagation path length from the ultrasonic surface wave propagation path length Q. The diameter of the object 1 can be measured in advance using a micrometer or the like at a single micron position, and the radius can also be determined in advance.

By measuring the propagation path length of ultrasonic surface waves, the second
From equation (1) in the figure, it is possible to measure the propagation path length of the ultrasonic transverse wave.

〔Effect of the invention〕

According to the present invention, no other measuring device is required for measuring the propagation path length of ultrasonic transverse waves, and continuous measurement becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. Fig. 2 is an explanatory diagram for calculating the propagation path length of an ultrasonic transverse wave from the propagation path length of an ultrasonic surface wave, and Fig. 3 shows the hardness Hs (
A relationship diagram is shown in which the relationship between (Shore hardness) and ultrasonic propagation velocity was determined experimentally. 1... Subject, 2... Transmitter, 3... Receiver, 4
... Ultrasonic transverse wave, 5 ... Ultrasonic surface wave, 6 ... Ultrasonic transmitting and receiving section, 7 ... Propagation time measurement section, 8 ... Path length calculation section, 9 ... Propagation velocity calculation Part, 10... Memory part, 11... Hardness calculation Figure 1 Horoscope h

Claims (1)

[Claims] 1. A hardened layer measuring device that nondestructively measures the thickness of a hardened layer of a cylinder whose surface has been hardened by measuring the propagation time and propagation distance of an ultrasonic beam. A non-destructive cured layer measuring device, characterized in that the distance between a wave transmitter that transmits the ultrasonic beam and a wave receiver that receives the ultrasonic beam is measured using ultrasonic surface waves.