JPH11248686A - On-line ultrasonic flaw detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic flaw detector capable of dispensing with transporting of materials to be tested including steel plates and improving the productive efficiency. SOLUTION: This detector which is connected to a steel plate treatment line 8 for treatment in manufacturing steel plates includes a ultrasonic flaw detector main body 4 and an on-line cooling device 1 set up on the upstream side thereof to cool steel plates 9 on both upper and lower faces thereof. It also includes an incoming side temperature gage 2 for measuring the temperature of the steel plates on the incoming side of the on-line cooling device 1 and a cooling control device 3 for controlling the cooling ability of the on-line cooling device 1 and the transporting speed of the passing steel plates 9, the cooling control device 3 functioning to calculate the cooling ability required to cool the surface temperature of the steel plates 9 to a temperature of preventing the occurrence of bubbles in water for a ultrasonic medium or the transporting speed of the steel plates from the measured values for the incoming side temperature and the thickness of the steel plates 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to rolling, heat treatment,
The present invention relates to an online ultrasonic flaw detector connected to a steel sheet processing line for performing various kinds of processing on steel sheet production such as shearing.

[0002]

2. Description of the Related Art An ultrasonic flaw detection test is often performed on a rolled steel sheet or a heat-treated steel sheet from the viewpoint of quality assurance. Therefore, it is required to efficiently perform an ultrasonic flaw detection test on a steel sheet conveyed from an on-line accelerated cooling facility or a heat treatment facility installed on the outlet side of a rolling mill.

In an ultrasonic flaw detection test of a steel sheet, for example, water is used as an ultrasonic medium between the ultrasonic sensor and the steel sheet as in the technique described in Japanese Utility Model Laid-Open No. 62-96060. In practice, a water film is formed by spreading water on the upper surface of a steel plate, and scanning is performed by contacting the water film with an ultrasonic flaw detector while scanning.

As described above, since water is used as a medium in the ultrasonic flaw detection test, it is necessary to sufficiently lower the temperature of the steel sheet. Therefore, conventionally, the test was performed after cooling on a cooling floor. In this case, the cooled steel sheet was transported to an ultrasonic flaw detector, or a test was performed on the spot.

For example, Japanese Patent Application Laid-Open No. Sho 62-30952 proposes a portable steel plate automatic ultrasonic flaw detector. In this technique, a scanner for scanning the ultrasonic flaw detector, a rail for sending the scanner, a control cart, and a water supply cart are carried in and a test is performed.

Further, Japanese Utility Model Laid-Open No. 61-48359 proposes a cooling device installed in an automatic ultrasonic inspection line upstream of the automatic ultrasonic inspection device. This device is a technology that includes a cooling water spray device and a temperature sensor, detects the temperature of a steel sheet, and performs cooling control to reach a set temperature.

[0007]

However, the test material is a heavy material such as a steel plate, and in order to transport it from the cooling floor to the test device, it is necessary to carry out a transport operation using a crane, a trolley or the like. A crane and a truck on the cooling floor are installed to carry the steel sheet from the exit side of the rolling mill or the heat treatment equipment and carry it out to the next process such as a finishing yard. Therefore, the equipment capacity of the transport equipment is set according to this purpose, and in order to carry out the work of transporting the test equipment, the transport equipment needs to be strengthened.

In the technology described in Japanese Patent Application Laid-Open No. Sho 62-30952, an automatic ultrasonic flaw detector is installed on a steel plate before each test, and after the test, the device is removed from the steel plate in order to carry out the steel plate. Must. A signal cable, a water supply hose, and a power cable for moving the scanner, which are not described in the gazette, may be connected between the ultrasonic flaw detector and the control trolley, the water supply trolley, and the like. is necessary.

In addition, it is difficult to automatically perform the test work and the work before and after the test work, particularly, the installation of the apparatus and equipment.
Since it depends on human labor, it is against labor saving.
Further, since the cooling floor is not originally a place for performing a test operation, it cannot be said that the working environment is good, and performing the test operation there has a problem in occupational health.

[0010] In addition, since a control cart, a water supply cart and the like are also installed around the test material, a space for that purpose must be secured. It is also necessary to secure a work space on the cooling floor.

In these conventional techniques, a cooling floor is used to cool a test material such as a steel plate to a testable temperature. Cooling in the cooling bed is basically spontaneous cooling, and the cooling rate decreases as the temperature approaches room temperature. Therefore, it takes a very long time to cool to a temperature at which the test can be performed, and there is also a problem that the ultrasonic flaw detection test reduces the production efficiency.

In the technique described in Japanese Utility Model Laid-Open Publication No. 61-48359, cooling of a steel sheet is performed by a cooling water spray device installed on a transport line at right angles to the transport direction. When the cooling water is sprayed on only one surface of the steel sheet as described above, a cooling strain is generated particularly when the cooling water is cooled from a high temperature range, which may make flaw detection difficult.

Although cooling control is performed based on the amount of cooling water, the control range is generally narrow only with the amount of cooling water, and cooling control is impossible. Further, in general, the processing speeds of the cooling water spray device and the automatic ultrasonic flaw detection device are different, and the latter processing speed is high, so that cooling is generally insufficient.

An object of the present invention is to solve the above-mentioned problems in the conventional method of cooling a metal plate, and to provide an ultrasonic flaw detector capable of improving production efficiency without the need to carry a test material such as a steel plate. With the goal.

[0015]

SUMMARY OF THE INVENTION The present invention relates to an on-line ultrasonic flaw detector connected to a steel sheet processing line for performing processing in the production of steel sheets. An on-line thermometer that measures the temperature of the steel sheet on the inlet side of the on-line cooling device, and a cooling device that controls the cooling capacity of the on-line cooling device or the conveyance speed of the steel sheet passing therethrough The cooling control device is provided, and the cooling control device is required to cool the surface temperature of the steel sheet to a temperature at which bubbles do not occur in water for the ultrasonic medium from the measured value of the entrance temperature and the thickness of the steel sheet. An online ultrasonic flaw detector having a function of calculating a cooling capacity or a transport speed of a steel sheet.

In the present invention, the treatment in the production of a steel sheet refers to various treatments in the production of a steel sheet, such as rolling, on-line heat treatment after the rolling, heat treatment, and shearing. Collectively. In addition,
The steel sheet temperature in these steel sheet processing lines is 200 ° C.
Before or after or more. Here, being connected to the steel sheet processing line means that a means for automatically conveying the steel sheet from the steel sheet processing line, such as a transport roll, is provided, and as a result, it is necessary to separately perform a transport operation. Disappears.

The on-line cooling device may be of any type as long as the steel plate can be cooled from both upper and lower surfaces and a certain amount of cooling water can be secured. By cooling the steel plate from both the upper and lower surfaces, deformation such as warpage of the steel plate in single-sided cooling can be prevented. The control range of the cooling capacity or the conveyance speed for determining the cooling water amount is as described below (the section of the embodiment).
What is necessary is just to determine according to the steel plate temperature from the connected steel plate processing line.

The cooling control device calculates a required cooling capacity or a required conveying speed from the temperature difference to be cooled and the thickness of the steel sheet. The temperature difference to be cooled is the difference between the measured value of the entrance temperature and the target temperature. Calculation of cooling capacity or transfer speed
Although heat transfer calculation may be used, it can be easily performed by putting together past actual values and giving them by a table or an empirical formula. Such an arithmetic function can be easily realized by a microcomputer or the like.

The target temperature for cooling the steel sheet is a temperature at which bubbles are not generated in water for the ultrasonic medium. Here, the temperature at which no bubbles are generated in water is because, when bubbles are generated in the water for the ultrasonic medium, the ultrasonic waves are irregularly reflected at the interface between the water and the bubbles, resulting in noise. This temperature is a temperature somewhat lower than 100 ° C. and varies depending on the conditions of the ultrasonic flaw detection test, but it is usually 80 to 90 ° C.

The cooling control device controls the cooling capacity or the transport speed of the online cooling device according to the calculation result. In this case, if the cooling capacity or the transport speed cannot be continuously controlled, the cooling capacity may be controlled to be equal to or higher than the calculation result, or to be equal to or lower than the calculation result.

Since the apparatus according to the present invention can be connected to various kinds of steel sheet processing lines before the ultrasonic flaw detection test by the transfer table, the work of transporting test materials such as steel sheets is unnecessary. In addition, since the steel sheet is cooled to an appropriate temperature by the on-line cooling device, it is possible to use an ultrasonic flaw detector using water as a medium even for a relatively high-temperature steel sheet immediately after various steel sheet treatments, thereby improving production efficiency. Improve.

[0022]

FIG. 1 is a side view schematically showing an example of an embodiment of the present invention. The entire apparatus is connected to a steel sheet processing line 8 in the preceding process by a transfer table 5. An entry-side thermometer 2 is installed on the entry side of this device, and transmits a measured value of the steel plate temperature to the cooling control device 3.

The cooling control device 3 calculates the required cooling capacity or transfer speed, and controls the cooling capacity or transfer speed of the online cooling device 1. Nozzle 1 for cooling capacity
1 is controlled by the amount of water.
Is controlled by the roll rotation speed.

The online cooling device 1 may be of any type, but here, a spray nozzle is used. The lower surface of the steel plate is cooled by using a spray nozzle from between the transport rolls. As specific equipment specifications, the line length of the cooling zone is 6 m, and the cooling water amount is 10 to 16
m ³ / min, and the transport speed is 0.1 to 1 m / s.

The cooling control device 3 calculates the cooling capacity or the transport speed. Here, since the control range of the cooling capacity is small, it mainly calculates the transport speed. The difference between the measured value of the entrance temperature and the target temperature (here, 80 ° C.) is calculated, and the required cooling time t is calculated from the relationship between the plate thickness and the cooling rate in the online cooling device 1.

FIG. 2 shows an example of the relationship between the plate thickness and the cooling rate. This drawing is input to the cooling control device 3 in the form of a table, and is used for calculating the cooling time t. Needless to say, instead of the relationship between the plate thickness and the cooling speed, the relationship between the plate thickness and the cooling time or the relationship between the plate thickness and the transport speed may be directly input.

Next, the cooling control device 3 divides the line length L of the cooling zone by the required cooling time t to obtain a transport speed V = L
/ T is calculated. These arithmetic functions are realized by a computer. In this case, the transport speed is of a four-stage speed change type, and the cooling time of the steel sheet is ensured by transporting at a transport speed lower than the obtained transport speed.

The temperature of the cooled steel plate 9 is checked by the outlet thermometer 6 installed in the cooling device, and the steel plate 9 is inserted into the ultrasonic flaw detector main body 4. Further, if feedback to the cooling control is performed using the measured value of the outlet thermometer 6, more appropriate cooling control can be performed. In the ultrasonic testing apparatus main body 4, the steel plate 9 is used.
Is cooled to an appropriate temperature, so that an ultrasonic inspection test with high accuracy can be performed without generating bubbles or the like. The outlet thermometer 6 does not need to be installed, but if the temperature results are collected by this, it is convenient for optimizing the cooling conditions of the online cooling device, studying the saving of cooling water, and the like.

In addition, when the length of the steel plate, such as a long object, is long, the transport table of the on-line cooling device and the ultrasonic flaw detector main body span both, so that both rotations need to be synchronized. Therefore, it is preferable to control the speeds of both transfer tables by a signal from the cooling control device.

In FIG. 1 described above, the transfer control device 31 controls the speed of the transfer table. When the transport control device 31 sends a signal to the flaw detection mechanism control device 32, the flaw detection mechanism control device 32 controls the ultrasonic flaw detection device main body 4 to perform ultrasonic flaw detection of the steel plate.

Since the cooling water contains a large amount of air bubbles generated on the surface of the steel sheet, it causes noise in ultrasonic flaw detection, lowering the measurement accuracy and making it impossible to perform ultrasonic flaw detection itself. For example, in the technique described in Japanese Utility Model Laid-Open Publication No. 61-48359, a mechanism for performing ultrasonic flaw detection while cooling a steel sheet is used, so that cooling water flows into the automatic flaw detection apparatus.

Therefore, it is desirable that the cooling water discharged from the on-line cooling device does not flow into the ultrasonic testing device main body. As one of means for solving this, the installation location of the online cooling device is set at a position that is longer than the length of the steel plate from the ultrasonic testing equipment main body. In this way, the steel sheet does not enter both the ultrasonic flaw detector main body in the on-line cooling device and the cooling water can be prevented from flowing into the automatic flaw detector.

Alternatively, as another means, the jet direction of the cooling water nozzle is directed to the upstream side. Thereby, the water flow on the steel plate is guided to the upstream side, so that the cooling water can be prevented from flowing into the automatic flaw detector. In this way, it is possible to perform ultrasonic flaw detection without a decrease in measurement accuracy or the like.

[0034]

According to the present invention, since the ultrasonic flaw detector can be connected to various steel sheet processing lines, the work of transporting test materials such as steel sheets becomes unnecessary. In addition, since the temperature is cooled to an appropriate temperature by the online cooling device, the ultrasonic flaw detector using water as a medium can be used even immediately after various steel sheet treatments, thereby improving production efficiency.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing one example of an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a relationship between a plate thickness and a cooling rate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Online cooling device 2 Inlet thermometer 3 Cooling control device 4 Ultrasonic flaw detector main body 5 Transport table 6 Outlet thermometer 8 Steel plate processing line (pre-process) 9 Steel plate 11 Nozzle 31 Transport control device 32 Flaw detection mechanism control device

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Akira Murayama 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (1)

[Claims] An on-line ultrasonic flaw detector connected to a steel sheet processing line for performing processing in steel sheet manufacturing, wherein an on-line cooling apparatus for cooling a steel sheet from both upper and lower surfaces is installed upstream of the ultrasonic flaw detector main body. In addition, it has an inlet thermometer for measuring the steel sheet temperature on the inlet side of the online cooling device, and a cooling control device for controlling the cooling capacity of the online cooling device or the conveyance speed of the steel sheet passing therethrough, The cooling control device determines the cooling capacity or the transport speed of the steel sheet required to cool the surface temperature of the steel sheet to a temperature that does not cause bubbles in the water for the ultrasonic medium from the measured value of the entrance temperature and the thickness of the steel sheet. An online ultrasonic flaw detector having a function of calculating.