JPH0443208B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) Regarding the improvement of the radiographic thickness gauge used for plate thickness measurement, the technical content described in this specification is applicable even when plate thickness is measured by installing a rolling mill radiographic thickness gauge. This paper proposes the development results for obtaining a radiographic thickness gauge that can accurately measure plate thickness without being affected by the vibration shock generated by a rolling mill. (Prior technology) The application of a radiographic thickness gauge to a plate rolling mill is to install a C-shaped frame exclusively for the radiographic thickness gauge at a position of 10 m or more from the rolling mill, and to A radiographic thickness gauge was installed to eliminate the effects of vibration and shock generated by the rolling mill. Radiographic thickness gauges can continuously measure the absolute thickness of hot-rolled materials, such as thick plates, over the entire length of the rolled material without contact, making it easy to reach the target thickness. When modifying plate thickness, etc.
It can be used for effective rolling through AGC control (Automatic Gauge Control). However, as mentioned above, when measuring plate thickness at a location more than 10m away from the rolling mill, there is a significant time delay from when the rolled material leaves the rolling mill until it reaches the radiographic thickness gauge. It was incompatible with AGC control. On the other hand, as a prior art, Japanese Utility Model Application Publication No. 57-65709 discloses a mechanism for protecting the radiation thickness meter from a rolled material that breaks during rolling when measuring plate thickness using a radiation thickness meter (X-ray thickness meter). has been done. However, the detector of a radiographic thickness gauge in particular is an electronic circuit structure whose main parts are a scintillator and a photomultiplier tube, and its natural frequency is usually
It is around 100 to 500 Hz, and if affected by the vibration shock (60 to 600 Hz) that occurs during rolling, it will resonate, making it impossible to accurately measure the plate thickness, and there was a risk of failure in a short period of time. Conventionally, type thickness gauges could not be installed near the housing of the rolling mill. (Problems to be Solved by the Invention) As mentioned above, the problems of conventional radiographic thickness gauges used for plate thickness measurements have been solved, and plate thickness can be measured by installing a radiographic thickness gauge in a rolling mill. An object of the present invention is to obtain a radiation transmission type thickness gauge that can accurately measure plate thickness without being affected by vibrations and shocks received from a rolling mill. (Means for Solving the Problems) This invention provides a radiation source container for storing a radiation source;
A detector for detecting radiation intensity is attached to a pair of connecting frame pieces that vertically sandwich the material to be rolled between the housings on the operating side and drive side of the rolling mill. is a radiographic thickness gauge that is constructed by interposing a high-frequency damping type shock absorber that combines shock absorbing mechanisms with different vibration and shock reduction characteristics between the frame piece, and the above-mentioned shock absorber is The damping mechanism is a high-frequency damping type having a resonance frequency characteristic of 50 Hz or less, which is sufficiently low compared to the vibration frequency component of 60 to 600 Hz, which is unique to the rolling mill. Figure 1 shows an example of the radiographic thickness gauge installed in a plate rolling mill. , 3a, 3b are the lowering screws, 4 is the upper back up roll, 5a, 5b are the upper back up roll yoke, 6 is the upper work roll, 7
is the lower back up roll, 8a and 8b are the lower back up roll yoke, and 9 is the lower work roll. Further, 10a, b are rolling mill housings 2a, 2
b is a connecting frame piece that sandwiches the material to be rolled vertically between
3 is a buffer device. Here, in order to obtain a radiographic thickness gauge that is not affected by the vibration shock of the rolling mill even if a radiographic thickness gauge is installed in the rolling mill and the plate thickness is measured, detection is performed using the shock absorber 13 described below. It is effective to hold the container 12. 2 and 3 are a side view and a plan view of the buffer device 13 that holds the detector 12. FIG. As is clear from the side view shown in FIG.
3b and a spring 13c, the vibration isolating rubber 13a absorbs vibrations of several hundred Hz, and the damper 1
3b has the function of suppressing the vibration of the rolling mill within a short period of time, and extremely reducing the transmission of vibration shock by means of the spring 13c. Furthermore, as shown in the plan view of FIG. 3, this shock absorber 13 fixes the detector 12 at three or more points (in this example, four points are held), so that vibrations in the vertical and horizontal directions generated in the rolling mill are prevented. In addition to absorbing shock, the structure also prevents rotational movement of the radiographic thickness gauge. Therefore, even if a radiographic thickness gauge is installed in a rolling mill, plate thickness can be accurately measured without being affected by vibrations or shocks. The above-mentioned radiographic thickness gauge was attached to the housings 2a and 2b on the operation side and the drive side of the rolling mill using the connecting frame pieces 10a and 10b, but it was also possible to attach the thickness gauge to the housings 2a and 2b on the operating side and drive side of the rolling mill using the connecting frame pieces 10a and b. It is also possible to hold it using a ripper guide or the like. Further, here, the detector 12 is attached to the upper part of the connecting frame pieces 10a and 10b, and the radiation source container 11 is attached to the lower part of the connecting frame piece 10a, but there is no problem even if the installation positions are reversed. (Example) Examples will be described below. As shown in Fig. 1, a radiographic thickness gauge (using a γ-ray thickness gauge) according to the present invention is used on a plate rolling mill (4-fold reversible type: back-up roll φ2400 x
It was installed between the housings of a rolling mill housing (5390 mm, work roll φ1200 mm x 5490 mm), and measured the vibrations and shocks generated in the rolling mill housing and the vibrations and shocks received by the gamma ray thickness meter (detector held by a shock absorber). The installation position of the gamma ray thickness gauge is 1500 from the mill center.
mm, 1000 mm above the pass line (detector), and 400 mm below the pass line (source). FIGS. 4a and 4b show vertical and horizontal vibration data of the rolling mill connecting frame piece 10a and vibration data of the detector 12 according to the present invention, arranged vertically and in comparison. The vibration/shock measured at the rolling mill connecting frame piece 10a is 60-300Hz, 5-10G in the vertical direction, and 60-600Hz, 1-5G in the horizontal direction, whereas the detector 12 according to the present invention It was 20-50Hz and 0.5G or less in the direction, and 18-28Hz and 0.5G or less in the horizontal direction. FIG. 5 shows an example of natural vibration data of a photomultiplier tube, which is a typical electronic component incorporated into the detector 12. Normally, the photomultiplier tube has a natural frequency around 430Hz, but the detector 12 is connected to the buffer device 1.
If the gamma ray thickness gauge fixed at 3 is used, the vibration shock generated in the rolling mill can be sufficiently reduced. Table 1 shows a comparison of the durability of the gamma ray thickness gauges.

[Table] In the example, a case where a gamma ray thickness meter is attached to a thick plate rolling mill is described, but the present invention is not limited to a thick plate rolling mill. Moreover, an X-ray thickness gauge may be attached instead of the γ-ray thickness gauge. (Effects of the Invention) According to the present invention, even if a γ-ray thickness meter is attached to a rolling mill to measure plate thickness, the influence of vibration and shock generated in the rolling mill can be reduced as much as possible, so accurate measurement can be achieved. value can be obtained. Furthermore, the present invention enables AGC control with high responsiveness, making it possible to significantly improve the desired plate thickness accuracy.

[Brief explanation of drawings]

Figure 1 is an external view of the main parts of a plate rolling mill, and Figure 2 is:
FIG. 3 is a side view of the buffer device 13 holding the detector 12, FIG. 3 is a plan view, FIG. 4 is an oscilloscope waveform photograph showing measurement data of vibrations occurring in the rolling mill housing, and FIG. This is an oscilloscope waveform photograph showing measurement data of natural vibration. 1... Material to be rolled, 2a, 2b... Rolling machine housing on operation side/drive side, 3a, 3b... Rolling screw, 4... Upper back up roll, 5a, 5
b...Upper back up roll, 6...Upper work roll, 7...Lower back up roll, 8
a, 8b...Lower backup roll check, 9
...Lower work roll, 10...Connection frame piece, 11...
...Radiation source container, 12...Detector, 13...Buffer device.

Claims (1)

[Claims] 1. A radiation source container that stores a radiation source and a detector that detects radiation intensity are placed between housings on the operation side and drive side of a rolling mill, sandwiching the material to be rolled above and below. A high-frequency damping type shock absorber that combines multiple shock absorbing mechanisms with different vibration and shock reduction characteristics is interposed between the detector for detecting radiation intensity and the frame pieces. A radiographic thickness gauge made of 2 The shock absorber absorbs vibration frequency components unique to the rolling mill60
The radiographic thickness gauge according to claim 1, comprising a high frequency attenuation type damping mechanism having a resonance frequency of 50Hz or less, which is sufficiently low compared to 600Hz.