JPH0222694Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hot rotary flaw detector for testing materials such as steel pipes and round bars.

In the manufacturing process of seamless steel pipes, steel bars, wire rods, etc., defects that occur during the processing process due to materials, defects in manufacturing equipment, setup, adjustment, etc., can be detected immediately after they occur. There is a strong need to detect problems early and take appropriate measures to improve yields.

Ultrasonic, magnetic flux leakage, or eddy current testing methods are used to detect flaws in this type of test material, but in many cases the flaws are detected after the material has been cooled. However, if the test material is cooled, it cannot meet the demand for on-line control that performs non-destructive testing during hot rolling or processing of the test material and provides immediate feedback on the results. In order to incorporate the flaw detection function into the process control loop, it is necessary to detect flaws in the hot rolled and processed state, but in this case, it is necessary to take measures to prevent changes in the characteristics of the test material due to temperature and overheating of the flaw detection method. It is. The present invention mainly relates to the latter, and aims to provide a compact and efficient cooling means for a flaw detection coil in eddy current type hot rotary flaw detection. Next, this will be explained in detail with reference to the drawings.

Figures 1 to 3 show embodiments of the present invention;
The figure is an end view of the flaw detection coil section, and FIGS. 2 and 3 are partial vertical sectional views, and the left end of FIG. 3 is joined to the right end of FIG. 2 to form one drawing. 1a-1 in these figures
d is a flaw detection coil on the circumference surrounding the test material 2.
They are attached to the rotating drum 3 at 90° intervals. In this example, the flaw detection coil 1 (subscripts will be omitted as appropriate) is an inductance coil that is excited by alternating current, and the change in inductance due to flaws in the material to be inspected becomes the flaw detection output. In this example, the number of flaw detection coils is 1a.
The number of flaw detection coils is 1d to 4, but this number can be increased or decreased as appropriate, and the type of flaw detection coil may be changed to any known suitable one. Reference numeral 4 denotes a DC excitation coil, which is a ring-shaped coil through which the test material 2 passes. In hot flaw detection, the magnetic permeability of the material to be tested changes depending on the temperature, and μ=1 at the Curie point. Near the Curie point, molecules move violently, producing a large flaw detection output even though there are no flaws. Further, the temperature of the material to be tested is not necessarily uniform in all parts, but there is temperature unevenness in the circumferential direction or in the longitudinal direction. Temperature unevenness leads to magnetic permeability unevenness, which causes fluctuations in the flaw detection output and therefore noise. DC excitation is effective as a countermeasure against these problems, and this can effectively reduce detection output changes, that is, noise generation.

The rotating drum 3 is provided with a water supply port 5 and a drain port 6 for the detection coil 1 . Further, the rotating drum 3 has a nozzle portion 7 projecting outward in the radial direction, and the nozzle portion forms an annular body to form flaw detection coils 1a to 1d.
The same number of drain ports 6a to 6d (a to d
(omitted in the drawing). The water supply port 5 is connected to a water chamber 8 formed by cylindrical bodies 10 and 9 and a partition wall 11 spirally surrounding the cylindrical body 10 based on the principle of an axial flow pump, and is connected to the left tip of the water chamber 8. A water supply part 12 is provided at the left tip of the water chamber 8 between the cylinders 9 and 11 when the double cylinders 8, 9, 10, and 11 rotate. When the heavy cylinder pump function parts 8, 9, 10, and 11 rotate, they send water in the direction of the arrow while rotating in a spiral manner.

A water supply seal part 13 is provided around the water supply part 12, and this includes a ring-shaped member 13a having an L-shaped cross section;
Ring-shaped member 13b with W-shaped cross section, packing 13
c, 13d, etc. Note that the water supply port to the ring-shaped water supply section 12 is not shown, and the water supply to the pump function section of the double cylinder bodies 8, 9, 10, and 11 is provided through a plurality of ports in the circumferential direction of the outer cylinder body 9. Hole 9
It is done through a.

A bearing 14 is provided at the rear of the pump function section of the double cylinder bodies 8 to 11, and a signal transmission mechanism 15 between rotating and stationary members using a slip ring or a rotary transformer is provided at the intermediate portion. Electrical connection between the flaw detection coil 1 and an external circuit is made by a signal transmission mechanism 15 and a conductive wire (part of which is shown by a chain line 16) running in a groove provided in the surface of the cylindrical body 9. 21 is nozzle 7
A ring-shaped cover surrounding the rotation locus prevents wastewater from scattering. Numerals 19 and 20 are inlet/outlet sleeves that are always in close proximity to the specimen 2 and have the function of always maintaining a distance from the sensing surfaces of the flaw detection coils 1a to 1d to prevent damage to the flaw detection coils. The outlet sleeve 19 is fixed to an outlet sleeve holder 22. The inlet sleeve 20 is fixed to an inlet sleeve holder 223.

The flaw detection coil 1 is movable in the radial direction as shown in FIG. That is, the support rod 17 of the coil is threaded and is screwed into a member 18 fixed to the rotating drum 3. Therefore, support rod 1
By turning 7, the flaw detection coil 1 moves forward and backward in the direction of the arrow, and the position of the flaw detection coil can be adjusted to the diameter of the material 2 to be inspected. In FIG. 1, this position adjustment mechanism is shown only for coil 1a, but coil 1a
The same is provided for b to 1d.

Next, to explain the operation of this flaw detector, the heated test material 2 enters from the left end of Fig. 2 in the direction of the arrow, and enters the third
It passes through to the right edge of the diagram and is inspected during this time. That is, the flaw detection coil 1 detects flaws on the circumferential surface of the test material 2 as the rotary drum 3 rotates, and on the other hand, since the test material moves straight, the entire circumferential surface of the test material is detected in a spiral manner. Since this device is equipped with a DC excitation coil 4, it is possible to adjust the excitation current of the coil according to the temperature of the material to be tested and apply an appropriate DC saturation magnetic field to the material to be tested. Flaws can be detected at any temperature in the material, including before and after the Curie point.

If the material being tested is at a high temperature, measures must be taken to prevent the flaw detector from overheating. Regarding this point, in the present invention, the flaw detection coil 1 is made of a heat-resistant type, and the cooling water is supplied by a double cylinder pump function part 8 that rotates together with the flaw detection coil.
Supplied by Further, drainage is performed by a plurality of nozzles 7 provided along the outer circumferential direction, the same as the number of flaw detection coils. This nozzle part 7 releases water by centrifugal force,
Therefore, cooling water to the flaw detection coil is powerfully supplied by the double cylinder pump function section 8 and the nozzle section 7.
Further, bearings 14, 14' and a signal transmission mechanism 15 are attached to the intermediate portion of the double-tube pump function section 8, and these are also effectively cooled by the double-tube pump function section. Note that the DC excitation coil 4 is stationary, and its cooling is performed by a known appropriate method.

The manufacturing process for hot-rolled steel bars and steel pipes involves rolling mills such as mandrel mills, reheating and soaking furnaces,
It consists of a stretch reducer, a cutting machine, a cooling bed, a straightening machine, etc., and the flaw detector of the present invention is installed on the entrance or exit side of the stretch reducer.

As is clear from the above description, the present invention can provide a compact, effective, and powerful cooling mechanism for the flaw detection coil in rotary hot flaw detection, and has great practical value.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is an end view of a flaw detection coil section, and FIGS. 2 and 3 are partial longitudinal sectional views. In the drawing, 1 is a flaw detection coil, 2 is a test material, 8 is an axial flow pump, 12 is a water supply section, 5 is a water supply port to the flaw detection coil, 6 is a drain port, 7 is a nozzle, and 15 is a signal transmission mechanism. .

Claims (1)

[Claims for Utility Model Registration] (1) Principle of a pump equipped with a double cylindrical body through which the test material penetrates, in a hot rotary flaw detector equipped with a coil that detects flaws while rotating around a heated test material that moves in a straight line. A fin-like screw partition using a fin-like screw is provided between the double cylinders, a water supply part is provided at one end of the cylinder, and a water supply port for the flaw detection coil is provided at the other end, so that the inner and outer peripheries of the cylinder are evenly cooled with water. Furthermore, after cooling the flaw detection coil, water is discharged through multiple nozzles provided on the outer periphery of the rotating disk (ring) by the action of centrifugal force, and a signal transmission mechanism is also installed to connect the flaw detection coil and the external circuit. A hot rotating flaw detector characterized by being attached to a cylindrical body. (2) The above-mentioned hot rotary flaw detector is characterized in that a fixed DC excitation coil is installed in front of the rotating drum on which a plurality of flaw detection coils are attached in order to generate lines of magnetic force in a direction in which the test object passes through the axis. A hot rotary flaw detector according to claim 1 of the utility model registration claim.