RU2772555C1 - Device for detecting defects on the surface of rolled section steel and pipes - Google Patents

Abstract

FIELD: rolling.

SUBSTANCE: invention is aimed to detect defects on the surface of rolled section steel and pipes. The essence of the invention consists in the fact that the device for detecting defects on the surface of rolled section steel and pipes contains a roller for transporting the object of control, a height-adjustable table and a measuring module mounted on it containing at least two rotating sensors designed to measure parameters characterizing the physical properties of the surface of the object of control, and/or to record their changes, at the same time, laser profilometers are used as sensors, located, as a rule, at an equal angular distance from each other around the object of control and, as a rule, in one section relative to the axis of the transport roller, and their measuring line is oriented along the direction of transportation of the object of control, and the minimum number of N rotating laser profilometers is determined by a given mathematical expression.

FIELD: expanding the scope of the device for detecting defects on the surface of rolled section steel and pipes of any cross-sections, improving the ability to detect variously oriented defects on the surfaces of control objects, increasing the operational reliability of the device, simplifying its design and increasing the resolution of its measuring module.

1 cl, 2 dwg

Description

The invention relates to the field of non-destructive testing of materials of metal products, and can be used to detect surface defects in rolled products, for example, bars, and pipes.

Widely known are devices for magnetic or eddy current testing of rolled products and pipes, which are measuring modules installed on tables, including eddy current or magnetic sensors, relative to which the objects of control are moved using a transport roller table. At the same time, when passing over the defects present on the surface of the test object, the sensors generate electrical signals, the amplitude of which depends on the depth and size of these defects.

In particular, the design of the installation for non-contact ultrasonic and/or eddy current and/or magnetic testing of cylindrical products is known according to the utility model patent of the Russian Federation No. 139681, publ. 04/20/2014, IPC G01N 29/04 (selected as a prototype), including a transport system designed to transport objects of ultrasonic or magnetic testing, a stator part located stationary or conditionally stationary relative to the transport conveyor during the control, a hollow rotor, on board of which there are at least two multichannel magnetic, eddy current or electromagnetic-acoustic transducers with drives and suspension elements, analog electronics blocks connected to them, a system for transmitting supply voltage to elements located on the rotor, a system for transmitting informative signals from the rotor to electronic modules located motionless relative to the transport system, and a computer complex containing a computer, additionally placed on board the rotor: mechanical, electrical and electronic elements for controlling the drives of ultrasonic, magnetic or eddy current transducers o change the rotation orbit of the above converters, blocks of analog-to-digital conversion and digital signal processing, as well as standard ports and devices for transmitting digital signals directly to the computer of the computing complex, while all informative signals, at least most of the informative signals with the sides of the rotor are transmitted in digital form, as a system for transmitting informative signals from the side of the rotor to the computer, a device for wireless transmission of information is used, consisting of a transmitter mounted on the side of the rotor and a receiver installed on the stator part of the installation.

To ensure the operation of this installation, as well as other similar devices, it is necessary that the gap between the surface of the test object and the sensors be relatively small - on the order of one millimeter and, at the same time, relatively stable along the entire length of the test object. Therefore, such devices are mainly used to control products of circular cross section. This implies two significant design drawbacks of such devices:

- with their help it is impossible to control objects of control of any other section, except for round, for example, hexagonal or rectangular;

- rotating sensors can be easily damaged by defects and irregularities present on the surface of the test object.

All this imposes very strict requirements both on the stability of the shape of the test object, and on its curvature and position on the transport roller table, which reduces the level of safety of using such devices.

Another common disadvantage of the known devices is their relatively low resolution both along the direction of movement of the control object and across it.

For example, the receiving coils of eddy current sensors have a characteristic size from several millimeters to several tens of millimeters. Therefore, all changes in the measured parameters of the test object will occur precisely on this characteristic base, which limits the accuracy of determining the size and shape of detected defects, especially for small defects. It is also known that the best application of such devices is the detection of predominantly longitudinally oriented surface defects, which have an extension in the direction of transportation of the test object, commensurate with the physical dimensions of the receiving coils. For this reason, known devices are poorly applicable to the detection of defects with a transverse orientation.

In addition, a feature of these devices is the use in them, as a rule, of only one pair of sensors located opposite, which is due to the fact that the sensors rotating in a relatively small orbit, equal to or close to half the diameter of the test object section, should not physically interfere with each other. friend. For this reason, to ensure high inspection performance, it becomes necessary to rotate the sensors with the highest possible angular velocity, which has a negative impact on the safety of the device, since the high angular velocity of rotation of the sensors can increase the likelihood of their destruction in collisions with protruding surface defects, and also accelerates wear of bearings, which leads to a decrease in the operational reliability of the equipment.

Other disadvantages of the known devices also include the need to fine-tune the orbit of rotation of the sensors relative to the dimensions of the section of the test object. This responsible procedure requires a high concentration of attention from operators, which means that it carries the risk of a negative manifestation of the human factor. In addition, the need for precise adjustment of the rotation orbit of the sensors significantly complicates the design of the measuring module.

The present invention solves the technical problems caused by the design shortcomings of the known devices for magnetic or eddy current testing of round billets and pipes, including their complexity, the presence of restrictions on the shape of the profile of the test objects, the low resolution of the measuring devices and the existing limitations of their functionality for detecting variously oriented surface defects of test objects.

The technical result of the present invention is to expand the scope of the device for detecting defects on the surface of long products and pipes of any sections, improving the ability to detect variously oriented defects on the surfaces of test objects, increasing the operational reliability of the device, simplifying its design and increasing the resolution of its measuring module.

The specified technical result is achieved using a device for detecting defects on the surface of long products and pipes, containing a roller table for transporting an object of control, a table adjustable in height and a measuring module installed on it containing at least two rotating sensors designed to measure parameters characterizing physical the properties of the surface of the test object and / or registration of their changes, while laser profilometers (their alternative name is laser triangulation sensors) are used as sensors, located, as a rule, at an equal angular distance from each other around the test object, and, as a rule, in one section relative to the axis of the transport roller table, and their measuring line is oriented along the direction of transportation of the test object, while the minimum number N of rotating laser profilometers is determined by the formula:

N ≥ V _max / B x ω _max (1), where:

V _max is the maximum (required for reasons of achieving a given device performance) speed of the test object, mm/s;

B is the working area of the laser profilometer in the direction of transportation of the test object, mm;

ω _max is the maximum allowable angular speed of rotation of laser profilometers, revolutions/s, which is determined by the formula:

ω _max = dx F / πD (2), where:

d is the minimum characteristic size of the defect in the direction perpendicular to the transportation of the test object;

F is the frequency of measurements performed by the laser profilometer;

D is the minimum diameter of the circle in which the section of the test object can be inscribed.

Figures 1 and 2 show an example of the design of the proposed device, which indicate:

1 - Measuring module;

2 - Safety cover;

3 - Stabilizing pressure rollers;

4 - Laser profilometer;

5 - Block of flaw detection electronics;

6 - Device lifting mechanism;

7 - Horizontal movement mechanism;

8 - Roller table.

The device for detecting defects on the surface of long products and pipes contains four laser profilometers 4 rotating in the same orbit, which are installed on a rotating measuring module 1. Stabilizing pressure rollers 3 located at the inlet and outlet of the device serve to fix the test objects transported along the roller table 8.

Blocks flaw detection electronics 5 provide pre-processing of signals coming from laser profilometers 4 and their transfer to a computer (the computer is not shown in the Figures). The mechanism for lifting the device 6 above the line of the roller table 8 provides its height adjustment, and the horizontal movement mechanism 7 ensures the device is brought to the service area. The safety of the operator is ensured by the safety cover 2.

The claimed device works as follows:

The first control object to be controlled enters the control zone and is pressed against the input stabilizing roller 3 on the move. Moving further along the roller table 8, the control object reaches the section in which the laser profilometers 4 rotate.

At the same time, their number, for example, N = 4, must satisfy formula (1), for which formula (1) is used for specific conditions in the form:

N ≥ V / B x ω (3).

For example, if the speed of the control object is V = 1500 mm/s; the capture width of the laser profilometer B = 200 mm in the direction of transportation of the test object, and the angular velocity of rotation of the profilometers ω = 2 rpm, then in this case, condition (3) is satisfied, since 4 > 1500/200 x 2 = 3.75. This means that the number of laser profilometers is chosen correctly and at a speed of V = 1500 mm/s, complete (without gaps) coverage of the workpiece surface with laser profilers is ensured.

Then calculate the minimum in the direction of rotation of the profilers 4 (or, which is the same, in the direction perpendicular to the axis of the workpiece), the size of the detected defect d.

For example, if the frequency F = 4000 Hz, and the cross section of the test object is round with a diameter D = 100 mm, then from formula (2) it follows that:

d = πD x ω / F (4).

Substituting specific values into formula (4), we obtain the value of the size of the detected defect:

d \u003d π x 100 x 2 / 4000 \u003d 0.157 mm.

That is, the minimum defect size in the direction perpendicular to the axis of the test object is 157 microns.

In the case, for example, if it is necessary to detect a defect of half the size (d = 80 microns), then, as can be seen from formula (4), it is necessary either to double the operating measurement frequency F - up to 8 kHz, or to halve the angular velocity ω of rotation laser profilometers - up to 1 revolution per second.

It can also be seen from formula (4) that a two-fold decrease in the diameter of the test object automatically leads to a doubling of the resolution (or, which is the same, to a decrease in the minimum detectable defect of size d) in the direction of rotation of the laser profilometers.

Claims (10)

A device for detecting defects on the surface of long products and pipes, containing a roller table for transporting the test object, a height-adjustable table and a measuring module installed on it, containing at least two rotating sensors designed to measure parameters characterizing the physical properties of the surface of the test object, and / or registration of their changes, characterized in that laser profilometers are used as sensors, located, as a rule, at an equal angular distance from each other around the test object and, as a rule, in one section relative to the axis of the transport roller table, and their measuring line is oriented along directions of transportation of the object of control, while the minimum number N of rotating laser profilometers is determined by the formula: N ≥ V _max / B x ω _max , where: V _max is the maximum speed of the test object, mm/s; B is the working area of the laser profilometer in the direction of transportation of the test object, mm; ω _max is the maximum allowable angular velocity of rotation of laser profilometers, rpm, which is determined by the formula: ω _max = dx F / πD, where: d is the minimum characteristic size of the defect in the direction perpendicular to the transportation of the test object; F is the frequency of measurements performed by the laser profilometer; D is the minimum diameter of the circle in which the section of the test object can be inscribed.

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