DD233878A1 - METHOD AND DEVICE FOR TESTING THE QUALITY OF SWEEPING - Google Patents

Abstract

The invention relates to a method for controlling the quality of welds by means of video radiography, in which the weld seam of the object to be examined is transilluminated stepwise with a Roentgen or gamma ray, whereupon the Roentgen recording of the seam and its surroundings generate corresponding electrical signals. The image is saved, displayed and evaluated, then the process step is repeated at the next place. According to the invention, two radiation sources (2, 3) irradiating the same area are provided, which are operated in an alternating pulse-like manner. Accordingly, electrical signals are generated which are compared with similarly generated signals of a pattern seam. Fig. 3

Description

For this 2 pages drawings

Field of application of the invention

The invention relates to a method and a device for testing the quality of welds.

Characteristic of the known technical solutions

As is well known, the quality of welds can be controlled by a radiographic method, by imaging the fluoroscopic seam on a film and evaluating the developed film, which documents the quality of the seam. There are also known means by which the X-ray image can be displayed by means of an industrial TV chain. In general, however, this solution is not used or recognized as a document, although the video image may be magnetically recorded and subsequently reproduced in any number.

By none of the known methods is it possible to obtain a correct spatial picture of the errors. Although there are cases where spherical storage can still be expected, there is no sharp shallow storage.

The X-ray image is the same for both cases, so that both seams are to be repaired.

However, it does not matter which seam surface the error is closer to, and from which starting point the scraping or the like is appropriately started for the purpose of repairing.

Consequently, there is no doubt that it is necessary to know exactly the spatial arrangement, the dimension and the shape of the seam defects. However, the currently known methods are not suitable for this purpose.

Object of the invention

The aim of the invention is to develop a method and to provide a device for its implementation, with which the spatial arrangement, the shape and the size of the seam defect points can be determined, the method should enable a documentable quality control.

Explanation of the essence of the invention

Accordingly, the invention relates to the testing of welds by means of videography, wherein the weld of the object to be tested stepwise, d. H. is illuminated from point to point with an X-ray or gamma ray and the X-ray image of the seam and its surroundings corresponding electrical signals are generated, after which the recording is stored and displayed simultaneously. The recording is evaluated and the procedure repeated on the next Steep.

The essence of Frfindung is that in the course of the examination perpendicular to the longitudinal axis of the seam to be tested and symmetrically to the vertical axis two with the same intensity obliquely downwards the same surface irradiating radiation sources are arranged, being symmetrical to the same vertical axis and parallel to the longitudinal axis and the transverse axis the signal field of the image recorder (directed to the irradiated surface) is arranged.

In this case, the axes of the radiation sources and the axis of the signal field fall in the same plane. The first radiation source is operated in the pulse mode and the obtained Röntgenruheaufahmeme converted into electrical signals, after which this first recording is stored. Thereafter, the second radiation source operates in pulsed mode. In the next phase of work, the two stored recordings are compared with a reference recording recorded using the same method, representing perfect seams with identical signal errors. If the identity is determined, the seam part is qualified as faultless and, if deviated, as faulty. On the basis of the first image, the size of the first error projection of the transverse axis and on the basis of the second image the second error projection are determined, whereupon the error coordinates X ₀ , Y ₀ are calculated according to the following formula:

-3- 757

^X o = ^L

X '+ X

X'-X

+ 2L

+ L

(L * X ₀ ).

L half the distance of the radiation source,

M is the height of the radiation source,

V the night thickness and

Δ 'is the distance between the signal field

and the lower level of the seam.

The calculated error coordinates are recorded, at the same time the sequential number of the step in the direction of the longitudinal axis is registered as a third error coordinate, whereupon the measuring device is moved parallel to itself by one unit. These process steps are repeated stepwise over the full length of the seam. Furthermore, the invention relates to a device for testing welds, in which above the subject to be tested seaming a radiation source and including a Biidaufnahmevorrichtung are arranged, wherein the latter an image display, an image memory and a special computer are connected. The gist of the invention is that a second radiation source is disposed over the article, with the axes of the first image pickup device, the first radiation source, and the second radiation source falling in the same plane and being connected to an actuating mechanism that moves them. The radiation sources are in this case arranged symmetrically to the vertical axis of the seam and directed obliquely downwards in such a way that the following conditions are met.

t_rK. , w7 2 L + q α

^yj 2 M "" 2^f

Kv G "2 ~ 2

in which:

t the diameter of the signal field,

Δ 'is the distance of the signal field from the lower level of the seam,

V the thickness of the seam,

L half the distance of the radiation sources,

M is the height of the radiation sources above the upper level of the seam,

g the width of the seam,

K is the lower diameter of the irradiated space,

G is the upper diameter of the irradiated space,

Y _{k is} the height of the crossing points of the ray cone over the seam and

Δ the distance of the crossing points of the beam cone under the seam,

describe.

The radiation sources operate in pulsed mode and are connected to a radiation source control unit which ensures an alternating work of the sources. To the actuating mechanism, a position signal emitting unit is connected, whose output is connected to the image memory, the image display and the special computer. The device also includes a central control unit which coordinates the individual functions and to whose inputs the outputs of the special purpose computers and a time pulse generator are connected. The outputs of the central control unit are located at the control inputs of the special computer, the control unit for the radiation sources and the actuating mechanism.

The inventive device is expediently designed so that the arithmetic unit contains a reference image memory, an image comparator, an intermediate image memory, the Spjzidlrechner, a unit for data input and a recorder memory. The video signal input of the arithmetic unit is connected to the signal inputs of the intermediate image memory, while the output of the intermediate image memory is connected on the one hand to the one data input of the special computer, on the other hand to the one signal input of the special computer and a fault memory. The position signal input of the arithmetic unit is located at the other data input of the special purpose computer and at the other signal input of the fault memory, while the feedback output of the special purpose computer is connected to the signal inputs of the central control unit. The control inputs of the mentioned units are connected to the control inputs of the central control unit, further the basic data input of the special computer is connected to the data input unit.

-4- 757

embodiment

The invention will be explained in more detail with reference to an embodiment below. In the accompanying drawings show:

1: the geometric relationships of the measuring arrangement according to the invention, FIG. 2: an error along the seam,

3 shows the block diagram of the device according to the invention.

As can be seen from FIG. 1, over the seam V of the object to be tested, at the height M, symmetrically to the vertical axis Y of the seam V, two radiation sources 1 are spaced apart from LL; 2 arranged downwards. The radiation sources 1 and 2 operate in pulsed mode and irradiate alternately, ie alternately at an angle α the object 1. The transverse axis X is parallel to the plane of the seam V, the longitudinal axis Z is arranged in the length. The seam V has the thickness v and width g. The space part irradiated by the radiation sources 2 and 3 has the upper diameter G and the lower diameter K, and the beam cones intersect at the height Y _k . The error H present in the seam V is mapped by the projecting beams Si and S _2, respectively, onto the signal field having the diameter t of the image recorder 4, which is located away from the axis by the distance Δ '. The first image shows the first error projection X ', the second image the second error projection X ", from which the error coordinates X ₀ and Y ₀ can be calculated using the equations given below.

X ¹ + X '*

^X o - ^L

X'-X "+ 2L

The error coordinate Z ₀ (in the direction of the longitudinal axis Z) of the error H is determined by the radiation sources 1 and 2, and the image pickup device 4 parallel to itself in the direction of the longitudinal axis Z by steps of length D _z shifts, wherein in each position Pair of shots is made. The sum of the unit steps, multiplied by the number of steps in FIG. 2 of the lengths DZ, gives the length 1 _{H of} the error H, the error coordinate Z ₀ = 1 _H , as can be seen from FIG.

According to the invention, the control of the seam V to be tested is such that the object 1 and 2 and above the signal field T of the image pickup device 4 are arranged, whereupon the radiation sources can be alternately operated in the pulse mode. Then the two Rötgenruheaufnahmen be converted into electrical signals and stored. In the next work phase, the two stored images are each compared with a reference recording, which have also been made using the inventive method of a flawless seam with the same signal field. If an identity is now determined, the seam part is qualified as faultless. In the event of a deviation, the seam is considered to be defective, whereupon the error coordinates X ₀ and Y _{0 are determined} in the manner described. At the same time, the sequence number of the step is registered in the direction of the longitudinal axis. Now another step follows, and the process and the qualification are repeated. The mentioned method steps are repeated step by step over the full length of the seam.

In all cases where a fault is detected, the faulty seam part, z. B. marked with a dye and provided with an identification number, whereby the error points are accurately identified. Knowing the error recordings and the coordinates, the skilled person can clearly make his decisions regarding a rework. Since in the method according to the invention the presence of an error or the flawlessness are clearly documented, the use of an X-ray film is unnecessary.

The block diagram of the device used to carry out the method according to the invention is shown in FIG. The object 1 to be tested with the seam V lies under the radiation sources 1, 2 and over the image recording device 4. The axes of the radiation source 2, 3 and the axis of the image recording device 4 fall in the same plane and are fastened to a common actuating mechanism 5. The radiation sources 2, 3 are arranged symmetrically with respect to the vertical axis Y of the seam V at a distance 2 L from each other directed downwards. For proper operation, it is indispensable that the radiation sources 2, 3, the seam V and the image pickup device 4 satisfy the following relationships:

^ c ₁ 2 M 2

£>£> £ > Yk> v and Δ <CA '2 2 2

in which:

t is the diameter of the signal field in the image acquisition device 4,

Δ the distance of the intersection points of the ray cone under the seam V,

Δ 'the distance of the signal field from the lower level of the seam V,

L half the distance of the radiation sources 2,3,

M is the height of the radiation sources 2, 3 above the upper level of the seam V,

g the width of the seam,

Y _{k is} the height of the crossing point of the ray cones above the seam,

ν the thickness of the seam,

K is the lower diameter of the irradiated space and

-5-757 84

G is the upper diameter of the irradiated space

describe.

The alternating, ie alternating pulsed operation of the radiation sources 2, 3 is ensured by the unit 7 controlling the radiation sources. The actuating mechanism 5 has the task to ensure the common stepwise movement of the radiation sources 2,3, the image pickup device 4 and the flaw marker 17, parallel to itself, along the entire seam V. On the actuating mechanism 5 is the position signal generating unit 6, which provides the mark signals for the image display 8, the image memory 9, the Fohlerspeicher 18 and the special computer 15. The output of the image pickup device 4 is connected to the inputs of the image display 8, the image memory 9, the image comparator 11 and the intermediate image memory 12. The reference image recorded before the measurement is stored in the reference image memory 10 whose output is at the other input of the image comparator 11 whose output is connected to the one input of the central control unit 13. The output of the intermediate image memory 12 is connected on the one hand to the data input of the special computer 15, on the other hand to the other signal input of the error memory 18. The output of the error memory 18 is connected to the error indicator 19 and the printing unit 20. The data input unit 16 is connected to a further data input of the special computer 15 determining the error coordinates, with which data relating to the seam V to be checked can be entered. The data of the special purpose computer 15 appear on the fault indicator 19 and on the printing unit 20, furthermore they control the function of the fault memory 18 and supply the signals required for the coordinated actuation of the entire device for the central control unit 13. At the signal inputs of the central control unit 13 lie the time pulse generator 14, which supplies the clock pulses of the special computer 15, the image comparator 11, the manual slide unit 21 and the switch 22 for manual or automatic operation.

At the same time, the central control unit 13 controls and coordinates the work of the radiation source controlling unit 7, the operation mechanism 5, the image display 8, the reference image memory 10 "of the intermediate image memory 9, the special purpose computer 15, and the flaw marker 17.

By means of the device according to the invention, the seam V present on the article 1 is tested as follows:

The article 1 is placed in the appropriate position in the machine, after which the device is set in motion.

The central control unit 13 emits signals for the unit 7 controlling the radiation sources, whereupon it activates the radiation sources 2, 3 in pulse mode, one after the other (alternately). The X-ray images are perceived by the image pickup device 4, the video signal appearing at its output is now visible on the image display, it is registered in the image memory 9, and also the marking signal of the position signal generating unit 6 is stored here. The image is compared in the image comparator 11 with the recording in the reference image memory 10 - representing a perfect seam - compared. An identity is reported to the central control unit 13, which documents this fact via the special computer 15 with the help of the printing unit 20 with the position signal and the signal formed from the marker signal together and shifts the device in a further measuring position. Thus, with the aid of the actuating mechanism 5, the radiation sources 2 and 3, the error marker 17 and the image pickup device 4 reach their next working position.

If the image comparator 11 now perceives an error, it is reported to the central control unit 13, which sets the program of the special computer 15 to determine the coordinates X ₀ , Y ₀ and the error coordinate Z ₀ in motion.

The special computer 15 receives the data relating to the error from the intermediate image memory 12. The calculated error coordinates X ₀ , Y ₀ and Z ₀ are printed with the position signal and the identification signal from the printer 20 and displayed together with the seam recording at the error indicator 19.

The error memory 18 has the task to store all data and errors relating to an error.

After the evaluation of an error point has been completed, the special computer 15 sends a signal to the central control unit 13, which triggers the marking of the error with the aid of the flaw marker 17 (eg with a dye gun) and the device by means of the actuating mechanism 5 in FIG the next measuring position switches on.

In this way, the device according to the invention controls the seam from step to step.

The image memory 9 ensures the documentation of the entire test, in an always reproducible manner, whereby the calculations can be performed several times.

From the above it can be seen that the invention has the following advantages over the traditional method:

- all film-related operations are unnecessary, making the process faster and cheaper;

- the information on the faults not visible on the films is also available, simplifying and speeding up the process of repair, in some cases even eliminating it;

- The distance between the defect and the seam surface can be determined directly;

- the test results can be documented with a very simple procedure, the documentation is reproduced ь ^! І ".ГасИ and at low cost;

- since exposition times eliminate the insertion and removal of the film,: L-i exchange and development, the test is considerably accelerated;

- By the application of the reference method and a microprocessor, the evaluation is completely automated.

Claims (7)

-1- 757 84 claims: 1. A method for controlling the quality of welds with video radiography, in which the weld of the object to be examined is transilluminated by an X-ray or gamma ray, whereupon the X-ray image of the seam and its surroundings corresponding electrical signals are generated, the image simultaneously in a Image recorder is stored, displayed and evaluated, whereupon this process is repeated at the nearest point of the seam, characterized in that perpendicular to the longitudinal axis of the seam to be tested and symmetrical to the vertical axis two downwardly directed, irradiating the same surface radiation sources of the same intensity are arranged , and that the signal field of the image recorder is arranged symmetrically to the same vertical axis and parallel to the longitudinal axis and to the transverse axis on the irradiated surface, wherein the axes of the radiation source and the axis of the signal field coincide in the same plane n, that then first made a Röntgenruheaufnahme and this is converted into an electrical signal, whereupon the first recording is stored, that then the second radiation source is pulsed and the two stored recordings, each with a previously prepared by the same method reference recording - the one flawless seam With the same signal field represents - are compared that then-if-between these images identity consists of-the seam part is qualified as flawless, while in a deviation, the seam is qualified as faulty, that based on the first shot the size of the first error in the direction of The second error projection is determined on the basis of the second recording, whereupon the error coordinates are calculated according to the following equations: in which L half the distance of the radiation source, M is the height of the radiation source, V is the throat thickness, Δ 'is the distance between the signal field and the lower level of the seam describe, that then the calculated error coordinates are registered, at the same time the sequence number of the step in the longitudinal axis is registered as a third error coordinate, and that then the measuring device is moved parallel to itself in the direction of the longitudinal axis by one unit, after which the individual steps on the entire length of the seam can be repeated. 2. The method according to claim 1, characterized in that the defective seam part is marked on the object and provided with an identification number, which is registered together with the associated error coordinates. 3. A device for carrying out the method according to claim 1 and 2, in which above the the seam to be tested carrying a radiation source and including an image pickup device are arranged and to the latter an image display, an image memory and a special computer are connected, characterized in that there is a second radiation source (3) above the object (1), that the axes of the first radiation source (2), the second radiation source (3) and the image pickup device (4) fall in the same plane, that an actuating mechanism (5) is provided in that the radiation sources (2, 3) are arranged symmetrically with respect to the vertical axis (Y) of the seam (V) and directed downwards so that the arrangement satisfies the following conditions: £ * - (Δ * + V) S,
2 2 M 2 ü> S>, 2 2 2 Y _k > V, Δ <Δ ', in which Δ the distance of the crossing points of the beam cone under the seam, t the diameter of the signal field, Δ 'is the distance of the signal field from the lower level of the seam, V is the throat thickness, K is the lower diameter of the irradiated space, G is the upper diameter of the irradiated space, L half the distance of the radiation sources, M is the height of the radiation sources above the upper level of the seam, g the seam width and Yi _{1 is} the height of the crossing points of the ray cone
describe, -2- 757 84 in that the radiation sources (2, 3) operate in impulse mode and are connected to an alternating function controlling unit controlling the radiation sources, that the actuating mechanism (5) is connected to a position signal emitting unit (6) whose output is connected to the image memory (9 ), the image display (8) and the special computer (15) is connected, and that the arrangement includes a functions tuning the central control unit (13), at the inputs of the outputs of the special computer (15) and a timing pulse generator (14) are connected while the outputs of the central control unit (13) are connected to the control inputs of the special purpose computer (15), the radiation source controlling unit (7) and the operating mechanism (5). 4. A device according to claim 3, characterized in that the computing unit of the device includes a reference image memory (10), an image comparator (11), an intermediate image memory (12), the special computer (15), a data input unit and a fault memory (18), in that the video signal input of the arithmetic unit is connected to the signal inputs of the image comparator (11) and of the intermediate memory (12) such that the output of the intermediate image memory (12) on the one hand to the one data input of the special computer (15) and on the other hand with the one signal input of the error memory (18) - which is controlled by the special computer (15) - connected, that the position signal input of the arithmetic unit at the other data input of the special computer (15 ) and the other signal input of the error memory (18), while the output of the image comparator (11) and the feedback output of the special computer (15) to the signal inputs of the central control unit (13) is connected, and that the control inputs of said units to the Control outputs of the central control unit (13) lie, while a data input unit (16) is connected to the input of the basic data input of the special computer (15). 5. Device according to claim 4, characterized in that to the special computer (15) and the error memory, an error indicator (19) and a printing unit (20) are connected. 6. Device according to claim 3 to 5, characterized in that on the object (your at the central control unit (13) lying fault spot markers (17) is provided. 7. Device according to claim 3 to 6, characterized in that to the central control unit (13), a change-over switch (22) for a manual or automated operation and a hand-operated sliding unit (21) are connected.