GB2105466A

GB2105466A - Measuring the deburring contour in longitudinal seam welded pipes

Info

Publication number: GB2105466A
Application number: GB08225592A
Authority: GB
Inventors: Otto Gotting; Leibnizstr Walter Hess; Friedrich Hohwahl; Reinhard Pawelletz
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1981-09-09
Filing date: 1982-09-08
Publication date: 1983-03-23
Also published as: FR2512546A1; GB2105466B; JPS5855854A; IT1190985B; DE3136150A1; IT8223135A0

Abstract

To determine the wall thickness profile of a longitudinally welded pipe in the region of the weld seam 2, an ultrasonic test head 3, coupled to the pipe by water stage 4 is reciprocated across the weld seam by servo motor 7. A plurality of wall thickness measurements are carried out, and stored so that on completion of a tranverse of the untrasonic test head a wall-thickness profile may be displayed. The profile may be compared with a standard profile in evaluation system 6 so that deburring faults may be detected and eliminated during production of the pipe. <IMAGE>

Description

SPECIFICATION The measurement of the deburring contour in longitudinal seam welded pipes The invention relates to the measurement of the deburring contour in longitudinal seam welded pipes by ultrasonic means.

It is known to check the internal deburring of pipes by ultrasonic means with the aid of angle test heads. A disadvantage in these methods is the fact that the testing evidence is undifferentiated as regards the type of fault.

Furthermore, edge-free deburring faults such as undercuts are not detected and a contour reproduction is not possible.

The invention seeks to provide a technique by which directly after the deburring defects which are present are detected, they can be evaluated and acted upon if necessary, immediately. To this end, in a method according to the invention of continuously measuring by ultrasonic means the deburring contour in a longitudinal seam welded pipe, a series of wall thickness measurements are carried out using at least one oscillating ultrasonic impulse wave test head as it crosses the deburring zone, the measurement of each oscillating movement being stored and reproduced to generate a deburring profile. A typical oscillating frequency is in the range 1 to 4 Hz.

The method of the invention may include the step of providing signals indicative of deviations from pre-set minimum and maximum values of the wall thickness. Further, provision may be made for comparing each measurement pulse with a preset profile, and initiating an evaluation of any deviations from this pre-set profile. In some embodiments, the wall thickness measurements are carried out twice over a given deburring zone.

Apparatus according to the invention for carrying out the above method comprises a transportable testing device with an oscillatable ultrasonic impulse wave test head and means for providing a precursory water stage, the device being connected to a wall thickness measuring instrument and a memory system; and means for generating a deburring profile therefrom. A plurality of test heads may be included in the testing device.

Using the apparatus of the invention, an operator can detect the deburring contour on, for example, on oscillograph screen in an analogous scale. Deviations from the pre-set profile can also be made evident. In this way, deburring faults are detected as and when they occur and can be eliminated without interrupting the flow of production, or they can be avoided. Thus an improvement in output can result with additionally a reduction of the deburring defects.

The invention will now be described by way example and with reference to the accompanying diagrammatic drawings wherein: Figure 1 shows in transverse elevation, a testing apparatus situated on the pipe; and Figure 2 illustrates the measurement technique in diagrammatic form.

In Figure 1, the testing apparatus 1 is arranged over the seam weld 2 and is equipped with one or more impulse wave test heads 3, a precursory water stage 4, a wall thickness measuring instrument 5, a memory and evaluation system 6, and a servo-motor 7.

Figure 2 shows the priciple of the ultrasonic impulse wave wall thickness instruments according to the counting method, with representation of the testing device, the ultrasonic signal 8, the processing times 9, the measurement gate 10, the oscillator-measurement frequency 11. In this drawing SI = transmitting pulse; OE = surface echo; RE I = first rear wall echo; RE II = second rear wall echo; t1 = precursory water stage; t2, t3 = pipe wall thickness; t4 = wall thickness-anticipated range.

Mode of Operation An ultrasonic signal 8 emanating from the impulse wave test head 3 passes through a precursory stage 4 in time t1 and on entry into the material 2 to be tested produces an ultrasonic signal 8. Through this signal 8 a counter is started, which counts a measurement frequency. After passing through the wall thickness 2 in time t2, an ultrasonic signal is produced in turn on the rear wall, by which the counter is stopped.

The measurement frequency pulses counted during the time t2 are proportional to the wall thickness. Each individual measured value in an interval of at least 0.1 mm on the oscillation stroke is stored. On completion of a stroke, all the stored values are represented corresponding to the oscillation path, whereby the deburring contour is reproduced full-scale on a screen or recorder.

The profile measured in this way is compared with the pre-set profile filed in the memory system 6. Deviations are detected and pre-given tolerance deviations are made known optically and acoustically.

In a preferred mode of application of the evaluation apparatus, the transverse over the contour to be tested amounts to 40 mm, and is divided into path pulses of 0.1 mm. The start pulse lies in the reversal point of the oscillation stroke.

With this start pulse the reversal point is cleared again and re-released. Consequently, for each 0.1 mm path pulse a storage of the measured value takes place. At the same time these measured values are fed digitally to a computer, in which the pre-set contour is filed. Through suitable calculator processes a contour comparison is carried out.

The re-call of the individual memory locations takes place in synchronism in the path pulse interval of 0.1 mm and is represented proportionally to time on a screen. Likewise, the pre-set contour and the comparison evaluation appear on the screen.

1. A method of continuously measuring by

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION The measurement of the deburring contour in longitudinal seam welded pipes The invention relates to the measurement of the deburring contour in longitudinal seam welded pipes by ultrasonic means. It is known to check the internal deburring of pipes by ultrasonic means with the aid of angle test heads. A disadvantage in these methods is the fact that the testing evidence is undifferentiated as regards the type of fault. Furthermore, edge-free deburring faults such as undercuts are not detected and a contour reproduction is not possible. The invention seeks to provide a technique by which directly after the deburring defects which are present are detected, they can be evaluated and acted upon if necessary, immediately. To this end, in a method according to the invention of continuously measuring by ultrasonic means the deburring contour in a longitudinal seam welded pipe, a series of wall thickness measurements are carried out using at least one oscillating ultrasonic impulse wave test head as it crosses the deburring zone, the measurement of each oscillating movement being stored and reproduced to generate a deburring profile. A typical oscillating frequency is in the range 1 to 4 Hz. The method of the invention may include the step of providing signals indicative of deviations from pre-set minimum and maximum values of the wall thickness. Further, provision may be made for comparing each measurement pulse with a preset profile, and initiating an evaluation of any deviations from this pre-set profile. In some embodiments, the wall thickness measurements are carried out twice over a given deburring zone. Apparatus according to the invention for carrying out the above method comprises a transportable testing device with an oscillatable ultrasonic impulse wave test head and means for providing a precursory water stage, the device being connected to a wall thickness measuring instrument and a memory system; and means for generating a deburring profile therefrom. A plurality of test heads may be included in the testing device. Using the apparatus of the invention, an operator can detect the deburring contour on, for example, on oscillograph screen in an analogous scale. Deviations from the pre-set profile can also be made evident. In this way, deburring faults are detected as and when they occur and can be eliminated without interrupting the flow of production, or they can be avoided. Thus an improvement in output can result with additionally a reduction of the deburring defects. The invention will now be described by way example and with reference to the accompanying diagrammatic drawings wherein: Figure 1 shows in transverse elevation, a testing apparatus situated on the pipe; and Figure 2 illustrates the measurement technique in diagrammatic form. In Figure 1, the testing apparatus 1 is arranged over the seam weld 2 and is equipped with one or more impulse wave test heads 3, a precursory water stage 4, a wall thickness measuring instrument 5, a memory and evaluation system 6, and a servo-motor 7. Figure 2 shows the priciple of the ultrasonic impulse wave wall thickness instruments according to the counting method, with representation of the testing device, the ultrasonic signal 8, the processing times 9, the measurement gate 10, the oscillator-measurement frequency 11. In this drawing SI = transmitting pulse; OE = surface echo; RE I = first rear wall echo; RE II = second rear wall echo; t1 = precursory water stage; t2, t3 = pipe wall thickness; t4 = wall thickness-anticipated range. Mode of Operation An ultrasonic signal 8 emanating from the impulse wave test head 3 passes through a precursory stage 4 in time t1 and on entry into the material 2 to be tested produces an ultrasonic signal 8. Through this signal 8 a counter is started, which counts a measurement frequency. After passing through the wall thickness 2 in time t2, an ultrasonic signal is produced in turn on the rear wall, by which the counter is stopped. The measurement frequency pulses counted during the time t2 are proportional to the wall thickness. Each individual measured value in an interval of at least 0.1 mm on the oscillation stroke is stored. On completion of a stroke, all the stored values are represented corresponding to the oscillation path, whereby the deburring contour is reproduced full-scale on a screen or recorder. The profile measured in this way is compared with the pre-set profile filed in the memory system 6. Deviations are detected and pre-given tolerance deviations are made known optically and acoustically. In a preferred mode of application of the evaluation apparatus, the transverse over the contour to be tested amounts to 40 mm, and is divided into path pulses of 0.1 mm. The start pulse lies in the reversal point of the oscillation stroke. With this start pulse the reversal point is cleared again and re-released. Consequently, for each 0.1 mm path pulse a storage of the measured value takes place. At the same time these measured values are fed digitally to a computer, in which the pre-set contour is filed. Through suitable calculator processes a contour comparison is carried out. The re-call of the individual memory locations takes place in synchronism in the path pulse interval of 0.1 mm and is represented proportionally to time on a screen. Likewise, the pre-set contour and the comparison evaluation appear on the screen. CLAIMS

1. A method of continuously measuring by ultrasonic means the deburring contour in longitudinal seam welded pipe wherein a series of wall thickness measurements are carried out using at least one oscillating ultrasonic impulse wave test head, as it crosses the deburring zone, the measurement of each oscillating movement being stored and reproduced to generate a deburring profile.

2. A method according to Claim 1 wherein the oscillating frequency is in the range 1 to 4 Hz.

3. A method according to Claim 1 or Claim 2 including the step of providing signals indicative of deviations from pre-set minimum and maximum values of the wall thickness.

4. A method according to any preceding Claim wherein the measurements are carried out twice over a given deburring zone.

5. A method according to any preceding Claim including the steps of comparing each measurement pulse with a pre-set profile, and initiating an evaluation of any deviations from this pre-set profile.

6. A method of measuring the deburring contour in a longitudinal seam welded pipe substantially as described herein with reference to the accompanying drawings.

7. Apparatus for measuring the deburring contour in a horizontal seam welded pipe comprising a transportable testing device with oscillatable ultrasonic impule wave test head and means for providing a precursory water stage, the device being connected to a wall thickness measuring instrument and a memory system; and means for generating a deburring profile therefrom.

8. Apparatus according to Claim 7 wherein the testing device includes a plurality of said impulse wave test heads.

9. Apparatus for measuring the deburring contour in a longitudinal seam welded pipe substantially described herein with reference to the accompanying drawings.