Recently, an ECHOGRAPH ALPT testing system was successfully commissioned for our customer Otto Fuchs in the German town of Meinerzhagen. The system is a test bridge whose unsupported length allows testing of aluminium billets (round bars) up to 7 m. The bar diameters are between 130 mm and 530 mm. On this test bridge a test carriage with 10 test systems is mounted. These test systems can be lowered individually. The central height adjustment is done automatically by entering the bar diameter. After determining the exact axial position of each part to be tested (by means of linear positioning system located at the stops), it is automatically selected which of the test systems will be used. Then, by entering the untested ends, the corresponding start and end positions of the test systems are set. For testing, continuous rotation of the bar is started with the help of a rotating roller station, whereby the rotational speed is individually selected according to the maximum possible pulse repetition frequency. Each of the test systems can be lowered onto the surface of the round bars and is guided on the surface with the help of a protective base and four rollers. The height clearance of the test systems is ± 40 mm to compensate for any straightness deviations. In addition, the inspection systems have a cardanic suspension with three degrees of freedom.
The ultrasound enters the bars via a guided water jet. During the test, internal defects are checked by means of perpendicular insonification. The coupling check is carried out by monitoring the surface echo and the backwall echo. Inspection with two angle probes per inspection system enables the detection of surface cracks. After inspection, the bars are taken to the exit side of the inspection bridge by means of a transport trolley and deposited there on another rotary roller station. While the next bar is examined in the inspection station, the detected defects as well as the uninspected ends are marked in colour at this exit-side rotary roller station.
In addition to the ECHOGRAPH-ALPT testing system, the scope of supply also included the infeed with separation, the rotary roller stations below the test bridge and in the outfeed, the marking station as well as the bar deposit in the outfeed and the entire safety fencing with CE declaration of conformity. The test is based on the specification AMS-STD-2154A according to class AA (0.8 mm FBH) up to a diameter of 264 mm and class A (1.2 mm FBH) for larger diameters. Due to a fast transverse transport underneath the test bridge and the high circumferential speed of up to 1 m/s, a total cycle time between 2.5 and 10 minutes can be achieved. The findings are provided in the form of strip charts and flaw tables. Set-up of the test system is carried out by means of adjusting blocks of different diameters. The elaborately manufactured adjusting blocks were provided with eroded flat bottom holes at different depths and with surface grooves. Each test flaw was applied five times into the adjusting blocks to enable fast and efficient adjustment of the 10 testing systems.