Ultrasonic Session III. Opened by Session Chairmen Mr. Erhard and Mr. Pohl. The TOFD topic attracted many people, even the radiography business has been interested in this Ultrasonic session, afraid of losing their market? TOFD & Akzeptanz kriterien - ein perfektes Team? - Abstract H.W. Ehring, F.H. Dyjkstra, J.A. de Raad, T. Touma, Bochum. Presented by Mr. Ehring, RTD Bochum Mr. Ehring pointed out that TOFD requires a good personnel training since the interpretation of screen results are not very simple to do. Main advantages are: defect recognition independent of defect orientation and the method is fast. Disadvantages are: It is difficult to apply on high grain size material, defect recognition in the near surface zone and weld root is only partly possible. These drawbacks can be offset by applying TOFD in combination with conventional impulse echo techniques. Mr. Dyjkstra, who was also present and assisted Mr. Ehring during a lively discussion, brought to our attention: A comprehensive program was applied in the Netherlands in 1995-1997 This showed excellent probability of detection results for TOFD. Whether TOFD is suitable or not should be decided on a case by case basis. No method is perfect under all circumstances. Combination with other methods can be a good solution. One attendee asked: Is TOFD preferable against impulse echo for defect recognition? The answer of Mr. Ehring was a simple "Yes". TOFD- und Impuls-Echo-Messungen an Rohrschweißnähten - Abstract G. Brekow, A. Erhard, H. Wüstenberg, Berlin. Presented by Mr. Brekow It is dangerous to use TOFD in cases where the method can give results contrary to the laws of physics, said Mr. Brekow. Also it can happen that mode conversion causes virtually defects where there are none, thus a clear interpretation is not possible. One questioner asked resignedly: What method can I count on for my work? The session chairman Mr. Erhard concluded: For wall thickness less than 8 mm Radiography can be used, for higher thickness ultrasonic impulse echo technique is suitable, and for extremely thick parts the ultrasonic tandem technique is recommended. TOFD can be used in selected cases for mechanized inspection, however, in combination with impulse echo only, which means it will definitely be expensive. Finally Mr. Dyjkstra suggested: Take the advantages of a combined System, that means 90% POD with Impulse-Echo, plus 90% POD with TOFD, put them together and you have 100% POD! QZFP an Schweißverbindungen mittels 3D-CAD-SAFT - Abstract V. Schmitz, S. Chakhlov, W. Müller, Saarbrücken. Presented by Mr. Schmitz. Defect sizing using the AVG method can result in errors of 3:1 to 6:1. With the SAFT method sizing accuracy can be almost 100%. In conclusion: from a fracture mechanics point of view the AVG method is not suitable. The main part of Mr. Schmitz's lecture introduced a 3D-CAD Model which presents the position of the defect within a drawing of the component. With today's PC techniques the program can run under WindowsNT even on a laptop. However, a simple 2-D task can need a full minute's computing time while a 3-D task can take several days. Panel Discussion Inspection Audit / Welding Audit - in collaboration or in competition (Here is a different review from the DGZfP in German) Moderator: J. Völker, Siemens Berlin On the Panel: C.O. Bauer, Wuppertal U.Cohrs, Blohm + Voss Inspection Hamburg M. Henrichs, HEW Hamburg H. Lorenz, Steinmüller Gummersbach K. Kolb, ZPKO Stuttgart M. Kröning, IzfP Saarbrücken R. Zwätz, SFV Duisburg (DVS) Mr. Lorenz presented the main problems of the EN 713 on a view sheet: - The EN 713 describes only the audit for welding work. - The responsibility is not clear. - The inspection audit costs more. - "Smuggler and Custom Officer" Don't get caught!. Mr. Heinrich: Today's economic situation makes out-sourcing necessary. For example, a complete vessel is now ordered (including NDT). The main contractor uses sub-contractors in inexpensive countries like Poland, Czechoslovakia, etc, and language problems can occur. Bad work is performed and everything must be checked and re-checked. Mr. Meier (MPA) from the audience said. Mr Hinrichs could split the orders, one for manufacturing and another for testing. (Lots of smiles at that; Mr. Meier wants to get orders!). Mr. Zwätz from the welding society SFV Duisburg (DVS) argues that quality doesn't come from testing, but from manufacturing. There was a lot of opposition to that statement. Mr. Heinrichs and Mr. Hueck (VEBA) said that in their experience this theory is wrong. It has been shown that people do better work if they know that their work will undergo a NDT quality check. Mr Kröning had another opinion: it is well known that some manufacturing processes are controlled much better by using NDT within the production process as a kind of sorting device. Mr. Steinhoff (BASF) said that it is necessary to bring the "Inspector vs. Welder" problem to the level of "weld audit vs. inspection audit". In another context he mentioned that "we may need an Internet audit also (but we all knew he was joking). Mr. Hueck: In a large organization the welding quality management has been well-organized for years, the new standard we are now discussing is already standard practice in our company. In general he suggested that all people should be aware of "MY individual work can effect Quality" and not always look to management to take responsibility. Mr Hinrichs: Quality needs must always match the demands of the component (risk), is it a weld of a nuclear power plant or a weld of a street light? Mr Diederichs: I don't really agree with Mr. Hinrichs. A bad street light on a highway can crash the window of a bus carrying 100 people and cause a terrible accident. The calculation of failure consequences is a very important issue. Just yesterday I heard some discussion of the ferry ESTONIA, when 700 people drowned in the East Sea. A 'simple' weld at the rear door was responsible because the weld repair was done very badly by unprofessional overlaid welding. Mr. Koch who was closely involved in the investigation of this accident confirmed that it was indeed poor welding quality that led to this terrible accident. Some speakers pointed out that knowledge exchange (education) between NDT and welding professionals is essential. Today the inspector knows little of the welder's job and vice versa. With respect to this, Mr. Diederichs stood up and gave an example of how the German Welding Society (DVS) ignored NDTnet's request for collaboration, was not communicative at all. We all need free exchange of information.

Mr. Völker closed the dispute by offering following terms as good goals for both disciplines: