02:24 May-15-2019 Re: Ultrasonic test austenitic cast steelsIn Reply to Roberto Bellomio at 20:53 May-14-2019 (Opening).
Dear Roberto, are you looking for an acceptance criteria or method of inspection? You can try to read ASME V Art. 5: Ultrasonic Examination Methods for Materials (for Methods of inspections) and for acceptance criteria, you have to make and agreement with the customer the most of the times, or what say the manufacturer.
14:25 May-20-2019 Re: Ultrasonic test austenitic cast steelsIn Reply to Anmol Birring at 17:17 May-18-2019 .
Ultrasonic testing of cast austenitic stainless steel is not basically feasible expecially on the piece in object. I point up "cast " and not "hot rolled or forging of ASS". There is a lot of reason why this methode is not applicable. In particular: (1) a cast structure of ASS have a highest dB/mm attenuation (2) the kind of solidification ( from liquid to solid) generates a particular structural morphology made of coarse grains and large dendrites resulting in highest noise. In other words no back ground echo .(3) Even using a low frequency longitudinal probe such as F= 0,5 - 1 Mhz , you should be forced to use large diameter one and this is not applicable to the piece of this thickness due the large width of the pulse and/or dead zone. Finally, the orientation of cast structure will give a different results in terms of dB /mm.
15:44 May-21-2019 Re: Ultrasonic test austenitic cast steelsIn Reply to Roberto Bellomío at 20:46 May-20-2019 .
the annex Norma is not applicable to cast austenic stainless steel (ASS). Just a look to page 44 you can verify that it refers to ferritic and martensitic SS. In the same Norma, it make not sense the sentence refered to cast austenitic and duplex SS at pag.43 ( ""Special measured must be specified by parts involved""). Special measured means "miracle" ? Why not inform that cast austenitic SS cannot be test by UT due to the reasons reperted to my previous mail ? A minimum of knowledge of metallurgie of stainless steels should be required to technicians (3 level) that generate this Norma.
Yes I agree with the comments before. This is not a trivial issue, but I trust the idea that the harder is the job, the more intresting is.
Please take a trip on the doc I've attached. If you think this doc intresting for your task, Ive got some references for probe producers I tested in a recent past.
15:44 May-22-2019 Re: Ultrasonic test austenitic cast steelsIn Reply to BRUNO ZILLI at 20:55 May-21-2019 .
Bruno, thank you for EJAM Annex.
As you know there is a lot of technical papers about this subject in NDT.net and the conclusion of these papers are +/- the same.
About EJAM annex, the Authors do not inform about the kind of ASS of Nuclear reactor in service. They said is the same of specimens. It is important to know the steel grade because , during the service, there is a precipitation phases and/or intermetallics in austenitic structure and at interface ferrite stingers/austenitic grains.The UT waves have a different behaviour in these conditions. Therefore, UT wave propagation and coeficient of attenaution ( dB/mm) could be very different. Just to say that the results obtained in the specimens could be very "far " when compared to the structure of reactor in service. An austenic grade such as 316 will have a structural different behaviour compared to a Super-austenitic or Ni -alloy structure. All thes ones have a austenitic structure but their structure ,after long lasting aging, will be different also in terms of behaviour in UT testing due to intermetallics, phase and coarse grain and so on. At end of story, the CASS is one of UT trouble even if the PA and next/future probles will reduce difficulties and inprove the capabilty of indications capabiltiy.
17:54 May-22-2019 Re: Ultrasonic test austenitic cast steelsIn Reply to tiziano ceccon at 15:44 May-22-2019 .
Yes the didnt specify the metallurgical structure, they noticed that the test had been made on both welded and thermically aged cass. To do a complete report, they should have reported the grain size and intermetallic phases. Probably they did it.
But in my opinion the conlclusion is intresting for us. The pod with traditional ut would be high, and sizing with customized double large probes too.
Now, it's up to Roberto. If the work is worth, there are producers around the world to make such probes.
Had He needed some references, I would have been glad to give him some names.
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