does anyone have experience in the UT for longitudinal defects of tubes with OD 88,9mm and wall thickness of 3,2mm acc. to SEP1915.
We want to use standard probes like MWB45-4 or MWK45-4 (they are available) which have to be adapted using test coupon of same dimensions with ineer and outer notch of 0,2 mm depth. It is a manual testing of 24m tubes.
I guess the probes are not the right ones, does anyone have a recommondation for it?
Thanks in advance
17:21 Mar-11-2009 Michel Couture NDT Inspector, , consultant, Canada, Joined Sep 2006 593
I'm not familiar with your acceptance criteria and don't know what your probe looks like from the part number either except maybe that it is a 45┬║ Degree angle. But, at first glance, I would probably use a 12 mm diameter, 5 MHz probe (if your code allows, if not 2.25 MHz) with a 60┬║ Degree shoes. By my calculation the maximum angle you can use for this inspection in order to inspect the Inside Diameter is 68┬║ Degree, so 60┬║ Degree would be fine. This angle will provide you with a longer Skip Distance. With a 45┬║ Degree, your Skip Distance should be 14.39mm (because of the pipe curvature), where a 60┬║ Degree would give you a Skip Distance of 27.74 mm. This longer Skip Distance will allow you to find detect without them sitting under your transducer. Also, the shoe should be shape to the diameter of the tube to offer maximum contact and steady signal response.
On the other, I wonder if you have given Eddy Current a taught? You don't give much information regarding the material of the tube, but I'm sure a Low Frequency Eddy Current (LFEC) probe could be made (I assume you have access to the inside of the tube). You may want to look at the following codes for guidance: ASTM E215, E426 and E690.
Hope this will be of help.
16:29 Mar-12-2009 Michel Couture NDT Inspector, , consultant, Canada, Joined Sep 2006 593
I,m sorry, I,ve made a mistake in my calculations. According the tube diameter you are inspecting, the Skip distance for a 45┬║ degree shoe will be 7.19 mm and with the 60┬║ degree, the Skip Distance will be 13.87 mm. These value only reinforce my advise to use a 60┬║ degree shoe since with the 45, any indication found in the first half-skip will most likely be under the shoe and harder to map out.
thanks for your advice. The test block will be ready next week then I will start my trials. I'll inform You about results.
The material shall made ready for higher requirements by this examination...
16:09 Mar-13-2009 Dent Consultant, NDE Manager and Level III/3, Consultant, Canada, Joined Nov 1998 204
Ultrasonic testing of seamless steel tubes for pressure purposes during or after production using direct contact angle beam probes is not state of the art.
Immersion or bubbler technique with a mechanized system has to be used. When using standard immersion probes the required beam angles are provided by simple inclination of the probe.
With a 3,2 mm wall thickness inner and outer defects may be detected with the same beam angle. The suited angle has to be verified with the required test tube containing notches.
As German Specification SEP 1915 is referenced: This steel iron specification (SEP) of the German Association for Steel and Iron (VDEh) is withdrawn since many years.
Actual standard now is EN 10246-7:2005
Non-destructive testing of steel tubes - Part 7: Automatic full peripheral ultrasonic testing of seamless and welded (except submerged arc welded) tubes for the detection of longitudinal imperfections
(for longitudinal imperfections only),
which soon will be replaced by an EN ISO standard. Draft standard is already available:
Non-destructive testing of steel tubes - Part 10: Automated full peripheral ultrasonic testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of longitudinal and/or transversal imperfections
(for longitudinal and transverse imperfections)
I am working in company that use special profilled tandem probes for flaws detection in thin pipe welds (2..8mm). There is the article on the web :
Maybe it will help you.
21:23 Mar-17-2009 S.Senthilkumar Engineering, QA/QC/NDT, NOV (National Oilwell Varco), Angola, Joined Mar 2006 36
thanks for all advices. It was very interesting getting to know your experiences.
Knowing that direct contact technique is not "stat of the art" I had to try my best to get costumer satisfaction... I calculated 45┬░ as best suitable angle. I tried 45┬░ and 60┬░, the latter was not successfull. So I used 45┬░ for testing at test block using inner and outer notches of 0.2mm depth. I draw a line on the screen for the good area (maximum curve), then I searched for the notches and their echoes were well to be seen as defects. I could convince all my collegues that this technique will be suitable to detect longitudinal defects as demanded by SEP1915.
The tubes are newly manufactured from France, surely detected by UT but the costumer wants that they should be tested using SEP1915.