where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

YXLON International GmbH
YXLON International - innovative High-Tech-Company with long traditionYXLON International develops, manufactures and markets digital radios ...
321 views
Technical Discussions
thanh
,
university, Vietnam, Joined Mar 2019, 3

thanh

,
university,
Vietnam,
Joined Mar 2019
3
10:37 Apr-19-2019
DNV-OS-F101

Dear colleague !
I have a question need your help. In OFFSHORE STANDARD DNV-OS-F101 (2013), APP E (H600 test welds) AUT Qualification sample. In Table E-2 Number of deliberate flaws for GMAW J prep welds. in defects type group Root & HP/radius regulated Specifically 29 defects per one but just beside is (7*). please show me what is "7". My identify in 601 "However,
EDM notch technique may substitute 70% of the total number of flaws in each flaw group.....Hence a minimum of 30% natural flaws shall be part of the data population". So, 7* is number of natural defect shall be induced in qualification sample ? 22 defects rest may substitute by EDM notch ? it right ?

 
 Reply 
 
Edward Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1282

Edward Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1282
14:56 Apr-19-2019
Re: DNV-OS-F101
In Reply to thanh at 10:37 Apr-19-2019 (Opening).

In my copy of OS-F101-2013, the HP/radius category in Table E-2 requires 29 flaws but in brackets it states (*6)...not *7 as you are stating. The comment column suggesting combining the 2 zones is only applicable when the zones are combined. The new edition of the standard is also significantly different in the requirements for a project-specific validation, requiring less than 29 observations.

Firstly, a note on the applicable standard. DNV-OS-F101 has been replaced by DNVGL-ST-F101 (https://rules.dnvgl.com/docs/pdf/dnvgl/st/2017-12/DNVGL-ST-F101.pdf). There is a significant change relating to the use of EDM notches in the latest edition.

The asterisk plainly defines the number at the bottom of Tables E-2, E-3 and E-4. There you read:
* Number of defects for project specific AUT procedure validation.
So your assumption is incorrect! *7 is NOT the number of natural defects.

Project specific AUT Procedure validations are detailed in the next section (Section I) of Appendix E of the 2013 edition and apply only to previously qualified systems/procedures.

For the initial qualification you will still need to conform to the larger number of flaws in each column of the Tables E-2, E-3 and E-4.

I pointed out that the old 2013 edition has been replaced by the 2017 edition because there is a very important sentence added with regards to the EDM notches. Also, the 3 tables are now grouped into a single table.

In the new standard you read in Appendix E 8.7.2 "... Machined imperfection techniques shall not be used to produce ID and OD surface breaking imperfections due to the similarity to the reference reflector for these channels."

Therefore the only place that EDM notches can be used in the fabrication of the qualification test welds is to prepare simulations of subsurface nonfusion flaws.

From personal experience I suggest you make quite a few more flaws in the test coupons than you see listed in the Tables in the DNV standard. EDM notches are often melted away as you make subsequent welding passes. So even though you measured the EDM notch after it was made and it was 15mm long and 3mm high, it may be only 5mm long and 0,5mm high (or not exist at all) after welding.
You are also to avoid flaws being too closely spaced along the length of the weld and also avoid stacked flaws.
Since you must eventually slice, polish and macro-photograph each flaw used for the POD qualification, you may find that you have introduced unwanted flaws that are too close to the flaws you had intended. As a result, your ultrasonic responses may be distorted and the detection and sizing analysis will not be suitable for the requirements of DNV.
Unsuitable defect-indications are to be removed from the data set. Therefore, you had best ensure that you have other suitable candidates to choose from.
Ed





 
 Reply 
 

Product Spotlight

Lyft™: Pulsed Eddy Current Reinvented

PEC Reinvented—CUI Programs Redefined Corrosion under insulation (CUI) is possibly the greatest u
...
nresolved asset integrity problem in the industry. Current methods for measuring wall thickness with liftoff, without removing insulation, all have severe limitations. Eddyfi introduces Lyft — a reinvented, high-performance pulsed eddy current (PEC) solution. The patent- pending system features a state-of-the-art portable instrument, real- time C-scan imaging, fast data acquisition with grid-mapping and dynamic scanning modes, and flexibility with long cables. It can also scan through thick metal and insulation, as well as aluminum, stainless steel, and galvanized steel weather jackets. Who else but Eddyfi to reinvent an eddy current technique and redefine CUI programs. Got Lyft?
>

NovaScope 6000

The all-digital Novascope 6000 is a portable, ultra-high precision thickness gauge for high-speed
...
thickness measurement. Novascope 6000 has unmatched capabilities and unique features including: •Superior Resolution with high contrast, high-speed color RF display •High pulser voltage •Real-time video output •Increased internal/external data storage •Programmable SetUp features •Battery & AC Powered
>

NDT Master Lecturer

In the program both university professors and practitioners will give lectures, which guarantees the
...
oretical depth and practical inside. Academic Director: Prof. Dr. Christian Boller
The following lecturers are not complete: Prof. Tadeusz Stepinski, Prof. Wieslaw Staszewski, Prof. Frank Walther, Prof. Giovanni Bruno, Prof. Gerd Dobmann, Prof. Philippe Guy
>

Teletest Focus+

Teletest Focus+ electronics have superior capabilities than rivals on the market. Beyond the usual
...
test features, Focus+ has 24 transmit channels and 24 receive channels, with an additional on-board switching capabilities. The instrument's frequency range is 10–300 kHz.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window