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 -

Ultrasonic Sciences Ltd
We specialize in the design and manufacture of automated and semi-automated ultrasonic testing systems, including multi axis, multi channels systems and phased array electronics.
797 views
Technical Discussions
Nigel
Engineering, - Specialist services
United Kingdom, Joined Oct 2000, 1096

Nigel

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1096
00:14 Oct-12-2006
Looking for root erosion in thin-walled duplex stainless steel welds

We have air coolers on our plant (oil & gas) part of which consists of a row of 1 inch dia, 1,6 mm to 3,5 mm wall thickness duplex (22% Cr, UNS31803) tubes TIG welded with matching filler metal to an 8 inch duplex header (wt 11 - 18mm). Weld ferrite content range 35% - 65%.

I am no corrosion engineer but it seems that duplex is susceptible to weld root erosion or cracking in case of wet-upset in an H2S environment. So we wish to check the weld roots for such whilst new equipment fabricated from material more-suited to the potential environment are procured.

A simulation test rig of one header with 4 or 5 tubes welded in place is being made for performance demonstration purposes. Do anybody have experience of such configurations? Is low-frequency eddy current a possibility? Or DC MPI - knowing that the permeability variations may produce non-relevant indications. As the material/configuration set-up is difficult to inspect I expect signal interpretation and evaluation will be a problem. Any ideas?


 
 Reply 
 
Sayed H. El-Nekhaly
R & D
Delta Steel Mill Company, Egypt, Joined Jun 2006, 7

Sayed H. El-Nekhaly

R & D
Delta Steel Mill Company,
Egypt,
Joined Jun 2006
7
05:52 Oct-20-2006
Re: Looking for root erosion in thin-walled duplex stainless steel welds
This type of corrosion known as intergranular corrosion. It result due to depletion of chromium to be concentrated on grain boundaries during welding of high chromium stailess steel. Traces of nitrogen within range (0.1 - 0.5%) added as alloying element in duplex stainless steel can prevent this type of corrosion. The mechanism occured by catching chromium as chromium nitrid which prevent depletion then corrosion cracking.


 
 Reply 
 

Product Spotlight

NEW! The PragmaPro Instrument Platform

The PragmaPro is based on a modular cartridge technology and supports various NDT instrument modal
...
ities such as UT, PAUT, ECT and many more. This new platform is based on a machined, powder-coated aluminum frame for shock-proofness, best sealing qualities and maximum heat dissipation. This is practical to extend the outdoor temperature range and/or to extend the power injected in the transducers. The PragmaPro is aiming at a very wide range of applications, such as weld scanning, corrosion mapping and composite testing.
>

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.
>

IRIS 9000Plus - Introducing the next generation of heat exchanger inspection.

Representing the seventh generation of the IRIS system, the IRIS 9000 Plus has nearly 200 years of c
...
ombined field inspection experience incorporated in its design. This experience combined with a strong commitment to quality and a history of innovation has made Iris Inspection Services® the undisputed leader in IRIS technology.
>

Navic - Steerable Modular Automated Scanner

The Navic is a modular, motorized, steerable scanner designed to carry multiple attachments used
...
in various scanning and inspection applications. The Navic is capable of weld scanning (girth welds and long seam welds), automated corrosion mapping, and tank scanning.
>

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