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720 views Technical Discussions Nigel Engineering, - Specialist services United Kingdom, Joined Oct 2000, 1094 Nigel Engineering, - Specialist services United Kingdom, Joined Oct 2000 1094 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  Translate  Close   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  Translate  Close   Product Spotlight NDT.net launches mobile-friendly design StandNDT.net NDT.net has revamped its website providing a mobile-friendly design.The front page received a comp ... letely new design and all other sections are now reacting responsively on mobile devices. This has been a major step to make our website more user- friendly. > 2 Showcases3 Videos MUSE Mobile Ultrasonic Equipment StandHillger Ing. Büro The MUSE, a portable ultrasonic imaging system, was developed for in-field inspections of light-weig ... ht structures. The MUSE consists of a motor-driven manipulator, a water circulation system for the acoustic coupling and a portable ultrasonic flaw detector (USPC 3010). The MUSE provides images of internal defects (A-, B-,C- and D-scan). > 3 Videos Ultrasonic Flaw Detector & Thickness Gauge: Smartor StandSIUI (Shantou Institute of Ultrasonic Instruments Co.,Ltd) SIUI’s newly launched Smartor is a combination of ultrasonic testing and ultrasonic thickness me ... asurement. ●IP 66 ●Compact size: 198 (W)* 128 (H) *520 (D) mm ●0.9kg only with battery ●5.7" LCD with high resolution 640×480 pixels ●One-hand operation ●Multiple conventional UT functions ●Smart Test Wizard ●Weld Simulation > 6 Showcases4 Videos Wireless TOFD scanner StandOKOndt GROUP Quick, accurate and highly reproducible welds testing. The System operates wirelessly and is compat ... ible with any type of Windows based Laptop, Desktop or Tablet. > 6 Showcases6 Videos more Showcases Share... Home Exhibition Archive Forum Jobs Members Events Directory NDT A-Z Advertise Privacy Policy Contact About © NDT.net - Where expertise comes together. The Largest Open Access Portal of Nondestructive Testing (NDT)- since 1996 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