1. September 13, 2011 David Workman Senior Engineer, Resistance and Solid-State Welding Email: dworkman@ewi.orgdworkman@ewi.org Phone: 614.688.5244 Resistance Seam Cladding

2. Resistance Seam Cladding for Linepipe – Background  CRA pipe ─316 SS or High-Ni alloys  CRA is becoming critical ─Gas applications with CO 2 and Cl ions ─Fluid applications with H 2 S ─Abrasion resistance  Very expensive as a solid pipe  Clad CRA pipe ─Reduced cost per foot of piping system ─Steel substrate with 2- to 3-mm clad layer  CRA cladding methods are: ─Roll bonding ─Metallurigical bonded ─50% of market ─Mechanical bond ─Plastic deformation of CRA ─30% of market  Other clad processes: explosion and arc cladding

3. Why Resistance Seam Clad?  Shorter turn time (reduced WIP)  Faster production rate  Simple parts configuration  Flexibility to alter pipe or CRA on the fly  Lower cost $/per foot less than other metallurgical cladding processes (estimated $1150/foot at 150-mm diameter)  Comparatively low capital investment  Ability to use DOM pipe

4. Flat Plate Trials – EWI Project No. 51549GTO  Trials between flat steel plate and 1- to 3-mm CRA clads  Thermal analyses associated with the process evaluated  Clads showed up to 100% bonding  Surfaces were flat to within 100 μm  Improved thermal profiles seen with thinner clad layers  Shear test failed in base metal  Proof of concept established

5. Weld Quality when Applying CRAs to Steel Pipe with RSeWC  Full-face bonding observed during testing  Shear tests failed consistently in the clad  Adaptation to pipes showed better than 90% bonding  No dilution seen on the sectioned pipe samples  Tracking and surface quality being addressed by improved tooling

6. Metallographic Sections  Narrow fusion zone apparent between CRA and Pipe  Free of voids  Fusion zones overlap to create continuous welded interface

7. Process Adaptations to Round Pipe – EWI Project No. 52864IRD  Adaptation of deep reach seam welding system ─200-kVA transformer ─Dedicated tooling for pipe positioning ─Flood cooling integral to the process  Steel pipe ~10-mm wall × 350-mm diameter  Inconel 625 liner rolled from sheet stock ~2-mm thick  Process adapted to the deep reach welding frame ─Lower speeds and currents

8. Functionality of the Welding System  Water cooling to protect wheels  Process adaptations for specific welding system  Industrial level cleaning of pipe for joining  Demonstrated overlays to create continuous attachments  Minimal residual heat from the process  Minimal disruption to clad surface  Wheel designs to minimize disruption of external pipe surface

9. How is it Applied to Line Pipes?  DOM pipes can be used or welded pipes  Internal pig is used to transfer force and current through the pipe section without compromising pipe wall  Normal high current Resistance seam welder is used to drive the system  Systems can be ganged to run multiple heads simultaneously  40-foot section very easily managed in production set- up

10. Why Does it Work?  The welding process is laid out to confine fusion zone to the CRA –Pipe ID interface ─Proprietary surface preparation techniques  Resistance seam welding is an established process for joining similar material thickness parts  Solidification of fusion zone occurs under welding force applied by wheels to create sound microstructure  Process is self regulating  Welding force maintains fit-up between CRA and Pipe ID

11. Modeling of Thermal Profile in Joint

12. Speed Effect on Thermal Profile in Joint

13. State of Technology  Shown to meet or exceed user quality specifications for flat plate applications  Round pipe applications require significant equipment investment to reach quality level of flat plate trials ─To date results are above required levels ─Further improvements are expected with tooling enhancement  Cost analysis shows that the process is lower cost than competitive technologies

14. Questions? David Workman Senior Engineer, Resistance and Solid-State Welding Email: dworkman@ewi.orgdworkman@ewi.org Phone: 614.688.5244