August 2009 Vol. 236 No. 8

TechNotes

Arc Energy Creates Specialist Site For Weld Overlay Cladding

A Center of Excellence for weld overlay cladding technology has been established by Arc Energy Resources at its Gloucestershire facility in the United Kingdom.

In addition to driving forward new technologies, the new site will act as a focal point for the extensive expertise built up over more than 25 years of supplying increasingly specialized weld overlay services for the oil and gas industries.

The company’s core technology is the design and manufacture of the mechanized weld overlay work stations and the associated control systems that coordinate welding conditions with the physical movements of the welding head and the work piece.

Understandably, research and development activities at the new center will focus on bringing new equipment and welding processes to the point where they are robust enough to be rolled out to production. Others activities are aimed at evaluating alternative non-destructive testing methods for weld overlay or supporting customer specified test programs.

All Arc Energy’s mechanized weld overlay workstations and control systems are designed and built in-house as machine tools to provide accurate control over the stepping and positioning of the welding head and welding parameters. Because the welding heads can be adapted to handle different welding processes, Arc Energy is able to offer its customers important benefits, including:

• Flexibility to clad pipe or more complex components.
• Reduced post-machining time through optimized filler deposition and smooth finish.
• Welding heads adaptable to GTAW or higher deposition rate processes.
• Welding audit trail: automatic parameter monitoring.
• Weld overlay of internal diameters down to 50 mm.
• Portability – the new generation of machines can be configured for site-based weld overlay.

As well as undertaking R&D projects to maintain its own technical advantage, the center carries out welding procedure qualifications and development projects for clients. Current projects include alternative non-destructive testing methods for weld overlay inspection, ongoing enhancements to weld overlay stations and control systems, welding process parameter optimization and new approaches to clad pipe butt welding.

Typical of the weld overlay cladding contracts recently completed by Arc Energy was a challenging order to clad the internal surfaces of two regulator globe valves for Dresser Inc., a leader in the supply of products and technologies for energy applications worldwide.

The 1,400-mm long, 16-inch diameter, 900# regulator globe valves are specially designed for high-pressure service in the oil and gas sector to control the flow of very aggressive fluids.

Alan Brown, Arc Energy sales director, says it was an extremely challenging project because many areas within the valve bodies were almost inaccessible to the company’s existing cladding workstations. Therefore, the company created dedicated fixtures to hold the valve bodies and a special welding torch to reach the inaccessible areas.

The cladding operation, using Inconel 625, was then performed in bands, which also meant frequent setting and resetting of the welding equipment. Arc Energy also carried out 100% non-destructive testing of the cladding to confirm its integrity, prior to returning the valves to Dresser for final machining.

Author
Alan Robinson, Arc Energy’s Managing Director, is a chartered edrngineer with a master’s of science degree in welding engineering.