TPi July 2017

Ring pair corrosion monitoring equipment – such as that provided by Teledyne and manufactured by Arc Energy Resources – is specified when high resolution, real-time metal loss measurement on the full pipeline diameter is required. Figures 2 and 3 show examples of Teledyne ring pair corrosion monitors – complete and in production. These are good examples of both weld overlay clad and fabricated products. Arc Energy Resources Arc Energy Resources’ weld overlay cladding services are used by clients in a large number of industry sectors where service conditions require corrosion-resistant properties. The company’s weld overlay and weld inlay service offers a reliable and high quality product. The scope of supply includes flanges, elbows, tees, reducers, pipes, dished ends, valves, vessel strakes, heat exchanger tubesheets, fabricated sub- assemblies and various other geometries. Cladding can be carried out on components as small as 20mm and as large as 4m in diameter. Overhead cranage exists up to 15T, though heavier components can be accommodated. In addition to the cladding workshops, Arc Energy Resources maintains a radiographic-quality fabrication facility and segregated stainless steel workshop, allowing it to project manage more complex structures such as pressure vessels and spools (both clad and unclad). The company also holds ASME U and U2 stamps, so can provide a full range of services in compliance with the ASME code. Arc Energy Resources’ machine shop provides CNC milling, turning and drilling to tight tolerances. It specialises in flanges, connectors and other subsea components. In-house NDT incorporates visual inspection, dye penetrant inspection (DPI), ultrasonic testing (UT), magnetic particle inspection (MPI), radiographic testing (RT), dimensional inspection and CNC coordinate measurement (CMM). This, along with in-house procurement, design-for-manufacture, project management and heat treatment facilities, allows Arc Energy Resources to provide a complete one-stop shop for all cladding, fabrication and machining requirements. Summary Corrosion continues to challenge the oil and gas industry. The control of corrosion requires a combination of calculation and prediction of likely product content, design of the pipeline, protection of the pipe bore and monitoring of the actual corrosion activity. With a comprehensive combination of these disciplines, successful control of corrosion can be achieved. Arc Energy Resources has over 22 years’ experience in the protection of pipeline equipment from corrosion and is happy to discuss solutions to any corrosion problems a client may be facing.

Figure 2: Teledyne ring pair corrosion monitor

will meet 316L composition. When Alloy 625 is used (as it is in the vast majority of clad pipelines), the usual acceptance standard for chemical composition is either 5% Fe or 10% Fe. While this measure does not give an absolute indication of corrosion resistance, it is a good indicator of the quality control mechanism in place during welding – a high level of iron means that the weld has penetrated too deeply into the base metal, causing the higher dilution. It is not a direct measure of corrosion resistance. Figure 1 shows an example of pipe weld overlay cladding. The component is a riser and, for this application, there were concerns regarding fatigue resistance. As a consequence, the acceptance standard for inspection was reduced to 1mm. The bores were machined smooth and the cladding was tested with dye penetrant and compression wave angle probes. Pre-production qualification testing will include corrosion testing to ASTM G48 practice A, at 50°C for Alloy 625 and ASTM A262 Practice E for 316L. Cladding is invariably undertaken with the gas tungsten arc process using hot wire addition to the wire consumable. Post-welding NDT for weld overlay clad pipe comprises visual inspection using video cameras, plus ultrasonic, dye- penetrant inspection. Acceptance standards are extremely tight (UT, Ø1.5mm flat bottomed hole; DP, Ø1.6mm indication). Testing also includes PMI, clad thickness measurement and, in some cases, laser surface recording. Corrosion monitoring Corrosion performance within pipes is monitored by means of intrusive devices such as smart pigs, which are intelligent sensing devices that are introduced into a pipeline and usually carried by the product along the length of the pipe. The devices are able to measure and transmit dimensional data regarding the pipe bore, and will highlight heavily corroded areas.

Figure 3: Corrosion monitor during weld

Arc Energy Resources Ltd – UK sales@arcenergy.co.uk www.arcenergy.co.uk

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TUBE PRODUCTS INTERNATIONAL July 2017

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