Welding technique boosts pipework productivity

GrowHow, the UK's largest manufacturer of ammonia, nitric acid and agricultural fertilisers, chose Arc Machines' (AMI) equipment to join high temperature, primary reformer catalyst tubes that carry a mixture of steam and natural gas for converting methane to CO and CO2, leaving nitrogen and hydrogen available for ammonia production. AMI provided full training and weld procedure qualification to a nominated sub-contractor appointed by GrowHow as well as supplying three M95-2375 orbital welding systems and a M227 power supply for the project, which required guaranteed high weld quality and speed unachievable by a manual process. Accuracy is key GrowHow's Ammonia Mechanical Engineer, Nick Oates, commented: "The catalyst tubes are heated up to around 890°C on their outside so it was crucial the weld quality met our strict criteria. Access was difficult and the work had to be carried out in a confined space, even so the Arc Machines equipment coped very well. Productivity was around 50% higher than using manual welding and the weld quality was excellent, but I was not surprised as we had used them before." In a situation where the quality of every weld is vital, the ability of AMI's equipment to cope with the thickness of the pipe wall and maintain weld integrity under very high acceptance standards for NDT gave the company significant advantages. The M95 weld head is rugged and easy to set up, which is also ideal for small diameter pipe and fitting welds that have limited axial or radial clearance, while the M227 is designed for high production welding of schedule pipe. It is a 225A pre-programmed or programmable, inverter-type, GTAW welding power supply and controller for automatic orbital welding applications that require the addition of filler material. High-integrity welds produced at the touch-of-a-button by the M227 portable suitcase-sized machine match or exceed the specifications required by industries such as chemical manufacturers, power generation and nuclear. Its compactness and rugged casing makes it ideal for field applications. AMI's technical sales manager, John Morris, explained: "Arc Machines' range of equipment is ideally suited for applications involving difficult working conditions. The automated orbital welding process offered not only reduces manufacturing time but also the fatigue aspect from the welder's point of view. Production savings "In this particular case Arc Machines' automated orbital welding equipment helped GrowHow make significant production savings compared to going down the manual route. Without utilising the M95 it would have been a really labour intensive job and the impact would have been a longer production time." GrowHow prides itself on technical excellence so AMI's system had to match up to very high specifications. Not only did its automated orbital welding complete the job faster and more accurately than a manual system, but it also provided a clean, high quality surface finish. AMI claims it has the largest range of orbital tube pipe and tube-sheet welding equipment in the market place today and a reputation for high manufacturing standards and customer service. The company has a long history of developing orbital welding applications for a broad span of industry sectors. AMI orbital welding equipment is utilised on a wide variety of pipe diameters, wall thicknesses and materials to produce precision welds and achieve consistent higher standards.