More than 140km of pipeline manufactured at Tata Steel’s recently enhanced double submerged arc welded (DSAW) mill has achieved an industry first by becoming the deepest to be laid in the Mexican section of the Gulf of Mexico.
The company was awarded a contract to supply 457mm OD x 28.6mm WT API 5L PSL2 X65MO line pipe from its large diameter 42” DSAW mill in Hartlepool, U.K., for the development.
The project marked the first time that a pipeline had been laid at water depths greater than 3,000ft in the Mexican section of the Gulf.
The mill has been the focus of significant recent investment to enhance technology and processes and increase power efficiency. More than 125 improvements were completed in 2015 to strengthen its overall operational and performance capability.
The improvements include significant upgrades to welding equipment using the latest closed loop digital weld control technology to deliver greater weld stability, reduced repair rates, and total traceability of the process. Tata Steel has also invested in a laser profiling system to provide a 3,600 point profile to monitor pipe straightness and provide a full dimensional survey of the pipe end. This data can be used to ensure minimum ‘hi/low’ in girth welding for high fatigue and other applications.
Energy efficient inverters have replaced more than 50 traditional transformers/rectifiers on production lines to enable quick and repeatable set ups at industry-leading levels while cutting the mill’s
electricity demand by nearly a third, allowing Tata Steel to produce more pipe with less energy.
The mill’s ‘O’ press control has been upgraded to optimize the forming process, ensuring uniform pressing along the full length of pipes to achieve optimum pipe shape. This has benefits for deepwater operations, as both the shape and balancing of the ‘forming ratio’ of the pipe are critical for deepwater collapse resistance.
Richard Broughton, Commercial Manager, Energy and Power, Tata Steel, said, “Our investment in the DSAW mill and our continuous improvement discipline enables us to offer extremely high integrity solutions to our clients for the most challenging of offshore and onshore projects.
“The overall benefit of the investments can be seen in the welding quality performance achieved during the project in the Gulf of Mexico. Where small diameter and thick wall pipe is typically more challenging, on this project a combined repair rate of 0.25 percent was achieved. This was delivered not only due to the investment in welding technology, but also through a program of continuous improvements in the welding area which has seen similar developments across many sizes of pipe.
“The manufacture also demonstrated a more sustainable approach to production, with reduced
energy utilization through the deployment of digital welding control. Our new inverter based power sources have significantly improved welding machine availability and have resulted in an increase in power efficiency from 60 percent to 95 percent.”