A new super-duplex stainless steel grade has been developed for subsea umbilicals: SAF™ 3007, the latest addition to the growing duplex family of Alleima. The new tube offers a safe, lighter, stronger and more efficient alternative to SAF™ 2507, the current standard. With superior strength, fatigue properties and excellent corrosion resistance, SAF™ 3007 delivers superior performance in harsh deepwater environments.
Text & images by Alleima
The new tube product represents the next generation of super-duplex seamless tubing developed specifically for the offshore oil and gas industry. It builds on the success of SAF™ 2507 (UNS S32750), which has become the industry standard, and further advances the duplex revolution that Alleima pioneered decades ago.
Strong energy demand
“Across the globe, the demand for energy is growing strong. We see a rising tide of activity in the oilfields off the coast of Brazil, in the Gulf of Mexico, North Sea and Southeast Asia. Following a dip during Covid, this new surge comes, underscoring the need for reliable, cost-efficient energy production,” says John Tokaruk, Global Product Manager for umbilical tubing at Alleima.
“As a market leader in umbilical steel tubing, we often get requests for a material matching SAF™ 2507 in reliability, but with reduced costs, improved fatigue life and enhanced pressure handling. SAF™ 3007 (UNS S83072) accomplishes all this with a ‘less is more’ approach. Thinner tube walls, thanks to its superior strength and fatigue properties, results in lower cost per meter. It offers the excellent corrosion resistance of SAF™ 2507, and a similar microstructure, as well as simplified welding due to thinner walls,” explains Mr Tokaruk.
Pioneers of super duplex
“Across the globe, the demand for energy is growing strong. We see a rising tide of activity in the oilfields off the coast of Brazil, in the Gulf of Mexico, North Sea and Southeast Asia. Following a dip during Covid, this new surge comes, underscoring the need for reliable, cost-efficient energy production,” says John Tokaruk, Global Product Manager for umbilical tubing at Alleima.
“As a market leader in umbilical steel tubing, we often get requests for a material matching SAF™ 2507 in reliability, but with reduced costs, improved fatigue life and enhanced pressure handling. SAF™ 3007 (UNS S83072) accomplishes all this with a ‘less is more’ approach. Thinner tube walls, thanks to its superior strength and fatigue properties, results in lower cost per meter. It offers the excellent corrosion resistance of SAF™ 2507, and a similar microstructure, as well as simplified welding due to thinner walls,” explains Mr Tokaruk.
| C | Si | Mn | P | S | Cr | Ni | Mo | W | N |
| ≤0.030 | 0.2 | 1.0 | ≤0.030 | ≤0.030 | 30 | 7 | 1.0 | 3.4 | 0.40 |
160 million meters sold
The optimization of SAF™ 2507 for subsea umbilicals, coupled with the dedicated Alleima mill in Chomutov, Czech Republic, ensuring fully integrated production from a single melt of 80% recycled steel in Sandviken, Sweden, guarantees high quality. The large reels, with long lengths of orbitally welded coils, soon set the industry standard. Over the past 30 years, Alleima has supplied more than 160 million meters (525 million feet) to all major fabricators and applications, equal to circling the world three times.
More tungsten and chrome
“To enhance the performance of SAF™ 2507, we fine-tuned the chemical composition. As a result, SAF™ 3007 features additional chromium at 30%, reduced molybdenum at 1 % and, for the first time, Alleima introduces tungsten at 3.4 % to the duplex family of tube alloys. The inclusion of tungsten in preference to molybdenum maintains the corrosion resistance after welding, which is crucial for the umbilical application. Taken together, these properties are ideal for ‘dynamic umbilicals’ that are floating and twisting below the ocean surface with high stress in chloride-rich environments,” says Charlotte Ulfvin, Senior R&D Researcher at Alleima.
“The launch of SAF™ 3007 marks the next step in our duplex evolution, fulfilling customer demands for a next generation umbilical tube with less material and thinner walls. Thanks to the refined chemical composition, we provide a lighter tube that streamlines the entire manufacturing process. It will be made available in a broad size range by the end of 2024,” concludes Tom Eriksson, Executive Vice President and Head of R&D at Alleima.
About this Tech Article
This tech article appeared in Stainless Steel World, April 2024 magazine. To read many more articles like these on an (almost) monthly basis, subscribe to our magazine (available in print and digital format) – SUBSCRIPTIONS TO OUR DIGITAL VERSION ARE NOW FREE.
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