Introduction
Stainless steels, particularly Duplex stainless steels, are valued for their corrosion resistance and mechanical strength, making them suitable for various industries such as offshore oil & gas, chemical processing, and construction. Duplex steels offer up to twice the mechanical strength of conventional stainless steels and are considered as substitutes for types like 304L, 316L, 904L, or 254SMO depending on environmental conditions.

Available Structural Sections
The document lists various structural sections available in laser-hybrid welded execution, including equal and unequal leg angle bars, tee-sections, UPN, UPA, UPE channels, IPE, HEA, HEB beams, and SHS/RHS sharp-edged sections. These sections conform to specific European norms for size and tolerances.

Welding Techniques
Duplex stainless steels can be welded using various methods, but laser-hybrid welding is highlighted for its effectiveness. This method combines laser and arc welding, achieving a balanced microstructure without the need for solution-annealing, thus maintaining corrosion resistance equivalent to the parent material. The welding process is standardized under EN ISO 15609-6 and EN 15614-14.

Corrosion Resistance
Duplex steels exhibit excellent resistance to localized corrosion, such as pitting and crevice attack. The pitting resistance equivalent number (PREN) is used to compare stainless steels. Testing standards like ASTM G48 and ASTM A 923 are referenced for evaluating corrosion resistance, with laser-hybrid welding showing superior results compared to other methods.

Mechanical Properties
Laser-hybrid welded sections have a monolithic structure with controlled heat input, resulting in superior mechanical properties. These sections demonstrate high wear resistance and fatigue strength, crucial for structures subjected to dynamic loads. The mechanical properties of the weld and heat-affected zones do not limit industrial applications.

Cost Saving Potential
Duplex steels offer significant cost savings in structural applications due to their higher yield strength. They allow for lighter sections without compromising structural performance. Charts illustrate the improved buckling load and weight savings of Duplex sections compared to standard austenitic stainless steels, highlighting a potential material saving of about 40% under similar load conditions.

Conclusion
Duplex stainless steels, particularly when welded using laser-hybrid techniques, provide enhanced mechanical and corrosion resistance properties, making them a cost-effective choice for structural applications. The document emphasizes the advantages of using Duplex over traditional austenitic stainless steels in terms of performance and cost efficiency.