Testing of Ferritic Stainless Steel Tubular Structural Elements

Stainless steel is gaining increasing usage in construction owing to its durability, favourable mechanical properties and its aesthetic appearance, with the austenitic grades being the most commonly utilised. Austenitic stainless steels have a high nickel content (8%-11%), resulting in high initial material cost and significant price fluctuations; this, despite its desirable properties, represents a considerable disadvantage in terms of material selection. Ferritic stainless steels, having no or very low nickel content, may offer a more viable alternative for structural applications, reducing both the level and variability of the initial material cost. In comparison to the most widely used austenitic grades, the ferritic grades typically have higher yield strengths (250-350 N/mm 2 ) and are easier to machine and work. Furthermore, by varying the chromium content (10.5%-29%), and with additions of other alloying elements, the required corrosion resistance for a wide range of structural applications and operating environments can be achieved. There is currently limited information available on the structural performance of this type of stainless steel. Therefore, to overcome this limitation, a series of material and crosssection tests have been performed, covering both the standard 1.4003 grade and the 1.4509 grade, which has improved weldability and corrosion resistance. The experimental results are reported, analysed and compared to the results of tests performed on other stainless steel grades. Finally, design recommendations suitable for incorporation into Eurocode 3: Part 1.4 (2006) have been proposed.