Stainless steel duplex stainless steels are achieved with an overall lower alloy content than similar-performing super-austenitic grades, making their use cost-effective for many applications. Duplex grades are characterized into groups based on their alloy content and corrosion resistance. Precipitation hardening stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths than the other martensitic grades. The most common, 17-4PH, uses about 17% chromium and 4% nickel. The designation "CRES" is used in various industries to refer to corrosion-resistant steel. Most mentions of CRES refer to stainless steel, although the correspondence is not absolute, because
Duplex stainless steel are higher. This can be a great advantage when strength is important. This is the case in bridges, pressure vessels or tie bars. Chemicals composition of grades from EN 10088-1 (2014) Standard are given in the table below: Mechanical properties from European Standard EN 10088-3 (2014) (for product thickness below 160mm): <nowiki>*</nowiki>for thickess ≤ 5 mm The minimum yield stress values are about twice as high as those of austenitic stainless steels. Duplex grades are therefore attractive when mechanical properties at room tempearature are important because they allow thinner sections. Duplex stainless steel Duplex stainless steels is the most recent