Super Duplex Stainless Steel.
A Super Duplex stainless steel is a type of Duplex stainless steel with enhanced corrosion resistance which is categorised by its PREN being greater than 40. A standard Duplex like the S31803 grade stocked by Brown McFarlane has a PREN of around 35. The Pitting Resistance Equivalent Number (PREN) is widely used as a means of comparing the relative corrosion resistance of different steel grades. The PREN is obtained by applying a mathematical formula to the chemical composition of a steel so that PREN = %Cr + (3.3 x %Mo) + (16 x %N).
As a part of the Duplex family of stainless steels Super Duplex stainless has a microstructure which is split roughly 50:50 between austenite and ferrite. It differs from Duplex in its chemical composition (with increased amounts of Molybdenum, Nickel, and Chromium) and its mechanical properties (higher proof stress and tensile strength). This highly alloyed product is especially designed for marine, chemical, and oil engineering applications requiring both high mechanical strength and resistance to corrosion in extremely aggressive environments (chloride-containing acids etc.).
Super Duplex stainless steel, relative to other stainless steel products, gives
- High corrosion resistance
- High resistance to stress corrosion cracking
- High yield strength and tensile strength
Brown McFarlane offers one of the largest ranges of high strength quenched and tempered structural steel plate in Europe.
It is not uncommon in our industry to find the same type of steel plate given different names by different engineers. Plates of this type are variously described as:
- High Strength Quenched and Tempered Steel Plate
- High Yield Quenched and Tempered Steel Plate
- High Strength Structural Steel Plate,
- High Yield Structural Steel Plate
- High Strength Low Alloy Steel Plate
Quenched and Tempered Steel Plate.
A variety of steel specifications is available including those with a minimum yield strength of 690 MPa and with a minimum yield strength of 890 MPa. The stock encompasses a range of sophisticated high strength low alloy steel plates from leading Western European producers and is supplied in plate thicknesses from 3 mm up to 300 mm.
Quenched and tempered structural steel plate has been developed for industrial uses where a combination of strength and outstanding toughness are necessary such as mining and quarrying, material handling, construction and earthmoving, and offshore fabrication. It has the considerable advantage of providing high strength while offering weight reductions which improves the efficiency of plant and equipment. It is used in the manufacture of cranes, forklift trucks, bridges, mooring equipment, vehicle chassis, to name but a few applications.
Specifications and grades from Brown McFarlane's stock include:
RQT® 701, RQT® 901 (proprietary brands manufactured by Tata Steel).
Fabrication of High Strength Quenched and Tempered Steel Plate.
High strength quenched and tempered steel plate can be easily welded and fabricated but its high yield strength and tensile strength compared with mild steel means that it should be treated with some caution. We have provided information which is intended as a basic guide to various fabrication methods. Please click here to view this. If you require more detailed advice on welding, machining, or forming then please contact any one of our offices.