Topics Covered
Introduction to Duplex Stainless Steel PlateDuplex Stainless Steel Classification / GradesDuplex Stainless Steel Corrosion ResistanceProperties of Duplex Stainless Steel 31803 / 1.4462Brown McFarlane Duplex Stainless Steel PlateAbout Brown McFarlane
Introduction to Duplex Stainless Steel Plate
Duplex stainless steel was developed to offer improved material properties over and above some of the technical weaknesses of standard austenitic and ferritic stainless steels. Duplex stainless steels have a mixed microstructure which is split roughly 50:50 between austenite and ferrite. By balancing a higher amount of chromium and molybdenum with a lower nickel content of typical austentic stainless steels, Duplex Stainless steel provides the following benefits:
- Higher strength which is around twice that of Type 304 austenitic stainless steel. This leads to reduced plate thicknesses being used in fabrications reducing the weight which is of particular significance in items such as pressure vessels, storage tanks, and structural applications such as bridges
- Good weldability in thick plates
- Improved resistance to localized corrosion (particularly pitting)
- Improved resistance to crevice corrosion
- Good low temperature toughness.
- Resistance to stress corrosion cracking of importance in many applications including hot water tanks, process plant, brewing tanks, and desalination plant.
Duplex stainless steels are continually being developed by steel makers to offer more unique material properties suitable for specific applications.
Duplex Stainless Steel Classification / Grades
Table 1. Some standard designations for duplex stainless steel alloys
|
Euronorm |
UNS |
BS |
En |
Grade |
|
1.4462 |
S31803
S32205 |
318S13 |
- |
2205 |
|
1.4507 |
S32520
S32550 |
- |
- |
UR52N+ |
Duplex Stainless Steel Corrosion Resistance
A key feature of Duplex stainless is its enhanced corrosion resistance. There is no single measure of corrosion resistance but 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). Using this formula 31803 Duplex stainless has a PREN of 35 which when compared with the PREN of Type 304 and Type 316 (18 and 24 respectively) demonstrates its superior corrosion resistance.
Due to its higher strength, longer component life cycle, and lower alloy composition, Duplex stainless can be a very cost effective solution to an engineering problem involving high levels of corrosion.
Properties of Duplex Stainless Steel 31803 / 1.4462
Table 2. Chemical Analysis (% max or range)
C
|
Mn
|
P
|
S
|
Si
|
Cr
|
Ni
|
Mo
|
N
|
0.03
|
2.00
|
0.03
|
0.02
|
1.00
|
21.0 - 23.0
|
4.5 - 6.5
|
2.5 - 3.5
|
0.08 - 0.20
|
Table 3. Mechanical Properties
Tensile MPa min
|
Yield MPa min
|
Elongation % min
|
Hardness Brinell max
|
620
|
450
|
25
|
293
|
Brown McFarlane Duplex Stainless Steel Plate
Brown McFarlane holds a comprehensive stock of Duplex stainless steel plate manufactured by Western European steel makers. All plates in stock are certified in accordance with NORSOK MDS D45 and to material grades 31803, 32205, and 1.4462. Plates are stocked as large format (up to 12,000 mm long and 3,000 mm wide) which is designed to minimise fabrication costs for customers by reducing the amount of welding required. The large format also provides the opportunity to make the best possible use of each plate when “nesting” the shapes required by customers.
Due to the specialised nature of Duplex Stainless Steel the majority of Brown McFarlane Duplex Stainless steel plate sales are made in cut and processed form.
Table 4. Brown McFarlane Stock the Following Range of Duplex Stainless Steels
Thickness (mm)
|
Plate Sizes (mm)
|
5
|
12000 x 2000
|
|
|
6
|
12000 x 2000 |
12000 x 2500
|
12000 x 3000
|
8
|
12000 x 2000 |
12000 x 2500 |
12000 x 3000 |
10
|
12000 x 2000 |
12000 x 2500 |
12000 x 3000 |
12
|
12000 x 2000 |
12000 x 2500 |
12000 x 3000 |
15
|
12000 x 2000 |
12000 x 2500 |
12000 x 3000 |
20
|
12000 x 2000 |
12000 x 2500 |
12000 x 3000 |
25
|
12000 x 2000 |
12000 x 2500 |
12000 x 3000 |
30
|
6000 x 2000
|
5000 x 2500
|
|
35
|
6000 x 2000 |
5000 x 2500 |
|
40
|
6000 x 2000 |
5000 x 2500 |
|
45
|
6000 x 2000 |
5000 x 2500 |
|
50
|
6000 x 2000 |
5000 x 2500 |
|
About Brown McFarlane
Brown McFarlane Limited is the UK's premier quality steel plate distributor and processor and holds the widest range of sizes and specifications of carbon and stainless steel plate in the UK. They have a history of over 120 years of metal trading.
Brown McFarlane has stockholding and processing facilities in the U.K., the
U.A.E. (Dubai), Belgium (Antwerp), and
Singapore as well as an office in China and a network of representatives around the world.
Brown McFarlane holds stock of steel plates in specifications which include many that are difficult to find from general steel stockholders such as duplex and super duplex stainless steel, ultra high yield quenched and tempered steel, hydrogen induced crack (HIC) resistant pressure vessel steel, and chrome molybdenum steel. Plates are available ex-stock from 3mm to 200mm thick, up to 18,500mm long, and up to 4,000mm wide.
This information has been sourced, reviewed and adapted from materials provided by Brown McFarlane.
For more information on this source, please visit
Brown McFarlane.