- High strength
- High corrosion resistance
- Microstructure of roughly 50% austenite and 50% ferrite
- Applications of Duplex include: Chemical Process, Petrochemical, Oil and Gas, Pharmaceutical, Sea Water, LNG, Nuclear Power, Solar Power and more
Duplex Stainless Steel
Types of stainless steel, covering the majority of grades available, can be put into 5 categories.
| Category | Description |
|---|---|
| Ferritic | Contain less than 0.10% carbon and are magnetic. |
| Austenitic | Most common type of stainless steel. Austenitic counts for over 70% of all steels on the market. |
| Martenistic | Shares some characteristics with ferritic but can have higher level of carbon up to 1%. Used where strength is more important than corrosion resistance. |
| Duplex | A combination of ferritic and austenitic steels. |
Precipitation Hardening – “With the addition of elements such as Aluminium, Copper and Niobium, these steels become extremely strong.” – What Is Stainless Steel? By Brown Mac
The Balance Of Austenite And Ferrite
Below is a comparison of two familiar steels Austenite 304 and Ferritic 430. The important elements in stainless steels can be classified into these two subsections. Each element favours either one structure or the other.
| Structure | Grade | EN No. | C | Si | Mn | P | S | N | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Ferritic | 430 | 1.4016 | 0.08 | 1.00 | 1.00 | 0.040 | 0.015 | – | 16.0/18.0 | – | – |
|
Austenite |
304 | 1.4301 | 0.07 | 1.00 | 2.00 | 0.045 | 0.015 | 0.11 | 17.5/19.5 | 8.0/10.5 | – |
Ferritisers – Cr, Si, Mo, W, Ti and Nb
Austenitisers – C, Ni, Mn, N, Cu
As you can see from the examples above, grade 304 has predominance of ferritisers and so it is ferritic in structure.
Corrosion Resistance Of Duplex Steels
- Higher general strength than other steel grades
- Easy to weld
- Structural toughness at a lower temperature range
- High resistance to stress-corrosion cracking
Ask us about Duplex stainless steel today. We have been specialising in the use of special alloys for tube fittings, pipe fittings and valves for over 40 years.