Duplex Stainless Steel UNS 31803 (F51), UNS 32205 (F60) By yaang

Deriving the Duplex name from the presence of both Austenite and Ferrite in similar proportions, Duplex Stainless Steels combine excellent corrosion resistance with high strength. The typical mechanical properties would be double that of a single phase austenitic grade such as 316, while, for example, offering superior stress corrosion cracking resistance in chloride solutions.

Standard Duplex Stainless Steels typically have a 22% Chromium and 5% Nickel and in the 1960's Langley Alloys developed the first 25% Chromium Duplex alloy, Ferralium 255, and coined the phrase Super Duplex.

Corrosion Resistant Stainless Steel Tube By yaang.com

In our product programme we offer our customers two classes of Stainless Steel grades that have an excellent resistance to corrosion stainless steel. Austenitic-ferritic Duplex stainless steels are characterised by their excellent mechanical qualities, particularly their high stress corrosion cracking resistance. They are especially well-suited for maritime applications and in the chemical industry. Their excellent resistance to corrosion enables them to withstand a chloride medium, particularly under mechanical stress. This makes them superior to austenitic steel in many cases.

Super Duplex Stainless Steel By yaang.com

The first-generation duplex stainless steel were developed more than 70 years ago in Sweden for use in the sulfite paper industry. Duplex alloy were originally created to combat corrosion problem caused by chloride-bearing cooling water and other aggressive chemical process fluid. Called duplex because of its mixed microstructure with about equal proportion of ferritic andaustenitic. Duplex stainless steel are a family of grade, which corrosion performance depending on their alloy content.

Stainless Steels: High Temperature Resistance By yaang.com

Stainless steels are most commonly used for their corrosion resistance. The second most common reason stainless steels are used is for their high temperature properties; stainless steels can be found in applications where high temperature oxidation resistance is necessary, and in other applications where high temperature strength is required. The high chromium content which is so beneficial to the wet corrosion resistance of stainless steels are also highly beneficial to their high temperature strength and resistance to scaling at elevated temperatures.

Introduction To Stainless Steels Grades And Families By yaang.com

Stainless steels are iron-based alloys containing a minimum of about 10.5% chromium; this forms a protective self-healing oxide film, which is the reason why this group of steels has their characteristic "stainlessness" or corrosion resistance. The ability of the oxide layer to heal itself means that the steel is corrosion resistant, no matter how much of the surface is removed. This is not the case when carbon or low alloy steels are protected from corrosion by metallic coatings such as zinc or cadmium or by organic coatings such as paint.

How do I choose which stainless steel to use? By yaang.com

Most decisions about which stainless steel to use are based on a combination of the following factors:

1. What is the corrosive environment? – Atmospheric, water, concentration of particular chemicals, chloride content, presence of acid.
2. What is the temperature of operation? – High temperatures usually accelerate corrosion rates and therefore indicate a higher grade. Low temperatures will require a tough austenitic stainless steel.