UNS S is a super austenitic stainless steel designed to withstand high pressures, stress corrosion cracking, and many other potentially hazardous events and materials. This high-end stainless steel contains high levels of chromium, molybdenum, nickel and nitrogen, which contribute to its excellent corrosion resistance and many other properties. This fact sheet will give you all the details you need to know about UNS S and its global equivalent grades.

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Fact Sheet

UNS S is commonly available worldwide in several forms and for use in many industries. Although it is a popular choice for components in the chemical, marine and oil and gas industries, it also has other applications.

Available forms of UNS S

Depending on the manufacturer, UNS S can be available in various formats to suit different uses, including:

• Coils
• Flanges
• Flats
• Fittings
• Hexagon bars
• Plates
• Round bars
• Sheets
• Tubes (Available as seamless, seam welded, cold redrawn (and/or annealed), and straight.

As previously mentioned, UNS S is commonly used in the gas and oil industries. Still, its high strength and good corrosion resistance make it a solid choice in seawater applications and many industrial environments. 

Applications of UNS S

• Chokes
• Heat exchangers
• Pumps
• Pipework
• Valves

Properties of UNS S

One of the critical properties of UNS S is its resistance to pitting and crevice corrosion, but additional benefits include its high ductility, impact strength and resistance to crevice corrosion. This steel can be used in sub-zero temperatures, and corrosive environments and is suitable as a replacement for the 300 series austenitic stainless steels. 

Mechanical Properties 

Physical Properties (at Room Temperature)

Global Equivalent Grades

The Unified Number System (UNS) designation for this high-grade steel is . Still, there are many different names for stainless steel UNS . Other common names include 254SMO or 6Mo. In Germany, the Werkstoff steel specification is 1., also known as Alloy 254.

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Masteel 

Our steel products can be used in a variety of applications around the world because of their high corrosion resistance. UNS S is particularly resistant because of its high molybdenum levels, which makes it ideal for saltwater applications and the oil and gas industries.  

Get in touch today for more information about UNS S or any of our other steel products.

S (1.) 254 SMO Super Austenitic Stainless Steel

S (1.), also known as 254 SMO, is a super austenitic stainless steel plate grade renowned for its exceptional corrosion resistance and versatility in demanding environments. Brown McFarlane is a leading supplier of S plate, offering a comprehensive selection to fulfil your project requirements.

Key Features

• Superior Corrosion Resistance: S excels in environments like seawater and other industrial settings due to its high molybdenum and nitrogen content. It offers exceptional resistance to pitting, crevice corrosion and uniform corrosion.
• Moderate Tensile Strength with High Ductility: This grade offers a good balance between strength and flexibility, making it suitable for various applications.
• Molybdenum and Nitrogen Alloyed: The addition of molybdenum and nitrogen significantly enhances the steel's corrosion resistance capabilities.

Why Choose Brown McFarlane for your S Plate Needs?

Developed specifically for the oil & gas, offshore, and paper industries, S offers superior properties compared to standard austenitic stainless steel grades. It is 6% Molybdenum and Nitrogen alloyed leading to it's high resistance to crevice and uniform corrosion.

• Extensive Stock: We maintain a vast inventory of S plate in various thicknesses and dimensions at our UK service centre, ensuring prompt availability for your project.
• Technical Expertise: Our experienced sales team possesses a deep understanding of S's properties and applications. We're happy to assist you in selecting the most suitable plate for your specific requirements.

• Customizable Solutions: Brown McFarlane offers custom cutting services to meet your exact size and shape specifications.
• Quality Assurance: All our S plates are sourced from reputable manufacturers and adhere to strict quality control standards.
• Global Delivery: We utilise our experienced logistics team to deliver S plates efficiently to any location worldwide.

Applications

• Valves
• Flanges & fittings
• Pulp & paper industry

• Pipework
• Pumps

Properties

Chemical analysis

Standard Grade C Mn Cr Ni Mo ASTM A240/A240M UNS S <0.020 <1 19.5 ' 20.5 17.5 ' 18.5 6.0 ' 6.5

Mechanical properties

The company is the world’s best s tube supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Grade Yield MPA Tensile MPA Elongation % (50mm) UNS S 300 min 650 ' 850 50

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