STAINLESS STEEL CHARACTERISTICS

Stainless steels are iron-based, heat resistant alloys. The presence of chromium in stainless steel at a minimum of 10% is what gives it its superior corrosion resistance. Like other types of steel, stainless steel is primarily iron and carbon but contains several alloying materials, the most prominent one being chrome. Nickel, molybdenum or nitrogen are other alloys that can be found in stainless.

Stainless Steel Properties

Stainless steel offers many desirable characteristics that have led to its wide application in parts and components for many industries. Its high chromium level makes it very resistant to corrosion. Steels that contain at least 10.5% of chromium are about 200 times as resistant to corrosion as steels without it. Aside from its strength and durability, stainless steel is also known for its ease of fabrication and increased formability. Other benefits include low maintenance and a long-lasting attractive appearance. Once stainless steel becomes in service, no additional treatment, coating or painting is required.

• Corrosion resistant
• High tensile streng
• Very durable
• Temperature resistant
• Easy Formability and Fabrication
• Low-maintenance (long lasting)
• Attractive appearance
• Environmentally friendly (recyclable).

Stainless Steel Grading System

There are many different numerical systems for stainless-steel, which are designated according their compositions, physical qualities, and applications. Each type of steel is classified based on its series numbers and given a numerical rating. The most popular numbers in the series are 200. 300. 400. 600. 2000. The most commonly used grades are 304 and Type 316 which consist austenitic-chromium nickel alloys. 400 Series cutlery stainless steels come from ferritic-martensitic chromium alloys. Type 420 has been called surgical steel. And type 440, razor blade steel.

Find out more on stainless Steel Types.

Stainless Steel Classifications

The four main types of stainless steels are classified according to their microstructure.

Feritic

Ferritic alloys have high chromium, which ranges from 10.5%-27%. Magnetic properties are also present. They offer excellent ductility as well as tensile property stability and resistance to corrosion.

Ferritic Steel Applications

Ferritic Stainless Steels can be used in many applications including automotive components and parts.

Austenitic

Austenitic grade stainless steels are perhaps the most popular type. They have a high chromium content, along with varying amounts or nickel, Manganese, Nitrogen, and carbon. Austenitic stainless steels fall into two categories: 300 series, and 200 series. The alloys that are used determine which subcategory they belong to. The addition of Ni is what distinguishes the austenitic structural 300 series. The 200 series is characterized by the addition of manganese or nitrogen. Grade 304 stainless steel is the most commonly used.

Austenitic Stainless Steel Applications

It is sometimes referred as 18/8 for its 18% of chromium to 8% of nickel. It has been used in structural components, automotive and aerospace equipment, kitchenware, cutlery. Grade 316 is a common stainless-steel. It is widely used in a range of products including food preparation, laboratory benches and medical and surgical equipment.

Learn about 304 vs.316 Stainless Steel

Martensitic

The 400 Grade series is where you will find Martensitic Stainless Steels. It has a low to higher carbon content. It contains 12% to 15% chrome and up 1% molybdenum. It is used where high strength, oxidation and corrosion resistance are desired along with creep resistance. Martensitic is also magnetic. It has high ductility.

Martensitic Stainless Steel Applications

Martensitic alloys are used to make a wide variety of parts and components. This includes compressor blades, turbine parts, kitchen appliances, bolts nuts screws, parts for pumps and valves, dental and surgery instruments, electric motors pump valves machine parts, sharp surgical instruments cutlery and knife blades.

As their name suggests, duplex stainless has a mixed structure of ferrites and austenites. The nickel content is low, while the chromium/molybdenum ratios are very high. The stainless steel has many desirable properties due to its duplex structure. This stainless steel is twice as strong and has excellent corrosion resistance compared to other austenitic/ferritic stainless steels.

Duplex Stainless Steel Applications

Duplex stainless-steel is a 2000 grade series that can be used for a wide range of applications. It is perfect for chemical, oil & gas processing and equipment as well as pulp & paper industries, shipping, trucking, biofuels and cargo tanks, transportation, food industry and construction.