All You Need to Know About the Different Types of Stainless Steel

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Stainless steel is one of the most widely used materials in the world. It comes in different types and categories, all of which are discussed here. Ever since its development a few centuries ago, stainless steel has evolved to become the world’s most versatile material. It has a variety of applications across the globe, more so in the industrial world. The increased utilization of the material is attributed to their numerous advantages that go to the user, especially the use of stainless steel pipes. 

Stainless steel materials are made of an iron alloy made of at least 12% chromium. This particular property increases the strength and formability and one more reason you need to buy 321 stainless steel tube, (besides they are even more resistant to corrosion without the need for further protection). Furthermore, whenever the product is damaged due to abrasion or maybe mechanical processes such as cutting, the chromium film will re-form back and continue to secure the steel.

Different Categories of Stainless Steel

Austenitic Stainless Steel

These materials are the most common and widely used stainless steel. They are characterized by a large volume of chromium content hence increased resistance to corrosion. Austenitic stainless steel is also known for its non-magnetic properties even though they tend to be magnetic when subjected to very cold working conditions. They are widely used in construction industries due to their relative strength as well as their welding and formability characteristics.

Ferritic Stainless Steel

The second most popular type of stainless steel is the Ferritic. Unlike the Austenitic stainless steel, the ferritic one is highly magnetic. These types of alloys are mostly hardened via cold working to increase its relative strength. Another differentiation factor is that ferritic stainless steel is way cheaper compared to the austenitic ones. This is mainly because of its low nickel content. In addition to that, ferritic steel tends to be weaker with low ductile properties compared to austenitic steels. Its appearance makes them suitable for indoor rather than outdoor applications.

Duplex and Super Duplex

The name of duplex stainless steel is derived from its structure. This implies that duplex and super duplex stainless steel have the microstructure of both austenitic and ferritic steel. They are relatively stronger compared to the austenitic steel even though they are not as quickly formed. They also have a higher corrosion resistance than austenitic steels. On top of that, they are highly magnetic and can be readily welded. Its resistance to stress corrosion, such as cracking, is also much higher compared to other types of stainless steel materials.

Types of Austenitic Stainless Steel

Grade 321

321 alloy is a type of steel with different constituents, for instance, titanium, chromium, and nickel which all work out to making it a better material. The metal is less corrosive to varying environmental aspects but seems to have good resistance to most oxidation agents and other materials that amplify corrosion. With high temperatures, the metal has been known to depict these traits at high temperatures not forgetting its developed weldability making work easier for most manufacturers. Described below are more uses and characteristics of this type of metal that you should familiarize with before you buy 321 stainless steel tube.

This type of steel reacts poorly under thermal treatment and could as such fail to harden during the process. Its strength can be amplified through cold working not forgetting to reduce the metal’s ductility. It can henceforth be used perfectly in the welding industry after adding titanium and carbides which are its stabilizing agents. Annealing is compulsory after these processes to demagnetize the materials used during the process other than the steel. Constructions projects call for utmost care and before you buy this tube consider the areas it could be advantageous in.

Application in the Industry

Storage of Liquefied Gases

The high strength and rigidity, especially at low temperatures make this type of metal very ideal for uses in areas of extreme cold conditions. It can be used in the storage of liquefied gases with perfect assurance of safe storage regardless of the surrounding temperature or altitude.


321 steel is tough in nature and its strength makes it very appropriate for making of cutting materials like other metals and stones. It can also be an essential tool in the drilling industry with one condition— the cutting material should be kept sharp at all times.


321 steel tubes can readily be welded but only through use of shielded fusion not forgetting the relevant resistance welding processes. The material can hence be welded without having to worry about the corrosion resistance resulting from the integration of weld annealing.

Two other types you need to know about:

  • Grade 304

The high tensile strength of about 621 MPa of this grade makes it the most common class of stainless steel. It is made up of a minimum of 18% chromium and about 8- 10% of nickel. Its operating temperature is estimated at 870C. A combination of all these properties plus its relative strength and durability make it an ideal material for a wide range of construction and industrial uses.

  • Grade 316

Last but not least is the grade 316 stainless steel. It has a relative tensile strength of about 579 MPa. This austenitic Steel has an operating temperature of about 8000C

Its properties make it resistance to chlorides than other alloys. This makes it suitable to operate in conditions that involve exposure to chlorides such as salt.

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