What is Stainless Steel

Stainless steel is a family of iron-based alloys that contain a minimum of approximately 11% chromium, a composition that prevents the iron from rusting, as well as providing heat-resistant properties. Different types of stainless steel include the elements carbon (from 0.03% to greater than 1.00%), nitrogen, aluminium, silicon, sulfur, titanium, nickel, copper, selenium, niobium, and molybdenum. Specific types of stainless steel are often designated by a three-digit number, e.g., 304 stainless.

Stainless steel's resistance to ferric oxide formation results from the presence of chromium in the alloy, which forms a passive film that protects the underlying material from corrosion attack, and can self-heal in the presence of oxygen.Corrosion resistance can be increased further, by increasing the chromium content to levels above 11%; addition of 8% or higher amounts of nickel;and addition of molybdenum (which also improves resistance to "pitting corrosion").

The addition of nitrogen also improves resistance to pitting corrosion and increases mechanical strength. Thus, there are numerous grades of stainless steel with varying chromium and molybdenum contents to suit the environment the alloy must endure.

Resistance to corrosion and staining, low maintenance, and familiar luster make stainless steel an ideal material for many applications where both the strength of steel and corrosion resistance are required. Moreover, stainless steel can be rolled into sheets, plates, bars, wire, and tubing. These can be used in cookware, cutlery, surgical instruments, major appliances, construction material in large buildings, industrial equipment (e.g., in paper mills, chemical plants, water treatment), and storage tanks and tankers for chemicals and food products. The material's corrosion resistance, the ease with which it can be steam-cleaned and sterilized, and the absence of the need for surface coatings have prompted the use of stainless steel in kitchens and food processing plants.

The types of stainless steel

Austenitic is the most widely used type of stainless steel. It has excellent corrosion and heat resistance with good mechanical properties over a wide range of temperatures. Austenitic steel is used in housewares, industrial piping and vessels, construction, and architectural facades.

Ferritic stainless steel has similar properties to mild steel (the most common steel), but better corrosion, heat, and cracking resistance. Ferritic steel is commonly used in washing machines, boilers and indoor architecture.

Martensitic stainless steel is very hard and strong, though it is not as resistant to corrosion as austenitic or ferritic grades. It contains approximately 13% chromium and is used to make knives and turbine blades.

Duplex stainless steel is a composite of austenitic and ferritic steels, making it both strong and flexible. Duplex steels are used in the paper, pulp, shipbuilding, and petrochemical industries. Newer duplex grades are being developed for a broader range of applications.

What is Stainless Steel Pipe

Stainless steel pipe is primarily used in piping systems for the transport of fluids or gases. Stainless steel pipe resists oxidation, making it a low-maintenance solution that is suitable for high temperature and chemical applications. Because it is easily cleaned and sanitized, stainless steel pipe is also desired for applications involving food, beverages, and pharmaceutical applications.

What is the difference between Pipe and Tube

The term “pipe” and “tube” are often used to describe the same product, but it is important to know the difference. Though they share the same cylindrical shape, steel pipes are measured by the interior diameter (ID), whereas steel tubes are measured by the outside diameter (OD) and wall thickness. Another difference is that pipes are used to transport fluids and gases, while tubes are used to build parts or structural components. 

What Is the Difference Between 304 Stainless Steel And 316 Stainless Steel?

300 series grade stainless steel is a chromium-nickel alloy that is manufactured into a range of products including steel tubes and steel pipes. Both 304 and 316 steel pipe is durable enough to maintain its strength at high temperatures, resist corrosion, and is easy to maintain.  The choice between material is highly dependent upon how you will use the pipe and the environment in which the pipe will be installed.

Type 304 stainless steel is perhaps the most common type used because it is corrosion-resistant and easy to sanitize. This type of steel is often used for food and beverage applications or in building applications.

Type 316 stainless steel is also corrosion-resistant and easy to clean but is more resistant to corrosion resulting from chemicals and solvents. Because of this, 316 stainless steel is preferred for industrial and surgical applications, or outdoor or marine applications due to its resistance to chloride corrosion.