What is stainless steel?
Stainless steel is a ferrous alloy resistant to rust and corrosion because it has a stable passivation layer, a micro-coating created by a chemical reaction with the base chromium. This layer protects stainless steel from moisture and self-heals itself in the presence of oxygen. That’s why even if stainless steel gets scratched, the passivation layer reforms quickly.
Stainless steel begins with a mix of carbon and iron, like all steel. But stainless steel also has a minimum blend of 10.5% chromium. This element provides stainless steel's resistance to oxidation, meaning it cannot rust.
How is stainless steel made?
Stainless steel can be made in two ways, either cast or wrought.
Cast stainless steel is made through the process of pouring liquid metal into a specialty mold at a steel foundry to meet a specific shape.
Wrought stainless steel is made into ingots, slabs, blooms, or billets in a steel mill and then reshaped using hammering and rolling equipment to form wire, sheet, etc. As a result, wrought stainless steel products are much more common than cast stainless steel products.
Types of stainless steel
There are different types of stainless steel, and it is a very adaptable group of alloy metals. This is because each type has different percentages of iron, chromium, and carbon. In addition, some other stainless steels have added elements like copper, nickel, manganese, or molybdenum.
Stainless steel grades
Here are the most common types of stainless steel grades:
• Ferritic stainless steel: 430, 444, 409
• Austenitic stainless steel: 304, 302, 303, 310, 316, 317, 321, 347
• Martensitic stainless steel: 420, 431, 440, 416
• Duplex stainless steel: 2304, 2205
Ferritic stainless steel
contains iron carbon and 10.5% to 18% chromium. Ferritic stainless steel is used in magnetic—engineering applications.
Austenitic stainless steel
contains iron, carbon, chromium, and a minimum of 8% nickel. Highly corrosive-resistant and non-magnetic. Our two most common stainless steel grades, 304 and 316, are austenitic stainless steel. Common for stainless steel pipe
, stainless steel tube
, stainless parts
, and stainless bollards
Martensitic stainless steel
contains 12% to 18% chromium and has a higher carbon content of 0.1% to 1.2% than ferritic stainless and austenitic stainless. In addition, martensitic stainless steel is magnetic, and its strength is more critical than weldability: in cutlery and aerospace.
Duplex stainless steel
contains the highest amount of chromium, between 19% to 32% and up to 4% molybdenum. Duplex stainless steels are about 50% split of ferritic stainless and austenitic stainless and, with the combined corrosion resistance and strength, are used in the construction industry, petrochemical industries, and in chloride-exposed applications.
How is stainless steel used?
Stainless steel has many applications because of the alloy's corrosion resistance and luster properties. For example, stainless steel is used in surgical instruments, cookware, food processing, chemical and pharmaceutical processing, industrial equipment in chemical and water treatment plants and labs, storage tanks for various liquids, including caustic chemicals, and many other applications for harsh environments. Stainless steel also has superior cleanability, which makes it perfect for the pharmaceutical and food processing industries.
Stainless steel can be manufactured in sheets, plates, tubing, bars, angle, rods, wire, and other pieces for use in many different applications ranging from stainless steel appliances to non-corrosive parts on industrial machinery.
We also provide stainless steel polishing services.