Hi and welcome to Metal Supermarkets, the Convenience Stores for Metal. I’m Jason Jackson, Operations and Development Manager. In this video blog series, we’ve been looking at the four main types of steel using our acronym C.A.S.T. which stands for carbon steel alloy steel stainless steel and tool steel. We’ve already talked about how steel is classified and looked closer into the first two types of steel from our acronym. Today we’ll take a closer look at the “S” Stainless steel Stainless steel typically contains between 10% and 20% chromium. It is the main alloying element and helps to make stainless steel extremely corrosion resistant. In fact, stainless steel is about 200 times more resistant to corrosion than mild steel. Stainless steel can be divided into five groups: Austenitic Ferritic Martensitic Duplex and Precipitation Hardening Austenitic steels make up the largest portion of the global stainless steel market and have a wide range of applications such as food processing equipment, kitchen utensils, medical equipment and more Austenitic stainless steel grades are
weldable, non-magnetic and not heat treatable. Typically, Austinitc stainless steels can be loosely divided into three groups Common chromium nickel which is the 300 series, Manganese chromium nickel nitrogen which is the 200 series and specialty alloys. Ferritic steals contain trace amounts of nickel, between 12% and 17% chromium, less than 0.1% carbon, and other alloying elements such as molybdenum, aluminum or titanium. Ferritic steels tend to have good ductility and formability but relatively poor high temperature strengths when compared to Austenitic grades. Ferritic stainless steels are magnetic but not heat treatable and often cost less than other stainless steels. Some Ferritic grades include 405 and 409 Martensitic steels contain 11% to 17% chromium, less than 0.4% nickel and up to 1.2% carbon. The higher carbon content of this heat treatable steel affects forming and welding. To obtain other useful properties and prevent cracking preheating and post weld heat treatment is required Martensitic stainless steels such as 403, 410, 410-Nickel Molybdenum and 420 are magnetic and heat treatable. They are often used for dental and surgical equipment knives and other cutting tools. Duplex steels typically contain 20% to 25% chromium and 5% nickel, along with molybdenum and nitrogen Duplex steels have higher yield strength and greater stress corrosion cracking to chloride than Austenitic stainless steels. Some applications include chemical plants and piping. Precipitation hardening steels are chromium nickel stainless steels that also contain alloying elements such as aluminum copper or titanium. These alloys allow the steel to be hardened by a solution and aging heat treatment. They can be there Austenitic or Martensitic in the aged condition. Hopefully this has given you a better idea of common types of stainless steel. Stay tuned for the final part of this video blog series where we will look closer at the last letter in our acronym C.A.S.T. Tool steel. If you need stainless steel for your next project Metal Supermarkets is the world’s largest supplier of small quantity metals. carrying over 8,000 types, shapes and grades of metal including various stainless steel grades cut to size and ready fast!