420 Stainless Steel VS 304

420 Stainless Steel Properties

It is used for many things, including knives, medical equipment, kitchenware and more. Due to its high content of chromium, it is resistant to temperature fluctuations and corrosion. It is also known as a strong and hard material. The downside to 420 stainless is that it has a lower heat resistance than 304 stainless. Due to its low carbon content, it is not suitable for welding.

304 Stainless Steel Properties

Its excellent corrosion resistance makes it a popular choice for manufacturing. It is superior in thermal conductivity to other types stainless steel. It can also withstand higher temperatures, without losing its integrity. It is therefore ideal for high-temperature applications, such as food processing equipment or boilers. It cannot, however, be heat treated to harden it, and so may not be suitable in some applications that require superior hardness or strength.

AISI Grade 304 is of the "Austenitic" type; it has about min. 8% nickel. AISI 300 series stainless steels like 316, 304, 309 or 321, contain a significant amount of nickel, causing them to have an austenitic structure.

This makes them more ductile, tougher, and gives them greater formability, It also gives them better strength at medium temperatures than carbon steels. At room temperature however their strength is less than most normal carbon steels. Also note that 300 series stainless typically contain low carbon when compared to normal non-stainless steels. This becomes relevant later.

AISI 420 does not have as high of a chromium content as AISI 304, nor does it contain significant nickel. Combined, this makes it less corrosion resistant. 420 can resist mild atmospheric corrosion but shouldn't be used in more aggressive corrosion conditions like salt spray. 420 can be heat treated to high strength and hardness levels, however. 300 series stainless cannot.