420 stainless steel is a high-carbon steel with a minimum chromium content of 12%. Stainless Steel grade 420 can be hardened through heat treatment. It offers good ductility in its annealed state and excellent corrosion resistance properties when the metal is polished, surface grounded or hardened. This grade has the highest hardness capability - RC50+ - among all the stainless steel grades with 12% chromium.
Stainless steel 410 is a basic martensitic grade which contains 11.5% chromium, offering both exceptional wear and corrosion resistance. SS 410 is corrosion resistant to some chemicals, food, mild acids, water, and air. It also proves adequate resistance to nitric acid, concentrated sulfuric acid, dilute acetic acid and naphtha. Elevated mechanical properties and corrosion resistance are achieved with stainless steel 410 when it's hardened and tempered.
300 Series stainless steels are classified as austenitic, and are hardenable only by cold working methods. These grades of stainless have chromium (approx. 18 to 30%) and nickel (approx. 6 to 20%) as their major alloying additions. Type 304 is the most widely used alloy of all stainless steels. 300 Series Stainless steel alloys resist corrosion, maintain their strength at high temperatures and are easy to maintain.