420 stainless steel construction. 420 is a general purpose stainless steel containing medium quantity of carbon. It has good strength and reasonable impact resistant properties in both hardened and tempered conditions as compared to 440 grades. It has good corrosion resistance qualities in mild atmosphere, domestic and industrial environments. It is resistant to ammonia, blood, carbonic acid, crude oil, detergent solutions, dilute nitric acid, fresh water, food acids, many petroleum products, steam and vinegar, etc. It is also called “surgical steel” because it is being used in production of surgical instruments on large scale around the world due to its good corrosion resistance and its easy machining qualities. It is also being used in cutting tools like: Knifes, Daggers, Swords, Haircutting Scissors and Domestic Scissors. Its grinding is easy and it produces a fine, vivid and smooth, polished surface. 420 steel, due to its excellent harden-ability, is capable of getting hardened up to 56 HRC Rockwell or higher depending upon carbon contents / composition. Useful for hunting, camping, fishing, collecting and other hobbies.