Chemical symbol: Cr. When used as an alloying element, chromium increases the hardenability of steel and in association with high carbon gives resistance to wear and abrasion. It is alloyed with nickel in heat-resisting alloys, and with iron (or iron and nickel) in stainless and heat resisting steels. Chromium has an important effect on corrosion resistance and is present in stainless steels in amounts of 12% to 20%. It is also used in high dutycast irons. Often used as a corrosion-resisting plating.