Allegheny Technologies Incorporated (ATI) is an American specialty metals company headquartered in Pittsburgh, Pennsylvania, in the United States. ATI is one of the largest and most diversified specialty materials and components producers in the world with revenue of $3.7 billion in 2015. ATI's key markets are aerospace and defense, oil & gas, chemical process industry, electrical energy, and medical. Products are titanium and titanium alloys, nickel-based alloys and superalloys, grain-oriented electrical steel, stainless and specialty steels, zirconium, hafnium, and niobium, tungsten materials, forgings and castings.