The process industries have used 300 series stainless steels for many years where the corrosion resistance of carbon steel is inadequate. Where stainless steels have proved inadequate there has been a tendency to utilise high nickel alloys with a greatly increased cost. This paper introduces Zeron 100 super duplex stainless steel and shows how its superior corrosion and stress corrosion cracking resistance, plus its high strength, can be utilised to provide a cost effective alternative to both austenitic stainless steels and high nickel alloys. The composition, mechanical properties and corrosion resistance are discussed showing that the combination of high strength and excellent corrosion resistance make it eminently suitable for a wide range of industrial applications.

The wide range of product forms in which Zeron 100 is available means that vessels, piping, valves and pumps can be made from a single alloy with no worries about galvanic compatibility. Zeron 100 has now been in service for up to ten years. The material is readily weldable with over one million joints now in service. The paper reviews examples of the applications of Zeron 100 including service experience in the petrochemical, chemical, fertiliser and mining industries.

The high strength and hardness of Zeron 100 gives it excellent resistance to erosion and erosion-corrosion and it is widely used for pumps and piping in mining and processing applications. The unique composition of Zeron 100 gives it excellent resistance to a wide range of chemicals including non-oxidising acids. This has led to a variety of applications in phosphatic and urea based fertiliser plants and in other chemical industries. The largest super duplex vessel built to date has been fabricated for a chemical company in the UK.

The use of appropriate design codes to reduce wall thickness and fabrication costs is discussed. It is concluded that, with the drive to cut initial capital cost of new plant, there are many more applications for super duplex stainless steel in the process industries.