ASTM A789 UNS S31803 Duplex Stainless Steel Tube For Chemical Process Plant

ASTM A789 UNS S31803 Duplex Stainless Steel Tube for Chemical Process Plant

ASME SA789 S31803 stainless steel tubing provides better pitting and crevice corrosion resistance than 316L or 317L austenitic stainless steel in almost all corrosive media. It also has high corrosion and erosion fatigue properties, as well as lower thermal expansion rates and higher thermal conductivity compared to austenitic stainless steels. The advantage of a duplex structure is that it combines the advantages of ferritic alloys, stress corrosion resistance, crack resistance, and high strength with the ease of manufacture and corrosion resistance of austenitic alloys.

Duplex ASTM A789 S31803 is a nitrogen-enhanced, duplex stainless steel developed specifically to address the common corrosion problems encountered with 300 series stainless steels. "Duplex" describes a family of stainless steels that are neither fully austenitic (e.g., 304 stainless steel) nor pure ferrite (e.g., 430 stainless steel). The structure of S31803 duplex stainless steel consists of an austenitic cell surrounded by a continuous ferritic phase. Under annealed conditions, S31803 contains about 40-50% ferrite. Often referred to as the workhorse grade, S31803 is the most widely used grade for duplex stainless steel tubing.

The use of S31803 stainless steel tubing should be limited to temperatures below 600 °F. Prolonged exposure to high temperatures can make S31803 stainless steel brittle.

Chemical Composition

Physical Properties

Heat Treatment Requirements

Duplex Stainless Steel Pipe Application

• Chemical processing
• Transport and Storage
• Oil and gas exploration and offshore rigs
• Oil and gas refining
• Marine environments
• Pollution control equipment
• Pulp and paper manufacturing
• Chemical process Plant