ASTM is the American Society for Testing and Materials, and A790 is " Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing." ASTM A790 covers seamless and longitudinally welded ferritic/austenitic steel pipe for general corrosion service, with particular emphasis on resistance to stress corrosion cracking. This general specification specifies the dimensions (ANSI B36.19), chemical composition, heat treatment, and tensile and hardness requirements for seamless straight seam welded steel pipe, mechanical property test, hydrostatic test or non-destructive electrical test, etc.
ASTM A790 covers a variety of grades of duplex (austenitic-ferritic) stainless steel pipes, common grades include UNS S31803, UNS S32205, UNS S32750 (also known as 2507), UNS S32760, UNS S32520, etc.
UNS S31803 (also known as 2205), ASTM A790 UNS S31803 is one of the most common duplex stainless steel pipe grades, offering good corrosion resistance and high strength. ASTM A790 UNS S31803 piping finds applications in oil and gas, chemical processing, desalination, offshore platforms, and many other environments where corrosion resistance, strength, and durability are critical. UNS S32205 is similar to UNS S31803, ASTM A790 UNS S32205 is also a common duplex stainless steel pipe grade with similar properties and applications.
ASTM A790 Pipe and Filler Metal Specification
| Pipe | Filler Metal | |
| UNS Designation | AWS A5.9 Class | UNS Designation |
| S31803 | ER2209 | S39209 |
| S32205 | ER2209 | S39209 |
| S31200 | ER2553 | S39553 |
