ASTM A688/A688M-04 - 1.9.2004
 
1. Scope

1.1 This specification covers welded austenitic stainless steel feedwater heater tubes including those bent, if specified, into the form of U-tubes for application in tubular feed-water heaters.

1.2 The tubing sizes covered shall be 5/8 to 1 in. [15.9 to 25.4 mm] inclusive outside diameter, and average or minimum wall thicknesses of 0.028 in. [0.7 mm] and heavier.

1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

 
2. Referenced Documents

A1016/A1016M-24a

Standard Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes (Includes all amendments and changes 10/30/2024).

A480/A480M-25b

Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip (Includes all amendments and changes 9/10/2025).

A941-26a

Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys (Includes all amendments and changes 4/15/2026).

A262-15(2021)

Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels

E112-25

Standard Test Methods for Determining Average Grain Size

E527-23

Standard Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)

SAE J1086

Practice for Numbering Metals and Alloys (UNS) Available from Society of Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http://www.sae.org.