ASTM A 688

This specification covers standard requirements for welded austenitic stainless steel feedforward heater tubes including those bent, if specified, into the form of U-tubes for application in tubular feed-water heaters. All finished straight tubing or straight tubing ready for U-bending shall be furnished in the solution-annealed condition. The steel shall conform to the required chemical composition for carbon, phosphorus, chromium, molybdenum, nitrogen, and copper. The material shall also conform to tensile properties such as tensile strength, yield strength, and elongation. The steel shall undergo mechanical tests such as tension test, hardness test, reverse bend test, flattening test, flange test, pressure test, hydrostatic test, and air underwater test. Nondestructive test (electric test) shall be performed and corrosion resisting properties shall be determined for each sample tube.