ASME SA249 covers nominal-wall-thickness welded tubes and heavily cold worked welded tubes made from austenitic steels for boiler, superheater, heat exchanger, or condenser service. TP304 is a general-purpose austenitic grade with good formability and corrosion resistance in many water, steam, and process environments.
| Element | UNS S30400 Requirement |
|---|---|
| Carbon, C | 0.08 max |
| Manganese, Mn | 2.00 max |
| Phosphorus, P | 0.045 max |
| Sulfur, S | 0.030 max |
| Silicon, Si | 0.75 max |
| Chromium, Cr | 18.00-20.00 |
| Nickel, Ni | 8.00-11.00 |
Under ASME SA249, welded tube is made from flat-rolled steel by an automatic welding process without filler metal. After welding and before final heat treatment, the tube is cold worked in both weld and base metal, or in weld metal only. Final heat treatment is performed in accordance with ASME SA249. For TP304, solution annealing is typically at 1900°F [1040°C] minimum, followed by rapid cooling.
| Item | ASME SA249 TP304 Requirement |
|---|---|
| Tensile strength, min | 75 ksi [515 MPa] |
| Yield strength, min | 30 ksi [205 MPa] |
| Elongation in 2 in. or 50 mm, min | 35% |
| Rockwell hardness, max | B90 |
| Vickers hardness, max | 200 |
| Tension test | One test for lots up to 50 tubes; two tubes for larger lots |
| Flattening test | One specimen from each end of one finished tube per lot |
| Flange test | One specimen from each end of one finished tube per lot |
| Reverse-bend test | One test per 1500 ft [450 m] of finished tubing |
| Hardness test | Two tubes per lot |
Key dimensional controls include wall thickness tolerance of ±10% of nominal wall. The weld thickness shall not exceed the wall thickness measured 90° from the weld by more than 6% of specified wall or 0.004 in. [0.1 mm], whichever is greater. Straightness shall not deviate by more than 0.030 in. [0.8 mm] in 3 ft [900 mm]. After final heat treatment, tubes are chemically descaled or pickled free of scale unless bright annealed.
ASME SA249 tubing is usually furnished from 1/2 in. [3.2 mm] inside diameter to 12 in. [304.8 mm] outside diameter, with wall thickness from 0.015 to 0.320 in. [0.4 to 8.1 mm]. Mechanical property requirements do not apply to tubing smaller than 1/2 in. [3.2 mm] inside diameter or 0.015 in. [0.4 mm] in thickness.
Yuhong Group supports ASME SA249 TP304 welded tube and related austenitic grades, together with U-bending, finning, tube bundle assembly, tubesheet, baffle, and head fabrication. Custom lengths, end finishes, U-bend radii, and bundle documentation can be reviewed against project requirements.
ASME SA249 TP304 welded tube is used in boilers, superheaters, heat exchangers, condensers, air-cooler bundles, and replacement tube projects. Technical highlights include no filler metal in the weld, post-weld cold working, controlled final heat treatment, wall tolerance control, and weld thickness control. These points support consistent tube-to-tubesheet fit and reliable forming, expanding, beading, forging, welding, and bending operations when properly manipulated.
Yes. ASME SA249 includes heat exchanger, condenser, boiler, and superheater tube applications. Grade selection should match temperature, corrosion, and stress conditions.
A sample is split longitudinally 90° on each side of the weld, opened, and bent around a mandrel with maximum thickness of four times the wall thickness. The weld shall show no cracks or overlaps from cold working.
Yes. We supply heat exchanger tubes, U-tubes, finned tubes, tube bundles, tubesheets, baffles, and heads for heat exchanger and air-cooler projects.
