ASTM A249 TP304 stainless steel tubes is always required for pressure system, we have many year experience to produce TIG welded tubes, that is the most used method for ASTM A249 tubes.
ASTM A249 welded stainless steel tube has good properties for boiler, super heater, heat exchanger and condenser, particular it provides good corrosion resistance and high strength.
ASTM A249 TP304 Stainless Steel Tube Specifications
| Standard | ASTM A249 |
|---|---|
| Material | TP304 |
| Tube Type | Welded tube |
| Finishes | Annealing pickling, bright Annealing |
| Outside Diameter | 6 up to 304.8 mm |
| Thickness | 0.5 up to 6 mm |
| Application | Heat exchanger system |
ASTM A249 TP304 Stainless Steel
ASTM A249 covers austenitic stainless steel tubes, with various grades, TP304 stainless steel is the most used grade, the equivalent is ASME SA249 TP304.
ASTM A249 TP304 Chemical Composition
| Grade | C | Si | Mn | Cr | Ni | S | P | Fe |
|---|---|---|---|---|---|---|---|---|
| TP304 | 0,08 | 1,0 | 2 | 18 – 20 | 8 – 11 | 0,03 | 0,045 | Bal. |
ASTM A249 TP304 Mechanical Properties
| Grade | Tensile Strength (Mpa) | Yield Point (Mpa) | Elongation (%) |
|---|---|---|---|
| TP304 | 515 | 205 | 35 |
ASTM A249 Stainless Steel Tube Manufacturing
ASTM A249 specification covers nominal wall thickness and heavily cold worked welded tube, it is a common standard to specify welded tube for heat exchanger, it requires a manufacturing process and a quality system.
Strip
Quality welded tube starts from quality strip, it requires fine edge condition and uniform wall, our material is offered by the best suppliers.
TIG Welding
We use tungsten inert gas (TIG) welding method, it is automatic to weld two edges of strip and form tubular shape, this process must achieve precise joint between bead and base metal.
Related: TIG Welding Stainless Steel Tube
Cold Working
After welding, inside and outside of tube most be forged to achieve high integrity, then have a correct properties, and also possess precise dimensions.
Heat Treatment
Annealing is a very important process, tubes are heated to required solution temperature and rapidly cooling, ASTM A249 TP304 stainless steel requires minimum solution temperature is 1040 degree, it can restabilize microstructure to ensure premium properties.
Bright Annealing Option
Bright annealing welded tube is often required, tube pass through in closed furnace, inserting hydrogen gas to isolate surrounding atmosphere, finally forming a passive oxide film on the surface.
Related: Bright Annealing Tubing
ASTM A249 TP304 Stainless Steel Tubes Sizes
We offer a large sizes and dimensions for heat exchanger tubes, common sizes are provided below, and others are available.
| Outside Diameter | 12.7, 15.88, 19.05, 25.4, 31.8, 38.1, 45, 50.8, 60.3, 76.2 mm |
|---|---|
| Wall Thickness | 0.51, 0.71, 0.89, 1.0, 1.25, 1.65, 2.11, 2.77, 3.05 mm. |
Quality Control System
Tube analysis shall conform to the requirements as to chemical composition specified on ASTM A249 TP304 grade, usually we use PMI method to identify the material.
Nondestructive Testing
In practice, eddy current tests perform well in the most case, to detect tube imperfection. Each tube is inspected by ECT.
Dimensional Inspection
All the tubes should be meet to requirements of ASTM A249 specification, including tolerance of the tube outside diameter (OD), wall thickness, and length, minimum wall thickness tube is available.
| OD | WTH | L | |
|---|---|---|---|
| ＜25.40 mm | ±0.10 mm | ±10.00% | OD＜50.8 mm +3.0 mm -0 mm OD≥50.8 mm +5.0 -0 mm |
| ≥25.4 ~ 38.1 mm | ±0.15 mm | ||
| ≥38.1 ~ 50.8 mm | ±0.20 mm | ||
| ≥50.8 ~ 63.5mm | ±0.25 mm | ||
| ≥63.5 ~ 76.2 mm | ±0.30 mm | ||
| ≥76.2 ~ 101.6 mm | ±0.38 mm | ||
| ≥101.6 ~ 190.5 mm | +0.38 -0.64 mm | ||
| ≥190.5 ~228.6 mm | +0.38 -1.14 mm | ||
Mechanical Tests
There are destructive tests are performed on tube samples these tests have tests flattening test, flange test, and reverse bend test.
Hardness Test
ASTM A249 TP304 requires hardness in Rockwell B90 maximum.
Corrosion Testing
ASTM A249 specification requires corrosion testing in SUPPLEMENTARY REQUIREMENTS, purchaser should indicate the test when it is needed, intergranular corrosion and weld decay tests are considered widely to be a reliable corrosion test.
