ASTM A554 TP304 Stainless Steel Polished Tubing
Nov 07, 2025
Leave a message
What Is ASTM A554 TP304 Tubing
ASTM A554 is the specification for welded stainless steel mechanical tubing, covering tubing in round, square, rectangular and irregular shapes. A key feature is the requirement for cold working of the weld seam after welding, which improves the overall strength and durability of the tubing. The specification also requires the tubing to be straightened and, where specified, polished using cold drawing processes, ensuring dimensional consistency and a smooth surface. TP304 tubing is made from 304 austenitic stainless steel and is typically polished to a bright surface for decorative and structural applications.
Chemical Composition
Composition of TP304 welded mechanical tubing per ASTM A554; the equivalent JIS designation is SUS304TK per JIS G3446.
| Element (wt %) | 304 |
|---|---|
| Carbon, max | 0.08 |
| Manganese, max | 2 |
| Phosphorus, max | 0.045 |
| Sulfur, max | 0.03 |
| Silicon, max | 1 |
| Chromium | 18.0-20.0 |
| Nickel | 8.0-11.0 |
Mechanical Properties
Minimum values for TP304 tubing in the solution-treated condition (1900°F / 1040°C).
| Property | 304 |
|---|---|
| Yield strength (ksi / MPa), min | 30 / 205 |
| Tensile strength (ksi / MPa), min | 75 / 515 |
| Elongation, min (%) | 35 |
Sizes and Surface Finishes
Round tubing is commonly available with outside diameters from 9.5 mm to 139.7 mm and wall thicknesses from 0.6 mm to 3.05 mm; square and rectangular tubing is supplied in a wide range of sections. Representative square and rectangular sections with theoretical weights are shown below.
| Square tube (in) | Wall (in) | Weight (lb/ft) |
|---|---|---|
| 0.750 x 0.750 | 0.065 | 0.605 |
| 1.000 x 1.000 | 0.065 | 0.827 |
| 1.500 x 1.500 | 0.120 | 2.252 |
| 2.000 x 2.000 | 0.120 | 3.050 |
| 3.000 x 3.000 | 0.120 | 4.750 |
| 4.000 x 4.000 | 0.250 | 12.210 |
| 6.000 x 6.000 | 0.250 | 19.020 |
| Rectangular tube (in) | Wall (in) | Weight (lb/ft) |
|---|---|---|
| 1.000 x 2.000 | 0.120 | 2.252 |
| 2.000 x 3.000 | 0.120 | 3.900 |
| 2.000 x 4.000 | 0.250 | 8.810 |
| 4.000 x 6.000 | 0.250 | 15.620 |
Common surface finishes include 2B mill finish, No. 4 finish, bright annealed (BA) finish and 400, 550 and 600 grit polished finishes. For ornamental purposes, #180, #320, #400 and mirror polishing are typical. As-welded mechanical tubing is generally supplied without stress relieving or annealing and without cold drawing or bead removal, which is the main reason mechanical tubing is cost-effective.
Applications
TP304 polished mechanical tubing is used for handrails, balustrades and building components, structural support, architectural decoration and furniture. Industrial applications include chemical and petrochemical processing, power generation, renewable energy, pulp and paper, process piping, oil and gas, food and beverage, and marine equipment.
Frequently Asked Questions
What does ASTM A554 cover? Welded stainless steel mechanical tubing in round, square, rectangular and irregular shapes, with cold working of the weld seam.
What is the difference between A554 and A312 tubing? A554 is mechanical tubing for structural and decorative use; A312 covers seamless and welded pipe for pressure and corrosion service.
What finish is used for decorative tubing? No. 4, BA and 400/550/600 grit polished finishes, including mirror polish.
Is A554 TP304 tubing welded or seamless? Welded; the weld seam is cold worked after welding to improve strength and durability.
What is the JIS equivalent? JIS G3446 SUS304TK for welded stainless steel mechanical tubing.
Can A554 tubing be used for structural support? Yes, it is commonly used for handrails, balustrades and structural building components as well as decoration.
Frequently Asked Questions
Q1. What is the chemical composition of TP304 per ASTM A554?
Carbon 0.08 max, manganese 2 max, chromium 18.0-20.0 and nickel 8.0-11.0; the equivalent JIS designation is SUS304TK per JIS G3446.
Q2. What are the minimum mechanical properties of TP304 tubing?
Yield strength 30 ksi (205 MPa) min, tensile strength 75 ksi (515 MPa) min and 35% min elongation in the solution-treated condition (1900 F / 1040 C).
Q3. What sizes are available in round tubing?
Outside diameters from 9.5 mm to 139.7 mm with wall thicknesses from 0.6 mm to 3.05 mm; square and rectangular sections are supplied in a wide range.
Q4. Why is the weld seam cold worked after welding?
Cold working of the weld seam after welding improves the overall strength and durability of the mechanical tubing.
Q5. What finishes are typical for decorative tubing?
2B mill finish, No. 4, BA and 400/550/600 grit polished finishes; for ornamental purposes, 180, 320, 400 grit and mirror polishing are typical.
Send Inquiry