Type 304 Square Tubes
About Type 304 Square Tubes
Type 304 stainless steel square tube combines excellent corrosion resistance and weldability with a 73,200 PSI tensile strength. Meets ASTM A269 specifications. Ideal for frames, railings, and architectural applications.
Quick Facts
- Material: 304 Stainless Steel
- ASTM Standard: A269
- Temper/Condition: Annealed
- Available Sizes: From 1/2" side, 0.049" to 0.065" wall
- Location: Los Angeles warehouse
- Services: Custom size, same-day pickup
Overview
Type 304 is the most common austenitic stainless steel, containing 18% chromium and 8% nickel for superior resistance to oxidation and corrosion. Its non-magnetic properties in the annealed condition and excellent formability make it highly versatile. This grade provides a good balance of strength, toughness, and fabrication characteristics, making it a reliable choice for a wide range of structural and decorative projects where environmental exposure is a concern.
The square tube shape provides structural efficiency for frames, supports, and posts, offering high strength-to-weight ratios and clean aesthetic lines. It is easily welded, cut, and formed, simplifying fabrication for projects like handrails, support columns, and machine frames. Available in a standard mill finish or a polished 180 grit satin finish for architectural applications, it can be adapted to both functional and cosmetic requirements.
Technical Specifications
Mechanical Properties
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 73,200 | PSI |
| Yield Strength | 31,200 | PSI |
| Elongation | 70 | % |
| Hardness | 123 | HB |
Chemical Composition (Typical)
| Element | Percentage |
|---|---|
| Chromium (Cr) | 18.0 - 20.0% |
| Nickel (Ni) | 8.0 - 10.5% |
| Carbon (C) | 0.08% max |
| Manganese (Mn) | 2.00% max |
| Silicon (Si) | 0.75% max |
| Phosphorus (P) | 0.045% max |
| Sulfur (S) | 0.030% max |
| Iron (Fe) | Balance |
Applicable Standards
- ASTM A269: Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service
Common Applications
- Architectural: Handrails, guardrails, and decorative trim - Excellent corrosion resistance and available polished finish.
- Food & Beverage: Equipment frames, support structures, and conveyor systems - Resists corrosion from food acids and cleaning solutions.
- Structural Framing: Lightweight frames for carts, workbenches, and enclosures - Good strength-to-weight ratio and easy fabrication.
- Marine: Non-critical components like grab rails and trim (for freshwater) - Good general corrosion resistance.
- Automotive: Custom framework and support brackets - Resists moderate temperatures and corrosive environments.
- Medical: Framework for medical stands and non-critical equipment - Easily sanitized and non-reactive.
- Signage: Posts and frames for indoor and outdoor signs - Withstands weather exposure and provides a clean look.
Working with Type 304 Square Tubes
Machining
304 stainless is tougher than carbon steel and tends to work-harden. Use sharp tooling, rigid setups, and slow speeds with heavy, constant feeds to prevent glazing. The use of chip breakers and a suitable coolant is recommended.
Welding
Excellent weldability with all common fusion and resistance methods, both with and without filler metals. For heavier sections, post-weld annealing may be required to restore maximum corrosion resistance by redissolving chromium carbides. Use AWS E/ER 308 filler rods.
Finishing
Can be mechanically polished to various finishes, including a #4 satin (180 grit) or a #8 mirror finish. It can also be passivated to enhance its natural corrosion resistance by removing free iron from the surface after fabrication.
Related Products
Frequently Asked Questions
Q: What is the difference between 304 and 316 stainless steel square tube?
A: 316 stainless steel contains molybdenum, which significantly enhances its resistance to chlorides and pitting corrosion, making it a better choice for marine or coastal environments. 304 is more cost-effective and suitable for most other applications.
Q: Is 304 stainless steel magnetic?
A: In its annealed, as-supplied condition, 304 stainless is austenitic and therefore non-magnetic. However, it can become slightly magnetic after cold working, such as bending or forming, due to the formation of martensite in the steel's crystal structure.
Q: Can I use 304 square tubing for a boat railing?
A: While 304 has good corrosion resistance, for saltwater marine environments, 316 stainless steel is strongly recommended. 304 is acceptable for freshwater boating applications or areas with minimal exposure to salt spray, but 316 provides superior long-term protection against pitting corrosion.
Stock & Custom Sizes
Available sizes from 1/2" x 1/2", with common wall thicknesses including 0.049" and 0.065". Standard lengths are 20 feet. Custom size available.
Same-day cutting and Los Angeles pickup available.
View Sizes & PricingNeed Type 304 Square Tubes? Contact Bobco Metals for availability and Los Angeles pickup.
Request a Quote Ask an Expert