304 Stainless vs 6061-T6
304 stainless and 6061-T6 aluminum represent the classic strength-versus-weight trade in metal selection. 304 is about three times denser but much stronger, tolerates far higher temperatures, and resists many chemicals better. 6061 is lighter, cheaper, more machinable, and a far better conductor of heat. Most general-purpose parts come down to whether you prioritize durability and corrosion resistance or weight and cost.
The verdict
Choose 304 stainless for strength, high-temperature tolerance, and broad corrosion resistance, especially in food, marine, and chemical service. Choose 6061-T6 aluminum when weight, cost, machinability, or thermal conductivity matter more, accepting its lower strength and temperature limit.
Side-by-side data
| Property | 304 Stainless | 6061-T6 |
|---|---|---|
| Category | Stainless Steel | Aluminum |
| Density (g/cm³) | 8.0 | 2.7 |
| Tensile strength (MPa) | 515 | 310 |
| Yield strength (MPa) | 215 | 276 |
| Elongation (%) | 40 | 12 |
| Hardness | 201 HB | 95 HB |
| Max service temp (°C) | 870 | 170 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 16 | 167 |
| Typically used for | General corrosion-resistant parts | All-round structural & machined parts — the default aluminum |
Which should you choose?
Choose 304 Stainless when…
- Higher strength is needed at the same volume despite the weight
- Service runs hot: 304 tolerates ~870 C vs 6061's ~170 C
- Broad corrosion resistance is required (304 rates 4.5/5)
- Building food, marine, medical, or chemical equipment
- High ductility helps for forming: 40% elongation vs 6061's 12%
- Surface hardness and wear resistance matter (201 HB vs 95 HB)
Choose 6061-T6 Aluminum when…
- Weight is critical: 2.7 g/cc is about one-third the density of 304 (8.0 g/cc)
- Lower cost is preferred: 6061 rates 2.0/5 vs 304's 3.0/5
- Easier machining matters (6061 at 4.5/5 vs 304's 2.5/5)
- High thermal conductivity is needed (167 vs 16 W/m-K)
- Building lightweight structural and machined parts
- Service stays cool, below ~170 C, within aluminum's limit
Key differences that matter
- Density is the central trade: 304 (8.0 g/cc) is roughly three times the mass of 6061 (2.7 g/cc).
- 304 is much stronger in tension (515 vs 310 MPa) and tolerates far higher temperature (~870 vs ~170 C).
- 6061 is cheaper (2.0/5 vs 3.0/5) and far easier to machine (4.5/5 vs 2.5/5).
- 304 resists corrosion better against many chemicals (4.5/5 vs 6061's 3.5/5), key for food and marine use.
- 6061 conducts heat roughly ten times better (167 vs 16 W/m-K), important for heat sinks and enclosures.
- 304 offers high ductility (40% elongation) for deep forming; 6061-T6 is more limited at 12%.
- For strength-to-weight, aluminum often wins; for absolute strength, temperature, and corrosion, 304 leads.
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Open the Material SelectorGet a Quote →Frequently asked questions
How much heavier is 304 stainless than 6061 aluminum?
About three times heavier. 304 has a density of 8.0 g/cc versus 2.7 g/cc for 6061-T6. That weight difference is the core reason aluminum is chosen for portable, aerospace, and weight-sensitive parts, while stainless is reserved for applications where its strength and corrosion resistance justify the mass.
Which is easier to machine, 304 or 6061?
6061-T6 by a wide margin. It rates 4.5/5 on machinability versus 2.5/5 for 304, which is gummy and work-hardens. Aluminum cuts faster with longer tool life and lower cost per part. If machining time and cost are priorities and the environment allows, 6061 is far more economical to produce.
Does 304 stainless resist corrosion better than 6061?
Generally yes. 304 rates 4.5/5 versus 6061's 3.5/5 and resists a broader range of chemicals, which is why it dominates food, marine, and medical equipment. 6061 has good corrosion stability for structural use but can be attacked by chlorides and acids that 304 handles better.
Can 6061 aluminum handle the same temperatures as 304?
No. 6061-T6 is limited to about 170 C, while 304 stainless tolerates roughly 870 C. For hot service such as exhaust, ovens, or process equipment, stainless is required. Aluminum loses strength as it warms, so 6061 should be kept to cooler-running applications where its weight and cost advantages apply.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.