The Raw Science of Stainless Steel vs. Aluminum
Stainless Steel and Aluminum, Compared
Unless otherwise stated, stainless steel parts sold anywhere are made of 304 alloy, and aluminum parts of 6061 alloy, being the most common alloys in use today.
Some material mechanical properties (how "strong" the material is) are dependent on the heat treatment applied to the metal in its production process. A range of minimum and maximum values is provided in the following table, as well as other relevant comparison points:
| Parameter | Stainless Steel (304) |
"High Grade" Aluminum (7075) | "Aerospace Grade" Aluminum (6061) |
|
Hardness Ability to withstand denting and scratching |
120 to 360 HB |
60 to 160 HB |
30 to 120 HB |
|
Strength (yield) Maximum pull stress before it permanently deforms |
220 to 860 MPa | 100 to 510 MPa | 55 to 370 MPa |
|
Strength (shear) Maximum shear stress before completely breaking off |
400 to 690 MPa | 150 to 340 MPa | 80 to 240 MPa |
|
Strength (ultimate) Maximum pull stress before completely breaking off |
500 to 1180 MPa | 230 to 590 MPa | 120 to 310 MPa |
|
Density How heavy it is for the same material volume |
7.8 g/cm3 | 2.8 g/cm3 | 2.7 g/cm3 |
| Rust and Corrosion Resistance | Very high resistance due to its alloy composition. | High resistance due to its outer layer corroding to a protective film. | High resistance due to its outer layer corroding to a protective film. |
| Food Interaction | No chemical reaction or leaching. Used heavily in the kitchen and the food industry. |
Some chemical reaction and aluminum leaching |
Some chemical reaction and aluminum leaching |
|
Ease of Manufacturing |
Harder to make due to its resistance to wear and abrasion; requires harder tools and slower processes. | Easy to make fairly soft and easily machined. | Easy to make fairly soft and easily machined. |
| Material Cost | ~30% more expensive | ~15% more expensive |