Aluminum vs Stainless Steel for CNC Machining: Complete Guide

Aluminum is the lightweight, cost-effective, and easier-to-machine option for most applications. Stainless steel offers superior strength, temperature resistance, and corrosion performance for demanding environments but at higher weight and machining cost.

Side-by-Side Property Comparison

PropertyAluminum 6061-T6Stainless Steel 304
Tensile Strength310 MPa (45 ksi)515 MPa (75 ksi)
Yield Strength276 MPa (40 ksi)205 MPa (30 ksi)
Hardness95 HB (Brinell)201 HB
Density2.70 g/cm³8.00 g/cm³
Machinability Rating90/10045/100
Thermal Conductivity167 W/m·K16.2 W/m·K
Melting Point582–652 °C1,400–1,450 °C
Tolerance±0.005 mm±0.01 mm

Key Differences

PropertyAluminum 6061-T6Stainless Steel 304Winner
Weight (Density)2.70 g/cm³8.00 g/cm³Aluminum
Tensile Strength310 MPa515 MPaStainless
Machinability90/10045/100Aluminum
Corrosion ResistanceGoodExcellentStainless
Thermal Conductivity167 W/m·K16 W/m·KAluminum
Machining CostLowHigh (2-3x)Aluminum

Which Material Should You Choose?

Choose Aluminum 6061-T6 when:

  • Weight-sensitive applications
  • High-volume production (faster machining)
  • Heat sinks and thermal management
  • Consumer electronics housings
  • Cost optimization
View Details Aluminum 6061-T6

Choose Stainless Steel 304 when:

  • Food and medical equipment
  • High-temperature applications
  • Chemical exposure environments
  • Higher strength requirements
  • Wear-resistant parts
View Details Stainless Steel 304

Not Sure Which Material to Choose?

Our engineers can recommend the best material for your application. Upload your design for a free consultation.

Get a Free Quote