Stainless Steel 303 vs 304: Machinability vs Corrosion Resistance

303 is optimized for machinability with added sulfur, making it ideal for high-volume turned parts. 304 offers better corrosion resistance and weldability, making it the standard for food, medical, and general-purpose applications.

Side-by-Side Property Comparison

PropertyStainless Steel 303Stainless Steel 304
Tensile Strength620 MPa (90 ksi)515 MPa (75 ksi)
Yield Strength240 MPa (35 ksi)205 MPa (30 ksi)
Hardness228 HB201 HB
Density8.03 g/cm³8.00 g/cm³
Machinability Rating78/10045/100
Thermal Conductivity16.2 W/m·K16.2 W/m·K
Melting Point1,400–1,420 °C1,400–1,450 °C
Tolerance±0.01 mm±0.01 mm

Key Differences

PropertyStainless Steel 303Stainless Steel 304Winner
Machinability78/10045/100Stainless
Corrosion ResistanceGoodExcellentStainless
WeldabilityPoorExcellentStainless
Surface FinishExcellentGoodStainless
CostSimilarSimilarTie
Food GradeNoYes (FDA)Stainless

Which Material Should You Choose?

Choose Stainless Steel 303 when:

  • High-volume turned parts
  • Complex screw machine parts
  • Parts not requiring welding
  • Shafts, fittings, and bushings
  • Cost optimization for machined parts
View Details Stainless Steel 303

Choose Stainless Steel 304 when:

  • Food contact equipment
  • Parts requiring welding
  • Marine or corrosive environments
  • Medical equipment
  • Architectural applications
View Details Stainless Steel 304

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