303 Stainless Steel Bar Supplier

Circle H Steel supplies 303 stainless steel round bar for high-speed machining applications. We stock a wide range of diameters and specialty long-length bars with cut-to-length, centerless grinding, and polished finishes. 303 offers the best machinability of the austenitic family, making it ideal for parts produced on CNC and automatic screw machines.

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303 Round Bar Specifications

Diameters

3/8" 7/16” 1/2” 9/16” 5/8”
11/16” 3/4” 13/16” 7/8” 15/16”
1 1/8” 1 3/16” 1 1/4” 1 5/16” 1 3/8”
1 7/16” 1 1/2” 1 9/16” 1 5/8” 1 11/16”
1 3/4” 1 13/16” 1 7/8” 1 15/16”  
2 1/8” 2 3/16” 2 1/4” 2 5/16” 2 3/8”
2 7/16” 2 1/2” 2 9/16” 2 5/8” 2 11/16”
2 3/4” 2 13/16” 2 7/8” 2 15/16”  

 

 

 

Lengths

Circle H Steel provides 303 round bar in a variety of lengths, but specializes in long-length stainless steel bar up to 28 ft. Benefits of long-length bar include having fewer items to stock, and having more feet of usable material for machining. 

303 Stainless Steel Properties

  • Chemistry: 18Cr–8Ni austenitic steel with sulfur and/or selenium additions for free-machining (per ASTM A582).
  • Corrosion Resistance: Good in mildly corrosive environments; not recommended for marine/salt-spray exposure due to pitting risk from sulfide inclusions.
  • Heat resistance: Intermittent up to ~760°C, continuous to ~870°C; Continuous use in 425-860°C range not usually recommended due to carbide precipitation.
  • Magnetism: Generally non-magnetic; may become slightly magnetic after cold work.
  • Machining: Excellent chip breakage and surface finish; Ugima® improved machinability version of grade 303 is available in round bar products, which machines significantly better than standard 303
  • Welding: Not generally recommended; if required, use 308L or 309 filler and accept reduced corrosion resistance; post-weld anneal where possible.
  • Heat treatment: Solution anneal ~1010–1120°C, rapid cool. Not hardenable by thermal treatment.

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Chemical Formula

  • Fe
    Balance
  • C
    < 0.15%
  • Cr
    17 - 19%
  • Ni
    8 - 10%
  • Mn
    < 2%
  • Si
    < 1%
  • P
    < 0.20%

Applications for 303 Round Bar

Typical applications include:

  • Nuts and Bolts
  • Bushings
  • Shafts
  • Aircraft Fittings
  • Electrical Switchgear Components
  • Gears

Or any heavily machined part where 303’s corrosion resistance is sufficient.

 

Comparing Stainless Steel Grades

  • 303 Round Bar
    • Best machinability
    • Lower corrosion than 304/316
    • Poor weldability
    • Non-magnetic (may become slightly magnetic after cold work).
  • 304 Round Bar
    • Better corrosion and formability than 303
    • Lower machinability.
  • 316
    • Best corrosion
    • Lower machinability.
  • 416
    • Very high machinability (martensitic)
    • Can be heat treated
    • Lower corrosion than 303.

 

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800.382.7748

8261 Monroe Rd,
Houston, TX 77061

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