Key Feature

The Superior Formability Austenitic Stainless Steel Bar Stock. Elevated nickel content (10.5-13.0%) minimizes work hardening, enabling extreme forming operations without intermediate annealing.

The optimal choice for deep drawing, spinning, and severe forming applications where 304 would work-harden excessively.

Common Designations

UNS S30500
AISI 305
ASTM A276 (Stainless Steel Bars)
ASTM A479 (Bars for Pressure Vessels)
EN 1.4303, X4CrNi18-12
JIS SUS305
AMS 5557 (Aerospace)

Specifically formulated for maximum formability; less common than 304 but critical for specific applications.

Chemical Composition (Typical wt.%)

C: ≤ 0.12
Cr: 17.0 - 19.0
Ni: 10.5 - 13.0Mn: ≤ 2.00
Si: ≤ 1.00
P: ≤ 0.045
S: ≤ 0.030

Higher nickel than 304 (10.5-13% vs 8-10.5%) stabilizes austenite and reduces work hardening.

Mechanical Properties (Annealed)

Tensile Strength: ≥ 500 MPa
Yield Strength: ≥ 190 MPa
Elongation: ≥ 45%
Hardness: ≤ 183 HB
Machinability: 50% of B1112 steel
n-value (strain hardening exponent): 0.45-0.50

Higher elongation and lower yield strength than 304, indicating superior formability.

Work Hardening Characteristics

Work Hardening Rate: Very low
Martensite Formation: Minimal
Springback: Reduced compared to 304
Forming Limit: Significantly higher than 304
Uniform Elongation: Excellent

Enables multiple forming operations without intermediate annealing or property degradation.

Physical Properties

Density: 7.90 g/cm³
Melting Range: 1399 - 1454 °C
Thermal Expansion: 17.2 × 10⁻⁶/K (20-100°C)
Thermal Conductivity: 16.3 W/m·K (100°C)
Consistently non-magnetic

Maintains austenitic structure even after severe cold working.

Available Forms

Rounds: 6mm - 150mm diameter
Squares: 6mm - 75mm
Hexagons: 6mm - 50mm
Flats: Various sizes
Wire: For cold heading applications

Commonly supplied in sizes suitable for cold forming operations.

Surface Conditions

Hot Rolled: Black bar
Cold Drawn: Bright, smooth finish
Centerless Ground: Precision dimensions
Polished: For specific applications
Peeled: Improved surface for forming

Cold drawn finish most common for forming applications.

Formability Metrics

• r-value (plastic strain ratio): 1.0-1.1
• Limiting Drawing Ratio (LDR): 2.2-2.3
• Minimum Bend Radius: 0.3t (annealed)
• Erichsen Cup Test: 11-12 mm
• Olsen Cup Test: 10.5-11.5 mm

Quantifiably better formability than 304 in all standard tests.

Corrosion Resistance

Excellent general corrosion resistance comparable to 304. Good resistance to atmospheric exposure, fresh water, food products, and mild chemicals.

Similar to 304; suitable for most applications where 304 is specified.

Machining Characteristics

• Similar to 304 in machinability
• Better chip control than 304
• Good surface finish achievable
• Slightly higher tool life than 304
• Standard tooling works well

Machining characteristics generally similar to 304 but with slightly better performance.

Key Standards

ASTM A276 305: Stainless Steel Bars
ASTM A479 305: Bars for Pressure Vessels
ASTM A484: General Requirements
EN 10088-3: Stainless Steel Bars
JIS G4303: Stainless Steel Bars
ASME SA479: Code Construction

Often specified for electronic and specialized forming applications.

Common Applications

• Cold-Headed Fasteners: Screws, bolts, nuts requiring multiple blows
• Deep-Drawn Components: Electrical connectors, socket contacts, shells
• Spun Parts: Reflectors, lighting fixtures, decorative housings
• Electronics: Shield cans, connector housings, chassis components
• Automotive: Complex trim parts, fuel system components, decorative elements
• Architectural: Complex formed panels, decorative elements
• Medical: Formed instrument parts, device housings, specialized components

Specifically selected where formability is the primary requirement.