Key Feature

The Free-Machining Martensitic Stainless. Sulfur/selenium additions provide exceptional machinability (85% of B1112) while maintaining heat-treatability and magnetic properties.

The most machinable martensitic stainless steel, ideal for high-volume production of precision components.

Common Designations

UNS S41600
AISI 416
EN 1.4005, X12CrS13
JIS SUS416
Variants: 416Se (selenium)

Available as 416 (sulfur) or 416Se (selenium); selenium offers better corrosion resistance.

Chemical Composition (Typical wt.%)

C: 0.15 (max)
Cr: 12.0 - 14.0
Mn: ≤ 1.25
Si: ≤ 1.00
P: ≤ 0.06
S: 0.15 (min)or Se: 0.15 (min for 416Se)

Sulfur/selenium content is critical for free-machining properties; typically 0.15-0.35%.

Mechanical Properties (Annealed)

Tensile Strength (Rm): ≥ 480 - 620 MPa
Yield Strength (Rp0.2): ≥ 275 - 345 MPa
Elongation (A): ≥ 20-25%
Hardness (HB): ≤ 217
Machinability: 85% of B1112

Excellent machinability even in annealed condition; properties improve with heat treatment.

Mechanical Properties (Hardened & Tempered)

Tensile Strength: Up to 1300 MPa
Yield Strength: Up to 1100 MPa
Hardness: Up to 42 HRC
Machinability (annealed): Excellent
Machinability (hardened): Poor

Typically machined in annealed condition, then heat treated for final properties.

Physical Properties

Density: 7.70 g/cm³
Melting Range: 1480 - 1530 °C
Thermal Conductivity: 24.9 W/m·K (100°C)
Strongly magnetic

Similar to other martensitic stainless steels; always magnetic.

Heat Treatment Capability

Austenitizing: 980-1010°C (air or oil quench)
Tempering Range: 150-650°C
Maximum Hardness: ~42 HRC
Annealing: 815-870°C, slow cool

Can be hardened to various levels depending on tempering temperature.

Corrosion Resistance

Moderate resistance to atmospheric corrosion, fresh water, and mild chemicals. Inferior to 410 due to sulfide inclusions. Not suitable for marine environments.

Suitable for many industrial applications; 416Se offers slightly better corrosion resistance.

Machining Characteristics

• Machinability Rating: 85% (vs 410: 50%)
• Surface Finish: Excellent
• Chip Formation: Short, broken chips
• Tool Life: 2-3× longer than 410
• Cutting Speed: 25-40% faster than 410

Enables high-speed production of complex parts with reduced tooling costs.

Key Standards (Coil)

ASTM A581 (Free-Machining Stainless Steel Wire)
ASTM A480 (General Requirements)
AMS 5610 (Aerospace)
EN 10088-3

Often specified for machined components in various industries.

Common Applications (from Coil)

• Fasteners: Screws, bolts, nuts, studs (machined)
• Valve Components: Valve stems, seats, trim parts
• Pump Parts: Shafts, impellers, wear rings
• Surgical Instruments: Forceps, clamps, instrument bodies
• Firearm Components: Barrels, receivers, small parts
• Automotive: Transmission parts, fuel system components
• General Machined Parts: Bushings, gears, precision components

Specifically selected where extensive machining is required on hardenable stainless steel.