Overview
SS416 (AISI 416 Stainless Steel) is a free-machining martensitic stainless steel belonging to the 400 Series Stainless Steel Family. It is essentially a modified version of SS410 with increased sulfur content, specifically designed to provide excellent machinability while maintaining moderate corrosion resistance and good mechanical strength.
SS416 is widely recognized as the most machinable stainless steel grade available, making it a preferred material for CNC machining, automatic screw machining, shafts, gears, valve components, fasteners, and precision turned parts.
Compared with SS410, SS416 offers significantly improved machinability but slightly reduced corrosion resistance and toughness.
Material Specification
| Property | Value |
|---|---|
| Material Designation | AISI 416 |
| Material Family | Free-Machining Martensitic Stainless Steel |
| UNS Number | S41600 |
| EN Grade | 1.4005 |
| Density | 7.75 g/cm³ |
| Magnetic Property | Magnetic |
| Standard Forms | Round Bar, Hex Bar, Rod, Wire, Forgings |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Chromium (Cr) | 12.0–14.0 |
| Sulfur (S) | 0.15–0.35 |
| Carbon (C) | ≤0.15 |
| Manganese (Mn) | ≤1.25 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.060 |
| Nickel (Ni) | ≤0.75 |
| Molybdenum (Mo) | ≤0.60 |
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | 480–650 MPa |
| Yield Strength | ≥275 MPa |
| Elongation | ≥20% |
| Hardness | ≤262 HB |
| Elastic Modulus | 200 GPa |
Hardened & Tempered Condition
| Property | Value |
|---|---|
| Tensile Strength | 700–1050 MPa |
| Yield Strength | 450–800 MPa |
| Hardness | 30–40 HRC |
| Wear Resistance | Good |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.75 g/cm³ |
| Melting Point | 1480–1530°C |
| Thermal Conductivity | 24.9 W/m·K |
| Electrical Resistivity | 0.57 μΩ·m |
| Thermal Expansion Coefficient | 9.9 × 10⁻⁶/K |
| Specific Heat Capacity | 460 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Good |
| Atmospheric Exposure | Good |
| Industrial Environment | Moderate |
| Fresh Water | Good |
| Marine Environment | Poor |
| Chloride Environment | Poor |
| Chemical Environment | Limited |
The sulfur additions that improve machinability reduce corrosion resistance compared with SS410 and SS304.
For outdoor and corrosive environments, passivation or protective coatings are recommended.
Heat Treatment
Annealing
| Parameter | Value |
|---|---|
| Temperature | 760–815°C |
| Cooling Method | Furnace Cool |
Hardening
| Parameter | Value |
|---|---|
| Temperature | 925–1010°C |
| Quenching | Oil or Air |
Tempering
| Parameter | Value |
|---|---|
| Temperature | 200–700°C |
| Purpose | Optimize Hardness & Toughness |
SS416 responds well to heat treatment and can achieve a useful balance of hardness, strength, and machinability.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | 416 |
| UNS | S41600 |
| EN (Europe) | 1.4005 |
| DIN (Germany) | X12CrS13 |
| JIS (Japan) | SUS416 |
| GB/T (China) | Y12Cr13 |
| ISO | X12CrS13 |
Available Forms
| Product Type | Availability |
|---|---|
| Round Bar | Yes |
| Hex Bar | Yes |
| Flat Bar | Yes |
| Precision Rod | Yes |
| Forging Stock | Yes |
| Machining Blank | Yes |
Typical Applications
CNC Machining Industry
- Precision Turned Parts
- CNC Machined Components
- Automatic Screw Machine Parts
- Swiss Machined Components
Valve & Pump Industry
- Valve Stems
- Valve Shafts
- Pump Shafts
- Flow Control Components
Automotive Industry
- Gear Components
- Fasteners
- Mechanical Assemblies
- Drive Components
Industrial Machinery
- Couplings
- Bushings
- Shafts
- Rollers
Tooling Industry
- Machine Tool Components
- Fixtures
- Jigs
- Precision Holders
Electronics Industry
- Connector Bodies
- Instrument Components
- Mechanical Hardware
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Turning | Outstanding |
| CNC Milling | Excellent |
| Swiss Machining | Outstanding |
| Automatic Screw Machining | Outstanding |
| Drilling | Excellent |
| Tapping | Excellent |
| Threading | Excellent |
| Grinding | Excellent |
| Heat Treatment | Excellent |
| Welding | Poor |
Advantages
Best Machinability Among Stainless Steels
Often considered the easiest stainless steel to machine.
Excellent Production Efficiency
Ideal for high-volume CNC and automatic machining.
Heat Treatable
Can be hardened for improved wear resistance.
Good Mechanical Strength
Suitable for load-bearing components.
Magnetic Material
Useful for magnetic applications.
Cost Effective
Lower production costs due to reduced machining time.
Limitations
Lower Corrosion Resistance
Inferior to SS304, SS316, and even SS410.
Poor Weldability
High sulfur content increases cracking risk during welding.
Reduced Toughness
Compared with SS410 and austenitic stainless steels.
Not Suitable for Marine Environments
Saltwater exposure can cause corrosion.
Comparison with Other Stainless Steels
| Property | SS416 | SS410 | SS303 | SS304 | SS316 |
|---|---|---|---|---|---|
| Machinability | Outstanding | Good | Outstanding | Good | Good |
| Corrosion Resistance | Moderate | Good | Good | Excellent | Outstanding |
| Heat Treatable | Yes | Yes | No | No | No |
| Hardness | High | High | Medium | Medium | Medium |
| Weldability | Poor | Fair | Poor | Excellent | Excellent |
| Magnetic | Yes | Yes | No | No | No |
Comparison with Common Engineering Metals
| Material | Density (g/cm³) | Machinability | Corrosion Resistance | Strength |
|---|---|---|---|---|
| SS416 | 7.75 | Outstanding | Moderate | High |
| SS410 | 7.75 | Good | Good | High |
| SS303 | 7.93 | Outstanding | Good | Medium |
| Aluminum 6061 | 2.70 | Excellent | Good | Medium |
| Brass C360 | 8.47 | Outstanding | Good | Medium |
| Carbon Steel 12L14 | 7.85 | Outstanding | Poor | Medium |
Available Surface Finishes
Mill Finishes
- Turned Finish
- Ground Finish
- Bright Drawn Finish
- Cold Finished Surface
Decorative Finishes
- Satin Finish
- Brushed Finish
- Mirror Polish
Functional Finishes
- Passivation
- Electropolishing
- Black Oxide Coating
- Hard Chrome Plating
- Nitriding
Frequently Asked Questions (FAQ)
What is SS416 stainless steel?
SS416 is a free-machining martensitic stainless steel designed to provide maximum machinability while maintaining good strength and moderate corrosion resistance.
What is SS416 used for?
Typical applications include:
- CNC Machined Parts
- Valve Components
- Pump Shafts
- Fasteners
- Precision Turned Components
- Mechanical Assemblies
Is SS416 magnetic?
Yes. SS416 is fully magnetic in both annealed and hardened conditions.
Can SS416 be heat treated?
Yes. SS416 can be hardened and tempered to improve strength and wear resistance.
What is the difference between SS416 and SS410?
| Property | SS416 | SS410 |
|---|---|---|
| Machinability | Much Better | Good |
| Corrosion Resistance | Lower | Better |
| Sulfur Content | Higher | Lower |
| CNC Machining | Excellent | Good |
What is the difference between SS416 and SS303?
| Property | SS416 | SS303 |
|---|---|---|
| Heat Treatable | Yes | No |
| Magnetic | Yes | No |
| Strength | Higher | Medium |
| Corrosion Resistance | Lower | Better |
Can SS416 rust?
Yes. SS416 has only moderate corrosion resistance and may rust in humid, marine, or chemical environments.
Is SS416 suitable for welding?
Generally no. Due to its high sulfur content, welding is not recommended.
Why is SS416 commonly used for CNC machining?
Because it combines:
- Exceptional Machinability
- Good Strength
- Heat Treatability
- Excellent Chip Breaking
making it ideal for high-volume precision-machined parts.
Does GCNOV provide custom manufacturing services for SS416?
Yes. GCNOV provides:
- CNC Turning
- CNC Milling
- Swiss Machining
- Precision Grinding
- Heat Treatment
- Surface Finishing
- Passivation
- Prototype Development
- Low-Volume Production
- Mass Production