Overview
SAE/AISI 1018 Steel is one of the most commonly used low-carbon steels in the manufacturing industry. It offers an excellent combination of machinability, weldability, strength, ductility, and affordability, making it a preferred material for CNC machining, shafts, pins, gears, fasteners, and precision mechanical components.
As part of the AISI 10XX Carbon Steel Series, 1018 contains approximately 0.18% carbon, providing higher strength than SAE 1010 while maintaining excellent fabrication characteristics.
SAE 1018 is widely used in:
- CNC Machining
- Precision Components
- Shafts & Pins
- Fasteners
- Mechanical Parts
- Hydraulic Components
- Automotive Components
- Industrial Equipment
Compared with SAE 1010, SAE 1018 provides better strength and machinability. Compared with SAE 1020, it offers slightly better cold-forming performance while maintaining similar mechanical properties.
Material Specification
| Property | Value |
|---|---|
| Material Designation | SAE/AISI 1018 |
| Standard | ASTM / SAE / AISI |
| UNS Number | G10180 |
| Material Family | Low Carbon Steel |
| Density | 7.87 g/cm³ |
| Magnetic Property | Magnetic |
| Standard Forms | Round Bar, Flat Bar, Sheet, Plate, Tube, Wire |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Carbon (C) | 0.15–0.20 |
| Manganese (Mn) | 0.60–0.90 |
| Phosphorus (P) | ≤0.040 |
| Sulfur (S) | ≤0.050 |
| Silicon (Si) | ≤0.30 |
The higher manganese content improves strength and machinability compared with SAE 1010.
Mechanical Properties
Cold Drawn Condition
| Property | Value |
|---|---|
| Tensile Strength | 440–540 MPa |
| Yield Strength | 370 MPa |
| Elongation | 15–20% |
| Hardness | 126–167 HB |
| Elastic Modulus | 200 GPa |
Hot Rolled Condition
| Property | Value |
|---|---|
| Tensile Strength | 370–460 MPa |
| Yield Strength | 220–300 MPa |
| Elongation | 25–30% |
| Hardness | 110–140 HB |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.87 g/cm³ |
| Melting Point | 1425–1510°C |
| Thermal Conductivity | 51.9 W/m·K |
| Electrical Resistivity | 0.16 μΩ·m |
| Thermal Expansion Coefficient | 11.7 × 10⁻⁶/K |
| Specific Heat Capacity | 486 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Moderate |
| Dry Atmosphere | Good |
| Humid Environment | Poor |
| Outdoor Environment | Poor |
| Marine Environment | Very Poor |
| Chemical Environment | Poor |
SAE 1018 is not corrosion resistant and should be protected by surface treatments such as:
- Zinc Plating
- Nickel Plating
- Chrome Plating
- Black Oxide
- Powder Coating
- Hot-Dip Galvanizing
Weldability
| Welding Process | Rating |
|---|---|
| MIG Welding | Excellent |
| TIG Welding | Excellent |
| Arc Welding | Excellent |
| Resistance Welding | Excellent |
| Spot Welding | Excellent |
SAE 1018 offers excellent weldability and is widely used in welded mechanical assemblies.
Machinability
| Process | Rating |
|---|---|
| CNC Turning | Excellent |
| CNC Milling | Excellent |
| Drilling | Excellent |
| Tapping | Excellent |
| Grinding | Good |
| Threading | Excellent |
| Broaching | Excellent |
Machinability Comparison
| Material | Machinability |
|---|---|
| 12L14 | Outstanding |
| 1215 | Outstanding |
| 1018 | Excellent |
| 1020 | Good |
| 1045 | Good |
SAE 1018 is one of the most popular carbon steels for CNC machining.
Heat Treatment
Annealing
| Parameter | Value |
|---|---|
| Temperature | 870–910°C |
| Cooling Method | Furnace Cool |
Normalizing
| Parameter | Value |
|---|---|
| Temperature | 900–950°C |
| Cooling Method | Air Cool |
Carburizing
| Parameter | Value |
|---|---|
| Application | Surface Hardening |
| Surface Hardness | Up to 58–62 HRC |
SAE 1018 is commonly carburized to obtain a hard wear-resistant surface with a tough core.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| SAE / AISI (USA) | 1018 |
| ASTM (USA) | ASTM A108 Grade 1018 |
| UNS | G10180 |
| GB/T (China) | 20# Steel |
| JIS (Japan) | S18C |
| EN (Europe) | C18E |
| DIN (Germany) | Ck18 |
| ISO | C18 |
Available Forms
| Product Type | Availability |
|---|---|
| Round Bar | Yes |
| Flat Bar | Yes |
| Square Bar | Yes |
| Steel Plate | Yes |
| Steel Sheet | Yes |
| Wire Rod | Yes |
| Tube | Yes |
| Mechanical Tubing | Yes |
Typical Applications
CNC Machining Industry
- Precision Shafts
- Pins
- Bushings
- Spacers
- Threaded Components
Automotive Industry
- Steering Components
- Mounting Brackets
- Suspension Components
- Mechanical Linkages
Hydraulic Industry
- Hydraulic Shafts
- Cylinder Components
- Valve Parts
- Couplings
Machinery Manufacturing
- Equipment Components
- Gear Blanks
- Rollers
- Mechanical Assemblies
Fastener Industry
- Bolts
- Studs
- Nuts
- Washers
General Engineering
- Structural Components
- Fabricated Parts
- Industrial Equipment
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Turning | Excellent |
| CNC Milling | Excellent |
| Laser Cutting | Excellent |
| Welding | Excellent |
| Bending | Good |
| Thread Rolling | Excellent |
| Carburizing | Outstanding |
| Black Oxide | Excellent |
| Zinc Plating | Excellent |
Advantages
Excellent Machinability
Ideal for CNC machining and automated production.
Good Strength
Stronger than SAE 1010 and many low-carbon steels.
Excellent Weldability
Compatible with all common welding methods.
Cost Effective
Lower cost than alloy steels and stainless steels.
Surface Hardening Capability
Excellent response to carburizing.
Wide Availability
Commonly stocked worldwide.
Limitations
Poor Corrosion Resistance
Requires protective coatings.
Limited Through-Hardening
Cannot achieve high hardness throughout the section.
Not Suitable for High-Stress Applications
For higher strength requirements, 1045 or alloy steels are preferred.
Limited Wear Resistance
Requires carburizing for wear-critical applications.
Comparison with Other Carbon Steels
| Property | 1018 | 1010 | 1020 | 1045 | 12L14 |
|---|---|---|---|---|---|
| Carbon Content | 0.18% | 0.10% | 0.20% | 0.45% | 0.15% |
| Strength | Good | Lower | Similar | Higher | Medium |
| Machinability | Excellent | Good | Good | Good | Outstanding |
| Weldability | Excellent | Excellent | Excellent | Good | Fair |
| Formability | Good | Excellent | Good | Moderate | Good |
Comparison with Engineering Materials
| Material | Yield Strength | Corrosion Resistance | Machinability |
|---|---|---|---|
| SAE 1018 | 370 MPa | Poor | Excellent |
| SAE 1020 | 350 MPa | Poor | Good |
| 1045 Steel | 530 MPa | Poor | Good |
| SS304 | 205 MPa | Excellent | Good |
| Aluminum 6061-T6 | 276 MPa | Good | Excellent |
| 12L14 | 415 MPa | Poor | Outstanding |
Available Surface Finishes
Raw Finishes
- Hot Rolled Finish
- Cold Drawn Finish
- Ground Finish
- Bright Finish
Protective Finishes
- Zinc Plating
- Nickel Plating
- Chrome Plating
- Black Oxide
- Hot-Dip Galvanizing
Decorative Finishes
- Powder Coating
- Spray Painting
- Electrophoretic Coating (E-Coating)
Frequently Asked Questions (FAQ)
What is SAE 1018 steel?
SAE 1018 is a low-carbon steel known for excellent machinability, weldability, and balanced mechanical properties.
What is SAE 1018 used for?
Typical applications include:
- Shafts
- Pins
- Bushings
- Fasteners
- Hydraulic Components
- CNC Machined Parts
What is the difference between SAE 1018 and SAE 1020?
| Property | SAE 1018 | SAE 1020 |
|---|---|---|
| Carbon Content | Slightly Lower | Slightly Higher |
| Machinability | Better | Slightly Lower |
| Strength | Similar | Slightly Higher |
What is the difference between SAE 1018 and 1045?
| Property | SAE 1018 | SAE 1045 |
|---|---|---|
| Strength | Lower | Higher |
| Hardness | Lower | Higher |
| Weldability | Better | Lower |
| Machinability | Better | Good |
Is SAE 1018 good for CNC machining?
Yes. SAE 1018 is one of the most commonly machined carbon steels due to its excellent machining characteristics.
Can SAE 1018 be heat treated?
It cannot be significantly through-hardened, but it responds exceptionally well to carburizing.
Can SAE 1018 be welded?
Yes. It offers excellent weldability with all common welding processes.
Is SAE 1018 suitable for shafts?
Yes. SAE 1018 is widely used for shafts, pins, and mechanical components.
Why is SAE 1018 popular in manufacturing?
Because it combines:
- Excellent Machinability
- Good Strength
- Easy Welding
- Low Cost
making it one of the most versatile engineering materials.
Does GCNOV provide custom manufacturing services for SAE 1018?
Yes. GCNOV provides:
- CNC Turning
- CNC Milling
- Precision Grinding
- Carburizing
- Black Oxide Finishing
- Zinc Plating
- Prototype Development
- Low-Volume Production
- Mass Production