Overview
SAE/AISI 1045 Steel is one of the most widely used medium-carbon steels in the manufacturing industry. It offers an excellent balance of strength, toughness, wear resistance, machinability, and heat treatment capability, making it a preferred material for shafts, gears, axles, pins, sprockets, and mechanical power transmission components.
As part of the AISI 10XX Carbon Steel Series, SAE 1045 contains approximately 0.45% carbon, providing significantly higher strength and hardness than SAE 1018 and SAE 1020.
SAE 1045 is commonly used in:
- CNC Machined Components
- Power Transmission Parts
- Shafts and Axles
- Gears and Sprockets
- Hydraulic Components
- Industrial Machinery
- Automotive Parts
- Agricultural Equipment
Compared with SAE 1020, 1045 offers much higher strength and wear resistance. Compared with 4140 alloy steel, it provides lower hardenability but better cost efficiency.
Material Specification
| Property | Value |
|---|---|
| Material Designation | SAE/AISI 1045 |
| Standard | ASTM / SAE / AISI |
| UNS Number | G10450 |
| Material Family | Medium Carbon Steel |
| Density | 7.85 g/cm³ |
| Magnetic Property | Magnetic |
| Standard Forms | Round Bar, Flat Bar, Plate, Forgings, Tube |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Carbon (C) | 0.43–0.50 |
| Manganese (Mn) | 0.60–0.90 |
| Silicon (Si) | ≤0.35 |
| Phosphorus (P) | ≤0.040 |
| Sulfur (S) | ≤0.050 |
The relatively high carbon content contributes to excellent strength and wear resistance.
Mechanical Properties
Hot Rolled Condition
| Property | Value |
|---|---|
| Tensile Strength | 565–700 MPa |
| Yield Strength | ≥310 MPa |
| Elongation | 16–20% |
| Hardness | 170–210 HB |
| Elastic Modulus | 200 GPa |
Normalized Condition
| Property | Value |
|---|---|
| Tensile Strength | 620–750 MPa |
| Yield Strength | 355–450 MPa |
| Hardness | 180–220 HB |
Quenched & Tempered Condition
| Property | Value |
|---|---|
| Tensile Strength | 750–950 MPa |
| Yield Strength | 550–700 MPa |
| Hardness | 22–32 HRC |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Melting Point | 1420–1490°C |
| Thermal Conductivity | 49.8 W/m·K |
| Electrical Resistivity | 0.17 μΩ·m |
| Thermal Expansion Coefficient | 11.1 × 10⁻⁶/K |
| Specific Heat Capacity | 486 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Moderate |
| Dry Atmosphere | Good |
| Outdoor Environment | Poor |
| Humid Environment | Poor |
| Marine Environment | Very Poor |
| Chemical Environment | Poor |
SAE 1045 is not corrosion resistant and generally requires surface protection.
Common protective treatments include:
- Black Oxide
- Zinc Plating
- Nickel Plating
- Chrome Plating
- Phosphate Coating
- Powder Coating
- Hard Chrome Plating
Weldability
| Welding Process | Rating |
|---|---|
| MIG Welding | Good |
| TIG Welding | Good |
| Arc Welding | Good |
| Resistance Welding | Fair |
| Spot Welding | Fair |
Because of its higher carbon content, preheating and post-weld stress relief may be required for critical applications.
Machinability
| Process | Rating |
|---|---|
| CNC Turning | Excellent |
| CNC Milling | Excellent |
| Drilling | Excellent |
| Tapping | Good |
| Grinding | Excellent |
| Threading | Excellent |
| Broaching | Good |
Machinability Comparison
| Material | Machinability |
|---|---|
| 12L14 | Outstanding |
| 1215 | Outstanding |
| 1018 | Excellent |
| 1020 | Excellent |
| 1045 | Good–Excellent |
| 4140 | Good |
1045 is one of the most popular materials for CNC-machined mechanical parts.
Heat Treatment
Annealing
| Parameter | Value |
|---|---|
| Temperature | 800–850°C |
| Cooling Method | Furnace Cool |
Normalizing
| Parameter | Value |
|---|---|
| Temperature | 870–920°C |
| Cooling Method | Air Cool |
Quenching
| Parameter | Value |
|---|---|
| Temperature | 820–860°C |
| Cooling Medium | Water or Oil |
Tempering
| Parameter | Value |
|---|---|
| Temperature | 400–650°C |
| Purpose | Toughness Adjustment |
Induction Hardening
| Property | Value |
|---|---|
| Surface Hardness | 50–58 HRC |
| Hardened Depth | 1–6 mm |
1045 is one of the most commonly induction-hardened steels worldwide.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| SAE / AISI (USA) | 1045 |
| ASTM (USA) | ASTM A29 Grade 1045 |
| UNS | G10450 |
| GB/T (China) | 45# Steel |
| JIS (Japan) | S45C |
| EN (Europe) | C45E |
| DIN (Germany) | C45 |
| ISO | C45 |
Available Forms
| Product Type | Availability |
|---|---|
| Round Bar | Yes |
| Flat Bar | Yes |
| Square Bar | Yes |
| Steel Plate | Yes |
| Forgings | Yes |
| Mechanical Tube | Yes |
| Ground Shafting | Yes |
| Precision Bar | Yes |
Typical Applications
Power Transmission Industry
- Drive Shafts
- Transmission Shafts
- Splined Shafts
- Couplings
Gear Manufacturing
- Spur Gears
- Helical Gears
- Sprockets
- Gear Blanks
Hydraulic Industry
- Hydraulic Rods
- Cylinder Components
- Pump Shafts
Automotive Industry
- Axles
- Steering Components
- Suspension Parts
- Transmission Components
Industrial Machinery
- Rollers
- Pins
- Bushings
- Mechanical Assemblies
Agricultural Equipment
- PTO Shafts
- Drive Components
- Wear Parts
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Turning | Excellent |
| CNC Milling | Excellent |
| Grinding | Excellent |
| Induction Hardening | Outstanding |
| Heat Treatment | Outstanding |
| Forging | Excellent |
| Laser Cutting | Excellent |
| Black Oxide | Excellent |
| Hard Chrome Plating | Excellent |
Advantages
High Strength
Significantly stronger than low-carbon steels.
Excellent Wear Resistance
Suitable for moving and rotating parts.
Heat Treatable
Can be quenched and tempered.
Induction Hardening Capability
Provides excellent surface hardness.
Good Machinability
Suitable for high-volume machining.
Cost Effective
Lower cost than alloy steels.
Limitations
Lower Weldability
More difficult to weld than 1018 and 1020.
Poor Corrosion Resistance
Requires surface treatment.
Limited Through Hardening
Less hardenable than alloy steels such as 4140.
Not Suitable for Marine Applications
Without protective coatings.
Comparison with Other Carbon Steels
| Property | 1045 | 1020 | 1018 | 4140 | 4340 |
|---|---|---|---|---|---|
| Carbon Content | 0.45% | 0.20% | 0.18% | 0.40% | 0.40% |
| Strength | High | Medium | Medium | Very High | Exceptional |
| Wear Resistance | Excellent | Moderate | Moderate | Outstanding | Outstanding |
| Weldability | Good | Excellent | Excellent | Moderate | Fair |
| Heat Treatment Response | Excellent | Limited | Limited | Outstanding | Outstanding |
Comparison with Engineering Materials
| Material | Yield Strength | Hardness | Wear Resistance |
|---|---|---|---|
| SAE 1045 | 550–700 MPa | Up to 58 HRC | Excellent |
| SAE 1020 | 350–420 MPa | Up to 55 HRC (surface) | Good |
| 4140 Alloy Steel | 655–950 MPa | Up to 60 HRC | Outstanding |
| SS304 | 205 MPa | Low | Moderate |
| 17-4PH | 860–1170 MPa | High | Excellent |
| Aluminum 6061-T6 | 276 MPa | Low | Poor |
Available Surface Finishes
Raw Finishes
- Hot Rolled Finish
- Cold Drawn Finish
- Ground Finish
- Turned Finish
Protective Finishes
- Black Oxide
- Zinc Plating
- Nickel Plating
- Chrome Plating
- Hard Chrome Plating
- Phosphate Coating
Decorative Finishes
- Powder Coating
- Spray Painting
- Electrophoretic Coating (E-Coating)
Frequently Asked Questions (FAQ)
What is SAE 1045 steel?
SAE 1045 is a medium-carbon steel known for its excellent strength, wear resistance, and heat treatment capability.
What is SAE 1045 used for?
Typical applications include:
- Shafts
- Gears
- Axles
- Sprockets
- Hydraulic Components
- Industrial Machinery
What is the difference between SAE 1045 and SAE 1020?
| Property | SAE 1045 | SAE 1020 |
|---|---|---|
| Carbon Content | Higher | Lower |
| Strength | Much Higher | Lower |
| Wear Resistance | Better | Lower |
| Weldability | Lower | Better |
Is SAE 1045 good for shafts?
Yes. 1045 is one of the most widely used shaft materials worldwide.
Can SAE 1045 be induction hardened?
Yes. It is one of the best carbon steels for induction hardening.
What hardness can 1045 achieve?
After induction hardening:
- Surface Hardness: 50–58 HRC
After quenching and tempering:
- Typical Hardness: 22–32 HRC
Is SAE 1045 suitable for gears?
Yes. 1045 is commonly used for medium-duty gears and sprockets.
Can SAE 1045 be welded?
Yes, but preheating is often recommended to avoid cracking.
Why is SAE 1045 widely used in mechanical engineering?
Because it combines:
- High Strength
- Excellent Wear Resistance
- Heat Treatability
- Good Machinability
- Cost Efficiency
making it ideal for power transmission and machinery components.
Does GCNOV provide custom manufacturing services for SAE 1045?
Yes. GCNOV provides:
- CNC Turning
- CNC Milling
- Gear Manufacturing
- Shaft Machining
- Induction Hardening
- Quenching & Tempering
- Grinding
- Hard Chrome Plating
- Prototype Development
- Low-Volume Production
- Mass Production