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1045 Carbon Steel: Properties, Process, Products
- John
SteelPRO Group offers high-quality 1045 steel products, including plates and bars. Our materials are available in black and hot-rolled states to facilitate easier machining and in a normalized condition for more precise dimensions and enhanced strength. Additionally, we provide customized sizing and solution consulting services to meet specific project needs.
What Is 1045 Carbon Steel?
1045 steel is a medium-carbon steel with about 0.45% carbon. It balances strength, toughness, and ductility well. This steel is primarily used for mechanical parts, automotive components, and industrial gears that require high strength and impact resistance. Compared to 1018 or 1020 low-carbon steels, 1045 steel can undergo more targeted heat treatments to achieve customized mechanical properties.
In its hot-rolled state, 1045 steel is easier to machine. When normalized, it has better mechanical strength. Moreover, 1045 can reach surface hardness up to Rc 60 through flame or induction hardening. This process significantly improves its wear resistance. The maximum section size for effective treatment is approximately 60mm. However, due to its lower alloy content and the risk of surface brittleness, nitriding or cyaniding 1045 carbon steel is generally not recommended.
1045 Steel Equivalent
Here is the list of equivalents to 1045 steel:
- GB/T 699: 45
- JIS G 4051: S45C
- ASTM A29/A29M: 1045
- DIN 17200: C45/1.1191
- ISO: C45E4
1045 Carbon Steel Products Forms And Supply Range
SteelPro Group offers 1045 steel products that meet international standards, available in cold-finished bars, hot-rolled bars, plates, and tubes. In addition to the following sizes, we also provide custom dimensions to meet your specific needs.
| Product Form | Diameter | Length | Thickness/Wall |
| Bars | 6 mm to 300 mm (0.24 in to 11.8 in) | 3000 mm to 6000 mm (118 in to 236 in) | – |
| Plates and sheets | – | 2000 mm to 6000 mm (78.74 in to 236.22 in) | 5 mm to 100 mm (0.20 in to 3.94 in) |
| Pipes and tubes | 20 mm to 200 mm (0.79 in to 7.87 in) | 6000 mm to 12000 mm (236.22 in to 472.44 in) | 2 mm to 20 mm (0.08 in to 0.79 in) |
| Forged products | 20 mm to 400 mm (0.79 in to 15.75 in) | 100 mm to 1500 mm (3.94 in to 59.06 in) | – |
| Rounds for machining | 10 mm to 300 mm (0.39 in to 11.8 in) | 3000 mm to 6000 mm (118 in to 236 in) | – |
Is 1045 Carbon Steel Good?
Yes. 1045 steel is flexible, providing a good mix of strength, toughness, and ease of machining. It’s suitable for parts like gears and shafts but isn’t as hard or wear-resistant as higher carbon steels.
1045 Carbon Steel Chemical Composition
| C | Mn | P | S |
| 0.43-0.5 | 0.6-0.9 | ≤0.04 | ≤0.05 |
Carbon Content in 1045 Carbon Steel
The 0.45% carbon content in 1045 steel enhances strength and hardness while maintaining machinability. However, it limits through-hardening, which is crucial for applications like gears and shafts that require high surface hardness.
1045 Carbon Steel Physical Properties
| Property | Metric Value | Imperial Value |
| Density | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Point | 1450-1500 °C | 2642-2732 °F |
| Thermal Conductivity | 51.9 W/m-K | 360 BTU-in/hr-ft²-°F |
| Specific Heat Capacity | 0.486 J/g-°C, ≥100 °C | 0.116 BTU/lb-°F, ≥212 °F |
The following table provides the coefficient of thermal expansion (CTE) and tempering temperature ranges for 1045 steel.
| CTE (Metric) | CTE (Imperial) | Temper (Metric) | Temper (Imperial) |
| 11.5 µm/m-°C | 6.39 µin/in-°F | 0.000 – 100 °C | 32.0 – 212 °F |
| 11.9 µm/m-°C | 6.61 µin/in-°F | 25.0 – 200 °C | 77.0 – 392 °F |
| 12.6 µm/m-°C | 7.00 µin/in-°F | 25.0 – 300 °C | 77.0 – 572 °F |
| 13.5 µm/m-°C | 7.50 µin/in-°F | 25.0 – 400 °C | 77.0 – 752 °F |
| 14.4 µm/m-°C | 25.0 – 600 °C | 8.00 µin/in-°F | 77.0 – 1110 °F |
| 14.8 µm/m-°C | 25.0 – 700 °C | 8.22 µin/in-°F | 77.0 – 1290 °F |
1045 Carbon Steel Mechanical Properties
| Property | Metric Value | Imperial Value |
| Tensile Strength | 570-700 MPa | 82,600-101,500 psi |
| Yield Strength | 310-410 MPa | 45,000-60,000 psi |
| Elongation | 12-18% | 12-18% |
| Hardness (HB) | 170-210 HB | 170-210 HB |
| Impact Toughness | 27 J (average) | 20 ft-lb |
| Modulus of Elasticity | 210 GPa | 30.5 x 10⁶ psi |
| Poisson’s Ratio | 0.29 | 0.29 |
| Shear Modulus | 80.0 GPa | 11600 ksi |
| Bulk Modulus | 163 GPa | 23600 ksi |
Forging 1045 Carbon Steel
Begin by pre-heating the steel to 750-800°C. Once it reaches this range, continue heating to 1100-1200°C, ensuring the temperature is uniform throughout the section. It’s crucial not to forge below 850°C because its ductility significantly decreases below this temperature, making it more prone to cracking.
Once forging is complete, the material can be air-cooled.
Heat Treatment of 1045 Carbon Steel
Annealing
Heat the steel to 800-850°C (1472-1562°F) and maintain the temperature until it is evenly distributed. After that, allow the material to cool slowly in a furnace to achieve the desired soft and ductile properties.
Stress Relieving
Heat the steel as quickly as possible to the austenitic range between 820-860°C (1508-1580°F). Once the steel reaches this temperature, cool it in either water or oil, depending on the hardness required.
After quenching, temper the material at 150-200°C (302-392°F) to relieve any stresses without affecting the case hardness.
Hardening
Heat the steel to 820-850°C (1508-1562°F) and soak for 10-15 minutes per 25mm (1 inch) of section thickness to ensure even heat penetration. Quench the steel in water or brine for rapid cooling.
Alternatively, heat it to 830-860°C (1526-1580°F), soak it, and then quench it in oil. Once it has cooled to hand-warm temperature, immediately temper the steel.
Normalizing
Heat the steel to 870-920°C (1598-1688°F) and soak for 10-15 minutes to ensure a uniform temperature. After that, let it cool in the air. This procedure improves the grain structure and boosts the material’s ease of machining and strength.
Stress Relieving
Heat the steel to 550-660°C (1022-1220°F) and soak for 1 hour per 25mm (1 inch) of section thickness. Cool it slowly in still air. This step helps relieve internal stresses without significantly affecting the steel’s hardness.
Tempering
Re-heat the steel to 400-650°C (752-1202°F) as needed, and soak for 1 hour per 25mm (1 inch) of section thickness. After soaking, cool the material in still air. Tempering reduces brittleness, improves toughness, and ensures the steel maintains the required hardness.
Machining 1045 Steel
1045 steel is easy to machine, especially when in a normalized or hot-rolled state. For best results, make sure to adjust your cutting parameters to suit the specific operation and keep tools sharp to avoid unnecessary wear. Proper coolant use will also help maintain efficiency and extend tool life.
Let us know if you need any guidance on machining 1045 steel for your specific needs!
Welding 1045 Steel
1045 steel can be welded, but it is not recommended in the fully hardened or tempered state due to the risk of cracking.
We recommend using low-hydrogen electrodes for the best results. For thicker sections, preheating the steel to 150-250°C (300-480°F) will help. Post-weld heat treatment (PWHT) is also essential to relieve stress and preserve the material’s properties.
What Is 1045 Steel Used for?
1.2312 steel is commonly used in the following applications:
- Injection Molds: For automotive parts like bumpers and dashboards.
- Plastic Molds: For appliance casings and consumer electronics.
- Die-Casting: For aluminum engine blocks and zinc components.
- Blow Molds: For plastic bottles.
- Tooling: For jigs and fixtures in aerospace and automotive.
Is 1045 Steel Good for Knives?
1045 steel can be used for knives but is not ideal for high-performance cutting tools. While it offers good strength, its wear resistance and edge retention are lower than high carbon steels like 1095 or D2.
1045 Steel VS 4140 Steel
4140 steel contains chromium and molybdenum, offering better hardenability, wear resistance, and strength at high temperatures. It’s ideal for high-stress applications, while 1045 is more affordable and easier to machine but lacks the strength and durability of 4140.
Get the Right 1045 Steel for Your Project
SteelPro Group offers 1045 steel in various forms, including cold-finished, hot-rolled, and custom sizes, all tailored to your needs. We also supply D2 tool steel, perfect for high-performance applications like blades.
