AISI 1020 Carbon Steel: Properties and Applications

At Aobo Steel, we understand the importance of selecting the right material. AISI 1020 (SAE 1020) carbon steel is a versatile plain carbon steel we frequently supply for various manufacturing needs. With over 20 years of forging experience, we have deep knowledge of its characteristics and applications.

1. Understanding 1020 Carbon Steel Classification and Composition

1.1 Classification (SAE/AISI System)

• Grade: AISI C1020 / SAE 1020
• Type: Plain Carbon Steel (Indicated by the first two digits, ’10’ in the SAE/AISI designation)
• Nominal Carbon Content: 20% (Indicated by the last two digits, ’20’). In practice, the carbon content typically ranges from 0.18% to 0.23%.

1.2 Chemical Composition

The typical chemical composition of 1020 steel includes:

• Carbon (C): 0.18% – 0.23%
• Manganese (Mn): 0.30% – 0.60%
• Phosphorus (P): 0.040% maximum
• Sulfur (S): 0.050% maximum
• Other Elements: May contain incidental amounts of Silicon (Si), Copper (Cu), Nickel (Ni), Chromium (Cr), or Molybdenum (Mo) within standard limits.

2. 1020 Carbon Steel Properties

SAE 1020 steel is well-regarded for several key properties:

• Machinability: It exhibits good machining characteristics, making it easy to work. It is often considered the most easily machined mold steel and is frequently used as a benchmark.
• Formability: Possesses good formability and is suitable for applications requiring shaping.
• Weldability: Generally considered weldable, though microstructural changes in the heat-affected zone (HAZ) should be considered. When slowly cooled after welding, its microstructure typically consists of pearlite (approx. 25%) and ferrite (approx. 75%).
• Hardenability: As a low-carbon steel, its hardenability is limited. This means it’s typically used for smaller cross-sections or applications where through-hardening is not the primary requirement. Alternative tool steels might be better suited for applications needing minimal distortion during heat treatment.

3. 1020 Carbon Steel Applications

Thanks to its balance of properties, 1020 steel finds use in various areas:

• Shafting: Commonly used for industrial shafts.
• Fasteners: Suitable for low-carbon threaded fasteners, especially in smaller diameters due to hardenability limits.
• General Manufacturing: Used in auto underbodies, firewalls, and chemical process equipment where high strength isn’t critical but good formability or corrosion resistance is needed.
• Plastic Molds: While not easily hubbed, it’s used for molds, often carburized to increase surface hardness and wear resistance for moderate production runs.

4. 1020 Carbon Steel Mechanical Properties

The mechanical properties of 1020 steel depend significantly on its condition (e.g., hot-rolled vs. cold-drawn):

4.1 Hot-Rolled:

• Yield Strength: ~205 MPa (30 ksi)
• Tensile Strength: ~380 MPa (55 ksi)
• Elongation: ~25%

4.2 Cold Drawn:

• Yield Strength: ~372 MPa (54 ksi)
• Tensile Strength: ~441 MPa (64 ksi)
• Elongation: ~15%

Note: These are typical values and can vary.

Like other low-carbon steels, 1020 exhibits a ductile-brittle transition, influenced by factors like grain size and alloying elements (Mn, Ni).

5. Supply Conditions

Leveraging our extensive experience and robust network of over 40 stable suppliers, Aobo Steel can provide 1020 steel in various forms and conditions to meet your specific manufacturing requirements:

• Forms: Bars (hot-finished, cold-finished), Forgings, Tubing, Sheet, Strip.
• Conditions: Hot Rolled, Normalized, Annealed, Cold Drawn.

Cold-finished (CF) shafting typically has a dull metallic luster surface finish.

Contact Aobo Steel today with your required dimensions and specifications. We are ready to provide a detailed quotation and discuss how 1020 steel can meet your project needs.