Steel 1020 properties
Designation and classification
Section titled “Designation and classification”AISI/SAE 1020 steel is a simple non-alloy carbon steel containing approximately 0.20% carbon, designated by the American standard with the digits 10XX (first digit indicates carbon steel and second digit absence of significant alloying elements). According to the European EN system, its closest equivalent is C22E (1.1151).
| Standard | Designation |
|---|---|
| AISI/SAE (USA) | 1020 |
| UNS | G10200 |
| EN (Europe) | C22E (1.1151) |
| DIN (Germany) | Ck22 |
| JIS (Japan) | S20C |
| AFNOR (France) | XC18 |
| BS (United Kingdom) | 070M20 |
| GOST (Russia) | 20 |
Chemical composition
Section titled “Chemical composition”The carbon content of 1020 steel is between 0.17% and 0.23% by weight, with manganese between 0.30% and 0.60% and controlled residual elements.
| Element | Content (% by weight) |
|---|---|
| Carbon (C) | 0.17 – 0.23 |
| Manganese (Mn) | 0.30 – 0.60 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.050 |
| Iron (Fe) | 99.08 – 99.53 |
Mechanical properties in as-supplied condition
Section titled “Mechanical properties in as-supplied condition”The ultimate tensile strength of 1020 steel in the as-supplied condition (hot rolled or cold drawn) is 395 MPa, with a Brinell hardness of 111 HB and an elongation of 36.5%.
| Property | SI Value | Imperial Value |
|---|---|---|
| Brinell hardness | 111 HB | 111 HB |
| Rockwell B hardness | 64 HRB | 64 HRB |
| Tensile strength (ultimate) | 394.72 MPa | 57249 psi |
| Yield strength (yield) | 294.74 MPa | 42748 psi |
| Elongation in 50 mm | 36.5 % | 36.5 % |
| Reduction of area | 66.0 % | 66.0 % |
| Modulus of elasticity | 200 GPa | 29000 ksi |
| Shear modulus | 80.0 GPa | 11600 ksi |
| Poisson’s ratio | 0.290 | 0.290 |
| Izod impact | 125 J | 92.2 ft‑lb |
Charpy impact (standard specimens):
| Temperature | Absorbed energy (J) | Absorbed energy (ft‑lb) |
|---|---|---|
| -30 °C | 16.9 | 12.5 |
| -18 °C | 18.0 | 13.3 |
| -3 °C | 20.0 | 14.8 |
| 10 °C | 24.0 | 17.7 |
| 38 °C | 41.0 | 30.2 |
| 65 °C | 54.0 | 39.8 |
| 95 °C | 61.0 | 45.0 |
| 150 °C | 68.0 | 50.2 |
Mechanical properties after heat treatment
Section titled “Mechanical properties after heat treatment”After carburizing and case hardening, the hardness of 1020 steel can exceed 65 HRC on the outer layer, while the core retains its original toughness and strength.
| Condition | Surface hardness | Core tensile strength |
|---|---|---|
| Carburized + quenched + low temper | 60 – 65 HRC | ≈ 395 MPa (57 ksi) |
| Carbonitrided + quenched | 58 – 63 HRC | ≈ 395 MPa (57 ksi) |
Note: 1020 steel does not respond to conventional hardening due to its low carbon content; it only surface hardens through diffusion of carbon or nitrogen.
Physical properties
Section titled “Physical properties”The density of 1020 steel is 7.87 g/cm³ (0.284 lb/in³), a typical value for low-carbon steels.
| Property | SI Value | Imperial Value |
|---|---|---|
| Density | 7.87 g/cm³ | 0.284 lb/in³ |
| Modulus of elasticity | 200 GPa | 29 000 ksi |
| Shear modulus | 80 GPa | 11 600 ksi |
| Poisson’s ratio | 0.29 | 0.29 |
Thermal properties
Section titled “Thermal properties”The thermal conductivity of 1020 steel at room temperature is around 51.9 W/m·K, decreasing with increasing temperature.
| Property | SI Value | Imperial Value | Note |
|---|---|---|---|
| Thermal conductivity (20 °C) | 51.9 W/m·K [VERIFY] | 360 BTU·in/(h·ft²·°F) | Estimated for 0.2% C steel |
| Specific heat | 486 J/(kg·K) [VERIFY] | 0.116 BTU/(lb·°F) | Estimated for carbon steel |
| Coefficient of thermal expansion (20‑200 °C) | 11.7 ×10⁻⁶ /°C [VERIFY] | 6.5 ×10⁻⁶ /°F | Estimated for carbon steel |
| Melting point | ~ 1 500 °C [VERIFY] | ~ 2 730 °F | Typical range for low-carbon steels |
Weldability and machinability
Section titled “Weldability and machinability”The machinability of 1020 steel is high in the cold-drawn or turned and polished condition, allowing drilling, turning, milling, and threading operations with standard cutting parameters. Weldability is equally good by all common processes (arc, MIG/MAG, TIG, resistance) provided the material has not been carburized or heat-treated, as the hardened surface layer can crack during welding.
Heat treatments
Section titled “Heat treatments”Annealing of 1020 steel is performed by heating between 870 °C and 910 °C, holding the temperature until complete homogenization, and cooling slowly in the furnace. Carburizing is carried out in a carburizing atmosphere at 880‑920 °C, producing a surface layer with sufficient carbon content for subsequent hardening by quenching. As an alternative, carbonitriding allows obtaining hard layers with lower temperature and less distortion.
Applications by industry
Section titled “Applications by industry”1020 steel is widely used in manufacturing components that require good weldability, machinability, and, after carburizing, high surface hardness. Some examples by sector:
- Automotive and transportation: shafts, pins, bushes, arbors, steering bolts, carburized gearbox parts.
- Construction and civil works: anchors, brackets, connecting plates, expansion bolts.
- General machinery: low-stress shafts, spacers, flanges, bushings, carburized cams.
- Appliances and metal furniture: support feet, welded structures, hinges.
- Agricultural industry: carburized blades, harrow tines, rollers.
Comparison with similar materials
Section titled “Comparison with similar materials”1020 steel differs from 1018 and 1025 mainly in its carbon content, which influences its mechanical strength and carburizing capability.
| Material | Carbon content (%) | Tensile strength (MPa) | Brinell hardness (HB) | Main characteristics |
|---|---|---|---|---|
| AISI 1018 | 0.15‑0.20 | ~ 370 | ~ 105 | Higher ductility, lower strength, better drawability |
| AISI 1020 | 0.17‑0.23 | 395 | 111 | Balance between machinability and weldability, carburizable |
| AISI 1025 | 0.22‑0.28 | ~ 450 | ~ 125 | Higher strength and hardness, lower weldability |
| EN C22E | 0.17‑0.24 | ~ 430 | ~ 130 | European equivalent with similar properties and slightly greater hardenability |
Frequently Asked Questions (FAQ)
Section titled “Frequently Asked Questions (FAQ)”What is the typical hardness of 1020 steel in the as-supplied condition?
Section titled “What is the typical hardness of 1020 steel in the as-supplied condition?”The most common Brinell hardness is 111 HB, equivalent to 64 HRB.
Can 1020 steel be hardened to increase its hardness throughout the entire thickness?
Section titled “Can 1020 steel be hardened to increase its hardness throughout the entire thickness?”No, its carbon content below 0.25% prevents conventional hardening; it can only be surface hardened by carburizing or carbonitriding.
What tensile strength does it achieve after carburizing?
Section titled “What tensile strength does it achieve after carburizing?”The core tensile strength remains around 395 MPa, while the carburized layer achieves surface hardness of 60‑65 HRC.
Is it suitable to weld 1020 steel parts after carburizing?
Section titled “Is it suitable to weld 1020 steel parts after carburizing?”Not recommended; welding on a carburized layer can cause cracks and loss of hardness. The ideal is to weld before the carburizing treatment.
What is the recommended annealing temperature for 1020?
Section titled “What is the recommended annealing temperature for 1020?”Annealing is performed between 870 °C and 910 °C with slow cooling in the furnace.
Which European standard is equivalent to AISI 1020 steel?
Section titled “Which European standard is equivalent to AISI 1020 steel?”The closest equivalence according to EN is steel C22E (1.1151).
References
Section titled “References”- azom.com: https://www.azom.com/article.aspx?ArticleID=6114
- engineeringtoolbox.com: https://www.engineeringtoolbox.com/aisi-sae-steel-numbering-system-d_1449.html
- steelnumber.com: https://www.steelnumber.com/en/equivalent_steel_iron_eu.php?zname_id=88