Jul 5 2012
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AISI 1020 has low hardenability properties and is a low tensile carbon steel with a Brinell hardness of 119 – 235, and a tensile strength of 410-790 MPa. It has high machinability, high strength, high ductility and good weldability. It is normally used in turned and polished or a cold drawn condition. Due to its low carbon content, it is resistant to induction hardening or flame hardening. Due to lack of alloying elements, it will not respond to nitriding. However, carburization is possible in order to obtain case hardness more than Rc65 for smaller sections that reduces with an increase in section size. The core strength will remain the same. Alternatively, carbon nitriding can be performed, offering certain benefits over standard carburizing.
AISI 1020 steel can be largely utilized in all industrial sectors in order to enhance weldability or machinability properties. It is used in a variety of applications due to its cold drawn or turned and polished finish property.
Chemical Composition
The chemical composition of AISI 1020 steel is;
| Element |
Content |
| Carbon, C |
0.17 - 0.230 % |
| Iron, Fe |
99.08 - 99.53 % |
| Manganese, Mn |
0.30 - 0.60 % |
| Phosphorous, P |
≤ 0.040 % |
| Sulfur, S |
≤ 0.050 % |
Physical Properties
The physical properties of AISI 1020 steel are;
| Physical Properties |
Metric |
Imperial |
| Density |
7.87 g/cc |
0.284 lb/in³ |
Mechanical Properties
The mechanical properties of AISI 1020 steel are;
| Mechanical Properties |
Metric |
Imperial |
| Hardness, Brinell |
111 |
111 |
| Hardness, Knoop (Converted from Brinell hardness) |
129 |
129 |
| Hardness, Rockwell B(Converted from Brinell hardness) |
64 |
64 |
| Hardness, Vickers (Converted from Brinell hardness) |
115 |
115 |
| Tensile Strength, Ultimate |
394.72 MPa |
57249 psi |
| Tensile Strength, Yield |
294.74 MPa |
42748 psi |
| Elongation at Break (in 50 mm) |
36.5 % |
36.5 % |
| Reduction of Area |
66.0 % |
66.0 % |
| Modulus of Elasticity (Typical for steel) |
200 GPa |
29000 ksi |
| Bulk Modulus (Typical for steel) |
140 GPa |
20300 ksi |
| Poissons Ratio |
0.290 |
0.290 |
| Charpy Impact |
| @Temperature -30.0 °C/-22.0 °F |
16.9 J |
12.5 ft-lb |
| @Temperature -18.0 °C/-0.400 °F |
18.0 J |
13.3 ft-lb |
| @Temperature -3.00 °C/26.6 °F |
20.0 J |
14.8 ft-lb |
| @Temperature 10.0 °C/50.0 °F |
24.0 J |
17.7 ft-lb |
| @Temperature 38.0 °C/100 °F |
41.0 J |
30.2 ft-lb |
| @Temperature 65.0 °C/149 °F |
54.0 J |
39.8 ft-lb |
| @Temperature 95.0 °C/203 °F |
61.0 J |
45.0 ft-lb |
| @Temperature 150 °C/302 °F |
68.0 J |
50.2 ft-lb |
| Izod Impact |
125 J |
92.2 ft-lb |
| Shear Modulus (Typical for steel) |
80.0 GPa |
11600 ksi |
Machining
In the cold drawn or turned and polished condition, AISI 1020 steel has high machinability. Following the recommendations of machine manufacturers, AISI 1020 steel can be used for drilling, turning, milling and tapping operations using suitable feeds, tool type and speeds.
Weldability
AISI 1020 can be welded by performing the most common welding processes. In the cold drawn or turned and polished condition, it has better weldability. It has been suggested that the welding process should not be performed in heat treated or carburized condition.
Heat Treatment
Annealing
AISI 1020 steel is heated at 870°C - 910°C followed by a period of holding for a specific amount of time, until the temperature remains constant all over the section. It is then cooled in a furnace.
Carburizing
AISI 1020 is heated to between 880°C - 920°C in a suitable carburizing atmosphere followed by holding for a sufficient amount of time to produce the required carbon content and case depth. After this, refining/hardening and tempering processes are carried out to optimize the core and case properties.
Core Refining
AISI 1020 steel is slowly cooled and re-heated at 870°C - 900°C followed by a period of holding until the temperature remains constant all over the section and is quenched in water, oil or brine.
Case Hardening
After performing the core refining process, it is re-heated to 760°C - 780°C followed by a period of holding until the temperature is consistent all over the section. It is then quenched in water.
Tempering
AISI 1020 steel is re-heated at 150°C - 200°C followed by a period of holding for a certain time until the temperature remains constant throughout the section. It is soaked for 1 hour per 25 mm of section, and then cooled under normal atmosphere. By performing the tempering process, the toughness of the case will be improved and grinding cracks will be reduced.
Normalizing
AISI 1020 steel is heated at 890°C - 940°C followed by a period of holding until the temperature remains constant throughout the section. It is soaked for 10 - 15 minutes and then cooled in still air.
Stress Relieving
AISI 1020 steel is heated to 650°C - 700°C followed by holding until the temperature remains constant all over the section and soaking for 1 hour per 25 mm of section. It is then cooled in still air.
Applications
AISI 1020 steel is used in case hardened condition and used for simple structural applications such as cold headed bolts.
AISI 1020 steel is also used to manufacture axles, general engineering and machinery parts and components, shafts and camshafts, gudgon pins, ratchets, light duty gears and spindles.
Article Updated on 31st July, 2019