Jun 18 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Heat Treatment
Forging
Hot Working
Cold Working
Annealing
Tempering
Hardening
Applications
Introduction
Carbon steels is a category of steel, which contains 0.12 to 2% carbon. This steel category gains hardness and strength with heat treatment when the percentage of carbon content increases but the ductility is reduced.
AISI 1020 carbon steel is a commonly used plain carbon steel. It has a good combination of strength and ductility and can be hardened or carburized.
The following sections will discuss in detail about AISI 1020 carbon steel.
Chemical Composition
The chemical composition of AISI 1020 carbon steel is outlined in the following table.
|
Element |
Content (%) |
|
Manganese, Mn |
0.30-0.60 |
|
Carbon, C |
0.18-0.23 |
|
Sulfur, S |
0.05 (max) |
|
Phosphorous, P |
0.04 (max) |
|
Iron, Fe |
Balance |
Physical Properties
The physical properties of AISI 1020 carbon steel are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
7.87 g/cm3 |
0.284 lb/in3 |
Mechanical Properties
The following table shows mechanical properties of cold rolled AISI 1020 carbon steel.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
420 MPa |
60900 psi |
|
Yield strength |
350 MPa |
50800 psi |
|
Modulus of elasticity |
205 GPa |
29700 ksi |
|
Shear modulus (typical for steel) |
80 GPa |
11600 ksi |
|
Poisson’s ratio |
0.29 |
0.29 |
|
Elongation at break (in 50 mm) |
15% |
15% |
|
Hardness, Brinell |
121 |
121 |
|
Hardness, Knoop (converted from Brinell hardness) |
140 |
140 |
|
Hardness, Rockwell B (converted from Brinell hardness) |
68 |
68 |
|
Hardness, Vickers (converted from Brinell hardness) |
126 |
126 |
|
Machinability (based on AISI 1212 steel. as 100 machinability) |
65 |
65 |
Thermal Properties
The thermal properties of cold rolled AISI 1018 carbon steel are given in the following table.
|
Properties |
Metric |
Imperial |
|
Thermal conductivity |
51.9 W/mK |
360 BTU in/hr.ft2.°F |
|
Thermal expansion co-efficient (@0.000-100°C/32-212°F) |
11.7 µm/m°C |
6.50 µm/m°C |
Other Designations
Other designations that are equivalent to AISI 1018 carbon steel include the following.
|
AMS 5054 |
AMS 5045C |
SAE J1397 |
ASTM A513 (MT 1020) |
ASTM A512 (1020, MT 1020) |
|
AMS 5045 |
AMS 5032B |
SAE J412 |
|
|
|
AFNOR CC 20 |
AMS 5032 |
SAE J403 |
MIL S-11310 (CS 1020) |
ASTM A29 |
|
SS 1450 |
AMS 5046 |
SAE J414 |
ASTM A830 |
MIL S-7952 |
|
DIN 1.0402 |
B.S. 070 M 20 |
ASTM A635 |
ASTM A787 (MT 1020) |
MIL S-16788 |
|
UNI C 20 |
B.S. 040 A 20 |
ASTM A827 |
ASTM A794 |
ASTM A108 |
|
MIL T-3520 |
ASTM A510 |
ASTM A519 |
ASTM A544 |
ASTM A575 |
ASTM A576
|
ASTM A659
|
|
|
|
Fabrication and Heat Treatment
Machinability
Machinability of AISI 1020 carbon steel is good at 65% compared to AISI 1112 carbon steel.
Forming
It is easy to form AISI 1020 carbon steel using all the conventional methods as this alloy is highly ductile.
Welding
AISI 1020 carbon steel can be welded easily using all of the traditional methods.
Heat Treatment
AISI 1020 carbon steel can be hardened by heating between 815- 871°C (1500 - 1600°F), which should be followed by water quenching. Then it should be tempered.
Forging
AISI 1020 carbon steel should be forged at 1260°C (2300°F) down to 982°C (1800°F).
Hot Working
AISI 1020 carbon steel can be hot worked in the range of 482 to 649°C (900 to 1200°F).
Cold Working
Cold working AISI 1020 carbon steel is possible using all the conventional methods. In case of prolonged cold working, it is recommended that stress relief annealing be carried out.
Annealing
Complete annealing of this alloy can be achieved between 871-982°C (1600 to 1800°F) followed by slow furnace cooling. This will provide the alloy with a tensile strength of about 65 ksi. A stress relief annealing can be performed if required at 538°C (1000°F).
Tempering
Tempering should be followed by heat treatment and quenching at 315 to 538°C (600 to 1000°F) based on the strength level required. For example 538°C (1000°F) temper provides the alloy with a tensile strength of 90 ksi.
Hardening
AISI 1020 carbon steel can be hardened by cold working and by heat treatment, quenching and tempering.
Applications
AISI 1020 carbon steel is used for simple structural applications such as cold headed bolts. It is commonly used in the case hardened condition.
The other applications of this alloy are as follows:
-
Pins
-
Shafts
-
Chains
-
Lightly stressed gears
-
Hard wearing surfaces
-
Case hardened components where core strength is not essential.