C-20 carbon steel is an unalloyed low carbon mild steel grade supplied as a hot rolled or bright drawn finish bar. As a low carbon steel grade it provides low strength with good machinability and is suitable for welding.
Grade Application:
Commonly used for general engineering C-20 is suitable for applications such as bolts, shafts, spaces, hubs, base plates, brackets. fixtures and jigs.
The following table shows the chemical composition of C20 steel:
Element
C
Mn
Si
S
P
Content(%)
0.25 Max
1.00 Max
0.05-0.35
0.06 Max
0.06 Max
Mechanical Properties:
MECHANICAL PROPERTIES
METRIC
IMPERIAL
Tensile strength
425 MPa
61600 psi
Yield strength
360 MPa
52200 psi
Shear modulus
80.0 GPa
11600 ksi
Bulk modulus
140 GPa
20300 ksi
Elastic modulus
190-210 GPa
27557-30458 ksi
Poisson’s ratio
0.27-0.30
0.27-0.30
Elongation at break
0.15
0.15
Reduction of area
0.4
0.4
Hardness Brinell
121
121
Hardness, Knoop
140
140
Hardness, Rockwell B
68
68
Hardness, Vickers
126
126
Machinability
65
65
Hardness:
Heat treatment:
When hardening C-20 heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities.
Hardening:
As a low carbon steel C-20 is not ideally suited for heat treatment (EN8 or EN9 may be a better suited option). If hardening is required heat to a temperature of 880-910°C. Quench in water and temper.
Tempering:
Physical Properties:
Thermal Properties:
PROPERTIES
METRIC
IMPERIAL
Thermal conductivity
51.9 W/mK
360 BTU in/hr.ft².°F
Forging Properties:
Stress Reliving:
Normalizing:
Annealing:
C-20 is commonly supplied bright drawn or as rolled. If annealing is required heat to 880-910°C, furnace cool.
Density:
Machine ability:
Surface ‘ripping’ is more evident in EN3 so lubrication is essential. Fairly high surface speeds should be used with moderate feeds. Screw cutting is easy with cutting oil and achieving a fine finish is achieved with slight polishing. Very nice to weld with good flow and strength.
