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.
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:
Elongation at break
Reduction of area
Hardness, Rockwell B
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.
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.
360 BTU in/hr.ft².°F
C-20 is commonly supplied bright drawn or as rolled. If annealing is required heat to 880-910°C, furnace cool.
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.