The most important alloy element in Carbonsteel is carbon (C). Possible other elements like manganese (Mn), silicium (Si) and aluminium (Al) can occur in low percentages. The amount of carbon determines the strength and is inversely proportional with the toughness and the weldability. If the carbon equivalent (CE) < 0.4%, the material is very weldable.
CE= %C + ( %Mn / 6 ) + ( (%Cr+%Mo+%V) / 5 ) + ( (%Cu+%Ni) / 15 )