|
Iron (Fe) |
Iron is the single
most important element in steel and comprises roughly
95% of the steel matrix. Other non-structural elements
are listed below. |
| Carbon (C) |
Increasing the amount
of carbon increases the strength and lowers the
ductility; current structural steels typically have
carbon ranging from .05% to .25%. |
| Manganese (Mn) |
Manganese has effects
similar to those of carbon. It is usually used in
amounts varying from .5 to 1.7% and is critical to the
production process because of the way it combines with
oxygen and sulfur. |
| Chromium (Cr) |
Chromium is primarily
used to increase corrosion resistance. In weathering
steels, like ASTM A588, the chromium content varies from
.1 to .9%. |
| Copper (Cu) |
Copper is also used
for corrosion resistance. It is found in amounts not
less than .2% for electric arc furnace (EAF) steel and
about .02 to .03% for basic oxygen furnace (BOF) steel.
|
| Silicon (Si) |
Silicon is one of the
two most important de-oxidizers of steel, meaning that
it is very effective in removing oxygen from the steel
during the pouring and solidification process. Typical
content is from.1 to .4%. |
| Aluminum (Al) |
Aluminum is the other
de-oxidizer used to remove oxygen from steel (killed).
It is also used for grain refinement. |
| Columbium (Cb) |
Columbium is used to
enhance the strength of steel and is one of key elements
in various HSLA grades. It has effects similar to those
of manganese and vanadium and is often used in
combination with vanadium. Due to weldability
requirements, columbium is unused in amounts less than
.05%, such as in A572, for example. |
| Molybdenum (Mo) |
This element
especially increases the strength of steel at elevated
temperatures, as well as providing corrosion resistance.
Molybdenum is particularly applicable for certain types
of A588 and A514 steel. In the latter, molybdenum
content may be as high as .65%. |
| Nickel (Ni) |
Nickel is a powerful
anti-corrosion agent and also is one of the most
important elements for improving the fracture toughness
of steel. Nickel contents vary between .25 and 1.5%,
depending on the specifics of the steel. |
| Vanadium (V) |
Vanadium aids in the
development of a tough, fine-grained steel structure.
Vanadium is an important alloying element in HSLA
steels, such as A572 and A588. |
| Sulfur (S) &
Phosphorus (P) |
Both elements have
detrimental effects on steel strength, but especially
ductility and weldability of steel. Sulfur promotes
segregation in the steel matrix. Sulfur and phosphorus
are both restricted to no more than .04 to.05%. |
