Various types of steel are
used depending upon the application. The main content of structural steel after
iron is carbon. Structural steel sections are normally utilized for the
construction of buildings, manufacturing sheds, transmission line towers, etc.
Structural steel is a category
of steel construction material that is produced with a particular cross section
or shape, and some specified values of strength and chemical composition.
Structural steel composition, strength, size, shape, strength, and storage are
controlled in most advanced countries. The word structural steel includes a
broad variety of low carbon and manganese steels that are used in great numbers
for civil and marine engineering applications. Numerous structural steels also
include minor quantities of significant additions of other elements like Nb, V, Ti and Al. These
are called High Strength Low Alloy or micro-alloyed steels. Structural steels
are manufactured in section and plate shapes and are normally used in bridges,
buildings, ships, and pipelines.
After iron, carbon is the most
important element in steel. The increase of carbon produces materials with high
strength and low ductility. The techniques used for the production of steel are
high- computerized stress analysis, precision stress analysis, and innovative
jointing. The types of structural steel sections normally used are beams,
channels, flats, and angles. The main kinds of structural steel are generally
categorized according to the under mentioned categories of chemical composition:
Carbon-manganese steels: The
major chemical ingredients are iron, carbon, and manganese. These are normally
called mild structural steels or carbon steels. The strength and ductility are
high, and being economical is therefore widely used. The famous category
amongst this type is ASTM grade A36.
High-strength, low-alloy
steels: This is a recent development in the steel industry. Chemical elements
are added to improve the strength. A commonly used type is ASTM grade A572.
High-strength tempered and
quenched alloy steels: These are used for structural purposes and generally
available is ASTM grade A514.
Fire-resistance rating is
determined by the time taken for the steel that is being tested to attain the
temperature fixed by the standard. Structural steel needs external insulation
that is also called fireproofing, to prevent the deterioration of steel in the
occurrence of a fire. On heating, the steel expands and becomes softer, and
finally the structural integrity is lost. If sufficient energy is provided,
steel may also melt. The transfer rate of heat to steel can be reduced by using
fireproofing materials. While concrete structures may be able to resist fire
damage without extra fireproofing, concrete may deteriorate, particularly if
the moisture content is high. Fireproofing is typically used in tunnels and
locations