steel

Structural steel

Steel-composed of iron, alloyed with various other materials (mainly carbon, sulphur & phosphorus).
The physical properties of steel depend on the nature and relative amounts of these special ingredients.
An increase in carbon content results in an increase in strength, but this is accompanied by a marked decrease in ductility.
Based on the carbon content, steel may be divided into the following categories:
Low carbon steel (<0.15%) ksi =" kilopound" 1000="ksi" 012="Kg/mm2" 895="N/m.m2" 145="ksi" 895="Mpa" 145="ksi" 703="kg/m.m2" 422="ksi" 1="N/m.m2" 807="Mpa" e="210,000N/mm2" m="mass" l=" length">32mmφ 1 from each 55 ton 1 from each 110 ton
Prestressing steels
Prestressing steels have very high yield strength in tension. The steel must be able to withstand the prestresses without suffering significant creep relaxation.
Pre-tensioning:
0.6-0.9% carbon, 0.5-0.9% manganese steel is suitable for pre-tensioning. It has better tensile properties than mild steel owing to the high carbon content and can be further enhanced by cold working to give
Characteristic strength = 1470-1720MPa
Min, 0.2% proof stress = 1250-1460MPa

Post-tensioning:
Cold drawn steel wire ropes
0.6-0.9% carbon, 0.5-0.9% manganese
Tensile strength of 1735-1850MPa
0.1% proof stress > 70% of tensile strength
Cold worked steel rods
0.5-0.6% carbon, 0.7-1.0% manganese, 1.5-2.0% silicon
Tensile strength of 1030-1110MPa
0.2% proof stress of 870-95-MPa