Low alloy steels are utilized for structural causes. That type of steels is needed to possess high yield stress, excellent ductility and high fatigue resistance. The high yield stresses consequence in direct weight saving in the structure part.
A typical low alloy structural steel will contain the given composition as:
C - 0.12 percent, Mn - 0.75 %m Si - 0.25 percent, Cu - 0.3 percent
It alloy steel has a yield strength of 350 N/mm2 and about 15 percent elongation after hot rolling. The presence of Cu enhances corrosion resistance whilst Mn and Si enhance weldability by preventing weld embrittlement.
Minute amounts of Ni, Cr and V added to these steels might enhance the yield strength to 625 N/mm2 if employed in quenched and tempered situation. Additions of Nickel, Cr and V do not affect the weldability.