Improved mild steel for structural purposes

THE majority of structures is usually constructed
from steels with yield points not more than 17 t.s.i.
but the recent developments in this field have led
to structural steels with yield points between
20 t.s.i. and 40 t.s.i. Additions of about 2% allo-
ying elements can produce appreciably higher yield strength. These low alloy steels show good impact properties and render them suitable for use at temp-eratures down to -50°C or even lower.The improvement
in yield, tensile and impact properties are not achi-
eved at the expense of weldability because carbon,
the principal cause of welding trouble, is maintain-
ed at a very low level. The type of steels to be dis-cussed has a low carbon I'5 Mn base with very small quantity of alloying elements, and it would not be improper to term them as improved mild steel.
By making use of strengthening mechanisms in mild
steel containing residual alloying addition, it would be
possible to use a cheaper steel in structures needing a
more highly alloyed steel, and a significant reduction
in cost can be achieved. Also, by replacing mild steel
with this improved variety, thinner sections can be used
in structures and this would increase the payload of
vehicle and a consequent reduction in freight cost.