Correct Answer - Option 2 : 240 N/mm
2
Explanation:
Bolts are classified as grade x. y where
-
x represents 1/100th of ultimate tensile strength and
- y represents the ratio of yield stress to ultimate tensile stress.
For a bolt of grade 4.6 implies that:
Ultimate strength, fu = 4 x 100 = 400 N/mm2
Yield strength, fy = 0.6 x ultimate strength = 0.6 x 400 = 240 N/mm2