Question

A mild steel specimen of cross-sectional area 250 mm2 and gauge length 100 mm is subjected to a tensile test and the following data is obtained: within the limit of proportionality, a load of 75 kN produced an extension of 0.143 mm, load at yield point = 80 kN, maximum load on specimen = 120 kN, final cross-sectional area of waist at fracture = 90 mm2, and the gauge length had increased to 135 mm at fracture.

Determine for the specimen:

(a) Young’* modulus of elasticity,

(b) the yield stress,

(c) the tensile strength,

(d) the percentage elongation, and

(e) the percentage reduction in area.

Answer 1

(a) Force F = 75 kN = 75000 N, gauge length

L = 100 mm = 0.1 m, cross-sectional area

A = 250 mm2 = 250×10−6 m2, and extension

x = 0.143 mm = 0.143 × 10−3 m.

Young’* modulus of elasticity,

(b) Yield stress

(e) Percentage reduction in area

(original cross-sectional area)