An alloy steel M10 15 screw is to be turned into a threaded

. An alloy steel M10 -1.5 screw is to be turned into a threaded hole and tightened to one half of its proof strength. Determine the maximum torque that should be used if the torque coefficient - 0.18. Proof Stress Tensile Stress Material MPa lblin2 MPa Ib/in Low/medium C steel 228 Alloy steel 33,000 120,000 414 60,000 1030 150,000 830 T CDF As A D 0.9382 p)2 4

Solution

Shear area = (3.14/4)x(10-(0.9382xp))² = 57.989 mm ²

strength = 0.5 x proof stress = 0.5 x 830 = 415 N/mm ²

Force = stress x shear area = 415 x 57.989 = 24065.435 N

Torque = C.D.F = 0.18 x 10 x 24065.435 = 43317.783 N-mm

= 43.317 N-m