A helical spring is to be constructed from a 4340 steel. The design calls for 5 coils, a coil-to-coil diameter of 12 mm, and a wire diameter of 3 mm.
Furthermore, a maximum total deflection of 5.0 mm is possible without any plastic deformation.
Specify a heat treatment for this 4340 steel wire in order for the spring to meet the above criteria. Assume a shear modulus of 80 GPa for this steel alloy, and that ty = 0.6y.
Note: heat treatment of the 4340 steel is discussed in Section 10.8.