1. You have been asked to select a material for a spring that is to be stressed in tension. It is to consist of 10 coils, and the coil-to-coil diameter called for is 15 mm; furthermore, diameter required such that the spring will not plastically deform when subjected to the above load.
2. 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 cri- teria. Assume a shear modulus of 80 GPa for this steel alloy, and that ty = 0.6y. Note:
Heat treatment of the 4340 steel is dis- cussed in Section 10.8.