II.7 - Mechanical Springs

Abstract

Springs are mechanical elements that exert forces or torques and absorb energy. The absorbed energy is usually stored and released later. The hot and cold working processes are used for springs manufacturing. Plain carbon steels, alloy steels, corrosion-resisting steels, or nonferrous materials can be used for spring manufacturing. Spring materials are compared by an examination of their tensile strengths, which require the material, its processing, and the wire size. The torsional yield strength can be obtained by assuming that the tensile yield strength is between 60 and 90% of the tensile strength. The helical springs are usually made of circular cross-section wire or rod. These springs are subjected to a torsional component and a shear component. There is also an additional stress effect due to the curvature of the helix. For helical springs the ends can be specified as plain ends; plain and ground ends; squared ends; and squared and ground ends. A spring with plain ends has a noninterrupted helicoid and the ends are the same as if a long spring had been cut into sections. A spring with plain and ground ends, or squared ends, is obtained by deforming the ends to a zero-degree helix angle.