Functional gradation of gear shafts made of cementation steel and its influence on damping and microstructure

The concept of gradation of materials leads to a continuous variation of mechanical properties by changing the microstructure. This can be obtained by suitable local thermal treatment promising the production of tailored mechanical properties. s study, the dynamical behaviour in terms of damping and resonance frequency of gear shafts as system response to excitation is investigated. The shafts are made of CrNiMo-cementation steel. They will be used for evaluation if the functional gradation by local thermal treatment is accomplishable and effective with respect to the reduction of noise or vibration. Damping was received as the damping ratio estimated by the transfer function using the half-power bandwidth method. All measurements were carried out at room temperature. raphs were taken and showed the successful manipulation of the local microstructure of the shafts by heat treatment. A measurable influence on the damping ratio and resonance frequency was identified.