Abstract
An improved technological process for surface treatment of leaf springs for the suspension of vehicle axles is presented which can significantly favor the residual stress state and thus improve their resistance to cyclic loading. The basic issue of the improved technological process is the thermomechanical treatment of the leaf spring surface consisting of stress-peening under defined elevated temperature. The paper discusses the manufacturing process emphasising the microstructural aspects and macroscopical residual stress-strain state in the region close to the surface. Draft solutions are elaborated and optimised with regard to the strength behaviour both by finite element analysis and experimentally. Approval of durability under operational loading is brought experimentally, prototype springs thereby being exposed on the test rig to standardised load spectra resulting from vertical loading and braking. The comparison of test results obtained from conventionally and thermomechanically treated leaf springs demonstrates the increase of fatigue life.