Improving the quality of aircraft fasteners by transverse running with flat plates

Abstract

For the strain hardening of aircraft fasteners, a surface plastic deformation method is proposed, based on running of blanks with smooth plates. The method allows processing parts that do not have center holes. Transverse running also eliminates the bending of the workpiece from the transverse loading forces action. Analytical dependences are obtained for determining the maximum possible contact area and relative compression for a transverse running. The quality of fasteners after transverse running with smooth plates provides the following favorable changes in the surface layer of metal: the formation of residual compressive stresses in the surface layers, a significant decrease in the initial roughness, an increase in the microhardness of the surface layer, the formation of a fine-grained structure, and the high accuracy of the machined parts diameter.

Structural changes in steel during hardening by deformation wave

“…The shape of the pulse is described by the dependence of the change in the impact force on time. The shape, amplitude and duration of a single pulse have a decisive influence on the fraction of the impact energy of the striker on the waveguide transmitted to the hardened material and spent on its elastic-plastic deformation, and therefore on the efficiency of WSH [1,[5][6][7][8]. The shape of the pulse depends not only on the geometric parameters of the striker and waveguide, the acoustic properties of their materials and the collision rate, but also on the properties of the material being strengthened.…”