Surface Technology - Shot Peening

Gears and machine components need ever tougher and harder surfaces because their mechanical stress and fatigue strength requirements are steadily increasing. For example, components for combustion engines and hydraulics are now subjected to pressures of up to 3,000 bar. 
ZELL has perfected the enhancement of surface fatigue strength by shot peening for large series with the development of its own plant engineering and special blasting technology. 


ZELL specialises in large-series manufactured parts such as cylinder heads, valve and throttle discs, gears, springs, connecting rods, shafts and hydraulic components. During the shot peening process, the part surface is irradiated with small spherical abrasives – glass beads, ceramic particles and cut wire shot are used as abrasives. Shot peening is a highly precise and reproducible process in terms of angle of impact, blasting time and pressure, blasting medium speed, type of blasting medium and degree of surface coverage. 

Each pellet that hits the part acts like a forging hammer and leaves a smooth domed imprint on the surface. The metal surface layer is stretched and the deeper layers of material counteract this elongation. In this way, shot peening induces a residual compressive stress in the surface of the treated metallic part. By ensuring uniform coverage, the peeing process creates a high residual compressive stress on the surface. This demonstrably improves the mechanical strength of the component. The outcomes are higher dynamic strength, less corrosion fatigue, no cracking, a longer service life and higher compressive strength due to the increased surface hardness. The ZELL blasting process ensures that components can reliably withstand the required loads.