Fatigue-based model for the droplet impingement erosion incubation
period of metallic surfaces
Abstract
Droplet impingement of metallic surfaces at high impact velocities
results, after some time, in erosion of the surface due to fatigue. By
extending our previously published analytical model to enable the use of
experimental fatigue data (S-N curves), here, for the first time, a wide
range of experimental liquid droplet erosion incubation period test
states for both ferrous (stainless steel AISI 316) and non-ferrous
(aluminium 6061-T6) engineering metals have been investigated. To
achieve this, the developed model includes additional surface hardening
and a residual compressive stress state at the surface due to a water
drop peening effect. As such, the interrelation of the physical and
mechanical properties that follows from the model has been used to
identify how changes in selected metal properties might enhance droplet
impingement erosion incubation life. Model predictions for both metals,
using fatigue data from S-N curves from different literature sources,
showed for the droplet impact velocity range of 140 to 400 m/s an
excellent agreement with results from a multi-regression equation as
determined from an ASTM interlaboratory test program.