The Quantification of Corrosion Damage for Pre-stressed Conditions: A Model Using Stainless Steel

Abstract

Stainless steel is used extensively within orthopaedics as part of varying surgical procedures such as trochanteric osteotomy, sternum closure, patella tendon repair and reconstruction, patellofemoral ligament reconstruction and internal fracture fixation. This study examines the changes in corrosion behaviour after applying plastic and elastic stresses. Furthermore it analyses how a tensile and a compressive load can affect the corrosion susceptibility of a material. Stainless steel test specimens were divided into three groups of seven to determine how corrosion susceptibility will change when a material is pre-stressed. Potentiodynamic testing was performed to investigate the pitting behaviour of ss304 after being exposed to pre-stressed conditions. All images graded exhibited both area and pit corrosion scores, which significantly differed between the 3 groups (p < 0.001). The samples that were destructively stressed under compression had a mean of 35.5 % corrosion damage (SD 14.5) which is significantly greater (p = 0.001) compared to a mean of 11 % (SD 4.5) corrosion damage present with a material destructively stressed under tension. This study has shown that a material’s corrosion susceptibility changes significantly after being pre-stressed regardless, whether this is mechanically loading it within its yield strength or destructively loading.