SEDL / STP / STP1438-EB / STP11152S



Mechanical and Corrosion Properties of Forged Hip Stems made of High-NitrogenStainless Steel

Windler, M
Director, Materials Research, and Research Scientist, Sulzer Orthopedics Ltd., Winterthur,

Steger, R
Director, Materials Research, and Research Scientist, Sulzer Orthopedics Ltd., Winterthur,


Pages: 11    Published: Jan 2003


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Source: STP1438-EB


Abstract

The purpose of the study was to determine the mechanical and corrosion roperties of forged, commercially available, femoral hip stems. Two different stem designs were selected (the MS-30, sizes 6 and 16, and the MUELLER straight stem, sizes 7.5 and 15.0). They were made of high-nitrogen stainless steel according to ISO 5832-9 and ASTM F1586. The samples for determining the mechanical properties were taken from the proximal part of the prostheses. The metallurgical and the potentio-dynamic corrosion behaviours were investigated in three different transverse cross-sectional planes. The mechanical properties in the forged condition were as follows: Yield strength 1051 – 1172 MPa, tensile strength 1138 – 1238 MPa and elongation 15 – 19%. Vickers hardness values of between 354 and 393 HV were measured. The breakdown potential fell from +1000 mV(SCE) (wrought bar) to +600 to +950 mV(SCE) (forged hip stems) for pH 4 and 37°C. The rotational bending fatigue value for 10 million cycles was 587 MPa.


Keywords:
high-nitrogen stainless steel, corrosion properties, mechanical properties, microstructure

Paper ID: STP11152S
Committee/Subcommittee: F04.12
DOI: 10.1520/STP11152S
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