THE EFFECT OF MECHANICAL DEFORMATION ON MAGNETIC-PROPERTIES AND MRI ARTIFACTS OF TYPE-304 AND TYPE-316L STAINLESS-STEEL

The purpose of this study was to evaluate the influence of composition and deformation of biomedical stainless steels on mechanical properti es, magnetic properties, and MRI artifacts. Type 304 and Type 316L sam ples were prepared using standard wire-drawing techniques. Mechanical properties were determined using standard test methods. The amount of ferromagnetic phase present was estimated using a Severn Gage and x-ra y diffraction. Magnetic held attraction and artifacts were determined using previously described techniques. The strength of both steels inc reased significantly with increasing deformation. None of the type 316 L wires transformed to the magnetic phase. The amount of magnetic phas e in the type 304 wires increased with increasing deformation. There w as no magnetic held attraction, and artifacts were minimal for all of type 316L wires and the undeformed type 304 wire. Deflection and artif acts were significant for the deformed type 304 stainless steel. These results provide guidance regarding the use of type 304 and type 316L stainless steels for bioimplants. In this regard, type 316L stainless steel seems to be a more acceptable material with respect to MR compat ibility.