Radu Stefanoiu

Stainless Steels with Biocompatible Properties for Medical Devices

Stainless steels, commercial as well as with special properties, are the principal metallic materials used for medical devices manufacturing. Stainless steels for medical devices should have superior mechanical properties, as: hardness, wear resistance, tensile strength, elongation, fracture toughness, creep resistance etc. This paper aims to present experimental researches regarding the obtaining in vacuum arc remelting device (VAR) of austenitic and martensitic stainless steels and their characterization from microstructure and microhardness point of view.

Obtaining and Characterization of Biocompatible Co-Cr as Cast Alloys

Biocompatible metallic materials used for surgical implants in human body should have superior mechanical properties, as: microhardness, wear resistance, tensile strength, elongation, fracture toughness, creep resistance etc. These results can be also obtained by strict setting and controlling of chemical composition, by adding chemical elements that lead at the improvement of the mentioned properties. In this paper has been presented experimental researches regarding the obtaining process of some biocompatible Co-Cr cast alloys, having different chemical compositions, using the method of vacuum induction melting (VIM). After the obtainment process, samples were characterised from microstructure and microhardness point of view.

Dissimilar Brazed Joints Between Steel and Tungsten Carbide

Brazing is a joining process used to obtain heterogeneous assemblies between different materials, such as steels, irons, non-ferrous metals, ceramics etc. Some application, like asphalt cutters, require quick solutions to obtain dissimilar joints at acceptable costs, given the very short period of operation of these parts. This paper presents some results obtained during the brazing of dissimilar joints between steel and tungsten carbide by using different types of Ag-Cu system filler materials alloyed with P and Sn. The brazing techniques used were oxygen-gas flame and induction joining. The brazing behaviour was analysed in cross sections by optical and electron microscopy. The metallographic analysis enhanced the adhesion features and the length of penetration in the joining gap. The melting range of the filler materials was measured using thermal analysis.