A new precipitation hardenable martensitic stainless steel, Sandvik Bioline 1RK91 ( 12%Cr – 9% Ni – 4%Mo – 2%Cu, UNS number S46910) has been developed and shown to exhibit very good properties for medical device manufacture such as surgical needles, bone drills, dental fixation devices etc.

Sandvik Bioline 1RK91 has been tested and concluded not to possess any cytotoxic potential according to standard in vitro tests. The features and benefits of this material include an excellent combination of properties such as very good corrosion resistance, ultra-high tensile strength combined with good toughness, excellent formability and dimensional stability etc. The aging response is exceptionally large and permits forming operations in a softer state followed by age hardening to the final ultra-high tensile strength state. Brittle fracture and flaking is prevented by the good toughness ensuring safe use of critical or slender devices. To a large extent the unique combination of properties of this stainless steel result from the special precipitation sequence developed during aging of the material. This includes nanometer sized quasicrystalline particles and this alloy is the first commercially available grade to utilize this feature.

Available as bar, wire, tube and strip Sandvik Bioline 1RK91 is used for the manufacture of medical devices. Originally developed for micro-surgical needles for eye, heart and cosmetic surgery it has now gained wide spread use for other medical devices.

The paper will present the material, its properties and examples of use for various medical applications.