| 摘要 |
The invention relates to a steel composition which is substantially free of nickel and which can be used for medical implants and/or jewellery manufacture. Some humans experience severe allergic reactions to Nickel and therefore there has been a desire for some time to provide a Nickel free steel. Nickel is an important constituent of surgical grade steel because it is a good austenite promoter, and steel thus formed has good strength properties and has paramagnetic characteristics which are essential for such steels. The absence of Nickel results in the formation of ferritic steel which is ferromagnetic, which cannot be used for medical implants. The invention results from the realisation that Nitrogen is a good promoter of austenitic steel structures, and although Nitrogen is a gas and thus generally insoluble in molten steel, a careful balance of additional alloying elements such as Manganese, Chromium, and Molybdenum, with Iron can result in a molten alloy in which Nitrogen can be dissolved at atmospheric pressure to a degree at which its austenitic steel structure promotion effects are readily appreciable. |
