Patent ID: 7662207
Filing Date: 2010-02-16
Classification: B22F,C21D,C22C

Abstract:
1. A super hard and tough austenite steel bulk material with an improved corrosion resistance, comprising an aggregate of austenite nano-crystal grains containing 0.1 to 2.0% (by mass) of nitrogen in solid-solution wherein said austenite nano-crystal grains are obtained by mechanical alloying (MA) using a ball mill or the like, and wherein some amount of a metal oxide or a semi-metal oxide is inevitably formed on the surface of MA powder products during MA processing, acting as a crystal grain growth inhibitor between or in said nanocrystal grains, or between and in said nano crystal grains, wherein said bulk material comprising an aggregate of austenite nano-crystal grains containing 0.1 to 2.0% (by mass) of nitrogen in solid solution has a steel forming and blending composition comprising 4 to 40% (by mass) of Mn, 0.1 to 2.0% (by mass) of N, 0.1 to 2.0% (by mass) of C and 3 to 10% (by mass) of Cr with the rest being substantially Fe.