| 摘要 |
PURPOSE:To prepare a steel with excellent abrasion resistance by a method wherein an austenite layer supersaturated with C is formed on the surface layer of the steel by excessive carburization and said C is precipitated out as proeutectic cementite as well as annealing is applied thereto. CONSTITUTION:A cast iron or a steel material is subjected to excessive carburization at a temp. of 950-1,150 deg.C in an atmosphere with carbon potential of 1.0% or more, pref., by a vacuum carubrizing method. Subsequently, the obtained cast iron or steel material having a surface layer part to which C is imparted in the solid solution limit or more of austenite is cooled and proeutectic Fe3C is precipitated out only in the surface layer part during cooling. Next, the cast iron or steel material in this condition is annealed, pref., from a temp. of 850-950 deg.C to generate martensite. As the result, a hard texture with extremely improve abrasion resistance can be formed on the surface layer part of said cast iron or steel material as well as, at the same time, the matrix material itself can be reinforced by annealing and the abrasion resistance can be improved extremely. |
