| 摘要 |
PROBLEM TO BE SOLVED: To provide a carburizing and quenching method where, even if the surface layer of a steel is subjected to carburizing treatment, and the steel is subjected to primary cooling till its refining, the amount of the strain applied to the steel can be reduced.SOLUTION: The structure of a steel made of a ferrite structure and a pearlite structure is heated so as to be an austenite, the surface layer of the steel in the state of the austenite structure is subjected to carburizing treatment with a carburizing gas, after the carburizing treatment, the surface layer of the steel is cooled to a temperature below the recrystallization temperature of the steel so that the austenite structure of the steel can be retained, thus dislocation is introduced into the austenite structure of the surface layer, the surface layer of the steel made of the austenite structure into which dislocation is introduced is temperature-increased to a temperature more than the recrystallization temperature of the steel or more, thus the austenite structure of the surface layer of the steel is refined with the dislocation as the nucleus, and subsequently, the structure of the steel is transformed into a martensite structure.SELECTED DRAWING: Figure 1 |
