| 摘要 |
A steel material, characterized in that it comprises 7 to 30 wt ppm of B and 10 to 70 wt ppm of N; and a method for producing the steel material, which comprises a first step (S1) of coating or surrounding a raw material steel with a boron compound, specifically, of forming a coating film comprising h- BN or the like on the surface of the raw material steel or surrounding it with a powder of B4C or the like, and a second step (S2) of nitriding the resultant raw material with a nitride gas while heating under a condition sufficient t o provide the above contents of B and N. B from the boron compound and N from the nitride gas are diffused into the raw material steel to produce the abov e steel material, wherein most part of B and N is dissolved in the metal structure constituting the material and is present in the form of a Fe(B, N) type solid solution or a Fe(C, B, N) type solid solution.
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