| abstract |
"STEEL SHEET FOR CARBURETTING, ANDnMETHOD OF PRODUCTION OF THE STEEL SHEET FOR CARBURETATION. "The present invention relates to a steel plate for carburization having improved forming capacity and toughness after carburation, and a method for producing it. A steel plate consisting, in % by weight, of C: more than or equal to 0.02%, and less than 0.30%, Si: more than or equal to 0.005%, and less than or equal to 0.5%, Mn: more than or equal to 0.01%, and less than or equal to 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.1%, Al sol .: more than or equal to 0.0002%, and less than or equal to 3.0%, N: more than or equal to 0.0001, and less than or equal to 0.035%, and the balance: Fe and impurities, in which the size mean of the ferrite crystal grain is less than 10 µm, the average equivalent circle diameter of the carbide is 5.0 µm or less, the percentage of the number of carbides with an aspect ratio of 2.0 or less is 80% or more in relation to the total carbides, the percentage of the number of carbides present in the ferrite crystal is 60% or more relative to the total carbides, and the average nitrogen concentration in a region ranging from the topmost surface of the steel sheet to a depth of 50 µm is 0.040% by weight or more and 0.200 Bulk% or less. |