| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel strip in which roll over upon blanking when it is worked into a component is reduced so as to reduce a cutting margin, and to which a carburizing treatment after the blanking can be obviated as well, utilizing a means of increasing the surface carbon concentration of the material in the stage of the stock (steel strip) before being fed to blanking. SOLUTION: In the carburized steel strip having satisfactory blanking property, the average hardness to a depth of 50μm in the surface layer part in the sheet thickness direction is≥170 HV, also, its metallic structure is composed of ferrite+pearlite, and a difference between the carbon concentration C<SB>S</SB>(mass%) in the surface and the average carbon concentration C<SB>M</SB>(mass%) in the steel,ΔC=C<SB>S</SB>-C<SB>M</SB>is≥0.1 mass%. This steel strip can be obtained through a process where a carburizing coating material comprising a solid carburizing agent by≥5 mass% is applied to the surface of a steel strip so as to be a dry coating film, thereafter, the steel strip is made into a coil shape in such manner that the contact pressure between the adjoining sheet faces with the coating film interposed reaches≥0.2 MPa, and is heated at 720 to 850°C in an inert gas atmosphere. COPYRIGHT: (C)2011,JPO&INPIT |
