TÔLE D'ACIER POUR CAPSULE-COURONNE, CAPSULE-COURONNE ET PROCÉDÉ DE FABRICATION DE TÔLE D'ACIER POUR CAPSULE-COURONNE

摘要

Provided is a steel sheet for crown cap which has excellent formability and from which a crown cap having a sufficient pressure resistance applicable to beverages having a high carbon dioxide content can be produced with the use of a soft liner even when the steel sheet is subjected to sheet metal thinning, the steel sheet for crown cap having: a chemical composition containing, in mass%, C: more than 0.0060 % and 0.0100 % or less, Si: 0.05 % or less, Mn: 0.05 % or more and 0.60 % or less, P: 0.050 % or less, S: 0.050 % or less, Al: 0.020 % or more and 0.050 % or less, and N: 0.0070 % or more and 0.0140 % or less, with the balance being Fe and inevitable impurities; a ferrite phase in a region from a depth of 1/4 of a sheet thickness to a mid-thickness part, the ferrite phase having a standard deviation of ferrite grain size of 7.0 µm or less; a yield strength of 560 MPa or more and 700 MPa or less in a rolling direction; and a difference of 25 MPa or more between a yield strength in a 2 % strain tensile test and a yield strength in a tensile test after heat treatment at 170 °C for 20 minutes, in the rolling direction.