Steel sheet for container and method of manufacturing the same

1. A steel sheet for a container, the steel sheet comprising

a cold-rolled steel sheet or a cold-rolled steel sheet plated with at least one metal selected from the group consisting of Sn, Fe and Ni, and

a composite film formed on the cold-rolled steel sheet or the plated cold-rolled steel sheet through an electrolysis process in a solution containing:

at least one metal ion selected from the group consisting of a Sn ion, an Fe ion, and a Ni ion;

a Zr ion;

a nitrate ion; and

an ammonium ion; and

at least one of a phosphate ion and a phenolic resin,

wherein the composite film is simultaneously precipitated through the electrolysis process,

wherein the composite film contains, in a single layer:

Zr of 0.1 to 100 mg/m 2 in equivalent units of metal Zr,

at least one element selected from the group consisting of:

Sn of 0.3 to 20 g/m 2 in equivalent units of metal Sn;

Fe of 5 to 2000 mg/m 2 in equivalent units of metal Fe; and

Ni of 5 to 2000 mg/m 2 in equivalent units of metal Ni, and

at least one of a phosphoric acid compound of 0.1 to 50 mg/m 2 in equivalent units of P and the phenolic resin of 0.1 to 50 mg/m 2 in equivalent units of C, and wherein the composite film does not substantially contain Cr.

2. The steel sheet for a container according to claim 1 , wherein

the solution for the electrolysis process further contains a fluorine ion, and

the composite film further contains a fluorine compound of not more than 0.1 mg/m 2 in equivalent units of F.

3. The steel sheet for a container according to claim 1 or 2 , wherein

the composite film is formed on a plating of the plated cold-rolled steel sheet, wherein the plated cold-rolled steel sheet has at least one side surface including at least one of a Sn-plated layer containing Sn of 0.3 to 20 g/m 2 in equivalent units of metal Sn, and a Ni-plated layer containing Ni of 5 to 2000 mg/m 2 in equivalent units of metal Ni.

4. The steel sheet for a container according to claim 3 , wherein

the at least one side surface of the plated cold-rolled steel sheet has the Sn-plated layer, and

at least part of the Sn-plated layer is alloyed with the cold-rolled steel sheet through a Sn-reflow treatment.

5. The steel sheet for a container according to claim 3 , wherein

the at least one side surface of the plated cold-rolled steel sheet has the Sn-plated layer, and

there is provided, below the Sn-plated layer, a Ni-plated layer, an Fe—Ni alloy plated layer, or a Ni-diffusion plated layer obtained through a thermal treatment after Ni plating.

6. The steel sheet for a container according to claim 5 , wherein

the at least one side surface of the plated cold-rolled steel sheet has the Sn-plated layer, and

all or part of the Sn-plated layer is alloyed with the cold-rolled steel sheet through a Sn-reflow treatment.

7. A method of manufacturing a steel sheet for a container, including:

applying an electrolysis process to a cold-rolled steel sheet or a cold-rolled steel sheet plated with at least one metal selected from the group consisting of Sn, Fe and Ni in a solution for the electrolysis process containing:

at least one metal ion of a Sn ion, an Fe ion, and a Ni ion;

a Zr ion;

a nitrate ion;

an ammonium ion; and

at least one of a phosphate ion and a phenolic resin,

simultaneously precipitating on the cold-rolled steel sheet or the plated cold-rolled steel sheet, and forming a composite film containing, in a single layer:

Zr of 0.1 to 100 mg/m 2 in equivalent units of metal Zr,

at least one element of:

Sn of 0.3 to 20 g/m 2 in equivalent units of metal Sn;

Fe of 5 to 2000 mg/m 2 in equivalent units of metal Fe; and

Ni of 5 to 2000 mg/m 2 in equivalent units of metal Ni, and

at least one of a phosphoric acid compound of 0.1 to 50 mg/m 2 in equivalent units of P and the phenolic resin of 0.1 to 50 mg/m 2 in equivalent units of C, wherein the composite film does not substantially contain Cr.

8. The method of manufacturing a steel sheet for a container according to claim 7 , wherein

the composite film is formed on a plating of the plated cold-rolled steel sheet, and wherein the plated cold rolled steel sheet has at least one side surface including at least one of a Sn-plated layer containing Sn of 0.3 to 20 g/m 2 in equivalent units of metal Sn, and a Ni plated layer containing Ni of 5 to 2000 mg/m 2 in equivalent units of metal Ni.

9. The method of manufacturing a steel sheet for a container according to claim 8 , wherein

the plated cold-rolled steel sheet has said at least one side surface including the Sn-plated layer, and

a Ni-plated layer, an Fe—Ni alloy plated layer, or a Ni-diffusion plated layer obtained through a thermal treatment after Ni plating is arranged under the Sn-plated layer.

10. The method of manufacturing a steel sheet for a container according to any one of claims 7 , 8 and 9 , further including

after the composite film is formed on the cold-rolled steel sheet or the cold-rolled steel sheet plated with at least one metal selected from the from the group consisting of Sn, Fe and Ni, applying a cleaning process of an immersion process or spray process with hot water at not less than 40° C. for not less than 0.5 second.

11. The steel sheet for a container according to claim 1 , wherein

Zr forms a gradation in the composite film in a film-thickness direction.

12. The method of manufacturing a steel sheet for a container according to claim 7 , wherein

Zr forms a gradation in a film-thickness direction.