Method for producing an Sn-based multilayer coated steel strip having improved corrosion resistance, weldability and lacquerability
AssigneeNippon Steel Corporation
InventorsSeizun Higuchi, Tomonari Oga, Masao Ikeda, Hirohumi Nakano
Life of this patent
Estimating the term…
Abstract
The Sn based multilayer coated steel strip for container-use is improved by the provision of a novel underyling coating of ternary Fe-Ni-P alloy which, mainly because of the Ni component, ensures a uniform deposition of the Sn layer, and mainly because of the P and Fe contents ensure a satisfactory remaining amount of free Sn for improving the weldability. The steel strip has a thin Sn plated layer and a chromate coating layer on the underlying coating.
Claims12
A method for producing a surface-treated steel strip for use as a container, having improved properties, characterized by, electroplating on the steel strip a Fe-Ni-P based underlying coating layer having a weight of from 10 to 300 mg/m.sup.2 and containing from 5% to 30% Ni and from 0.1% to 10% P, and then electroplating a Sn layer, heating and melting the Sn plated layer to form a Fe-Ni-Sn-P based alloy, while leaving metallic Sn on the layer of the Fe-Ni-Sn-P based alloy, and subsequently forming a chromate coating layer.
A method for producing a surface-treated steel strip for use as a container, having improved properties, characterized by, electroplating on the steel strip a Fe-Ni-Sn-P based coating layer having a weight of from 50 to 1500 mg/m.sup.2 and containing from 2% to 20% Ni, from 0.05% to 5% P, from 20% to 50% Fe, the balance being Sn, electroplating a Sn layer on the Fe-Ni-Sn-P layer, and subsequently forming a chromate coating layer.
Dependencies are inferred from the claim text.