A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 m.

A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 m.

The present invention provides a method for manufacturing a metal sheet. In this method, at least one of the following equations is satisfied: $\begin{array}{cc}\frac{Z}{d}+18\ln \left(\frac{Z}{d}\right)<8\ln \left(\frac{P}{V}\right)-27.52& \left(A\right)\\ f{O}_2<\frac{2.304.Math.{10}^{-3}}{{(27.52+\frac{Z}{d}+8\ln (}^{}}\end{array}$

The present invention provides a method for manufacturing a metal sheet. In this method, at least one of the following equations is satisfied: $\begin{array}{cc}\frac{Z}{d}+18\ln \left(\frac{Z}{d}\right)<8\ln \left(\frac{P}{V}\right)-27.52& \left(A\right)\\ f{O}_2<\frac{2.304.Math.{10}^{-3}}{{(27.52+\frac{Z}{d}+8\ln (}^{}}\end{array}$

An installation for continuous hot-dip coating of a metal strip is provided. The installation includes a tank containing a bath of molten metal, a metal strip running through the bath and a confined wiping device. The confined wiping device includes at least two wiping nozzles placed on each side of a path of the strip after the strip has left the bath of molten metal. Each nozzle has at least one gas outlet orifice and an upper face. The confined wiping device also includes a confinement box adjacent each upper face. The confinement boxes are open on a face which faces the strip. Each box includes at least one upper part and two lateral parts.

An installation for continuous hot-dip coating of a metal strip is provided. The installation includes a tank containing a bath of molten metal, a metal strip running through the bath and a confined wiping device. The confined wiping device includes at least two wiping nozzles placed on each side of a path of the strip after the strip has left the bath of molten metal. Each nozzle has at least one gas outlet orifice and an upper face. The confined wiping device also includes a confinement box adjacent each upper face. The confinement boxes are open on a face which faces the strip. Each box includes at least one upper part and two lateral parts.

An installation for continuous hot-dip coating of a metal strip is provided. The installation includes a tank containing a bath of molten metal, a metal strip running through the bath and a confined wiping device. The confined wiping device includes at least two wiping nozzles placed on each side of a path of the strip after the strip has left the bath of molten metal. Each nozzle has at least one gas outlet orifice and an upper face. The confined wiping device also includes a confinement box adjacent each upper face. The confinement boxes are open on a face which faces the strip. Each box includes at least one upper part and two lateral parts.

An installation for continuous hot-dip coating of a metal strip is provided. The installation includes a tank containing a bath of molten metal, a metal strip running through the bath and a confined wiping device. The confined wiping device includes at least two wiping nozzles placed on each side of a path of the strip after the strip has left the bath of molten metal. Each nozzle has at least one gas outlet orifice and an upper face. The confined wiping device also includes a confinement box adjacent each upper face. The confinement boxes are open on a face which faces the strip. Each box includes at least one upper part and two lateral parts.

Zn alloy plated steel material having excellent weldability and processed-part corrosion resistance and a method for production of Zn alloy plated steel material are provided. In the Zn alloy plated steel material comprising base steel material and a Zn alloy plating layer, the Zn alloy plating layer includes, by wt %, Al: 0.1-5.0%, Mg: 0.1-5.0%, as well as a remainder of Zn and inevitable impurities. The Zn alloy plated steel material includes a lower interface layer and an upper interface layer between the base steel material and the Zn alloy plating layer, wherein the lower interface layer is formed on the base steel material and has a dense structure, and the upper interface layer is formed on the lower interface layer and has a network-type or island-type structure.

Zn alloy plated steel material having excellent weldability and processed-part corrosion resistance and a method for production of Zn alloy plated steel material are provided. In the Zn alloy plated steel material comprising base steel material and a Zn alloy plating layer, the Zn alloy plating layer includes, by wt %, Al: 0.1-5.0%, Mg: 0.1-5.0%, as well as a remainder of Zn and inevitable impurities. The Zn alloy plated steel material includes a lower interface layer and an upper interface layer between the base steel material and the Zn alloy plating layer, wherein the lower interface layer is formed on the base steel material and has a dense structure, and the upper interface layer is formed on the lower interface layer and has a network-type or island-type structure.