A hot-dip galvanized steel sheet having a good appearance and good adhesion to a coating, the hot-dip galvanized steel sheet having a composition containing, on a mass basis: C: 0.08% or more and less than 0.20%, Si: 0.1% to 3.0%, Mn: 0.5% to 3.0%, P: 0.001% to 0.10%, Al: 0.01% to 3.00%, and S: 0.200% or less, a remainder being Fe and incidental impurities, wherein the hot-dip galvanized steel sheet includes an internal oxidation layer and a decarburized layer, the internal oxidation layer having a thickness of 5 m or less, the decarburized layer having a thickness of 20 m or less, and 50% or more by area of the internal oxidation layer is composed of a Si oxide containing Fe and/or Mn represented by Fe.sub.2XMn.sub.2-2XSiO.sub.Y, wherein X ranges from 0 to 1, and Y is 3 or 4.

The present invention provides a deformed part created by forming a coated metal sheet into a part, the coated metal sheet comprising a steel substrate, at least one face of which is coated with a metal coating deposited by dipping the substrate in a bath, said coating comprising between 0.2 and 0.7% by weight of Al, the remainder of the metal coating being Zn and inevitable impurities, wherein an outer surface of a metal coating of the deformed part has a waviness Wa0.8 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:

[00001]$\begin{array}{cc}\frac{Z}{d}+18.Math..Math.\ln \left(\frac{Z}{d}\right)<8.Math..Math.\ln \left(\frac{P}{V}\right)-27.52& \left(A\right)\\ f.Math..Math.O_2<\frac{2.304.Math.{\mathrm{.10}}^{-3}}{{\left(27.52+\frac{Z}{d}+8.Math..Math.\ln \left(\frac{V}{P}.Math.{\left(\frac{Z}{d}\right)}^{2.25}\right)\right)}^2}& \left(B\right)\end{array}$

wherein: Z is the distance between the metal sheet and the nozzle along the main ejection direction (E), Z being expressed in mm, d is the average height of the outlet of the nozzle along with the running direction of the metal sheet in front of the nozzle, d being expressed in mm, V is the running speed of the metal sheet in front of the nozzle, V being expressed in m.Math.s.sup.1, P is the pressure of the wiping gas in the nozzle, P being expressed in N.Math.m.sup.2, and fO.sub.2 is the volume fraction of oxygen in the wiping gas. A metal sheet, part and land motor vehicle are also provided.

A cold-rolled sheet is provided. The cold-rolled sheet is annealed and pre-coated for the fabrication of press hardened parts, composed of a steel substrate for heat treatment with a carbon content C.sub.0 between 0.07% and 0.5%, expressed by weight, and a metal pre-coating on at least the two principal faces of the steel substrate. The substrate comprises a decarburized area on the surface of each of the two principal faces. The depth p.sub.50% of the decarburized area is between 6 and 30 micrometers, and p.sub.50% is the depth at which the carbon content is equal to 50% of the content C.sub.0. The sheet does not contain a layer of iron oxide between the substrate and the metal pre-coating. Processes are also provided.

A hot-rolled steel sheet having a tensile strength of 900 MPa or more, the hot-rolled steel sheet consisting of, in mass %, C: greater than 0.050% and less than or equal to 0.10%, Si: greater than or equal to 0.1% and less than or equal to 2.0%, Mn: greater than or equal to 1.0% and less than or equal to 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.01%, Al: greater than or equal to 0.005% and less than or equal to 0.05%, N: less than or equal to 0.01%, Ti: greater than or equal to 0.10% and less than or equal to 0.20%, Nb: greater than or equal to 0% and less than or equal to 0.06%, B: greater than or equal to 0% and less than or equal to 0.03%, Ca: greater than or equal to 0% and less than or equal to 0.005%, and the balance: Fe and impurities. An average crystal grain size is less than or equal to 7.0 m, and an X-ray random intensity ratio in {211} <011> orientation that is parallel to a rolled surface and a rolling direction is less than or equal to 2.5.

A method of producing a galvannealed steel sheet whereby favorable coating appearance can be obtained with high coating adhesion even in the case of galvannealing a steel strip whose Si content is 0.2 mass % or more, and a decrease in tensile strength can be prevented by lowering the alloying temperature. Mixed gas of humidified gas and dry gas, and dry gas are supplied to a soaking zone in an annealing furnace. The mixed gas is timely supplied from a position of lower half of the soaking zone. The dry gas is timely supplied from near an upper hearth roll in the soaking zone, and furnace gas is timely discharged from a gas discharge port located higher than the upper hearth roll, to control a dew point in at least an uppermost part of the soaking zone to 20 C. or more and 0 C. or less.

A high-strength galvanized steel sheet includes a base steel sheet having a specific chemical composition and a zinc coating layer disposed on the surface of the base steel sheet in a coating weight per side of 20 g/m.sup.2 to 120 g/m.sup.2, wherein the amount of hydrogen measured by a specific method is 0.05 mass ppm to 0.40 mass ppm; and I.sub.Si.sup.sur/I.sub.Si.sup.bulk and I.sub.Mn.sup.sur/I.sub.Mn.sup.bulk calculated by a specific method are not more than 2.0 and not more than 3.0, respectively.

A hot-dip galvanized steel sheet having a good appearance and good adhesion to a coating, the hot-dip galvanized steel sheet having a composition including, on a mass basis: C: 0.20% to 0.50%, Si: 0.1% to 3.0%, Mn: 0.5% to 3.0%, P: 0.001% to 0.10%, Al: 0.01% to 3.00%, and S: 0.200% or less, a remainder being Fe and incidental impurities, wherein the hot-dip galvanized steel sheet includes an internal oxidation layer and a decarburized layer, the internal oxidation layer having a thickness of 4 m or less, the decarburized layer having a thickness of 16 m or less, and 50% or more by area of the internal oxidation layer is composed of a Si oxide containing Fe and/or Mn represented by Fe.sub.2XMn.sub.2-2XSiO.sub.Y, wherein X ranges from 0 to 1, and Y is 3 or 4.

To more reliably suppress LME and blowhole formation while maintaining excellent corrosion resistance.

A plated steel sheet according to the present invention, includes: a steel sheet as a base material; a plating layer located on at least part of a surface of the steel sheet; and an oxide layer located on a surface of the plating layer, where a chemical composition of the plating layer is made up of prescribed components, and Zn and impurities as the balance, and when a position at a depth of 5 nm from an uppermost surface of the oxide layer is observed by X-ray photoelectron spectroscopy (XPS), a value of an intensity ratio ([AlO]+[MgO])/[ZnO]) calculated from intensity of peaks respectively attributed to an AlO bond, an MgO bond, and a ZnO bond is 5.0 or more.

This plated steel sheet includes a base steel sheet, a plated layer formed on a surface of the base steel sheet, and an oxide film formed on a surface of the plated layer, the plated layer has a chemical composition containing Sc: 0.000010 to 4.0% in mass %, and has a cross section, in the thickness direction, in which the area fraction of an intermetallic compound phase containing Sc and having an equivalent circle diameter of 5.0 m or less is 0.1 to 10.0%, and the oxide film has a thickness of 10 nm or more.