A cold rolled and annealed steel sheet includes by weight: 0.6<C<1.3%,15.0<Mn<35%, 6.0<Al<15%, Si<2.40%, S<0.015%, P<0.1%, N<0.1%, iron and inevitable impurities, optionally one or more of Ni, Cr and Cu in an individual amount of up to 3% and optionally one or more of B, Ta, Zr, Nb, V, Ti, Mo, and W in a cumulated amount of up to 2.0%, a microstructure of the sheet comprising at least 0.1% of intragranular kappa carbides, at least 80% of the kappa carbides have an average size below 30 nm, the remainder being made of austenite, an average grain size of the austenite being below 6 μm, an average aspect ratio of the austenite being between 1.5 and 6, an average grain size of the ferrite, when present being below 5 μm, and an average aspect ratio of the ferrite, when present, being below 3.0.

Provided is a stainless steel substrate for a solar cell, the stainless steel substrate including, by mass %, Cr: 9% to 25%, C: 0.03% or less, Mn: 2% or less, P: 0.05% or less, S: 0.01% or less, N: 0.03% or less, Al: 0.005% to 5.0%, Si: 0.05% to 4.0%, and a remainder including Fe and unavoidable impurities, in which an oxide film containing (i) Al.sub.2O.sub.3 in an amount of 50% or more or containing (i) Al.sub.2O.sub.3 and (ii) SiO.sub.2 in a total amount of 50% or more is formed on a surface of stainless steel having a composition which contains Al: 0.5% or more and/or Si: 0.4% or more and satisfies the following expression (1).
Cr+10Si+Mn+Al>24.5  (1)

This relates to a process for manufacturing a recovery annealed coated steel substrate for packaging applications and a packaging steel product produced thereby.

The invention relates to a method for the production and removal of a temporary protective layer for a cathodic coating, particularly for the production of a hardened steel component with an easily paintable surface, wherein a steel sheet made of a hardenable steel alloy is subjected to a preoxidation, wherein said preoxidation forms a FeO layer with a thickness of 100 nm to 1,000 nm and subsequently a melt dip coating is conducted, wherein, during the melt dip coating, a zinc layer is applied having a thickness of 5 to 20 μm, preferably 7 to 14 μm, on each side, wherein the melt dip process and the aluminum content of the zinc bath is adjusted such that, during the melt dip coating, an aluminum content for the barrier layer results of 0.15 g/m.sup.2 to 0.8 g/m.sup.2 and the steel sheet or sheet components made therefrom is subsequently heated to a temperature above the austenitizing temperature and is then cooled at a speed greater than the critical hardening speed in order to cause hardening, wherein oxygen-affine elements are contained in the zinc bath for the melt dip coating in a concentration of 0.10 wt.-% to 15 wt.-% that, during the austenitizing on the surface of the cathodic protective layer, form a thin skin comprised of the oxide of the oxygen-affine elements and said oxide layer is blasted after hardening by irradiation of the sheet component with dry ice particles.

The present invention relates to a coated substrate material. The substrate can be a steel alloy and the microstructure in the steel alloy can be altered with a low temperature coating process. The present invention also relates to a method to coat the substrate at the low temperature. The present invention also relates to a coating wherein the melting temperature of the coating is reduced with a dopant compared to the melting temperature without the dopant. The present invention also relates to a method to make the coating with the dopant.

A coated steel sheet includes a chemical composition including in weight %: 0.13%≤C ≤0.22%; 1.2%≤Si≤1.8%; 1.8%≤Mn≤2.2%; 0.10%≤Mo≤0.20%; Nb≤0.05%; Al≤0.5%; Ti≤0.05%; and a remainder being Fe and unavoidable impurities. A structure of the steel sheet consists of, by volume fraction, 3% to 15% of residual austenite and 85% to 97% of martensite and bainite. The structure includes at least 65% of martensite and does not including ferrite. At least one face of the coated steel sheet includes a metallic coating. The steel sheet has a yield strength of at least 800 MPa, a tensile strength of at least 1180 MPa, a total elongation of at least 14% and a hole expansion ratio HER of at least 30%.

A method for producing a high strength coated steel sheet having a yield strength YS of at least 800 MPa, a tensile strength TS of >1180 MPa, a total elongation >14% and a hole expansion ratio HER >30%. The steel contains in weight %: 0.13%≤C≤0.22%, 1.2%≤Si≤1.8%, 1.8%≤Mn≤2.2%, 0.10%≤Mo≤0.20%, Nb≤0.05%, Al≤0.5%, the remainder being Fe and unavoidable impurities. The sheet is annealed at a temperature TA higher than Ac.sub.3 but less than 1000° C. for more than 30 s, then quenched by cooling temperature QT between 325° C. and 375° C., at a cooling speed sufficient to obtain a structure consisting of austenite and at least 60% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85 and 97% of the sum of martensite and bainite, without ferrite, then heated to a partitioning temperature PT between 430° C. and 480° C. and maintained at this temperature for a partitioning time Pt between 10 s and 90 s, then hot dip coated cooled to the room temperature. Coated sheet obtained.

A method for the manufacture of a cold rolled, recovered TWIP steel sheet coated with a metallic coating is provided including the following steps: (A) the feeding of a slab having the following composition: 0.1<C<1.2%, 13.0≤Mn<25.0%, S≤0.030%, P≤0.080%, N≤0.1%, Si≤3.0%, and on a purely optional basis, one or more elements such as Nb≤0.5%, B≤0.005%, Cr≤1.0%, Mo≤0.40%, Ni≤1.0%, Cu≤5.0%, Ti≤0.5%, V≤2.5%, Al≤4.0%, 0.06≤Sn≤0.2%, the remainder of the composition making up of iron and inevitable impurities resulting from elaboration; (B) Reheating such slab and hot rolling it; (C) A coiling step; (D) A first cold-rolling; (E) A recrystallization annealing; (F) A second cold-rolling; and (G) A recovery heat treatment performed by hot-dip coating.

A process for manufacturing a non-stamped prealloyed steel coil, sheet or blank, comprising the following successive steps of: providing a non-stamped precoated steel coil, sheet or blank composed of a steel substrate covered by a precoating of aluminum, or aluminum-based alloy, or aluminum alloy, wherein the precoating thickness is comprised between 10 and 35 micrometers on each side of the steel coil, sheet or blank, then heating the non-stamped steel coil, sheet or blank in a furnace under an atmosphere containing at least 5% oxygen, up to a temperature .sub.1 comprised between 750 and 1000 C., for a duration t.sub.1 comprised between t.sub.1min and t.sub.1max, wherein: t.sub.1min=23500/(.sub.1729.5) and t.sub.1max=4.94610.sup.41.sub.1.sup.13.08, t.sub.1 designating the total duration in the furnace, .sub.1 being expressed in C. and t.sub.1min and t.sub.1max being expressed in seconds, then cooling the non-stamped steel coil, sheet or blank at a cooling rate V.sub.r1 down to a temperature .sub.i, then maintaining the non-stamped steel coil, sheet or blank at a temperature .sub.2 comprised between 100 and 500 C., for a duration t.sub.2 comprised between 3 and 45 minutes, so to obtain a diffusible hydrogen less than 0.35 ppm.

A coated steel substrate including a coating comprising nanographite having a lateral size between 1 and 60 m and a binder, wherein the steel substrate has the following compositions in weight percent: 0.31C1.2%, 0.1Si1.7%, 0.15Mn1.1%, P0.01%, S0.1%, Cr1.0%, Ni1.0%, Mo0.1%, and on a purely optional basis, one or more elements such as Nb0.05%, B0.003%, Ti0.06%, Cu0.1%, Co0.1%, N0.01%, V0.05%, the remainder of the composition being made of iron and inevitable impurities resulting from the elaboration and a method for the manufacture of the coated steel substrate.