A steel sheet having a tensile strength (TS) of 1180 MPa or more, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 ?m in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 ?m, the lowest Si concentration L.sub.Si and the lowest Mn concentration L.sub.Mn in the region within 4.9 ?m in the thickness direction from the surface of the steel sheet and a Si concentration T.sub.Si and a Mn concentration T.sub.Mn at a quarter thickness position of the steel sheet satisfy a specified formula.

This cold-rolled steel sheet has a predetermined chemical composition, in which a metallographic structure of a t/4 portion, which is at a ? position of a sheet thickness t from a surface of the cold-rolled steel sheet in a sheet thickness direction has a predetermined structure, and in both an edge portion, which is at a position 50 mm away from an end portion of the cold-rolled steel sheet in a width direction, and a center portion of the cold-rolled steel sheet in the width direction, a metallographic structure of a 20 ?m portion, which is at a position 20 ?m away from the surface in the sheet thickness direction, includes, by volume percentage, ferrite and bainite: 75.0% or more and 100.0% or less in total, and martensite and tempered martensite: 0.0% or more and 25.0% or less in total, an average grain size of the martensite and the tempered martensite in the metallographic structure of the 20 ?m portion is 5.0 ?m or less, and a metallographic structure of a 75 ?m portion, which is at a position 75 ?m away from the surface in the sheet thickness direction, includes, by volume percentage, ferrite and bainite: 0.0% or more and 15.0% or less in total.

A high strength cold rolled steel strip or sheet has a steel composition comprising (in wt. %) 0.15-0.25 C, 0.3-0.5 Si, 2.0-3.0 Mn, 0.5-1.0 Al, 0.005-0.5 Cr, a thermal stability ?>0, where ?=68?500?C+4?Mn+60?Al?22?Si, the content of C, Mn, Si, Al in weight %, and a mechanical stability (k.sub.p) 5-35, mechanical properties fulfilling the following condition: tensile strength (R.sub.m)?980 MPa, and optionally at least one of the following conditions: yield strength (R.sub.p0.2)?400 MPa, yield ratio (R.sub.p0.2/R.sub.m)?0.65, Total Elongation (A.sub.25)?10%; and a microstructure comprising: Retained austenite (RA)?8%. A method manufacturing the steel strip or sheet and an automotive structural part comprising the steel sheet also are provided.

A method for depositing metallic coatings on a substrate including an annealing step, in an annealing furnace, forming on said substrate, a ferritic surface layer having a thickness from 10 m to 50 m and a microstructure comprising in surface fraction up to 10% of cumulated amount of martensite, bainite and the balance being made of ferrite, a skin pass step, a coating step, inside a vacuum chamber, wherein a metallic vapour is ejected towards at least a side of said substrate to form a surface layer of at least one metal.

A stainless steel sheet has a surface quality in which a core height Sk is 1.50 m or less, a reduced peak height Spk is 0.20 m or less, and an areal material ratio Smr2 that separates a reduced dale from a core is 80% or less, where the core height Sk, the reduced peak height Spk, and the areal material ratio Smr2 are as specified in JIS B 0681-2:2018. The stainless steel sheet has a whiteness of 50 or greater and an image clarity of 1% or greater.

A steel sheet contains, in mass %, C: 0.15 to 0.45%, Si: 1.5% or less, Mn: 1.7% or less, P: 0.03% or less, S: less than 0.0020%, sol. Al: 0.20% or less, N: 0.005% or less, B: 0.0015 to 0.0100%, and at least one of Nb and Ti in a total amount of 0.005 to 0.080%, with the balance being Fe and incidental impurities. The area fraction of martensite with respect to the total area of the microstructure is 95 to 100%, and the diameter of prior grains is less than 11.0 m. The number density A of precipitates having an equivalent circular diameter of 500 nm or more satisfies the formula: A (particles/mm.sup.2)8.510.sup.5[B].

A high strength steel sheet includes a specific microstructure having a specific chemical composition and satisfying the formulas (1) and (2) defined below:

[00001]$\begin{array}{cc}\mathrm{KAM}\left(S\right)/\mathrm{KAM}\left(C\right)<1.& \left(1\right)\end{array}$ wherein KAM(S) is a KAM (Kernel average misorientation) value of a superficial portion of the steel sheet, and KAM(C) is a KAM value of a central portion of the steel sheet,

[00002]$\begin{array}{cc}\mathrm{Hv}\left(Q\right)-\mathrm{Hv}\left(S\right)8& \left(2\right)\end{array}$ wherein Hv(Q) indicates the hardness of a portion at sheet thickness and Hv(S) indicates the hardness of a superficial portion of the steel sheet.

Provided is a high strength steel sheet with high stretch flangeability and high YR in the rolling direction as well as in the direction orthogonal to the rolling direction with TS of 1180 MPa or more. The high strength steel sheet has a prescribed chemical composition and steel microstructure. In particular, an average grain size of the hard phase is 5.3 m or less, the volume fraction-carbon concentration ratio of retained austenite () is 0.10 or more and 0.45 or less, and the integration degree of {112} <111> orientation is 1.0 or more.

A hot rolled steel sheet having a composition including the following elements 0.38%Carbon0.5%, 1%Manganese2%, 0.1%Silicon0.7%, 0 01%Aluminum0.1%, 0.3%Chromium1%, 0.002%Boron0.05%, 0.002%Phosphorus0.02%, 0%Sulfur0.005%, 0%Nitrogen0.01%, 0%Molybdenum0.5%, 0%Vanadium0.5%, 0%Niobium0.05%, 0.001%Titanium0.1%, 0%Nickel1%, 0%Copper1%, 0%Tin0.1%, 0%Lead0.1%, 0%Antimony0.1%, 0.0001%Calcium0.01%, 0%Magnesium0.0010%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet including in area fraction, at least 94% Martensite, 0% to 5% Residual Austenite and carbides of Chromium, Niobium, Vanadium and Iron from 0% to 5%.

A hot-rolled steel sheet which has excellent rigidity along with high strength, excellent workability, and excellent LME resistance is provided. A hot-rolled steel sheet of the present embodiment consists of, in mass %, C: 0.040 to 0.120%, Si: 0.01 to 0.60%, Mn: 0.50 to 1.50%, P: 0.025% or less, S: 0.010% or less, Al: 0.010 to 0.070%, N: 0.0070% or less, Ti: 0.055 to 0.200%, and B: 0.0010 to 0.0050%, with the balance being Fe and impurities. In the microstructure of the hot-rolled steel sheet, an area fraction of bainitic ferrite is 85% or more and the dislocation density is 8.010.sup.13 to 100.010.sup.13/m.sup.2. The average equivalent circular diameter of Ti carbides in the hot-rolled steel sheet is 10 nm or less, and the average equivalent circular diameter of grains of the bainitic ferrite is 15 m or less.