A cold-rolled and heat treated steel sheet, has a composition comprising 0.1%C0.4%, 3.5%Mn8.0%, 0.1%Si1.5%, Al3%, Mo0.5%, Cr1%, Nb0.1%, Ti0.1%, V0.2%, B0.004%, 0.002%N0.013%, S0.003%, P0.015%. The structure consists of, in surface fraction: between 8 and 50% of retained austenite, at most 80% of intercritical ferrite, the ferrite grains, if any, having an average size of at most 1.5 m, and at most 1% of cementite, the cementite particles having an average size lower than 50 nm, martensite and/or bainite.

The present disclosure relates to the technical field of rails welding, and particularly to a method for optimizing microstructure of a rail welded joint, the method comprises the following steps: step 1): subjecting a rail web area of a to-be-cooled welded joint which is obtained by flash butt welding to an accelerated cooling by means of an accelerated cooling device and by using compressed air as a cooling medium, measuring and monitoring temperature of a central position of the rail web of the welded joint while cooling; step 2): stopping the accelerated cooling when the temperature of the central position of the rail web drops to a preset temperature, then placing the welded joint in air and naturally cooling to room temperature, wherein the rail is a pearlite rail having a carbon content of 0.6-0.9 wt %.

To improve the formability of dual phase steels, the martensite phase is tempered. It may form a ferrite-carbide structure. The tempering step occurs after martensite has been formed in the dual phase steel. The tempering step can occur in a box annealing step or it can be performed in a continuous fashion, such as on a continuous annealing, continuous tempering heat treating, or continuous coating line. The tempering step can further comprise a temper rolling on a temper mill after the heating step.

A high-strength high-elongation tinned primary plate and a double cold reduction method therefor. The tinned primary plate comprises the following components by weight from 0.065 to 0.12% of carbon, from 0.2 to 0.8% of manganese, from 0.003 to 0.015% of nitrogen, the remainder being iron and the inevitable trace impurities. The tinned primary plate is necessarily subjected to double cold reduction at a reduction of 513% and a rolling tension of 50100 MPa. The tinned primary plate has a yield strength of Rp.sub.0.2520 MPa, and percentage elongations in rolling direction RD, 45 direction and perpendicular direction TD, which are all greater than or equal to 10% after bake-hardening.

A steel wire has a microstructure that is completely ferritic, a mixture of ferrite and cementite or a mixture of ferrite and pearlite and has a weight content of carbon C such that C<0.05% and a weight content of chromium Cr such that Cr<12%. The process for drawing the wire comprises: at least one first uninterrupted series of steps of drawing the wire from a diameter D to a diameter d, at least one second uninterrupted series of steps of drawing the wire of diameter d to a diameter d, and one or more intermediate steps between the first and second uninterrupted series of steps of drawing the wire, the wire having a temperature less than or equal to 300 C. during the or each intermediate step.

An exemplary embodiment of the present invention provides an enamel steel sheet, including: by wt % (% by weight), 0.01 to 0.05% of C, 0.05 to 0.8% of Mn, 0.001 to 0.03% of Si, 0.03 to 0.12% of Al, 0.001 to 0.02% of P, 0.001 to 0.02% of S, 0.004% or less (excluding 0%) of N, 0.001 to 0.003% of B, 0.003% or less (excluding 0%) of O, and the balance of Fe and inevitable impurities. The enamel steel sheet according to an exemplary embodiment of the present invention includes an oxide layer in an inside direction from a surface, and a thickness of the oxide layer is 0.006 to 0.030 m.

A steel sheet for hot press comprises: a predetermined chemical composition; and a steel microstructure that includes ferrite and cementite and in which Mn/Mn is 1.4 or more, where Mn is a Mn concentration of the ferrite and Mn is a Mn concentration of the cementite.

The present invention relates to tool steels which present an extremely high conductivity while maintaining high levels of mechanical properties the manufacturing process thereof. Tool steels of the present invention are able to undergo low temperature hardening treatments with good homogeneity of the microstructure and can be obtained at low cost.

The invention relates to the use of a Q&P steel for production of a formed component (2) for high-wear applications, wherein the Q&P steel has a hardness of at least 230 HB, especially at least 300 HB, preferably at least 370 HB, and a bending angle of at least 60, especially at least 75, preferably at least 85, determined to VDA238-100, and/or a bending ratio of r/t<2.5, especially r/t<2.0, preferably r/t<1.5, where t corresponds to the material thickness of the steel and r to the (inner) bending radius of the steel.

Method for the manufacture of a galvannealed steel sheet includes the following steps: A) the provision of a pre-coated steel sheet coated with a first coating comprising iron and nickel, such steel sheet having the following chemical composition in weight percent 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<2.0%, 0.05<Al<1.0%, 0.75<(Si+Al)<3.0% and on a purely optional basis, one or more elements such as Nb0.5%, B0.005%, Cr1.0%, Mo0.50%, Ni1.0%, Ti0.5%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, B) the thermal treatment of such pre-coated steel sheet at a temperature between 600 to 1000 C., C) the hot-dip coating of the steel sheet obtained in step B) with a second coating based on zinc and D) an alloying treatment to form a galvannealed steel sheet.