A steel sheet has a composition comprising, by weight: 0.010%≤C≤0.080%, 0.06%≤Mn≤3%, Si≤1.5%, 0.005%≤Al≤1.5%, S≤0.030%, P≤0.040%, Ti and B such that: 3.2%≤Ti≤7.5% and (0.45×Ti)−1.35≤B≤(0.45×Ti)−0.43, optionally Ni≤1%, Mo≤1%, Cr≤3%, Nb≤0.1%, V≤0.1%, the remainder being iron and unavoidable impurities resulting from the smelting. The steel sheet has a structure consisting of ferrite, at most 10% of austenite, and precipitates comprising eutectic precipitates of TiB.sub.2, the volume fraction of TiB.sub.2 precipitates with respect to the whole structure being of at least 9%, the proportion of TiB.sub.2 precipitates having a surface area lower than 8 μm.sup.2 being of at least 96%.

Provided is a martensitic stainless steel having excellent productivity and high corrosion resistance, which comprises, as percentages by weight, 0.45 to 0.60% carbon, 0.02 to 0.08% nitrogen, 0.2 to 0.4% silicon, 0.3 to 0.6% manganese, 12 to 15% chromium, one or more kinds of 0.1 to 1.5% molybdenum or 0.1 to 1.5% tungsten and Fe and other unavoidable impurities as remnants.

The invention relates to a steel plate, the chemical composition of which comprises, the contents being expressed by weight: 0.010%≦C≦0.20%, 0.06%≦Mn≦3%, Si≦1.5%, 0.005%≦Al≦1.5%, S≦0.030%, P≦0.040%, 2.5%≦Ti≦7.2%, (0.45×Ti)−0.35%≦B≦(0.45×Ti)+0.70%, and optionally one or more elements chosen from: Ni≦1%, Mo≦1%, Cr≦3%, Nb≦0.1%, V≦0.1%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting.

A low-cost and high-formability 1180 MPa grade cold-rolled annealed dual-phase steel plate and a manufacturing method thereof are provided. The dual-phase steel plate has the following chemical composition by mass percentages: C: 0.1%-0.125%, Si: 0.4%-0.8%, Mn: 2.6%-2.9%, Al: 0.01%-0.05%, Nb: 0.01%-0.03%, and Ti: 0.01%-0.03%, the remainder being Fe and unavoidable impurities. By reasonable design of alloy elements and manufacturing processes, the dual-phase steel plate of the invention achieves a strength of 1180 MPa grade at a low cost, obtains a fine and uniform martensite-ferrite dual-phase structure that ensures excellent elongation rate and cold bending performance, and has good formability. The dual-phase steel plate has a yield strength of more than 850 MPa, a tensile strength of more than 1180 MPa, an elongation rate of 8% or more, and a parameter (R/t), characterizing the 90-degree cold bending performance, of 2.5 or less.

A steel sheet has a composition comprising, by weight: 0.010%≤C≤0.080%, 0.06%≤Mn≤3%, Si≤1.5%, 0.005%≤Al≤1.5%, S≤0.030%, P≤0.040%, Ti and B such that: 3.2%≤Ti≤7.5% and (0.45×Ti)−1.35≤B≤(0.45×Ti)−0.43, optionally Ni≤1%, Mo≤1%, Cr≤3%, Nb≤0.1%, V≤0.1%, the remainder being iron and unavoidable impurities resulting from the smelting. The steel sheet has a structure consisting of ferrite, at most 10% of austenite, and precipitates comprising eutectic precipitates of TiB.sub.2, the volume fraction of TiB.sub.2 precipitates with respect to the whole structure being of at least 9%, the proportion of TiB.sub.2 precipitates having a surface area lower than 8 μm.sup.2 being of at least 96%.

A device and method for producing a continuous strip-shaped composite material including a base material of metal, which is unwound in the form of a metal strip by a first coil-unwinding apparatus, and at least one cladding material of metal, which is unwound in the form of a metal strip by a second coil-unwinding apparatus. The metal base and cladding metal strips unwound by the respective coil-unwinding apparatuses are brought together in the hot state of at least 720 degrees Celsius. The unwound base and cladding metal strips brought toward each other and are joined by hot-rolling such that a single continuous strip-shaped composite material is thereby formed by roll cladding such that the composite material includes the base material and the cladding material.

An on-line solution heat treatment process for austenitic stainless steel plates is disclosed, which comprises continuous casting billet heating, high pressure water dephosphorization, rough rolling, finish rolling, softening process, ultra fast cooling, straightening, cutting to length, shot peening, pickling. The process of the present invention makes full use of the residual rolling temperature, without the need of reheating steel plates from the room temperature to the solid solution temperature. Compared with the conventional steel plate rolling process, the process needs to perform the softening process on the steel plates after rolling to ensure that the deformed austenite is fully softened before cooling. After the softening process, ultra fast cooling is performed to cool the steel plates from above 800° C. to below 430° C. so as to prevent intergranular chromium depletion caused by a large amount of precipitation of high chromium carbides from affecting the stain resistance of stainless steel.

Disclosed herein is a light-gauge, ultra-high strength weathering steel sheet with a composition, material properties, and surface characteristics that make it suitable for hot-stamping applications and making hot-stamped products. Also disclosed herein is a high friction rolled carbon alloy steel strip free of prior austenite grain boundary depressions and having a smear pattern. Still further disclosed herein is a high friction rolled carbon alloy steel strip that has been surface homogenized to provide a thin cast steel strip free of a smear pattern.

A steel sheet has a composition comprising, by weight: 0.010%≤C≤0.080%, 0.06%≤Mn≤3%, Si≤1.5%, 0.005%≤Al≤1.5%, S≤0.030%, P≤0.040%, Ti and B such that: 3.2%≤Ti≤7.5% and (0.45×Ti) −1.35≤B≤(0.45×Ti) −0.43, optionally Ni≤1%, Mo≤1%, Cr≤3%, Nb≤0.1%, V≤0.1%, the remainder being iron and unavoidable impurities resulting from the smelting. The steel sheet has a structure consisting of ferrite, at most 10% of austenite, and precipitates comprising eutectic precipitates of TiB.sub.2, the volume fraction of TiB.sub.2 precipitates with respect to the whole structure being of at least 9%, the proportion of TiB.sub.2 precipitates having a surface area lower than 8 μm.sup.2 being of at least 96%.

A method and a device for producing a continuous strip-shaped composite material. The device has at least one first casting machine, using which a continuous strand is produced, in particular from steel, at least one rolling stand, which is arranged in line with the first casting machine and downstream thereof. A fully solidified slab of the strand produced using the first casting machine can be hot rolled, and at least one second casting machine, using which a further continuous strand is produced from metal. Between the casting machines, on the one hand, and the rolling stand, on the other hand, a merging unit is arranged, by means of which the slabs can be moved in the direction toward each other in the hot state. The rolling stand is designed as a roll-cladding unit, by which a composite formed from the merged slabs can be hot rolled.