Notching equipment for a steel strip, a method of notching a steel strip, a cold rolling equipment, and a method of cold rolling that make it possible to perform cold rolling on a material without weld breaks, even if the material is a brittle material or a high alloy material such as a silicon steel sheet or a high-tensile steel sheet with high Si and Mn contents. The notching equipment includes a shearing device and a grinding device. The shearing device performs shearing on both edge portions in the steel-strip width direction including the joint to form a first notch. The grinding device grinds end surfaces of both the edge portions of the joint in the steel-strip width direction to form a second notch.

A welding machine for welding together the tail of a billet to the head of a second billet along a feeding direction, the machine comprising a carriage adapted to slide along the feeding direction, said carriage supporting a first structure integrally fixed to said carriage; first clamping means, provided on said first structure, for clamping the head of the second billet; a second structure connected to the first structure and sliding, parallel to the feeding direction, with respect to both the first structure and the carriage; second clamping means, provided on said second structure, for clamping the tail of the first billet; wherein first adjustment means are provided for adjusting the position of the second structure with respect to the first structure along said feeding direction; and second adjustment means are provided for adjusting the position of the second structure with respect to the first structure on a plane transversal to the feeding direction, so as to align the second clamping means with the first clamping means along said feeding direction.

A method for joining hot slabs, which can be fed in succession to at least one roll stand. Joining sides of the hot slabs facing each other are, by pendular friction welding and/or vibration friction welding, simultaneously integrally bonded to a single metal intermediate piece arranged between the joining sides, by oscillatingly moving the intermediate piece at least largely parallel to the joining sides, while the joining sides are pressed against the intermediate piece and are held stationary; or simultaneously integrally bonded to at least one separate metal intermediate piece each, the intermediate pieces being arranged between the joining sides, by pressing the intermediate pieces arranged in series between the joining sides and oscillatingly moving the intermediate pieces at least largely parallel to the joining sides and oppositely to each other, while the joining sides are pressed against the intermediate pieces and held stationary.

A method for the manufacture of a cold-rolled steel sheet of thickness e.sub.f between 0.5 mm and 3 mm is provided. At least two hot-rolled sheets of thickness e.sub.i are supplied and butt welded, so as to create a welded joint (S1) with a direction perpendicular to the direction of hot rolling. The at least two hot-rolled sheets are pickled by continuous passage through a bath, then the assembly is cold rolled, in a step (L1), to an intermediate thickness e.sub.int, the direction of cold rolling (DL.sub.1) coinciding with the direction of hot rolling. The cold rolling is carried out with a reduction ratio

[00001]${\mathrm{.Math.}}_1=\mathrm{Ln}\left(\frac{e_i}{e_{\mathrm{int}}}\right)$

such that:

[00002]$0.3.Math.5\frac{\mathrm{Ln}.Math..Math.\left(\frac{\mathrm{ei}}{e.Math..Math.\mathrm{int}}\right)}{\mathrm{Ln}.Math..Math.\left(\frac{e.Math.i}{e.Math.f}\right)}0.6.Math.5,$

then the welded joint (S1) is removed so as to obtain at least two intermediate cold-rolled sheets. Then the two intermediate cold-rolled sheets are butt welded, so as to create a welded joint (S2), the direction of which is perpendicular to the direction of hot rolling, then the assembly of the at least two intermediate cold-rolled and welded sheets is cold-rolled, in a step (L2), to the final thickness e.sub.f, the direction (DL.sub.2) of the cold rolling step (L2) coinciding with the direction of rolling (DL.sub.1).

Notching equipment for a steel strip, a method of notching a steel strip, a cold rolling equipment, and a method of cold rolling that make it possible to perform cold rolling on a material without weld breaks, even if the material is a brittle material or a high alloy material such as a silicon steel sheet or a high-tensile steel sheet with high Si and Mn contents. The notching equipment includes a shearing device and a grinding device. The shearing device performs shearing on both edge portions in the steel-strip width direction including the joint to form a first notch. The grinding device grinds end surfaces of both the edge portions of the joint in the steel-strip width direction to form a second notch.

A rolling plant for rolling billets or blooms, the plant defining a longitudinal feeding axis X of said billets or blooms and comprising a feeding area for feeding said billets or blooms; a rolling train; a longitudinal roller table to transport the billets or blooms from said feeding area to said rolling train along said longitudinal feeding axis X; a welding machine adapted to move forwards and backwards along said longitudinal roller table to weld billets or blooms to one another when moving from said feeding area to said rolling train;
characterized in that said welding machine is slidingly suspended from a bridge and is adapted to translate parallel to said longitudinal feeding axis X, and said bridge is arranged at the longitudinal roller table and is adapted to translate transversely to said longitudinal feeding axis X, whereby in a first operating position of the bridge the welding machine occupies part of the longitudinal roller table and can move forwards and backwards along said longitudinal feeding axis X, whereas in a second operating position of the bridge the welding machine makes said longitudinal roller table clear.

A steel sheet that is welded and then cold rolled to a thickness between 0.5 mm and 3 mm, the deformation ratio created by cold rolling in the base metal is equal to ?.sub.MB, for which the deformation ratio created by the cold rolling in the welded joint is equal to ?.sub.S, where: $0.4?\frac{\mathrm{.Math.S}}{\mathrm{.Math.}MB}<0.7.$

A six-high rolling (also known as sexto) mill stand that is suited for hot rolling an intermediate strip into a thin strip that is less than 0.8 mm thick. A combined casting and rolling installation that includes the six-high rolling mill stand allowing for hot rolling in long uninterrupted sequences, without any change of the work rolls to obtain a strip with good geometry due to moderate rolling forces.

A martensitic steel including the following elements, expressed in percentage by weight 0.1%C0.4%; 0.2%Mn2%; 0.4%Si2%; 0.2%Cr1%; 0.01%Al1%; 0%S0.09%; 0%P0.09%; 0%N0.09%; and can contain one or more of the following optional elements 0%Ni1%; 0%Cu1%; 0%Mo0.1%; 0%Nb0.1%; 0%Ti0.1%; 0%V0.1%; 0.0015%B0.005%; 0%Sn0.1%; 0%Pb0.1%; 0%Sb0.1%; 0%Ca0.1%; the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel having microstructure by area percentage including cumulative presence of residual austenite and bainite between 0% and 25%, the remaining microstructure being martensite at least 70%, and with an optional presence of ferrite between 0% and 10%.

A plant and a process for uncoiling wire rod from wire-rod coils produced in rolling mills. In particular, an apparatus provided with a control system that makes it possible to considerably reduce, if not completely eliminate, the risk of accidents for the operators, thus achieving a degree of safety that meets the most demanding standards. The plant includes the differential activation of devices that break down a safe area in order to guarantee a completely safe process of continuous uncoiling and manual operation.