A steel strip notching method including forming a notch at an end portion of a joint in a strip width direction formed by joining a trailing end of a preceding steel strip to a leading end of a succeeding steel strip, and removing a region of the notch through grinding by cutting the region with a rotary grinding tool by feeding the tool in the strip width direction, feeding the tool in a strip vertical direction at a feed rate within a predetermined range with respect to a feed rate of the tool in the strip width direction, giving a predetermined feed amount in a strip longitudinal direction while feeding the tool by a predetermined feed amount in the strip width direction simultaneously with feeding the tool in the strip vertical direction, and cutting the region while oscillating the tool in the strip longitudinal direction.

A martensitic steel including the following elements, expressed in percentage by weight 0.1%≤C≤0.4%; 0.2%≤Mn≤2%; 0.4%≤Si≤2%; 0.2%≤Cr≤1%; 0.01%≤Al≤1%; 0%≤S≤0.09%; 0%≤P≤0.09%; 0%≤N≤0.09%; and can contain one or more of the following optional elements 0%≤Ni≤1%; 0%≤Cu≤1%; 0%≤Mo≤0.1%; 0%≤Nb≤0.1%; 0%≤Ti≤0.1%; 0%≤V≤0.1%; 0.0015%≤B≤0.005%; 0%≤Sn≤0.1%; 0%≤Pb≤0.1%; 0%≤Sb≤0.1%; 0%≤Ca≤0.1%; 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%.

Tubular structures, systems, and methods are generally directed to support structures having structural properties similar to thick-walled structures while being formed using materials having thickness amendable to rolling and welding and, thus, useful for rapid and cost-effective fabrication.

A combined casting and rolling installation that produces hot-rolled strip with a final thickness<1.2 mm, and includes a first continuous casting installation and a second continuous casting installation, each producing slabs from liquid steel; a slab manipulator that conveys the slabs into a walking beam furnace that conveys the slabs into a rolling installation and heats the slabs to rolling temperature. The rolling installation includes a rough rolling mill forming rough-rolled strips from the heated slabs; a coil box forming a coil from the rough-rolled strip and unwinding the rough-rolled strip; a joining device forming an endless rough-rolled strip by connecting its ends without filler material; a multi-stand finishing rolling mill finish-rolling the endless rough-rolled strip to form a finished strip with the final thickness; a cooling section forming the hot-rolled strip; and a plurality of coiling devices coiling the hot-rolled strip.

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 workpiece made of plate is subjected to a treatment which locally modifies its magnetic permeability. Subsequently, the magnetic permeability of the workpiece is examined locally resolved by a probe in order to find at least one surface region which is suitable for intended processing, and the processing is performed locally limited to the selected region.

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 workpiece made of plate is subjected to a treatment which locally modifies its magnetic permeability. Subsequently, the magnetic permeability of the workpiece is examined locally resolved by a probe in order to find at least one surface region which is suitable for intended processing, and the processing is performed locally limited to the selected region.

According to one aspect, a tubular structure may include a base and a wrap. The base may have a first surface and second surface opposite one another, the first surface defining an elongate cavity, and the base having a tubular shape defining a longitudinal axis extending along the elongate cavity. The wrap may be supported on the second surface of the base, the wrap including a plurality of layers, and each layer having a first longitudinal edge and a second longitudinal edge coupled to one another along a respective spiral seam associated with the given layer and extending about the longitudinal axis of the base.

A welding machine, preferably of the flash welding type, designed to facilitate maintenance of the clamping means, e.g. clamps, of the two longitudinal metal products to be welded. Advantageously, a first structure provided with first clamping means and a second structure provided with second clamping means are supported in a first part of the carriage delimited by a first beam and a second beam of the carriage that are parallel to the feeding direction X, while the at least one transformer is fixed to the carriage and supported in a second part of the carriage arranged laterally outside the first part. Moreover, the two upsetting cylinders are arranged along a plane Y inclined by an acute angle different from zero relative to a horizontal plane and passing through a passage zone of the longitudinal metal products along a feeding direction X.