A welding machine, preferably of the flash butt 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 parallel to the feeding direction, while at least one transformer is fixed to the carriage and supported in a second part of the carriage, arranged laterally outside the first part.

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 cold-rolled steel strip manufacturing facility includes: a joining device configured to join a trailing end of a preceding steel strip and a leading end of a following steel strip to form a joined steel strip; a looper configured to store the joined steel strip; a heating device configured to heat a joint portion between the preceding steel strip and the following steel strip over an entire width direction; and a cold rolling mill configured to cold-roll the joined steel strip for which the joint portion was heated by the heating device, wherein the heating device is switchable between an output state and a non-output state, and during a period in which the joint portion passes through the heating device, is switched to the output state.

A processing method of NPR steel rebar rod is disclosed. The NPR steel rebar is cold processed and has a yield strength of 800˜950 MPa, a tensile strength of 900˜1100 MPa, and a percentage elongation at maximum force of not less than 10˜40%. The processing method comprises the following steps: a I-shaped placing step L20, an uncoiling step L30, a flattening step L40, a butt welding step L50, a sandblasting step L60, a straightening step L70, a pointing step L80, a hydraulic head-pushing step L90, a cold drawn spiral ribbing step L10, a straight forward continuous wire drawing and traction step L11, a pre-straightening step L12, a fine straightening step L13, and a cutting-off step L14. The processing method can meet the automatic intelligent production requirements of NPR steel rebar, cold rolled spiral NPR steel rebar, and pre-stressed NPR steel rebar.

A processing method of NPR steel rebar rod is disclosed. The NPR steel rebar is cold processed and has a yield strength of 800˜950 MPa, a tensile strength of 900˜1100 MPa, and a percentage elongation at maximum force of not less than 10˜40%. The processing method comprises the following steps: a I-shaped placing step L20, an uncoiling step L30, a flattening step L40, a butt welding step L50, a sandblasting step L60, a straightening step L70, a pointing step L80, a hydraulic head-pushing step L90, a cold drawn spiral ribbing step L10, a straight forward continuous wire drawing and traction step L11, a pre-straightening step L12, a fine straightening step L13, and a cutting-off step L14. The processing method can meet the automatic intelligent production requirements of NPR steel rebar, cold rolled spiral NPR steel rebar, and pre-stressed NPR steel rebar.

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%.

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 ε.sub.MB, for which the deformation ratio created by the cold rolling in the welded joint is equal to ε.sub.S, where:

[00001]$0.4\le \frac{\mathrm{.Math.S}}{\mathrm{.Math.}MB}<0.7.$

A processing plant for metal strips (1) has a welding machine, a strip store downstream of the welding machine and a processing device downstream of the strip store. The metal strips are welded to form a continuous strip with the welding machine, which is stored in the strip store and output from there to the processing device. The metal strips are connected via diagonally extending weld seams. To join the weld seams, first the strip head (2) and the strip foot (3) of the metal strips are twisted and the two strips are connected by forming the weld seam. The weld seam extends only transversely to the transport direction (x) during the welding process. Finally, the strip head and the strip foot of the metal strips are twisted back again. As a result, the weld seam now extends diagonally to the transport direction (x).

The present invention relates to an intermediate blank connection system for hot-rolled strip headless rolling and a connection method, and belongs to the technical field of intermediate blank connection for strip steel headless rolling. The connection system and the connection method realize matching of an intermediate blank connection device and speed of a unit through a translation drive system. A mounting frame is used to provide support for cutting devices, and the cutting devices are divided into two groups arranged in the mounting frame to achieve clamping of a front slab and a rear slab respectively. Interlaced dovetail cutting edge structures are used to achieve cutting and ensure a good longitudinal stress state. Finally, a certain difference is set in sizes of width directions between cutting edges, to ensure that there is certain extrusion deformation in a process of forming dovetail cutting groove connection, and enhance a connection effect. At the same time of realizing a good intermediate blank connection effect finally, a structure of the connection device is greatly simplified, and investment and operating cost is reduced.

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 ${\mathrm{.Math.}}_1=\mathrm{Ln}\left(\frac{e_i}{e_{\mathrm{int}}}\right)$
such that: $0.35\le \frac{\mathrm{Ln}\left(\frac{\mathrm{ei}}{e\mathrm{int}}\right)}{\mathrm{Ln}\left(\frac{ei}{ef}\right)}\le 0.65,$
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 dire