Method of manufacturing zirconium alloy tubular products containing (wt. %): niobium—0.9-1.7; iron—0.04-0.10; oxygen—0.03-0.10; silicon—less than 0.02, carbon—less than 0.02, and zirconium—as the base of the alloy. This includes an ingot melting by multiple vacuum arc remelting, mechanical processing of the ingot, heating, hot working of the ingot, subsequent mechanical processing for the production of tubular billets, heat treatment of the tubular billets, application of a protective coating and heating to a hot pressing temperature, hot pressing, removal of the protective coating, multi-stage cold radial forging, vacuum thermal treatment, multiple cold rolling runs with a total deformation degree of 50-80-% per run and a tubular coefficient of Q=1.0-2.7 with intermediate vacuum thermal treatment after each cold rolling operation, and final vacuum thermal treatment of the resulting tubular products carried out at the final size with subsequent final finishing operations.

Manufacturing method for tubular products made of zirconium-based alloy includes melting an ingot by multiple vacuum arc remelting, mechanical processing of the ingot, heating, multi-stage hot forging of the ingot for production of a forged piece, subsequent mechanical processing of the forged piece for production of the a round-profile blank, manufacturing of tubular billets, their quenching and tempering, application of a protective coating, heating to a hot pressing temperature, hot pressing, removal of the protective coating, vacuum thermal treatment, multiple cold rolling steps in order to produce tubular products, with intermediate vacuum thermal treatment after each cold rolling, and a final vacuum thermal treatment being carried out at a final size with subsequent final finishing operations. The tubular products can be used as the structural components of a core in water-cooled nuclear reactors. The method can provide increased processibility, high strength, and corrosion resistance of tubular products.

Manufacturing method for tubular products made of zirconium-based alloy includes melting an ingot by multiple vacuum arc remelting, mechanical processing of the ingot, heating, multi-stage hot forging of the ingot for production of a forged piece, subsequent mechanical processing of the forged piece for production of the a round-profile blank, manufacturing of tubular billets, their quenching and tempering, application of a protective coating, heating to a hot pressing temperature, hot pressing, removal of the protective coating, vacuum thermal treatment, multiple cold rolling steps in order to produce tubular products, with intermediate vacuum thermal treatment after each cold rolling, and a final vacuum thermal treatment being carried out at a final size with subsequent final finishing operations. The tubular products can be used as the structural components of a core in water-cooled nuclear reactors. The method can provide increased processibility, high strength, and corrosion resistance of tubular products.

Manufacturing method for zirconium alloy tubular products containing (% wt.): niobium—0.9-1.7; iron—0.10-0.20; oxygen—0.10-0.20; silicon—less than 0.02, carbon—less than 0.02, zirconium—the alloy base. The method includes melting an ingot by multiple vacuum arc remelting, mechanical processing of the ingot, heating, multi-stage hot forging for production of the forged piece, subsequent mechanical processing of the forged piece for production of tubular billets with vacuum thermal treatment, application of a protective coating, heating to a hot pressing temperature, hot pressing, removal of the protective coating, vacuum thermal treatment, multiple cold rolling steps with a total deformation degree of 58-74% per run and a tubular coefficient of Q=1.18-2.01, with intermediate vacuum thermal treatment in order to produce tubular products, and final vacuum thermal treatment being carried out at the final size with subsequent final finishing operations.

Manufacturing method for zirconium alloy tubular products containing (% wt.): niobium—0.9-1.7; iron—0.10-0.20; oxygen—0.10-0.20; silicon—less than 0.02, carbon—less than 0.02, zirconium—the alloy base. The method includes melting an ingot by multiple vacuum arc remelting, mechanical processing of the ingot, heating, multi-stage hot forging for production of the forged piece, subsequent mechanical processing of the forged piece for production of tubular billets with vacuum thermal treatment, application of a protective coating, heating to a hot pressing temperature, hot pressing, removal of the protective coating, vacuum thermal treatment, multiple cold rolling steps with a total deformation degree of 58-74% per run and a tubular coefficient of Q=1.18-2.01, with intermediate vacuum thermal treatment in order to produce tubular products, and final vacuum thermal treatment being carried out at the final size with subsequent final finishing operations.

A controller (2) and method for controlling a stretch-reducing mill (1) for rolling tubes are presented. The stretch-reducing mill (1) has several roll stands (10) arranged behind one another in a conveying direction (F) of the tubes (R) and at least one outlet-side wall thickness measuring device (20). The controller (2) is set up to receive measurement data from the wall thickness measuring device (20) which identifies one or more outlet-side wall thicknesses (s.sub.r) of a tube (R) exiting from the last roll stand (10) and one or more of the received measurement data wall thickness on the inlet-side (s.sub.l_t), preferably to determine an inlet-side wall thickness profile of the tube (R) before entering the first roll stand (10), and preferably to calculate and control one or more of the roll stands (10), taking into account the determined inlet-side wall thicknesses (s.sub.l_t).

Pilger rolling train, which operates continuously for producing a tube, includes a pilger rolling mill for reducing the diameter of a hollow blank to form the tube, a first buffer for a plurality of tubes, wherein the first buffer has a device for bundling a plurality of tubes in a bundle, an annealing furnace for simultaneous annealing of a plurality of tubes, a second buffer for a plurality of tubes, wherein the second buffer for the tubes has a device for separating the plurality of tubes out of a bundle, and a straightening machine for straightening the separated tubes in succession, wherein the devices are disposed, in the direction of flow of the tube, in the aforementioned sequence, and wherein an automated transport device for the tube is provided between, respectively, the pilger rolling mill, the first buffer, the annealing furnace, the second buffer and the straightening machine.

Pilger rolling train, which operates continuously for producing a tube, includes a pilger rolling mill for reducing the diameter of a hollow blank to form the tube, a first buffer for a plurality of tubes, wherein the first buffer has a device for bundling a plurality of tubes in a bundle, an annealing furnace for simultaneous annealing of a plurality of tubes, a second buffer for a plurality of tubes, wherein the second buffer for the tubes has a device for separating the plurality of tubes out of a bundle, and a straightening machine for straightening the separated tubes in succession, wherein the devices are disposed, in the direction of flow of the tube, in the aforementioned sequence, and wherein an automated transport device for the tube is provided between, respectively, the pilger rolling mill, the first buffer, the annealing furnace, the second buffer and the straightening machine.

A method for producing hot-rolled, seamless pipes having at least one wall thickening which can be arranged at any positions over the length of the pipe, wherein by means of a multiple-stand mandrel bar rolling mill, the rolls roll a hollow shell on a mandrel bar as an inner tool to a required nominal wall thickness and produce at specified positions over the length of the pipe a required wall thickening on the outer side of the pipe by opening the rolls in the rolling stands. The thickened wall is produced and finish-rolled by two rolling stands that are consecutive as seen in the rolling direction, in which the deviations of the finished contour of the thickening from an ideal circular cross-section are minimised, wherein the rolling stands located upstream are likewise opened as to avoid any contact of the rolls of these rolling stands with the previously produced thickening.

A method for producing hot-rolled, seamless pipes having at least one wall thickening which can be arranged at any positions over the length of the pipe, wherein by means of a multiple-stand mandrel bar rolling mill, the rolls roll a hollow shell on a mandrel bar as an inner tool to a required nominal wall thickness and produce at specified positions over the length of the pipe a required wall thickening on the outer side of the pipe by opening the rolls in the rolling stands. The thickened wall is produced and finish-rolled by two rolling stands that are consecutive as seen in the rolling direction, in which the deviations of the finished contour of the thickening from an ideal circular cross-section are minimised, wherein the rolling stands located upstream are likewise opened as to avoid any contact of the rolls of these rolling stands with the previously produced thickening.