RO121896B1 - Method and rolling stand for producing wire, bar stock or seamless pipes - Google Patents

Abstract

The invention relates to a method and a rolling stand for producing wire, bar stock and seamless pipes. According to the invention, the method compulsory comprises a main roughing stage carried out by means of a three-roller reversing rolling mill in at least one rolling stand, used both for rolling pipes and for producing wires or bars, by bringing the mandrel bar used for pipes out of the operative position, the resulting product being finished with a finishing mill. The claimed rolling stand for carrying out the method comprises a three-roller reversing rolling mill (5) which, for the roughing stage, is provided with multiple stands for rolling steel bars and pipes, and a device (7) for removing the mandrel bar used for pipes, when the rolling stand is used for bars or wires.

Description

The invention relates to a method and a rolling plant for the manufacture of seamless wire, rod or pipe on a rolling plant of the molten material, optionally comprising in the direction of lamination a pipe rolling mill, an elongating rolling mill with several boxes, as the main grinding stage, a rolling mill, a finishing mill and a wire rolling block, as well as devices connected before, after or between them, roller conveyors, separation devices and a cooling bed.

In order to allow a better loading of the lamination system and for the manufacture of pipes no more lamination installation is needed than for the manufacture of wire, rods or other such laminates, it has been made known, by DE 19935647 A1 , lamination of wire, bars or other similar products, as well as lamination of seamless pipes on the same lamination plant in two lamination lines, in which part of the aggregates of the installation is used both for lamination of pipes (seamless pipes) and for lamination massive (wire, bars and more). Although by this the total number of aggregates required can be reduced, because for example the furnaces, the separating devices, the cooling bed and portions of the roller conveyor can be used generally, however, after the furnace which heats the rolling material to the rolling temperature. and after a transverse transport device, placed after the furnace, a line of lamination for wire or rods and one for pipes, that is to say, two separate lines of lamination, placed in parallel, are required. They come together in a single rolling line only much later, in the material flow, respectively in the rolling direction. The invention therefore aims to achieve a method of lamination and a laminating installation of the type previously specified, which will allow an optimized working regime, with an even lower consumption of installations.

This is achieved according to the invention, by a method by which in the main step, for grinding, a reversible three-cylinder rolling mill is used, used for both pipe rolling and mass rolling, for the manufacture of bars, wire, etc., where in massive rolling, the rolling pin used for rolling the pipes is brought into a non-functional position, and the cylinders prepared for bar-type steel, which are the cylinders calibrated for a strong reduction in diameter, replace the calibrated cylinders for the rolling of pipes. By reversible laminator, sometimes referred to as reversible pipe laminator, the specialist understands a laminator equipped with several successive laminate boxes with an internal rolling pin, as known for example from DE-Z “Monthly books of the miner and metallurgist” 130 ( 1985), booklet 7, pages 204 pp. 211.

While in the known mills, the massive rolling line is separated from the pipe rolling line, according to the invention, a single line can be used for both purposes, which means that not only the investment costs are much lower, but also production and maintenance expenses. At the basis of this use is the consistent application to the maximum of the three-cylinder technology, because it has been seen that a universal lamination is possible, despite the requirements that contradict each other - to the lamination of pipes, to avoid the disadvantages due to the process, the external diameter usually it is slightly modified, and the required stretching is achieved through the central groove, while a large reduction in diameter must be ensured in order to obtain the desired grinding. This is because compared to the pipe rollers with ordinary oblique cylinders, having two boxes, in the core area of the material there are no firing stresses, but compression stresses, which significantly limits the danger of internal defects. The behavior at tensions in the laminate, in the case of rolling in two or three oblique cylinders, is described in detail in the Manufacture of pipes, Stahleisen Publishing House 1975, pages 28 to 31.

RO 121896 Β1

When switching from one type of lamination to another, different cylinders are provided according to the invention, 1 for pipe lamination and mass lamination, where, according to the different calibration, adapted, the section is different, but the outer form remains the same, so that can make a simple replacement. The concrete number of groups of three cylinders, respectively cages, in the main degreasing stage, is guided by the desired degree of degreasing, where the reductions of the lamination step, respectively the distribution of the reduction to the steel bars, differ from the case of the lamination of the pipes. The measures to be taken here according to the load, respectively the hollow block inside and 7 respective material characteristics, are known.

A convenient embodiment of the method according to the invention provides that for the pipe mill 9 located prior to the main grinding step, a roller with oblique cylinders, consisting of three cylinders, of which grooved cylinders for massive rolling, with the rod of 11 is used. rolled out, to replace the steel rod cylinders, prepared with calibrated cylinders for a reduction in diameter. The roller with three cylinders with 13 cylindrical rollers, according to the invention, then allows, with the extracted rolling pin, - (in the case of massive rolling), the manufacture of different diameters of steel rods, in the sense of a pre-reduction, that is to say 15 a section reduction relative to the total reduction of all the mills involved, proportionally. 17

A rolling plant for carrying out the method has a reversible rolling mill with three cylinders and several boxes, made for taking over the rolling operations of the bars or pipes, and a device for removing the rolling pin according to the invention. The reversible laminator, respectively, in the main degreasing stage, takes 21 in the frame either one or the other of boxes, respectively-sets of cylinders consisting of three cylinders.

For the replacement, suitable boxes can be prepared near the reversible laminator, which then, after removing the previous boxes from the frame, are brought into working position. As an alternative, there is a cassette type construction variant or it is also possible to replace only the 25 cylinder, with the box housing remaining in the frame. The rolling pin can be moved to a non-functional position when retrofitting the three-cylinder reversible roller, for the purpose of 27 mass rolling, in the simplest way, by means of the rolling pin fastener. This is also true for the rolling pin rod 29 of the oblique cylindrical roller, which is optionally placed before the main grubbing step, for the case of pipe rolling, and which according to a variant of the invention, is realized by also as a three-cylinder, oblique roller, universally usable.

A preferred embodiment of the invention provides that a speed regulator is available for the reversible rolling mill in the main grinding step. Thus, the rolling speeds that are different for the pipe and rod rolling can be conveniently achieved. If the 35-roll mill after the main grinding stage conveniently has two boxes of units at a distance from each other and between them a movable shears end, then the defective ends 37 from the rolling of the massive blocks can be cut into one. very simply, before rolling on. In order to laminate the pipes, this scissors can be dropped. After 39 the firing mill is a subsequent heating furnace. From there, the heat-treated steel bar or the alloy or non-alloy steel pipes reach the finishing mill. It may be a plate mill 41, a reducing mill or a reducing elongating mill or a combination of these aggregates. 43

If the bar steel is to be rolled as a wire, after the cooling bed a roller conveyor is connected according to the invention, which carries out the transport to the wire block. 45

The method and the rolling plant for the manufacture of wires, bars or pipes according to the invention has the advantage that it allows the use of a single lamination line for both 47 wires and bars, as well as for pipes.

RO 121896 Β1

The invention is presented in detail below, in relation to the figure, which shows the schematic diagram of the rolling plant according to the invention, in the above view.

The universal lamination system, represented in the diagram of the installation, works in a line, - that is, unlike the drawing representation, the installation part represented in the lower half of the figure is connected linearly to the installation parts of the upper half of the drawing, which is marked by the dashed line, - a material with which it is fed (the load), to obtain a product either in the form of seamless pipes, or in the form of wire, or other similar laminates obtained by massive rolling.

The figure shows a furnace 1 with a loading device 2 for the rolling material, respectively the blocks, which consist for example of extrusion molded material. In the oven, the blocks are heated to the rolling temperature. In the embodiment shown, a heated block is transported from there to a roller with oblique cylinders for pipes 3, made as a roller with 3 oblique cylinders, where the block is inserted through a penetration channel and is brought to the form of a hollow block on from the inside, by applying on a rod provided with a rolling pin, to be prepared for the following lamination, for making the seamless pipe. Such a roller with oblique cylinders 3, in the constructive version with 3 cylinders, is known from the manufacture of pipes.

If it is not intended to laminate pipes, but bars or wire, in the roller with oblique cylinders, made with 3 cylinders, a massive reduction of the block and a compression of the structure takes place, when the rolling pin is retained, respectively removed in off the lamination line.

From the roller with oblique cylinders 3, made with 3 cylinders, the loading of the empty blocks inside or of the massive blocks takes place in the following lamination installations. They comprise a main gearing step 4, which is made here with a reversible rolling mill 5 and which here has 6 boxes and 3 cylinders. But other variants are possible, such as the number of boxes. Then a firing mill 6 follows, which here presents two box units 6a and 6b. Both the reversible roller 5 with 3 cylinders and several boxes and the draw roller 6, as well as between the two drawer units 6a and 6b of the draw roller 6, shears for the moving ends 8, 9 are provided.

In the manufacture of pipes, in the reversible laminator 5 with 3 cylinders and 6 boxes, the elongation of an empty block is made inside and after the extraction of the rolling pin, the action taken by the fixing device of the rolling pin, is then reduced as blum in the two units. of drawers 6a, 6b of the rolling mill 6, while when rolling the massive blocks, already the reversible rolling mill 5 with 3 cylinders and 6 boxes reduces the steel bar by reducing the diameter, as well as the rolling mill 6. before the reduced blum or the steel bar reduced to be final laminated in a plate mill, respectively - a reduction and grinding mill 10 and brought to the form of a pipe, respectively - of a bar, the laminated material is brought to the required temperature in a subsequent heating oven 11.

A saw interspersed on the output side of the laminator with plate, respectively - of the rolling and reduction laminator 10, sub-divided the pipe, respectively - the steel bar, in the desired lengths. The pieces cut to the final lengths are then transferred to the cooling bed 13. If, on the contrary, the steel bar is to be rolled in wire form, it is transported to a wire rolling block 15, by means of an extension of the roller conveyor of the cooling bed. 14.

The universal rolling installation described thus allows, through a single line, the seamless pipe rolling, as well as bars or wire. For mass rolling in the reversible 3-cylinder and 6-box rolling mill, the calibrated cylinders for rolling the pipes are replaced with calibrated cylinders for rolling the massive blocks, and the rolling dome is removed from the working position, for example - by moving to the original retracted position of the device. for fixing the rolling pin.

Claims (7)

8. Lamination plant according to one of claims 3 to 7, characterized in that it has a plate mill and / or a reduction and degreasing mill, 1. Method of manufacturing the seamless wire, bar or pipe on a 3-laminate installation of a heated metallic blank, optionally comprising a pre-grinding phase with a pipe-mill and, necessarily, a main grinding phase with a laminator 5 elongator with several boxes and at least one box with three cylinders and a finishing phase with a finisher, the laminating plant also comprising a laminating block of wire 7 and auxiliary devices, coupled before and after the lamination devices or interleaved between they such as: preheating oven, heating oven, roller conveyors and a 9-cooling bed, characterized in that, in the main phase of degreasing, a reversible three-cylinder rolling mill is used in both cages for rolling pipes, as well as for 11 mass lamination for the manufacture of bars, wire or other similar products, by removing the needle milling used for the rolling of pipes from the working position and the provision of 13 calibrated cylinders for a reduction in diameter larger than that from the rolling of pipes, to the rolling mills for rolling steel bars, instead of the calibrated cylinders for rolling 15 pipes. A method according to claim 1, characterized in that, for a 17-pipe mill connected before the main degreasing phase, a reversible three-cylinder mill (3) is used, the groove cylinders of which for mass lamination replace, under the conditions. 19 cutting rod with rolling pin, ready-made steel bar roller, with calibrated cylinders for ordinary diameter reduction for bar-type steel rolling. 21 3 placed after the subsequent heating furnace (11), as a finisher (10) for wire and steel bars. 3. Laminating plant for laminating heated metallic material in the form of wire, rods or seamless pipes, optionally comprising in the direction of lamination a 23 pipe mill, an elongating laminator with several boxes as the main degreasing step, a drawing roller, a finishing roller and a wire rolling block, as well as installations connected before, between and after them, such as a preheating oven and a subsequent heating oven, roller conveyors and a cooling bed, characterized in that, 27 for the main gutting phase, there is provided a reversible rolling mill (5) with three cylinders and several boxes, for the rolling of steel bars and pipes, and a device for removing the rolling pin (7). ). 4 Laminating plant according to claim 3, characterized in that the pipe cloud 31 coupled prior to the main degreasing phase is provided to operate as a roller with oblique cylinders, having two or three cylinders, and is intended for rolling the steel bars 33 or pipes and has a device for removing the rolling pin stem. 9. Lamination plant according to one of claims 3 to 8, characterized in that it has an extension of the roller conveyor, located behind the bed. 5. Laminating plant according to claim 3 or 4, characterized in that, for the three-roll reversible mill (5) of the main degreasing phase, a speed regulator is provided, which regulates the usual speed of the cylinders both when laminating the pipes. , 37 as well as the rolling of steel bar. 6. Laminating plant according to one of claims 3 to 5, characterized in that the firing mill (6) has two boxes units (6a, 6b) which are at a distance from each other and which are between them. has a cutting edge scissors (9), which can be introduced by displacement between them. 7. A rolling plant according to one of claims 3 to 6, characterized in that, for the final rolling heating, it also comprises a subsequent heating furnace (11), which follows the firing mill (6). . 45 RO 121896 Β1 7 cooling (11), which carries out the transport to the wire rolling block (15).