RU2387496C2 - Tube-forming installation for rolling seamless hot-deformed tubes of large and mean diametres - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: tube-forming installation includes furnaces for heating ingots and workpieces, roll tables for transportation of heated ingots and workpieces, two skew rolling mills for conversion of ingots and workpieces on a short holder into hollow shells, two transfer bogies for transportation of shells to pilger mills, two pilger mills for rolling of shells to tubes in profiling rolls on a long holder - mandrel, impact saws for tube cutting, furnace for tube heating before grooving, mill for tube grooving as to diametre, and two regular six-high cluster machines; at that, two skew rolling mills are located parallel in process line; outlet side of the first skew rolling mill is located at the inlet side of the other skew rolling mill and equipped with transmission grid; skew rolling mills have individual carry-over tables from furnaces for heating ingots and workpieces to inlet sides of those mills and individual transmission bogies from outlet sides to pilger mills.

EFFECT: providing manufacture of tubes in small batches without loss of efficiency, fabrication of tubes of diametre 465-550 mm from carbon and alloyed steel grades and tubes with diametre of more than 325 mm from difficult-to-form grades of steel and alloys from one heating, increasing flexibility of tube-forming installation and reducing production cost of tube products.

3 cl, 1 dwg

Description

The invention relates to the field of metallurgy, in particular to tube-rolling plants for rolling seamless hot-deformed pipes of large and medium diameters, which include an oblique rolling mill for flashing ingots and billets into sleeves for subsequent rolling them into pipes with a diameter of 325-450 mm from carbon and alloyed steel grades, piercing ingots and billets into thick-walled sleeves and their subsequent heating and rolling into thin-walled sleeves for rolling pipes with a diameter of more than 465 mm from carbon and alloy grades , flashing ESR ingots and billets into sleeves and their subsequent heating and rolling into thin-walled sleeves for rolling pipes with a diameter of more than 325 mm from hard-deformed grades of steel and alloys and can be used in the manufacture of seamless hot-deformed pipes with a diameter of 325-550 mm from carbon, alloyed and hard-to-deformed grades of steel and alloys in pipe-rolling plants incorporating pilgrim mills.

Pipe rolling plants with pilgrim mills are one of the main pipe rolling plants for the production of long, especially thick-walled and profile pipes for special purposes, square, conical, stepped, fin, etc. Known pipe rolling installation (TPU 8-16 "OAO" ChTPZ ") for rolling pipes with a diameter of 325-550 mm, which includes two methodical furnaces, a two-roll oblique rolling mill (piercing mill) with a drive power of 2750 kW, two pilgrim mills, two saws for cutting pipes to measured lengths, a heated feed-through furnace, a 5-stand calibration mill and two six-roll straightening machines.

A disadvantage of the known TPU 8-16 "is the insufficient drive power of the oblique rolling mill, which leads to double flashing and loss of productivity when rolling pipes with a diameter of more than 325 mm from hard-deformed steel grades and alloys and pipes with a diameter of 465-550 mm from carbon and low alloy steel grades (TI158 -Tr.TB1-38-97 "Production of seamless hot-rolled pipes for steam boilers and pipelines according to TU14-3-460-75 and TU14-3-420-75", TI158-Tr. TB1-56-97 "Production of seamless hot-rolled pipes grade 20 steel for the refining industry about TU14-3-587-77 ", TI158-Tr. TB1-51-2002" Production of seamless hot-rolled pipes from steel 15X5M according to TU14-3R-62-2002 "and TI158-Tr. TB1-53-2002" Production of seamless hot-rolled pipes made of corrosion-resistant steel grades with high surface quality according to TU 14-3R-55-02001 ").

The disadvantage of this equipment is the fact that double flashing of ingots and billets leads to double heating and, consequently, to increased metal consumption, lower productivity of the pilgrim installation and an increase in the cost of their conversion. Heating the sleeves for the second firmware (rolling) leads to uneven heating of the sleeves, due to the increased length, curvature and unevenness of their tilting along the bottom of the methodological furnaces. The piercing (rolling) of unevenly heated sleeves on mandrels with a diameter of 425 mm or more with a ratio D / S≥6.0 leads to their uneven cooling in the piercing mill and additional curvature, which in turn leads to an increased difference in pipes on the pilgrim mill and, as consequence, to increased consumption of metal during redistribution (ingot - billet) - finished pipe.

Known modernized tube-rolling installation with pilgrim mills, including two ring furnaces for heating ingots and billets to a plasticity temperature, a horizontal press for pre-flashing ingots and billets into glasses, a heating furnace in front of the oblique rolling mill (elongator), oblique rolling mill (elongator) for rolling cups and bottom firmware, two feeding apparatuses, two pilgrim stands for rolling sleeves into tubes in profile rolls, two hot cutting saws, a heating furnace before calibration, calibration mill and straightening mill (V.Ya. Osadchy and others. "Technology and equipment of pipe production", Moscow "INTERMET ENGINEERING", 2007, p. 195).

The disadvantage of this equipment is that when flashing on a horizontal press, the lateral difference is 6.5-12.5%, and on a Kosovalkovy mill (oblique rolling mill) - 2.5-4.5%. The installation of an additional furnace to heat the glasses in front of the mill elongator leads to additional waste of metal, and therefore, increased consumption of metal. For flashing ESR ingots and workpieces from hard-to-deform grades of steel and alloys, it is necessary to install a powerful press with a complex hydraulic system, which leads to additional energy and metal consumption of the equipment.

The closest technical solution is the scheme of the modern technological process for the production of pipes on TPA with pilgrim mills, including: two or one ring furnace for heating ingots and billets, an apparatus for descaling, a press for flashing ingots and billets into glasses, an annular furnace for heating glasses, 2- or 3-roll oblique rolling mill for rolling glasses and bottom flashing, installation for charging mandrels into sleeves, two pilgrim stands, two impact saws for cutting pipes to measured lengths, mustache an installation for removing mandrels from pipes, a bath for cooling mandrels, a unit for applying grease to mandrels, a furnace for heating pipes in front of calibration or reduction mills, a calibration-reduction mill and one or two straight six-roll machines (V.Ya. Osadchy and others. Technology and equipment for pipe production. - M.: INTERMET ENGINEERING, 2007, p.196, fig. 6.10).

This equipment has two extra energy-consuming and metal-consuming units, namely, a press for flashing ingots and billets into glasses and an annular furnace for heating glasses, aimed at improving the quality indicators and geometric dimensions of hot-deformed pipes, but does not solve the main problem, namely, reducing the consumption coefficient metal, the possibility of producing long pipes with a diameter of more than 325 mm from hard-deformed grades of steel and alloys, increasing the productivity of TPU with pilgrim mills during atke pipe diameter 465-550 mm and 273-450 mm pipes of small batches.

The objective of the proposed composition of the equipment of a pipe rolling plant with pilgrim mills for rolling seamless hot-deformed pipes of large and medium diameters is to exclude from the equipment two energy-intensive and metal-intensive units that give increased difference between the glasses and the burning of metal when the glasses are heated in an annular heating furnace, reducing the consumption coefficient of the metal and increasing productivity of pipe rolling plants with pilgrim mills due to installation in technological of two oblique rolling mills in parallel, the output side of the first oblique rolling mill should be located opposite the input side of the second oblique rolling mill and equipped with a transfer grill, the oblique rolling mills have individual transport roller tables from the furnace to the entrance sides of the mills and individual transfer trolleys from the output sides to the pilgrim mills, which, in addition to sequential flashing and rolling of ingots and billets with a diameter of 630-650 mm, makes it possible to produce pipes from hardly deformed steel grades and alloys with a diameter of more than 325 mm, to exclude downtime of the second mill when rolling pipes with a diameter of 273-450 mm in small batches, i.e. on the first oblique rolling mill, piercing the ingots and billets into the sleeves of one diameter, and on the second oblique rolling mill into the sleeves of another diameter, for rolling pipes of different diameters on the pilgrim mills.

The technical result is achieved by the fact that the tube rolling plant for rolling seamless hot-rolled pipes of large and medium diameters, including furnaces for heating ingots and billets, a roller conveyor for transporting heated ingots and billets, an oblique rolling mill for piercing ingots and billets on a short mandrel into hollow sleeves, two transfer trolleys for transporting sleeves to pilgrim mills, two pilgrim mills for rolling sleeves into tubes in profile rolls on a long mandrel - mandrel, impact saws for cutting ki pipes, a furnace for heating pipes before calibration, a mill for calibrating pipes by diameter and two straight six-roll machines, a pipe-rolling installation contains two oblique rolling mills that are located in parallel in the production line, the output side of the first oblique rolling mill is opposite the input side of the second oblique mill rolling and equipped with a transfer grill, and oblique rolling mills have individual transport roller tables from the furnace to the input sides of the mills and individual transfer trolleys from the exit bottom sides to pilgrim mills.

A comparative analysis of the inventive tube rolling plant with the prototype shows that the tube rolling plant contains two oblique rolling mills that are parallel in the production line, the output side of the first oblique rolling mill is opposite the input side of the second oblique rolling mill and equipped with a transfer grill, the oblique rolling mills have individual transport live rolls from the furnace to the input sides of the mills and individual transfer trolleys from the output sides to the pilgrim mills. Thus, the inventive pipe-rolling installation for rolling seamless hot-rolled pipes of large and medium diameters meets the criterion of "inventive step".

Comparison of the claimed pipe-rolling installation not only with the prototype, but also with other technical solutions in the art, did not reveal the signs that distinguish the claimed pipe-rolling installation from the prototype, which corresponds to the patentability of "inventive step".

The invention is illustrated by the scheme, which shows the technological process of production of pipes on TPA with pilgrim mills. Initial ingots and billets are fed to the workshop in railway cars and unloaded by electromagnetic cranes, and billets of non-magnetic steel and alloy grades are delivered to the warehouse by special gripping devices. From the warehouse, ingots and billets are fed to inspection grids for inspection, repair (if necessary) and weighing. Useful ingots and billets are transported by roller conveyors to the loading mechanism of one of the two ring furnaces 1-1 or 1-2. After heating to a plasticity temperature (depending on the grade of steel and alloy), the ingot or billet is unloaded from the furnace by the manipulator and fed to the 2-1 or 2-2 rolling table for descaling, and then to one of the oblique rolling mills 3-1 or 3 -2, where the operation of flashing them into sleeves is performed. When in-line pipe production in accordance with GOST or TU, an oblique mill 1-1 is involved in the work. When rolling pipes with a diameter of 465-550 mm from ingots and billets with a diameter of 630-650 mm, the process of flashing ingots and billets is carried out in an oblique rolling mill 1-1 in sleeves on a mandrel with a diameter of 325-375 mm with a ratio D / S = 4,2-5 , 0. Thick-walled sleeves from the output side of the oblique rolling mill 1-1 along an inclined transfer trolley are fed to the driving roller table of the oblique rolling mill 1-2, where they are rolled on a mandrel with a diameter of 425-525 mm into sleeves with a rise in diameter of 3.0-3.5% and the ratio D / S = 5.0-9.5. The oblique rolling mills are located in the TPA technological line with the pilgrim mills in parallel, the output side of the first oblique rolling mill is located opposite the input side of the second oblique rolling mill, and the transfer of thick-walled sleeves from the first mill to the second is performed using an inclined transfer grill. A similar technological process is also carried out when rolling pipes from hardly deformable grades of steel and alloys with a diameter of more than 325 mm, namely, workpieces with a diameter of more than 500 mm are sewn into thick-walled sleeves in the first oblique rolling mill, and then rolled into thinner-walled sleeves in the second oblique rolling mill. When rolling pipes in small batches in order to reduce the downtime of one of the pilgrim mills by eliminating transshipment, it is advisable to pierce the ingots and billets into sleeves of one diameter on one mill, and on the second mill oblique into sleeves of another diameter. On one of the pilgrim mills, rolls are transshipped to complete the task for rolling pipes of a given size and assortment, and on the second pilgrim mill, pipes of continuous production are rolled without stopping. After the mills for oblique rolling of the sleeve according to the existing technological process, operations are carried out: extra-charge charging of the mandrels into the sleeves 4, rolling of pipes on pilgrim mills 5-1 and 5-2, cutting of lashes of pipes into measured lengths with impact saws 6-1 and 6-2, heating pipes in furnace 7 for calibrating them in 2- or 3-roll calibration mills, calibrating pipes in calibration mill 8, cooling pipes in sprayer 9 to obtain mechanical properties from rolling heating and straightening pipes in six-roll straightening machines 10-1 and 10-2 . After editing the pipes according to the existing technology, they enter the finish.

Therefore, in order to improve the geometric dimensions of sleeves, reduce metal consumption, eliminate double heating and increase the performance of pilgrim installations, it is necessary to flash ingots and billets into thick-walled sleeves for rolling pipes with a diameter of 465 mm and more in the first mill oblique rolling, and rolling into thin-walled sleeves - in in the second mill, in the first mill of oblique rolling, pierce the ingots and billets with a diameter of 630-650 mm into sleeves the size in diameter on the mandrel with a diameter of 325-375 mm with a ratio of D / S = 4.2-5.0, and in about the second oblique rolling mill to roll on a mandrel with a diameter of 425-525 mm in sleeves with a rise in diameter of 3.0-3.5% and the ratio D / S = 5.0-9.5, and the oblique rolling mills are installed in the pipe rolling line installations with pilgrim mills in parallel, the output side of the first oblique rolling mill is located opposite the input side of the second oblique rolling mill. Such an arrangement of oblique rolling mills and the technological parameters of flashing and rolling ingots and billets into sleeves for rolling pipes with a diameter of 465-550 mm can eliminate reheating of the sleeves for rolling, increase the performance of the pilgrim installation by eliminating downtime of the second pilgrim mill, and increase the accuracy of the geometric dimensions of large pipes diameters and reduce metal consumption in their production. When rolling pipes from hardly deformable grades of steel and alloys with a diameter from 325 mm to 550 mm, it is necessary to increase the power of the drives of the oblique rolling mill by 2 times or more. Since the pipes of this assortment in the general TPU program range from 5.0 to 10.0%, it is more expedient to carry out the process of flashing and rolling the sleeves of this assortment in 2 oblique rolling mills in order to save energy resources.

The proposed pipe-rolling installation for rolling seamless hot-rolled pipes of large and medium diameters and its composition of equipment allow the rolling process to be carried out according to the following options:

- flashing ingots and billets into sleeves and rolling pipes of in-line production using oblique rolling mill 3.1;

- firmware of ingots and billets into sleeves on mill 3-1, followed by rolling out on the second mill 3-2, operating in the mill-elongator mode;

- compression of the ingots in diameter on the first mill of oblique rolling 3-1 without a mandrel (seal), followed by flashing into the sleeves on the second mill of oblique rolling 3-2;

- firmware of ingots and billets on a 3-1 oblique rolling mill into sleeves of one diameter, and on another 3-2 mill into sleeves of a different diameter for rolling pipes of different sizes (diameters) on pilgrim mills.

The proposed pipe-rolling installation and arrangement of equipment for the production of seamless hot-rolled pipes of large and medium diameters on pipe-rolling units with pilgrim mills in comparison with the traditional firms Mannesman-Demag (Germany) and Innocenti (Italy) have the following advantages: in the technological process the press for calibrating the faces of the ingots (press rolling firmware), the horizontal press, the intermediate ring furnace for heating the glasses are not involved, but will be installed flax only one skew rolling mill. Replacing the press roll piercing mill or hydraulic press with an oblique rolling mill will increase the accuracy of the sleeves in the wall thickness, and consequently the pipes up to ± 10.0% instead of ± 12.5%, increase the maneuverability of the entire tube rolling unit and the possibility of producing pipes with smaller ones in batches (up to one pipe), it will make it possible to produce pipes from hardly deformable grades of steel and alloys with a diameter of more than 325 mm from one heating, will make it possible to parallel production of pipes of different grades and sizes, increase productivity installation by reducing technological downtime for transshipment and tool replacement, to exclude additional heating of the sleeves when rolling pipes with a diameter of 465-550 mm from carbon and alloy steel grades and sleeves when rolling pipes with a diameter of more than 325 mm from difficult to deform grades of steel and alloys, to exclude additional heating of glasses in an intermediate ring furnace, reduce the cost of pipes as a result of eliminating additional equipment and replacing the technological tool of a horizontal press (containers, punches and m Tritz) on the rolls and the mandrel mill rolling oblique, as well as reduce energy consumption and cut staff.

Thus, the installation of two oblique rolling mills in the TPU production line in parallel with the displacement of the output and input sides will allow the portfolio of orders to be formed by pipes in small batches without loss of productivity, to rolled pipes with a diameter of 465-550 mm from carbon and alloy steel grades and pipes with a diameter of more than 325 mm from hard-deformed grades of steel and alloys from one heating, to increase the flexibility of the pipe rolling installation, and reduce the cost of pipe products.

Claims (3)

1. A tube rolling installation for rolling seamless hot-rolled pipes of large and medium diameters, containing furnaces for heating ingots and billets, a rolling table for transporting heated ingots and billets, an oblique rolling mill for flashing ingots and billets on a short mandrel into hollow shells, two transfer trolleys for transportation sleeves for pilgrim mills, two pilgrim mills for rolling sleeves into pipes in profile rolls on a long mandrel - a mandrel, impact saws for cutting pipes, a furnace for heating pipes before libration, a mill for calibrating pipes by diameter and two straight six-roll machines, characterized in that it contains a second oblique rolling mill located in the production line parallel to the first oblique rolling mill. 2. The pipe-rolling installation according to claim 1, characterized in that the output side of the first oblique rolling mill is located at the input side of the second oblique rolling mill and is equipped with a transfer grill. 3. The pipe-rolling installation according to claim 1, characterized in that the oblique rolling mills have individual transport roller tables from the furnace for heating ingots and billets to the input sides of the oblique rolling mills and individual transfer trolleys from their output sides to the pilgrim mills.

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