WO2009038495A1

WO2009038495A1 - Vertical hydraulic press for producing large-diameter steel seamless pipes

Info

Publication number: WO2009038495A1
Application number: PCT/RU2008/000281
Authority: WO
Inventors: Nikolai Vasil'evich Pasechnik; Boris Aleksandrovich Sivak; Arkady Nikolaevich Kurovich; Aleksey Grigor'evich Sergeev; Oleg Mikhailovich Shukhat
Original assignee: Otrkytoe Akzionernoe Obshestvo 'moscow Committee Of Science And Technologies'
Priority date: 2007-09-17
Filing date: 2008-05-06
Publication date: 2009-03-26
Also published as: EP2239132A4; RU2349457C1; EP2239132A1

Abstract

The invention relates to plastic metal forming, in particular to pressing pipe-producing facilities. Said invention makes it possible to combine billet punching and pipe pressing operations into a single press operating cycle and to carry out operational punching and pressing strokes by means of a common drive, thereby reducing the number of the required processing facilities, simplifying the structural design, reducing the power, size and the mass of the press and decreasing investment costs.

Description

VERTICAL HYDRAULIC PRESS

FOR THE PRODUCTION OF STEEL SEAMLESS PIPES

LARGE DIAMETER

The invention relates to the field of metal forming, namely, to press equipment for the manufacture of pipes.

Seamless large-diameter steel pipes are mainly used in various large power plants, including nuclear power plants, and chemical production units with increased parameters (pressure, temperature) of the working medium. One of the most technically advanced and economically sound technological processes for producing such pipes are processes based on the use of the hot pressing method. This method is characterized by an optimal deformation pattern and a high degree of one-time deformation. It provides the manufacture of high quality pipes for dimensional accuracy and shape, surface condition, structure and mechanical properties of the metal.

Extrusion of large-diameter seamless pipes is carried out on heavy-duty vertical hydraulic extrusion presses. When pressing, a hollow billet is used. This is due to the fact that equipping these presses with an additional powerful drive for flashing a solid billet would significantly complicate the design of the press and would lead to an additional increase in its height and weight.

As analogues of the present invention - a vertical hydraulic press for the production of large-diameter seamless steel pipes - presses with a force of 300 MH and 350 MH from Kameron (Great Britain) (Avеru D. Нow Сamerop vеrticallu expеgudes sеаlеmеss ріре // Меtal Ргогсс, 1977 v. 3, No. ₅ 2, p. 52 - 57). The presses have a movable bed and are equipped with a lower drive, which ensures easy access to working cylinders and simplifies their maintenance. The presence of a movable bed, carrying a certain supply of kinetic energy, allows you to more reliably overcome the initial (peak) resistance of the pressed workpiece. Pressing is carried out by a direct method with the expiration of the pipe vertically upwards. The vertical extrusion pattern contributes to an even distribution of the temperature of the workpiece metal and technological clearances in the pressing tool in cross section, which favorably affects the straightness of the pipes obtained. The 350 MH press produces pipes with an outer diameter of 200 mm to 1200 mm with a wall thickness of 12 mm to 200 mm and a length of 13 m.

The closest analogue of the invention adopted as a prototype in this application is a 450 MH press jointly developed by NKMZ (Ukraine) and VNIIMETMASH (Russia) (AK Popov, F. Kaganovsky, OM Shykhat. Press complex for the production of seamless steel large diameter pipes // Heavy Engineering, 1990, N ° 1, pp. 18-22).

The prototype, like the aforementioned analogues of the invention, has a movable bed with a lower drive. An upper movable beam is attached to the upper cross member of the bed, and a lower movable beam is installed on the lower cross beam. Between the movable traverses there is a stationary traverse of the press. In the corners of the latter columns are fixed, which serve to direct the movement of the movable bed. The press rests on the foundation plate with the lower ends of the guide columns. On a fixed traverse from the bottom, there are housings for six cylinders of the main drive of the press, designed to carry out the pressing working stroke. The plungers of these cylinders are connected to the lower movable traverse. Cylinder lift cylinders and container holder drive cylinders are located in the upper part of the press, and mandrel drive cylinders in its lower part. On a stationary press traverse there is a table on top. The table is equipped with a drive for its displacement from the vertical axis of the press in the horizontal plane when changing the container and the stamp.

As on the above-mentioned press-analogues, the pressing of the pipe on the press of the prototype is also performed with the flow of metal up. Before pressing, a matrix is installed on the upper end of the container. Then, when the hollow die is fixed to the mandrel that is fixedly fixed on the press table, a heated hollow billet is installed on the upper end of the die. The mandrel moves through the hole in the workpiece to the upper position. Following this, the container with the matrix is lowered until the latter stops in the upper end of the workpiece. During the subsequent working stroke of the press, the container and the matrix continue to move downward, and the workpiece supported by the stamp is pushed up in the form of a tube up into the annular gap between the matrix and the mandrel. The separation of the pressed pipe from the pressure switch is carried out using a notch installed on the end face of the stamp.

The prototype press is designed for pressing steel pipes with an outer diameter of 530 mm to 1420 mm with a wall thickness of 17 ... 100 mm and a length of 4 ... 12 mm.

The main disadvantages of the production of large-diameter steel pipes in hydraulic presses of all known designs are the high capital costs for the creation of the main technological equipment and significant operating costs for its operation.

This is primarily due to the fact that these presses provide the pressing of pipes only from previously prepared hollow billets. Thus, in addition to a heavy-duty press for pressing pipes and all other necessary technological equipment (heating, finishing, etc.), the tube press the complex should include press and heating equipment to obtain a hollow billet for pressing from the original solid ingot. Thus, in the production of pipes on Kameron presses, hollow billets are manufactured by closed flashing using powerful vertical presses with a force of 90 MH and 140 MH, and ingots for flashing are heated in large gas rotary hearth rotary kilns. Obtaining hollow billets on a 450 MH prototype press should be performed on forging presses with a force of 25 MH and 60 MH by upsetting, flashing, broaching and rolling the ingot on mandrels, followed by machining of the hollow billets. Attempts to develop the design of extrusion presses for the manufacture of large-diameter pipes with a powerful needle drive to enable the ingot to be pierced on these presses do not lead to positive practical results, because associated with an additional complication of the design, increase in size and weight of the press. At the same time, the press prototype 450 MH, which does not provide ingot firmware, already has impressive dimensions and weight: overall dimensions - 15.0 x 31.1 m; total height - 52.7 m, the mass of the press with mechanisms (without pumping and storage station) - 20,000 tons.

The main objectives of the invention according to this application are to significantly reduce capital costs when creating a press complex for the production of large-diameter seamless steel pipes and operating costs for the operation of such a complex. This is achieved by reducing the amount of basic technological equipment required, reducing the complexity and increasing the productivity of the pipe manufacturing process by providing the possibility of flashing the original ingot on the extrusion press itself immediately before pressing, as well as by simplifying the design, reducing the power, size and weight of this press. Thus, the invention eliminates the biggest disadvantages of all known analogues and prototype.

Achieving the stated objectives of the claimed invention is ensured by the fact that the proposed vertical hydraulic press for the production of large-diameter seamless steel pipes contains a movable bed with upper and lower crossbars and a container holder with a drive located between them and a fixed crosshead. In the corners of this crosshead, the guide columns of the bed are fixed, a sliding table is installed on top of it, and the main drive is located below. The drive includes a group of working cylinders, the bodies of which are mounted on a fixed beam, and the plungers are connected to the lower cross member of the bed. The press also contains a technological tool consisting of a container, a mandrel, a stamp and a die. In this case, the mandrel is fixed on the upper cross member of the movable bed, and the stamp is installed in an additional cross member located between this cross member and the container, equipped with an auxiliary drive for moving the stamp relative to the mandrel. The set of the technological tool is supplemented with a plug for firmware, and the pressing matrix and the plug for firmware are placed on the press table. An emphasis is placed on the lower cross member of the movable bed to push the pressed pipe out of the matrix, and a vertical groove is made in the stationary cross-beam to allow the pipe to move from the press axis to the pushing position.

The invention is illustrated by the drawings in FIG. 1 and 2 (on two sheets). In FIG. 1 shows a general view of the press; FIG. 2 shows the sequence of technological transitions of pipe manufacturing on this press.

The press (Fig. 1) consists of the following main components: a movable bed, a fixed beam, guide columns, a table, container holder and technological tool.

The movable bed contains the upper 1 and lower 2 cross members connected by two prefabricated plate frames 3. On the lower cross member there is an abutment 4 for pushing the pressed pipe out of the matrix. Between the cross members of the bed there is a fixed beam 5, which is fixed in a horizontal plane relative to the foundation with the help of four lateral supports 6. Four columns 7 are fixed in the corners of this beam, which serve to guide the movement of the bed. The upper ends of the columns are connected by a cross member 8, and the lower ends by a base 9, through which the press rests on the foundation. A table 10 is placed on top of the stationary traverse. The table has the ability to move in the horizontal direction using a drive (not shown in the drawing). Under the fixed traverse is the main press drive, including a group of hydraulic working cylinders 11. The cylinder bodies are mounted on this traverse, and the plungers are connected to the lower cross member of the bed. A vertical groove is made in the fixed cross member for displacing the pressed pipe from the pressing axis. Between the upper cross member and the press table there is a container holder 12 with a drive 13 for moving the container holder along the axis of the press. The press is also equipped with a drive for lifting the movable bed with plungers 14.

The technological tool of the press includes a container 15, a mandrel 16, a stamp 17, a plug 18 for piercing the ingot, and a die 19 for pressing the pipe. The container is placed in the container holder of the press, and the mandrel is mounted on the upper cross member of the bed. The stamp is installed in the additional cross member 20. This cross member is located between the upper cross member and the container. It is equipped with an auxiliary drive, providing the ability to move the stamp relative to the mandrel. Cylinders 21 of this the drive is mounted on the upper cross member of the bed. The cap and the matrix are placed on two working positions of the press table.

The manufacture of pipes on the press is as follows (Fig. 1 and 2).

In the initial state (Fig. 1), the movable bed with the mandrel and the container holder with the container are in the highest position. An additional cross member with a stamp is lowered relative to the upper cross member of the bed so that the lower end of the stamp is located at the exit of the working cavity of the container. The table occupies a position in which the plug is located on the axis of the press. A heated solid ingot with technological glass-graphite lubricant deposited on its lateral surface and placed in the form of a disk on its upper end face is fed by a manipulator (not shown) to the axis of the press in the space between the container and the table and is mounted on the plug. Then the container goes down and is pressed to the table, while the ingot is inside the container.

Ingot firmware starts. Previously, the die is lowered onto the ingot. Then, under the action of the main drive of the press, the working stroke of the bed with the mandrel fixed on it begins. First, the mandrel upsets (presses) the ingot until the gaps between its side surface and the container disappear. In the process of precipitation, the ingot is shortened, and the stamp moves at the same time, still leaning on the ingot with its end face. After the ingot is pressed out, the mandrel, continuing its downward movement, is introduced into the ingot and flashes it, forming an inner cylindrical cavity in it (Fig. 2, pos. “A”). In this case, the displaced metal of the ingot moves upward, towards the movement of the mandrel, and at the same time, acting on the end face of the stamp, also moves it up together with the additional cross member on which the stamp is fixed. Thus, when flashing the top bar the cross member of the bed and the additional cross member move towards each other. At the final moment of the firmware, both crossbars are closed. After flashing in the stitched ingot, at its lower end there is a partition (bottom) of small thickness.

Following the insertion of the ingot, the pipe is pressed. To do this, first, the container holder with the container, the bed with the mandrel and the additional cross member make a small upward stroke. The table moves a matrix with technological glass-graphite lubricant in the form of a washer with a hole on its upper end face to the axis of the press (Fig. 2, pos. “B”). The container is lowered onto the matrix. The following is the working stroke of the pressing. Under the action of the main drive of the press, the bed with the mandrel and the additional cross member with the stamp, pushed by the upper cross member of the bed, move down. Under pressure from the side of the stamp, the metal of the hollow billet (sleeve) is displaced in the form of a pipe into the annular gap between the die and the mandrel (Fig. 2, item “c”). Pressing ends when a part of the under-pressed blank of small thickness (pressostat) remains in the container near the matrix, and a small distance remains between the additional cross-member and the upper end of the container equal to the thickness of the pressostat. (Fig. 2, pos. "g"). When flashing and pressing, glass-graphite grease on the contact surfaces of the ingot with the container, the mandrel and the matrix, thanks to its good heat-insulating and anti-friction properties, effectively protects the pressing tool from overheating and reduces friction between the ingot and the tool. In this case, the glass component of the lubricant under the influence of the temperature of the ingot becomes liquid, and the lubricant is displaced with a thin layer on the contact surfaces of the mandrel and the matrix.

After pressing, the pressed pipe is removed from the press. Under the influence of the drive of its lifting, the press bed moves upward, removing the mandrel from the pressostat and the container (Fig. 2, pos. "g"). Next, the container with the press stick located in it rises above the table until it stops in an additional cross member. In this case, the pressostat, supported from above by a stationary stamp, is released from the container. Then the table moves the matrix with the pipe in it to the pipe removal position, while simultaneously installing a plug on the axis of the press for flashing the next ingot. In this case, the pipe moves in the longitudinal groove of the fixed beam (Fig. 2, pos. "E"). The bed moves to its highest position. During this movement, the emphasis fixed on the lower cross member of the bed acts on the lower end of the pressed pipe, pushing it up through the die. Finally, with the help of a cargo crane, the pipe is pulled out of the die by the pressure switch (Fig. 2, item “e”). This completes the pipe manufacturing cycle.

From the description of the design and operation of the press it is clear that their main distinguishing features are:

• use of continuous ingots for the production of pipes on the press;

• combining ingot flashing operations and pipe pressing in one working cycle of the press;

• implementation of the working moves of firmware and pressing from one common drive;

• it is possible to flash thinner shells and, accordingly, to reduce the proportion of deformation attributable to pressing;

• pipe pressing is carried out vertically downward;

• pressing is carried out by a movable stamp, and the container is stationary when flashing and pressing;

• the pressostat does not separate from the pressed pipe on the press.

Due to the above differences, the above objectives of the present invention are achieved. The use of the inventive press for the manufacture of large-diameter seamless steel pipes will significantly increase the technical and economic indicators of the production of such pipes consumed by the key sectors of the economy - power engineering, gas and oil sectors, the chemical industry and some others.

Claims

CLAIM

Vertical hydraulic press for the production of large-diameter seamless steel pipes, containing a movable bed with upper and lower cross members, a container holder with a drive located between them and a fixed cross beam, on which the guide columns of the bed are fixed at the corners, a retractable table is installed on top, and the main drive is placed below, including a group of working cylinders with housings mounted on a fixed traverse and plungers associated with the lower cross member, as well as a technological tool, consisting of a container, a mandrel, a stamp and the die, characterized in that the mandrel is mounted on the upper cross member of the movable bed, the stamp is installed in the additional cross member located between this cross member and the container, equipped with an auxiliary drive for moving the stamp relative to the mandrel, the set of the technological tool is supplemented with a firmware plug moreover, the pressing matrix and the plug for firmware are placed on the press table, an emphasis is placed on the lower cross member of the movable bed for pushing out the pressed pipe from the matrix, and in a stationary traverse, a vertical groove is made to ensure the pipe moves from the press axis to the pushing position.