RU2663916C2 - Solid-rolled strong frames from the centrifugally cast workpiece-washer manufacturing method - Google Patents

Abstract

FIELD: manufacturing technology.SUBSTANCE: invention relates to the solid-rolled strong frames manufacturing from the deformable alloys. Performing the workpieces-washers casting by the centrifugal casting method under the inert gas atmosphere by means of the melt feeding into the rotating mold and the workpieces-washers rolling. After the workpieces-washers casting, they are turned, and heated in the furnace, performing their shrinkage in height by means of the hydraulic press and then enabling the workpieces-washers rolling on the radial-axial annular rolling mill. Workpieces-washers turning is performed on the turning-and-boring machine with the tolerance, depending on the material shrinkage, foundry defects occurrence depths and the workpieces-washers wall thickness. On the workpieces-washers outer surface allowances for the turning are set less than on the inner side.EFFECT: as a result, the part production is accelerated, energy costs are reduced and the frames reliability is increased.3 cl, 5 dwg, 1 tbl

Description

The invention relates to the processing of metals by pressure and metallurgy of alloys based on aluminum and magnesium - in particular, to methods for the manufacture of ring blanks and can be used in rocket science and aircraft manufacturing to produce solid semi-finished products in the form of frames, i.e. without welded joints [B21H 1/06].

The frames are the main power elements in the design of missiles, which take on and experience the main alternating and axial loads in joint and autonomous missile flights, therefore, the original ring blanks for the manufacture of frames must have high reliability and increased mechanical properties.

Currently, at rocket and space plants, power frames of all products of rocket and space technology, both mass-produced and promising, are made of extruded profiles. The number of stages of serial technology for the manufacture of frames from welded extruded profiles:

1. Pillar casting;

2. Peeling the ingot;

3. Cutting an ingot;

4. Ingot heating;

5. Profile pressing;

6. Profile cutting;

7. Annealing profile;

8. Profile bending on the press;

9. Cutting ends;

10. Cleaning the edges;

11. Welding;

12. Cleaning the seams;

13. Annealing;

14. Editing in the press;

15. Milling with intermediate X-ray control.

Moreover, operations 7. and 8. are repeated 3-4 times in a cycle, depending on the diameter of the frame (see [http://referatwork.ru/category/tehnologii/view/478283_tehnologicheskiy_process_izgotovleniya_obechayki]).

According to the existing technology, frames from aluminum or magnesium-based alloys are made of 2, 3 and 4 parts obtained by flexible extruded strips into half rings, flash butt welding (aluminum alloys) or manual welding (magnesium alloys) of rings, annealing and machining. Due to the low technological effectiveness of the welding process of aluminum and magnesium profiles of large cross-section, almost all welds require welding after preliminary machining and x-ray control, which significantly increases the complexity and, especially, affects their quality and reliability. In the process of stacking compartments of compartments, there are cases of destruction of the frame along the weld due to its insufficient strength associated with an unstable and complex process of manual welding, which leads to irreparable defects and delayed delivery of the product.

Contact-butt welding of aluminum extruded profiles is performed on unique welding machines, which are currently not manufactured in Russia and in the world. Due to significant physical wear and tear, this equipment often fails. Due to unscheduled repairs, equipment downtime reaches 4 months a year, which affects the rhythm of production and significant financial costs, as well as jeopardizing the implementation of the production plan. The known technology for the manufacture of frames from solid rolled aluminum rings (see

[http://referatwork.ru/category/tehnologii/view/478283_tehnologicheskiy_process_izgotovleniya_obechayki]), the starting material of which is ingots obtained by the technology of semi-continuous casting with the formation of a columnar structure. The number of stages of the technology for the manufacture of solid-rolled frames from an ingot obtained by semi-continuous casting:

1. Pillar casting;

2. Peeling the ingot;

3. Cutting an ingot;

4. Ingot heating;

5. Forging an ingot;

6. Ingot heating;

7. Draft;

8. Firmware;

9. Rolling the ring.

After removal of surface defects, the ingots are cut into billets, which are heated in a furnace. Hot workpieces are upset on the press and a hole is stitched in the center. In subsequent processing, the hole is accelerated and the rim is precisely sized in height.

However, this technological process of obtaining a ring product determines, in addition to obtaining an ingot, precipitation and firmware, multiple heating and replanting of the workpiece, which is necessary to relieve stresses of obtaining a fine-grained isotropic structure, necessary during subsequent rolling.

Based on the foregoing, the process has a high complexity of manufacturing the product, low CMM (material utilization), and, accordingly, significant cost, as well as multiple heating lead to a decrease in the level of mechanical and structural parameters of the product.

The known technology for producing blanks-washers by centrifugal casting is described in detail in RU 2520249, publ.: 06.20.2014. It describes a setup for producing ring castings of magnesium alloys by centrifugal casting in an inert gas medium containing a sealed chamber with an inert medium, a rotating round table attached to a drive shaft of an electric motor located outside the sealed chamber, a cylindrical mold with a lid mounted on a rotating round table, characterized in that it is equipped with a melting furnace, an electric heated metal wire, made in the form of a siphon, one end of which is placed in a melting furnace with rofessional shutter of liquid molten metal, and the other end is placed in a sealed chamber and the metering cup, positioned centrally of the mold coaxially metalloprovoda.

However, the solution as a whole is limited to the process of producing ring castings from magnesium alloys by centrifugal casting and does not describe a method for manufacturing solid-rolled power frames from a centrifugally cast billet-washer. The closest analogue is RU 2487776, publ.: 20.07.2013, a method for producing large-sized ring semi-finished products from wrought aluminum alloys, including casting, deformation processing and annealing, characterized in that the casting is obtained by centrifugal casting in an inert gas medium, and the melt is fed to the mold with the maximum possible second flow rate equal to 1-4% per second at the beginning of casting and 0.02-0.08% per second at the end of casting of the total mass of the casting with a gradual decrease in consumption inversely proportional to the times casting, and the mold rotation speed is gradually increased by 0.4-6.0% per minute from the initial speed, and the deformation processing is carried out by two-stage rolling of the casting during compression of 5-10% at each pass and the total deformation of 25-30% in the first stage and with a compression of 15-20% with each pass and a total deformation of 65-70% in the second stage.

However, the solution as a whole is limited to the process of producing ring castings from aluminum alloys by centrifugal casting and does not describe a method for manufacturing solid-rolled power frames from a centrifugally cast billet-washer.

The objective of the invention is to propose a method for the manufacture of solid-rolled power frames from a centrifugally cast billet-washer.

The technical result of the invention is to simplify the production process to three stages, accelerate the production of parts, reduce energy costs, increase the reliability of frames, reduce the complexity of manufacturing frames, strength characteristics of frames correspond to the strength characteristics of extruded profiles.

The specified technical result is achieved due to the fact that the claimed method of manufacturing solid-rolled power frames from a centrifugally cast billet-washer, characterized by obtaining large-sized annular semi-finished products from wrought alloys, including casting, deformation processing and annealing, and casting is obtained by centrifugal casting in an inert gas environment wherein the melt is fed into the mold, and the deformation processing of the ring rolling is carried out by two-stage rolling of the casting, distinguishing the fact that after receiving the blanks-washers by centrifugal casting, they are turned with an allowance, and turning is carried out on a turning and rotary machine; in the process of turning blanks-washers give such necessary geometric parameters in height, outer and inner diameters of the blanks, which are sufficient for the subsequent receipt of a given volume of metal during subsequent operations; the allowance specified for turning is selected depending on the shrinkage of the selected material, the depth of casting defects and the wall thickness of the castings, while the allowances for turning on the outer surface of the centrifugally cast billet are less than those on the inside; Turned workpieces are heated in an oven, placed on a hydraulic press, and the workpieces are upset by height, and then transferred to a radially axial ring rolling mill, and the heated washer workpiece is moved between the heating furnace, press and the ring rolling mill by a manipulator. Turning is carried out preferably on a two-column turning-rotary machine, which are cutting conditions:

Table rotation speed - 8.8 rpm;

Feed - 0.6 mm / min per revolution during roughing;

Feeding - 0.4 mm / min per revolution during finishing when approaching the specified size;

Depth of cut - 5 mm per side during roughing;

Depth of cut - 2 mm per side during finishing while approaching the specified dimensions.

The sequence of processing on a turning and rotary machine is carried out in the following order: first, based on the cams for the outer diameter, the inner diameter is processed in size, then the upper end in height of the workpiece in size; further, the workpiece-washer is flipped on the table of the turning and rotary machine; then, based on the cams for the inner diameter, the outer diameter is machined to a size, then the upper end along the height of the workpiece to a size.

Brief Description of the Drawings

In FIG. 1 shows a installation diagram for the production of washer blanks by centrifugal casting, where: 1 - a resistance furnace, 2 - an airtight melter, 3 - a loading hatch, 4 - a metal pipe, 5 - a sealing seal, 6 - a liquid shutter made of metal, 7 - a sealing seal , 8 - sealed chamber, 9 - removable cover, 10 - round table, 11 - foundry mold, 12 - mold cover, 13 - mold fastener table, 14-dispenser, 15 - casting machine shaft, 16-electric motor, 17 - V-belt drive .

In FIG. 2 shows a diagram of the formation of the structure of the casting in a rotating form, where 18 and 19 are the zones of the first and second stages of melt crystallization, respectively. In FIG. 3 shows a photograph of a finished casting obtained in a rotating form. In FIG. 4 shows a flowchart of the method, where 20 is a vertical centrifugal injection molding machine, 21 is a turning and rotary machine, 22 is a radially axial ring rolling mill, 23 is a manipulator, 24 is a heating furnace, 25 is a hydraulic press for upsetting workpieces in height.

In FIG. 5 shows a photograph of a finished workpiece obtained by the claimed method. The implementation of the invention

The proposed method will include only three stages, namely:

1. Obtaining blanks-washers by centrifugal casting;

2. Turning blanks-washers;

3. Rolling the ring.

Obtained by centrifugal casting workpieces-washers in a neutral environment have significant advantages, namely:

- eliminates the possibility of fire, oxidation and gas saturation;

- directional crystallization of the melt occurs from the periphery to the center;

- in the process of forming castings, it is possible to improve the mold filling of the mold with the melt under the action of pressure developed by centrifugal forces;

- provides an increase in the density of castings due to the reduction of shrinkage pores, sinks, gas, slag and non-metallic inclusions.

To obtain a blank washer in a neutral environment, use a vertical centrifugal injection machine 20 (see Fig. 4).

The preparation of solid-rolled rings from centrifugally cast billet washers can be implemented using the device shown in FIG. 1, similar to the prototype. The device (see Fig. 1) contains the following equipment: a melting furnace 1 with a hermetic fuse 2, in the cover of which there is a loading hatch 3 and an input pipe for a metal wire 4 (a pipe from a titanium alloy when casting an aluminum alloy). An electrically heated metal conduit made in the form of a siphon, one end of which is immersed in a liquid seal from a molten metal 6 through a sealing seal 5, and the other end is inserted into a sealed chamber 8 of a centrifugal injection molding machine through a removable cover 9 through a sealing electrically insulating seal 7. A round chamber is installed inside the sealed chamber table 13, on which a casting cylindrical mold 11 with a cover 12 is mounted. At the bottom of the mold, coaxially with the dispenser glass, a distribution finned flange 10 is attached, receive are cast metal shot stream. A metering cup 14. The metering cup is a heated crucible designed for a volume of 25-50 kg of melt, having a sock for draining metal and an adjusting locking device with a shutter, is rigidly attached to the mold top and lid of the sealed chamber from below, coaxially with the mold and the metal wire. gate type. The stopper has three positions: “closed”, “open” (start of casting), “partially open” (during casting).

The round table with the help of a rigidly attached shaft 15 is driven into rotation by an electric motor 16 through a V-belt drive 17.

The heating of the metal wire 4 and the dispenser cup 14 is carried out from an external source of electrical power.

Installation works as follows:

In the cooler 2, after loading the initial product, the manhole cover 3 closes and an inert atmosphere is created in the installation by successive evacuation to a residual pressure of 0.5 mm Hg. and filling with inert gas to an overpressure of 0.05 atm.

When the temperature of the metal in the furnace reaches the melting temperature, an inert gas is supplied to the melting furnace, which sparges through the siphon through the melt, thereby mixing it.

The metal wire and the metering cup are preheated to a temperature that is 10-50 ° C higher than the melting temperature of the metal.

Then, when the temperature of the metal in the furnace is 5-20 ° C higher than the melting temperature of the metal, by creating a pressure of 0.3-0.7 atm in the smelter, the melt is fed through a metal wire 4 to the sealed chamber of a centrifugal injection machine. The molten metal through a metal wire enters the dispenser glass and fills its volume to a fixed level, while the stopper of the dispenser glass is in the “Closed” position and accordingly the slide gate is closed. After filling the dispenser glass with metal, the stopper position is set to the “Open” position as a result of which the slide gate opens and the melt through the nose of the dispenser glass enters the rotating mold on the ribbed flange, thereby starting the centrifugal casting process. The melt falling onto the rotating ribbed flange by centrifugal forces is pressed onto the side wall of the mold, gradually filling its volume to the center. Then, after 1-3 seconds, the stopper is moved to the “Partially open” position, the slide gate partially overlaps the toe of the dispenser glass, providing a further uniform flow of the melt into the rotating mold. The rotational speed of the mold during centrifugal casting is 300-2500 rpm (depending on the outer diameter of the casting, having a range from 1000 to 2500 mm). After casting is complete, the process is stopped by venting the inert gas overpressure in the smelter.

The mold rotates until the melt solidifies completely, which is accomplished by cooling the heat transfer to the mold wall, occurring on the outer surface and along the ends of the casting (after the formation of a shrink gap between the casting and the mold, the contact transfer from these surfaces is partially replaced by heat radiation), as well as due to convection of neutral gas from the side of the free surface of the casting. After cooling the annular blank, the rotation of the mold stops, the lid of the sealed chamber with the dispenser glass opens, then the mold cover opens. Further, using a special grip on the inner surface of the ring, the blank washer is removed.

The melting furnace 1 is cooled to crystallize the liquid shutter, the hatch opens, a new loading of the source metal is performed, and, after the inert atmosphere is created in the smelter and the metal is heated, a repeated casting cycle of the ring blanks is performed.

After receiving the blanks-washers by centrifugal casting, zones of the first 18 and second 19 stages of crystallization of the melt are obtained (see Fig. 2, Fig. 3). Next, it is necessary to turn them, which is carried out on a turning and rotary machine 21 (see. Fig. 4).

Turning is carried out both to give the workpiece washers the geometrical parameters necessary to obtain a given volume of metal for the subsequent operation, and to remove surface casting defects (non-slit, gravel, sinks, cracks, etc.) in height, external and internal diameters of the workpieces. The allowance set for turning depends on the shrinkage of the selected material, the depth of casting defects and the wall thickness of the castings. On the outer surface of the centrifugal cast billet, allowances for turning are set less than on the inside. So for aluminum and magnesium alloys they are 10-15 mm per side.

Billets can be processed, for example, on a two-column turning and rotary machine (model 1553).

Cutting modes:

Table rotation speed -8.8 rpm;

Feed - 0.6 mm / min per revolution during roughing;

Feeding - 0.4 mm / min per revolution during finishing (when approaching the specified size);

Depth of cut - 5 mm per side during roughing;

Depth of cut - 2 mm per side during finishing (when approaching the specified dimensions).

The sequence of processing on a two-column turning and rotary machine is as follows.

Due to the uneven inner surface of the washer blank, the turning is carried out in the following order:

1. Based on the cams for the outer diameter, the inner diameter is processed into a size, then the upper end (along the height of the workpiece) is sized.

2. The billet-washer is flipped on the table of the turning and rotary machine.

3. Based on the cams for the inner diameter, the outer diameter is machined to a size, then the upper end (along the workpiece height) to a size.

Currently, castings, stampings, rolled products are used as blanks for ring rolling. The range of manufactured rings for power frames is constantly expanding both in geometric parameters and in the materials used, such as magnesium alloys. This requires the development of new approaches to modeling and optimization of the ring rolling process.

The present invention for the manufacture of power frames is proposed to use as blanks for ring rolling blanks-washers obtained by centrifugal casting, followed by turning them.

The use of the ring rolling process for blanks-washers is the most important condition for achieving the best results in terms of accuracy and a given shape of the finished ring with minimum energy costs, minimum power spent on ring deformation and maximum material utilization. Ring rolling of blanks-washers in order to obtain frames of specified geometric parameters must be carried out on a radially axial ring rolling mill 22 (see Fig. 4), which is part of the following ring-rolling complex: a heating chamber furnace 24, a hydraulic press 25 for upsetting the blanks in height, radial axial ring rolling mill 22.

As mill 22, any mill known in the art can be used (see http://meer.sms-group.com/fileadmin/user_upload/pdf/publicationgroup/schmiedetechnik/RW_RAW_RU_10-14.pdf).

In the chamber furnace 24, the workpiece is heated, then, using the press 25, the workpieces are upset by height. Then the workpiece is moved to the radial-axial ring rolling mill 22. The heated workpiece-washer is moved between the heating furnace, press and ring rolling mill 22 by the manipulator 23. Any manipulator known from those used in ring rolling can be used as a manipulator (see http: // www.dango-dienenthal.de/en). On the ring rolling mill 22 form the final product-frame (see example in Fig. 5).

As a result of the implementation of the invention, a number of significant advantages are achieved:

- increased reliability of frames due to the lack of welds;

- reduces the complexity of manufacturing frames;

- the production cycle of frames is reduced;

- no less than 1.5 times reduced the cost of manufacturing frames (for magnesium alloy);

- strength characteristics correspond to the strength characteristics of extruded profiles.

Table 1 shows a comparison of the complexity and costs of manufacturing solid-rolled frames from MA2-1pch alloy compared to existing serial technology.

Thus, the use of seamless-rolled power frames made of aluminum or magnesium alloys made of centrifugally cast billet washers will not only increase the reliability of products with a significant reduction in labor intensity, but also due to the increased mechanical characteristics, reduce the weight of the frames.

Claims (3)

1. A method of manufacturing solid-rolled power frames from wrought alloys, comprising casting the workpieces-washers by centrifugal casting in an inert gas medium by supplying melt to the rotating mold and rolling the workpieces-washers, characterized in that they are machined and machined after workpieces-washers are heated, heated in an oven they perform their upsetting in height by means of a hydraulic press and then provide rolling of the blanks-washers on a radially axial ring rolling mill, while turning the blanks-washers is carried out on a turning- aruselnom machine with an allowance depending on the shrinkage of the material, the depth of the casting defects and wall thickness washers blanks, wherein at the outer surface of blanks washers allowances under the refacing is set smaller than the inner. 2. The method according to p. 1, characterized in that the turning is carried out on a two-column turning and rotary machine, which sets the cutting mode at which the table rotation speed is 8.8 rpm, the feed for roughing is 0.6 mm / min per revolution, feed during finishing when approaching the specified dimensions - 0.4 mm / min per revolution, the depth of cut to the side during roughing - 5 mm, the depth of cut to the side when finishing when approaching the specified size - 2 mm. 3. The method according to p. 1 or 2, characterized in that the order of processing on a turning and rotary machine is carried out in the order in which, first, based on the cams for the outer diameter, the inner diameter is processed in size, then the upper end along the height of the workpiece in size , then the billet-washer is flipped on the table of the turning and rotary machine, after which, based on the cams for the inner diameter, the outer diameter is processed in size, then the upper end in height of the workpiece in size.

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