WO2009054749A1 - Method and production line for producing foam aluminium sheets - Google Patents

Abstract

The invention relates to powder metallurgy, in particular to foam aluminium production. The inventive method involves the filling of a powder mixture into a sheath, heating it in a through-type furnace (6) to a temperature not less than 500°C, the hot compaction thereof, the cutting of the compacted rolled billet into sheet billets and the high-temperature heat treatment for a foaming process. The sheath is formed from two uniformly supplied coiled strips. The lower part of the sheath with a base and flanged walls is formed from the first coiled strip (1). Afterwards, the second coiled strip (4) is superimposed upon the lower part of thesheath and the thus assembled billet is sent for canting the flanged sections. The inventive production line comprises a device for supplying the powder mixture for heating, the through-type furnace (6), a heated chute with rollers, a stand for heat compacting of the powder mixture rolled billets, the shears (9) for cutting billets to length, an outgoing roller table (10) and a sheet billet-foaming furnace (13). The production line is also provided with a device for filling the powder mixture into the sheath. Said invention makes it possible to produce quality billets with uniform mechanical characteristics.

Description

 Method and production line of foam aluminum sheets

The invention relates to the field of powder, metallurgy and can be used in the manufacture of products for civil engineering, elevator building, shipbuilding, mechanical engineering, road construction and other industries where such properties as lightness, buoyancy, incombustibility, heat resistance and sound insulation are required.

^• A known method (adopted as an analogue), including pre-compaction of the powder, heating the material to a temperature of at least 500 ° C, its hot compression in the rolls at the same temperatures. As an aluminum powder, granular powder with a grain size of 50-200 μm is used. The powder is poured into a closed shell made of sheet steel with a thickness of 0.5-2.0 mm, with equal or different wall thicknesses in contact with the rolls during compression, and having a cross-sectional shape close to the shape of the sheet blank. Next, the casing together with the powder is heated to 500-600 ⁰ C and at these temperatures the casing with the powder is compressed in rolls with a diameter of at least 500 mm, with a linear speed of the rolls of 0.03-0.3 m / s and to a thickness determined by the expression:

H ₁ = (O, 8-l, O) - [H _o -po / pi + (fi + f ₂ ) - (l-po / Pi)] where: H] is the thickness of the materials together with the shell at the exit of the rolls, mm;

H ₀ - the thickness of the material together with the shell at the entrance to the rolls, mm;

Po is the density of the filling material at the entrance to the rolls, g / cm ³ ;

P ₁ - theoretical density of the material, g / cm ³ ; f _s fg - shell wall thickness in contact with rolls at a reduction mm. After this, the shell is cooled, cut and the finished sheet stock is removed from it. In addition, the shell is made in the form of a trough-shaped tray with a lid. To obtain subsequently from the sheet blank foam aluminum sheets,, 0.5-1.0 May is added to the powder before compaction. % porophore powder (TiH ₂ ), a, heating the shell with the powder for subsequent compression in the rolls is carried out up to 500-550 ⁰ C. Granules of aluminum powder are pretreated with polymethylsiloxane or polyethylsiloxane before compaction (RU JV2 2206430 B22FЗ / 18 from 06.20.2003, ) The disadvantages of this method are that:

- it is focused on piece low-performance rolling;

- the steel shell is technological and must be removed after crimping, creating significantly expensive production waste.

A known production line for the production of porous and non-porous metal sheets (adopted as an analogue) is characterized by the fact that it contains a hopper with a metal powder of vertical design, with horizontal design: a belt conveyor, a cold rolling mill, a heating furnace for foaming cold rolled sheets, a transport rolling table, a hot rolling mill and winders for winding hot rolled sheets, while the conveyor belt is made receiving metal powder from the hopper, passing capacity with it through a deformation zone stand cold-rolling and cold-rolled sheet conveying a foaming heating furnace (Patent 10324904A B22FZ / 18 B22FZ / 11, H01M4 / 8 from 27.02.1998, Japan).

The disadvantages of the known line include cold deformation of the powder, which requires very large rolling forces, and low efficiency in the formation of new strong metal bonds, both at the points of contact with a clean surface and at the points of contact through a metallized oxide film. The known method and technological line (adopted as a prototype), realizing the production of porous semi-finished products from powders of aluminum alloys, which include: a powder mixture dispenser, a continuous heating furnace with a conveyor belt passing through it for receiving a cold powder mixture, transporting a heated powder mixture and dispensing a heated powder powder mixture in a vertical chute equipped with heating and vibration-compaction powder mixture devices, hopper - wiring and proc a horizontal stand for hot compaction of the powder mixture, cross-section scissors for measured lengths of the hot compacted sheet and high-temperature processing devices for foaming the hot compacted sheet (patent RU N ° 2200647 B22FЗ / 11, C22C 1/08 of 03.20.2003).

The line allows for hot compaction with fairly high deformations. However, the prototype has the following disadvantages:

- uneven mechanical properties across the width of the compacted sheet stock;

- high energy costs due to two heatings, additional heating and compacting of the powder mixture with significant heat transfer to the rolls;

- vertical execution of the production line, requiring a specialized production building and complicating the combination of reliable process control with fire and explosion safety, as well as the need for protection for environmental cleanliness.

The objective of the invention is to obtain high-quality, with uniform mechanical characteristics, both ^' in width and length, sheet blanks, reducing their cost, as well as the process of producing foam with high adaptability, at reduction to an acceptable level of explosion and fire conditions of the production process.

The problem is solved in that in a method comprising filling the powder mixture into a shell made of steel or aluminum alloys, heating the rolled stock from the powder mixture in the shell in a feed furnace to a temperature of at least 500 ° C., hot compacting the rolling stock, cutting compacted rolling blanks on sheet blanks of measured length, placing sheet blanks in a mold and subsequent high-temperature heat treatment to carry out the foaming process at a liquidus temperature of powder of the alloy, the formation of the shell is carried out from two uniformly fed roll strips of unlimited length, while first, from the first roll strip, the lower part of the shell is formed, including the base and walls with flanges, then, as it is filled with compacted vibration, the powder mixture is applied to the lower part the shell a second roll strip with a width equal to the width of the upper surface of the lower part of the shell with flanges, and direct the assembled workpiece to rolling the flanged sections about the entire length.

In addition, the hot compaction of the powder mixture in the shell is carried out in a closed caliber of the work rolls, while the depth of incision of the calibers is determined by the formula:

^D (l - cosα) + # - h _n > ^ - cos and where: h _n - depth of cut of the caliber; - α - angle of capture;

Δh - compression of the powder mixture; H is the thickness of the rolling billet, while the work rolls for hot compacting the powder mixture in the shell are lubricated with smokeless grease, for example, a suspension colloidal graphite in water type "Aquadak". (V.M. Shteinberg,

I.L. Akaro, "Forging and stamping production", Moscow, Mechanical Engineering, 1977, pp. 150-160).

Implementing this method of production line _. aluminum foam sheets containing a powder mixture supply device for heating, a continuous heating furnace, a heated chute with rollers feeding the powder mixture for compacting, a hot compacting stand for the rolling mixture from the powder mixture, shears for transverse cutting of the compacted rolling material into sheet lengths of measured length, a discharge roller table and a furnace for foaming sheet blanks, supplemented by installation in front of a powder mixture supply device for heating by a powder mixture packaging device in a casing with a shape close to the shape of the rolling billet, including two bending mills for forming the lower and upper parts of the casing, equipped with their unwinders of roll strips, while between the bending mills there is a transport mechanism for moving the lower part of the casing, rough and finishing batchers for filling powder casing mixtures and the mechanism for applying the upper part of the shell to its lower part, in addition, the mechanism for promoting the lower part of the shell is made in the form of two or more driven three-roller gr UPP of the pulling rollers, while the lower roller of the group is made of two-support with a groove in the central part of its barrel with a width and depth exceeding at least 2 mm of the width and depth of the shell, and the upper rollers, left and right, are made cantilever and in contact with the lower part of the shell only at the width of its flanges, as well as the dispensers and the mechanism of advancement, the lower part of the shell of the device for packing the powder mixture into the shell are mounted on the vibrator body, while, in front of the foaming furnace, slappers and perpendi are installed ulyarnye to the line axis, and the front of the stove shlepper foaming mechanism equipped sheet problem b the workpieces in the mold and behind the foaming furnace are equipped with a mechanism for issuing the sheet blank from the mold, and also, behind the feed kiln, press shears for transverse cutting of the rolled stock are installed, while scissors for longitudinal cutting of the side edges of the sheet blank are installed behind the discharge roller, and in the stand compaction of the powder mixture in the shell installed work rolls with internal heating.

Such a design of the foam aluminum sheet production line allows:

- reduce production space due to the completeness of the technological process c. one production line from the supply of the powder mixture to the finished product,

- increase the productivity of the process due to the reduction to a minimum ^'production pauses,

- receive panels of sufficiently large dimensions,

- reduce energy costs during hot compaction of the powder mixture in the shell due to the compaction in work rolls heated to 150 - 300 ⁰ C and lubricated with a suspension of colloidal graphite in water such as "Aquadak", as well as when foaming sheet blanks not cooled due to hot planting.

- create conditions for the maximum possible mechanization and automation of the production of foam sheets due to the stabilization of the operation of each line mechanism in time.

- to improve the quality of sheet blanks due to the uniformity of the process of compacting the rolled stock in a closed gauge, which reduces bloating of the blank.

- to increase fire safety, as well as environmental safety due to the exclusion of operations with an open powder mixture in a hot state. The proposed method and line for the production of foam aluminum sheets are shown in the figures, where: FIG. 1 shows a diagram of an implementation of the method of manufacturing foam aluminum sheets, FIG. 2, section AA is shown in FIG. L of the formed lower part of the shell, FIG. 3, section B-B is indicated Fig.l of the lower part of the shell filled with a powder mixture, Fig. 4, is a sectional view of BB of the Fig. 1 formed rolling billet comprising a shell and vibration-compacted powder mixture, Fig. 5, shows the production line of foam aluminum sheets, Fig. b, shows a plan of the foaming section earnest preforms (view on arrow A of Figure 5) Figure 7 is a diagram of cross section AA 5 by pinch rolls advancing mechanism bottom part of the shell.

According to FIG. 1, the roll strip 1 is continuously fed to the formation of the lower part of the casing in the bending mill 2, where the profile shown in FIG. 2 is formed, which is the lower part of the casing, including the base and walls with flanges of 30-50 mm.

где; h_н - глубина вреза калибра; α - угол захвата;As the formed lower part of the workpiece moves, from the dispensers 3, a powder mixture is fed into its internal cavity until the entire cavity is fully filled (see sections B-B of FIG. 3). Then, a second flat roll strip 4 having a width equal to the width of the lower part of the shell according to the flanges and the assembled workpiece is set on the lower bending part of the filled powder mixture and set into the second bending mill 5, which rolls the flanged sections of both parts of the shell, thereby completing the formation of the rolling billet from powder mixture in the shell. The rolling billet is heated in a continuous furnace 6. to a temperature not lower than 500 ° C and through an insulated wiring 7 served for compaction in the closed caliber of the work rolls 8, having a depth of "h _to " made by a value determined from the expression:

Where; h _n - insertion depth of caliber; α is the angle of capture;

Δh - compression of the powder mixture;

H is the thickness of the rolling billet.

With the height of the closed gauge “h”, the lateral exit of the powder mixture from the deformation zone is excluded, and with the width of the closed gauge close to the width of the rolled billet, a uniform degree compacted over its entire width is ensured. Lubrication of closed gauge working surfaces with smokeless grease, such as a suspension of colloidal graphite in water of the “Akvadak” type, reduces energy consumption for compaction to 10–25%.

The sheet billet emerging from the work rolls is cut to measured lengths with flying shears, transverse cutting 9. The sheet billet is transferred to the roller table 10 and, if there is a defect, is taken out of the stream by the scraper. To trim the lateral edges, the sheet blank is fed into slitting shears 11. The sheet blank cut from all sides enters the mold 12 and the foaming furnace 13. The finished sheet of foam aluminum is removed from the mold and delivered to the receiving roller table of the furnace 14, where it is cooled and then fed to storage .

The proposed foamed aluminum sheet production line shown in FIG. 5, 6 and 7, contains:

The first unwinder with its roll strip 1; first bending mill 2; a vibrator 15 and mounted on it a draft and finishing batchers for supplying a powder mixture 3 (For - draft, 36 - fair), and the mechanism for advancing the lower part of the casing 16, made in the form of two or more drive three-roller groups of pulling rollers shown in FIG. 7, wherein the lower ^' roller of the group is double-supported with a groove in the central part of its barrel with a width and depth exceeding at least 2 mm the width and depth of the shell, and the upper rollers, left and right, are made by cantilever and contacting with the lower part of the shell on the width of the flanges.

The following are installed: a second unwinder 4; a mechanism for applying a flat roll strip of the unwinder to the lower part of the shell 17; second bending mill 5; mechanism for packaging the front end of the rolling billet 18; feed-through heating furnace 6; press shears 19; heat insulating wiring 7; rolling stand 8; volatile. scissors 9; deflection roller conveyor with deflector 10: slitting shears 11; live roll behind scissors slitting 20; Schlepper in front of the foaming oven 21; mold 12 and a foaming furnace for sheet blanks 13; a discharge roller table 22 and a slapper behind the furnace 14 for the removal of foamed sheet blanks; a section for extracting a sheet of foam aluminum from the mold 23 and a bypass rolling table for transferring the molds from this section to the slapper located in front of the foaming oven 24.

The work of the proposed line is as follows. A roll strip is continuously fed from the first unwinder to the molding of the lower part of the sheath in the first bending mill. The formed lower part of the shell, made of the base and side walls with flanges, is fed to the section of the vibrator, where the draft and finishing batchers fill the lower part of the shell with a powder mixture.

The movement mechanism of the lower part of the shell of Fig. 7, mounted on the body of a working vibrator, provides uniform movement of the lower part of the shell in the process of filling its inner cavity with a powder mixture. Roll strip from the second the unwinder is fed into the mechanism for applying a flat roll strip to the lower part of the shell. The assembled billet is taken by the second bending mill 5, rolling the flanged sections of the shell filled with a powder mixture. The front section of the shell 300 - 500 mm long, unfilled with the powder mixture, is adopted by the packaging mechanism of the front end of the molded billet.

In the continuous furnace 6, a continuously moving rolling billet is heated. In emergency situations or when the mill is technologically necessary to stop the mill, flying press shears installed behind the continuous heating furnace are put into operation.

The temperature of the rolling billet at its inlet to the work rolls is maintained by a heat-insulating wiring guiding the rolling billet into the closed caliber of the work rolls heated to a temperature of 150 - 300 ⁰ C.

The rolling stand compacts the powder mixture in the shell at a compression ratio of up to 62%.

The compacted workpiece emerging from the work rolls is fed into transverse cutting flying shears and cut by them into dimensional sheet blanks, which enter the longitudinal cutting shears to trim the sides.

A sheet blank cut from all sides by a roller conveyor is fed to the slapper in front of the foaming oven and installed in front of the shape of one of the chambers of the foaming oven. The pusher feeds the sheet blank into the mold, then the sheet blank into the foaming oven. After foaming, the mold with the foamed aluminum sheet is issued to the slapper installed behind the foaming oven for transportation to the extraction section of the foamed aluminum sheet from the mold, and the non-cooled form is fed to the splinter in front of the foaming oven, ready to receive the next sheet blank. Thus, the performance of hot compaction of the powder mixture in a shell formed directly in the production line is from two evenly fed. roll strips of unlimited length, while at the beginning of the first roll strip, the lower part of the shell is formed, including the base and walls with flanges, then, as it is filled with compacted vibration with a powder mixture, a second roll strip with a width equal to the width is applied to the lower part of the shell the upper surface of the lower part of the shell with flanges, and direct the workpiece to rolling flanged sections along the entire length, and the implementation of the proposed method in the production line of foam aluminum sheets I am in the form of an installation in front of the powder mixture feeding device of the powder mixture packaging device in a shell with a shape close to the shape of a rolling billet, including two bending mills, to form the lower and upper parts of the shell, equipped with their roll unwinders, while there is a transport mechanism between the bending mills advancement of the lower part of the shell, draft and finishing, the dispenser for filling the powder mixture into the shell and the mechanism for applying the upper part of the shell to its lower part The foamed aluminum sheet production line allows you to:

- reduce the cost of production of finished foam sheets due to the provision of:

- minimum energy consumption for heating for foaming and compacting the powder mixture in a rolling stand,

- high performance lines,

- increased mechanization and automation of the process,

- convenience of service, to increase the explosion and fire safety of the production of foam sheets.

Claims

Claim 1. A method for the production of foam aluminum sheets, including filling the powder mixture into a shell made of steel or aluminum alloys, heating the rolling stock from the powder mixture in the shell in a feed furnace to a temperature of at least 500 ° C, hot compacting the rolling stock, cutting the compacted rolling stock into sheet blanks of measured length, placing sheet blanks in a mold and subsequent high-temperature heat treatment for foaming at a liquidus temperature of the powder melt, characterized in that the formation of the shell is carried out from two evenly fed roll strips of unlimited length, while first from the first roll strip, the formation of the lower part of the shell, including the base and the walls with flanges, is performed, then, as it is filled with compacted vibration with a powder mixture, impose on the lower part of the shell a second roll strip with a width equal to the width of the upper surface of the lower part of the shell with flanges, and direct the assembled workpiece to. rolling flanged sections along the entire length. 2 .. A method for the production of foam aluminum sheets according to claim I _3, characterized in that the hot compaction of the powder mixture in the shell is carried out in a closed caliber of work rolls, while the depth of cut of the gauges is determined by the formula: R (l-cosa) + H- - h> - 2_ cos and where; h _n is the depth of cut of the caliber, α is the angle of capture; Δh - compression of the powder mixture; H is the thickness of the rolling billet. 3. A method of manufacturing sheets of foam aluminum according to any one of paragraphs.l, 2, characterized in that the work rolls for hot compaction of the powder mixture in the shell are lubricated with smokeless grease. 4. The production line of foam sheets containing a device for supplying a powder mixture for heating; a continuous heating furnace, a heated chute with rollers feeding the powder mixture for compaction, a hot compaction cage of the powder billets, a shear for cutting the compacted billets into sheet billets of measured length, a discharge roller table and a furnace for foaming sheet billets, characterized in that before a device for supplying a powder mixture to a heating device; a device for packing a powder mixture in a shell with a shape close to the shape of a rolling stock is installed its two bending mill to form upper and lower shell parts provided with their uncoiler roll strips, the mills are arranged between the bending transport mechanism advancing the bottom of the shell, roughing and finishing dispensers for filling into the shell of the powder mixture and blending mechanism top part of the shell. on its lower part. '' 5. The production line of foam aluminum sheets according to claim 4, characterized in that the mechanism for advancing the lower part of the shell is made in the form of two or more drive, three-roller groups of pulling rollers, while the lower roller of the group is made two-support with a groove in the central part of its barrel with a width and depth exceeding at least 2 mm the width and depth of the shell, and the upper rollers, left and right are made cantilever and in contact with the lower part of the shell only at the width of its flanges. 6. The production line of foam aluminum sheets according to claim 4, characterized in that the dispensers and the mechanism for promoting the lower part of the shell 1 ^" 5 shell powder packaging devices are mounted on the vibrator body. 7. The production line of foamed aluminum sheets according to claim 4, characterized in that in front of the furnace and behind it foaming are installed Schleppers perpendicular to the axis of the line. 8. The production line of foam aluminum sheets, 4 in each, characterized in that press scissors for transverse cutting of the rolled billet are installed behind the feed-through furnace. 9. The foam aluminum sheet production line, according to any one of paragraphs 4, 8, characterized in that scissors for longitudinal cutting of the side edges of the sheet blank are installed behind the discharge roller table. 10. The foam aluminum sheet production line according to claim 4, characterized in that work rolls with internal heating are installed in the casing in the casing of the hot compacting of the powder mixture.