RU2140355C1 - Method and device for hot moulding of products of powdered material (alternative embodiments) - Google Patents

Abstract

FIELD: building industry, applicable for manufacture of high-strength concrete and reinforced-concrete products. SUBSTANCE: in the method for hot moulding of products of powdered material by dies moulding of loosely filled powdered material between the readily deformable separating wall and greased moulding die transferring heat is accomplished by loading the intermediate medium by the tapered surface of the loading die, when it moves in the duration perpendicular to the direction of moulding, towards the vertex of the taper angle of the die tapered surface. The device has a moulding die with heating elements, loading die in the form of a tapered yoke, intermediate powder medium, separating readily deformable wall. Gas- discharge ducts are made in the insert base. A guide surface is made in the lower part of the loading die. The inner surface of the loading die upper part is step-wise conjugated with the tapered surface of the lower part. The heating elements may be installed on the outer surface of the moulding die. EFFECT: reduced power consumption, specific consumption of materials, enhanced capacity. 4 cl, 2 dwg

Description

 The invention relates to the construction industry and can be used for the manufacture of high-strength concrete and reinforced concrete products (pipes, supporting structures, etc.).

 It is known to use hot pressing for pressing cement stone with a pressure of 50/250 MPa, which allows the formation of a cement stone that surpasses the cement grade in strength indicators by 8-10 times, i.e. the material obtained by strength indicators is 3-5 times stronger than steel (see A. A. Pashchenko, member of the Academy of Sciences of the Ukrainian SSR, etc. "Formation of the structure of pressed cement stone. Journal" Cement "N 1, 1990, p.21 -22).

 In this case, the hot pressing of cement stone was carried out in laboratory devices that do not allow the manufacture of large products in the form of pipes, supporting structures, etc.

 Thus, the hot pressing of concrete products reduces the consumption of concrete and cement by increasing the strength characteristics of concrete. For example, increasing the strength of concrete can reduce the wall thickness of the pipe, i.e. reduce material consumption for pipe manufacturing.

 A known method of hot pressing products from metal powders, including pre-molding the workpiece and its hot isostatic pressing in a mold by transferring pressure through a granular medium with preliminary heating and pressing of a granular medium under a pressure equal to the pressure of the isostatic pressing at a temperature not exceeding the sintering start temperature material of the workpiece (see AS 1007731, MKI B 22 F 3/14).

 The disadvantage of this method of hot pressing is the difficulty in implementing due to the need for preforming of the workpieces (equipment for preliminary and final pressing of the workpieces is required), which leads to increased energy consumption and low productivity (time is spent on preforming the workpieces).

 There is also known a method and apparatus for sintering powder in a powder filler, which consists in the fact that the sintered metal powder is introduced into the porous mass of a granular refractory filler, which uniformly transfers pressure to the sintered powder, and then the porous filler is placed in a plant with which multiaxial compression is carried out powder, informing the mass of the effort, the axes of which intersect in the center of the porous mass, with each axis directed at right angles to adjacent axes, simultaneously with the application of pressure along true excipient heated sintering embedded therein a metal powder. In the first stage of sintering, independent efforts of the first magnitude are simultaneously applied to the porous filler, which act sequentially and cyclically on the sintered powder, in the third final stage, simultaneously, third forces are applied to the filler, which exceed the forces in the second stage of sintering (see US patent 4414028, MKI B 22 F 3/14, B 22 F 3/16, NKI 419/31).

 However, this method of hot isostatic pressing of powders has the following disadvantages.

 Firstly, this method is difficult to implement, because multilateral application of pressure by punches requires sophisticated equipment (hydraulic cylinders, dies, etc.), while the movement of punches in the specified method requires complex adjustment of the pressing equipment.

 Secondly, the specified method of loading the punches with an intermediate powder among strictly in the direction of movement of the punches requires significant energy.

 Thirdly, the specified method does not allow to produce hollow products (pipes), which reduces the scope of this method, i.e. technological capabilities of the method.

 The closest in technical essence and the achieved effect is a device for A. with. N 1016068, cl. In 22 F 3/02, 1981, containing an elastic matrix, a forming punch, a clip with an inner conical surface, an insert, upper and lower segments and a device for a.s. N 1265010, CL In 22 F 3/02, 1986, containing an elastic matrix, a punch made in the form of a conical mandrel, a clip, a cover, a pallet, spring rings, segments and fasteners.

 The specified method due to the wedge allows you to apply significant pressure to the pressing material (up to 700 MPa) at relatively low external pressure on the end face of the wedge.

The disadvantage of this method of pressing is that it cannot be used for hot pressing due to the fact that the elastic matrix is destroyed at temperatures above 100 ^o C. In addition, devices of the known method do not allow heat to be applied to the pressed powder mixture.

 The objective of the invention is the expansion of technological capabilities, reducing energy consumption, material consumption of compressed products, increasing productivity and simplifying devices of the method of hot pressing of products.

 This problem is solved in that the free-sprinkled powdery material is pressed between an easily deformable separation wall and a heat-forming forming punch lubricated by heat transfer by loading the intermediate powder medium without heating it with the conical surface of the loading punch while moving it in the direction perpendicular to the pressing direction, away from the top of the taper angle the surface of the punch, while the hot-pressing device with a pore press the gusset-like material on the outer surface of the forming punch is provided with an intermediate powder medium, an easily deformable dividing wall, heating elements installed in the cavity of the forming punch, a latch, a liner and grease placed on the outer surface of the forming punch, while channels for exhausting gas are made in the base of the insert, and the loading punch is made of two parts - the upper and lower, and on the lower part of the loading punch a guide p is made the surface mating with the surface of the base, and the inner surface of the upper part of the loading punch is stepped in conjunction with the conical surface of the lower part. The hot-pressing device for hollow products with pressing powder material onto the inner surface of the forming punch is provided with an intermediate powder medium, an easily deformable dividing wall, heating elements mounted on the outer surface of the forming punch, and channels for exhaust gases are made in the pallet and cover of the device, and the upper guide part loading punch is stepped in conjunction with a conical surface.

 The proposed method of hot pressing is illustrated by the following devices.

 Example 1

 In FIG. 1 shows a device for hot pressing hollow products in the form of pipes with a pressing of powdered material on the outer surface of the forming punch.

 The device contains a hollow loading punch in the form of a conical cage, consisting of upper 1 and lower 2 parts, an intermediate powder medium 3, an easily deformable wall 4, a base 5, a forming punch 6, heating elements 7, a lubricant 8 laid on the outer surface of the forming punch 6, liner 9 and latch 10.

 The device operates as follows.

 First, a lubricant 8 is applied to the forming punch 6, and then a dividing wall 4 is installed on the base 5 with the forming punch 6. After that, the pressed powder is poured into the gap between the forming punch 6 and wall 4. Next, install the lower part 2 of the loading punch and into the cavity formed by the wall 4 and the inner surface of the lower part 2 of the loading punch, fill in the intermediate powder medium 3, install the liner 9, fix it with the latch 10 and add the refractory mass 3 to the upper end of the lower part 2 of the loading punch. After that, put on the upper part 1 of the pressing punch. Having completed the assembly of the device, the heating devices 7 are turned on and the forming punch 6 is heated, which in turn brings heat to the pressed powder material (powder). Then, a force is applied to the upper part 1 of the loading punch by a press (not shown in FIG.). Under the action of the press, the upper 1 and lower parts of the loading punch are moved vertically to the side from the top of the corner of the conical surface of the punch and the pressed powder is pressed through the powder medium 3 and the separation wall 4 to the forming punch 6. In this case, to enhance the pressing effect and equalize pressure the height of the molded product part of the granular mass between the inner surface of the part 2 of the loading punch and the liner 9 by the step of the upper part 1 of the loading punch moves inside l camera device.

 In the process of pressing powdered material at high temperature, air and gases are released from it, which are discharged through special channels made in the base 5 and insert 9.

 At the end of the pressing process, the heating elements 7 are turned off and the device is cooled. After that, the loading punch (parts 2 and 1), the powder medium 3 are removed, the retainer 10 with the insert 9 are also removed and the pressed product is removed.

 To obtain the next product, the cycle is repeated again.

 Example 2

 In FIG. 2 shows a device for hot pressing products with a pressing of powdered material on the inner surface of the forming punch.

 The device contains a loading punch 1 in the form of a conical mandrel with a step and with upper and lower guide parts, an intermediate powder medium 2, an easily deformable dividing wall 3, a forming punch 4, on the inner surface of which is lubricated 5, a cover 6, a pallet 7, fixing elements 8 and heating elements 9.

 The device operates as follows.

 First, a loading punch 1 is inserted into the opening of the pallet 7, the loading part of which is interfaced with the opening of the pallet 7, and then a forming punch 4 is installed on the pallet 7, attaching it to the pallet 7 with fixing elements 8 and applying grease 5 to its inner surface. After that, a separating wall 3 is installed on the pallet 7 and the pressed powder material (powder) is filled in the cavity formed by the wall 3 and the inner surface of the forming punch, and an intermediate powder medium 2 is filled in the cavity between the loading punch 1, the separation wall 3 and the cover 6. Next, install the upper cover 6 and fasten it with the fixing elements 8 to the forming punch 4. When finished, turn on the heating elements 9 and heat the forming punch 4, which in turn odvodit heat to compressible powder. After that, a force is applied to the loading punch 1 by a press (not shown in FIG. 2). Under the action of the press, the punch 1, moving along the axis of the device, unclenches the intermediate powder medium 2 with a conical surface, which in turn transfers pressure to the pressed powder through the separation wall 4. Moreover, to enhance the pressing effect and equalize the pressure along the height of the pressed product, part of the granular mass 2 between the surface of the opening of the lid 6 and the surface of the loading punch 1 is moved by the step of the loading punch 1 inside the chamber of the device.

 In the process of pressing the powdered material at high temperature, air and gases are released from it, which are discharged through special channels made in the pallet 7 and cover 6.

 At the end of the pressing process, the heating elements 9 are turned off and the device is cooled. After that, the loading punch 1 is returned to its original position, the lid 6 is removed, the powder medium 2 is poured, the product is removed.

 To obtain the next product, the cycle is repeated again.

 As a material of the dividing wall (4 in Figs. 1 and 3 in Fig. 2), it is possible to use tin from steel X18H9T, and as an intermediate powder medium (3 in Figs. 1 and 2 in Fig. 2), for example, powder can be used crystalline graphite grade GL-1 according to GOST 5279-74.

These devices were designed for pressing products in the form of pipes. The following materials were used as pipe material:
1) Portland cement with a / c = 0.125.

 2) "dry" concrete mixtures (the composition of the mixtures will be patented).

A pressing pressure of 50 MPa was used at a temperature of 200 ^o C. The strength of the sample pipe from Portland cement in comparison with GOST increased by 200%. The strength of concrete samples in comparison with GOST increased by 100%.

 For the manufacture of faceted hollow products, the forming punch can be made faceted, and accordingly, the loading punch can be made in the form of a faceted conical prism or a conical holder with faces.

 For the manufacture of solid products, the forming punch is flat.

 The execution of the step (s) on the loading punch leads to a uniform distribution of pressure along the height of the product (pipe), i.e. to the isostaticity of the pressing process, with several steps on the loading punch can be performed several (when pressing large items).

 From the above description of the method it can be seen that the proposed method of hot pressing allows the manufacture of products of various shapes (pipes, hollow and solid supporting structures), which extends the technological capabilities of the proposed method and comparison with the known, and thereby the aim of the invention is achieved - the expansion of technological capabilities of the method.

 Further, the above examples of the method show that loading the pressed powder through the intermediate powder medium by the conical surface of the loading punch (parts 1.2 in FIG. 1, detail 1 in FIG. 2) allows, in comparison with the known method, to reduce energy costs for manufacturing one product per due to the application to the loading punch of a lower external pressure than during direct compression in the known one by using the wedge effect in the proposed method, i.e. to achieve the goal of the invention is to reduce energy consumption.

 In addition, the location of the heating elements directly at the forming punch leads to a reduction in heat loss, i.e. no need for heating the intermediate powder medium. In the known method, the intermediate powder medium is also heated during pressing. Thus, energy costs for manufacturing products are also reduced.

 The execution of gas outlet channels in the process devices leads to the elimination of the operation of evacuation of the pressed powder material, which leads to an increase in productivity, i.e. to achieve the objective of the invention is to increase productivity.

 The above examples 1 and 2 show that in the proposed method, in comparison with the known method, there is no need for hydraulic cylinders, dies, pre-compaction of the pressed powder, vacuum operation, etc., which achieves the aim of the invention is to simplify the hot pressing method.

 Further, as already mentioned above, hot pressing allows you to increase the strength of cement stone by 8-10 times, which in turn allows you to reduce the wall thickness of a concrete pipe by 2-3 times on average compared with the walls of pipes obtained by traditional technologies, and, thus Thus, reduce the material consumption of the pipe.

 Thus, the proposed method of hot pressing reduces the material consumption of products, and this is the purpose of the invention is to reduce the material consumption of products.

 From the above it follows that the new features of the proposed method create a positive effect and thereby meet the criterion of "significant differences".

Claims (3)

 1. A method of hot pressing articles of a powder material with punches through an intermediate powder medium and a dividing easily deformable wall, characterized in that the pressing of a freely poured powder material between an easily deformable dividing wall and a lubricated heat-transfer forming punch is carried out by loading the intermediate powder medium without heating it, the conical surface of the loading punch when moving it in a direction perpendicular to to the pressing board, away from the top of the taper angle of the conical surface of the punch.  2. A device for hot pressing hollow articles of a powdery material containing a forming punch, loading the punch in the form of a conical cage and a base, characterized in that it is provided with an intermediate powder medium and a dividing easily deformable wall, heating elements installed in the cavity of the forming punch, a latch, liner and grease placed on the outer surface of the forming punch, while in the base of the liner there are channels for exhaust gases, and The pressing punch is made of two parts - the upper and lower, and on the lower part of the loading punch there is a guide surface mating with the surface of the base, and the inner surface of the upper part of the loading punch is stepwise mated with the conical surface of the lower part.  3. A device for hot pressing hollow articles of a powdery material containing a loading punch in the form of a conical mandrel having upper and lower guiding parts, a clip, a cover and a tray, characterized in that it is provided with an intermediate powder medium and a dividing easily deformable wall, heating elements, mounted on the outer surface of the forming punch, while in the pallet and the lid of the device channels are made for the removal of gases, and the upper guide part of the loading punch on stepwise conjugated with a conical surface.

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