RU2284236C1 - Tool for compacting charge materials - Google Patents

Abstract

FIELD: electric metallurgy, possibly manufacture of consumable electrodes for melting highly reactive metals and alloys, particularly for melting ingots of titanium and it alloys.

SUBSTANCE: tool includes body fixed to ram and having cone like protrusion coaxially formed at side of working end and supporting movable sleeve having cone opening and working surface. Inner surface of movable sleeve is provided in addition with cylindrical portion supporting members for restricting axial motion of sleeve. There is step between cylindrical and cone surfaces of movable sleeve. Working surfaces of cone protrusion and of movable sleeve are shaped ones. When movable sleeve is in its upper limit position said working surfaces are adjoined one to other. It provides elimination of gaps between pressure pad and die at working stroke of press.

EFFECT: lowered efforts for removing pressure pad out of die, uniform specific pressure at pressing between outer layers and mean part of electrode.

1 dwg

Description

The invention relates to the field of electrometallurgy and can be used in the manufacture of consumable electrodes for melting highly reactive metals and alloys, in particular for the smelting of ingots from titanium and its alloys.

A known method of semi-continuous pressing through a cone matrix into a compound electrode for vacuum arc melting of titanium alloys (Melting and casting of titanium alloys. Edited by V.I.Dobatkin. M., Metallurgy, 1978, S. 265-271, Fig. 107, 108 )

The known method of pressing allows to obtain a sufficiently long and uniform cross-sectional electrode with a good surface and acceptable curvature from bulk materials that differ from each other in shape, density, mass, size, coefficient of friction between themselves and the walls of the matrix. The working matrix is heated to 100-200 ° C in order to obtain the optimal coefficient of friction between the electrode and the walls of the matrix. It is known that titanium alloys, regardless of their type and geometrical dimensions, are prone to contact setting (increased adhesion both between themselves and with other metals). Fine fractions of the charge, mainly a titanium sponge, which makes up 60-95% of the total volume of the pressed electrode, easily penetrate into the gap formed by the press washer and the matrix wall, where they accumulate and adhere to their surfaces, forming jumpers that impede the movement of the stamp. The electrode is pushed through the matrix in jerks. This leads to a decrease in the density and strength of the electrode, increases the likelihood of its breaking during dressing and transportation. A similar process is especially characteristic for alloys with a small amount of ligature and waste.

The strength of the jumpers formed during the pressing process can reach critical values. Cases of jamming of the press washer in the container and breakage of the shank of the press stamp during the reverse stroke of the press were observed.

A known method of manufacturing a consumable electrode for smelting ingots of high alloy titanium alloys (RF patent 2015845, IPC B 22 F 3/02, publ. 07/15/1994.), Including mixing bulk materials, feeding them into a cone matrix, pressing the mixture with simultaneous bursting through the die in one stroke of the punch, while the punch press washer is equipped with a curly working surface. The last portion of the charge is pressed with a press washer having a flat working surface that forms a similar surface at the end of the electrode.

The pressing occurs due to the compression resistance of the pressed electrode when it is pushed through the die. The disadvantage of this method is that the specific pressure near the walls of the mold is several times greater than in the central part of the electrode. In this regard, the movement of the sponge in the middle part of the electrode is ahead of the movement of the sponge in its outer layers, as a result of which tensile stresses arise in its outer layers, leading to the formation of cracks; the strength of the electrode decreases, which can lead to breakage or breakage in the furnace. The figured surface of the press washer redistributes the diagram of the stresses arising in the electrode, but does not eliminate them.

Known composite press washer, made in the form of a housing with a conically aligned conical protrusion on the side of the working end for installing a removable ring with a conical hole, the angle of the cone made more than the friction angle, and the diameter of the smaller base of the conical hole of the ring made less than the diameter of the upper base conical protrusion (RF patent 2238812, IPC B 21 C 25/00) - prototype.

This design is used in the processing of metals by pressure in the production of profile products, mainly pipes of high accuracy. It can be used with cyclic technology, as requires installation on the press stamp at the beginning of each working stroke. In addition, it does not prevent the formation of jumpers between the side surfaces of the stamp and the die.

The tasks to which the invention is directed are:

- ensuring the stability of the pressing force by preventing the formation of jumpers from the charge material in the gaps between the movable and stationary nodes of the pressing tool;

- increase the strength characteristics of the pressed electrode;

- prevention of emergency situations during pressing, leading to breakage of the pressing tool.

The technical result achieved by the implementation of the invention is:

- elimination of gaps between the press washer and the matrix during the working stroke of the press;

- reduction of efforts when removing the press washer from the matrix due to the formation of a gap between their surfaces during the reverse stroke of the press;

- equalization of specific pressure during pressing between the outer layers and the middle part of the electrode.

The specified technical result is achieved by the fact that the tool for compacting charge materials, comprising a housing fixed to the press stamp with a conical protrusion coaxially located on the side of the working end with a working surface on which a sleeve with a working surface is mounted with the possibility of axial movement, the inner surface of the sleeve is made with a conical and cylindrical sections, a ledge between them and located on the cylindrical section of the axial movement of the sleeve, the worker the surfaces of the conical protrusion and the movable sleeve are made curly from the condition of ensuring interfacing with each other at the extreme upper position of the movable sleeve.

The invention is illustrated by the drawing, which shows a diagram of the operation of the press washer (in the left half - the beginning of the working stroke, in the right - the end). The prefabricated press washer comprises a housing 1 with surfaces: conical 2 and working 3, a movable sleeve 4 with surfaces: conical 5, cylindrical 6, working 7 and ledge 8, axial displacement clamps 9, consisting of pins 10 that move in grooves 11, located in the press stamp 12, the sleeve and the centering ring are mated on a conical surface with a cone angle γ.

The press washer works as follows: before pressing, the cone die is sealed with a gasket. After receiving the initial briquette, the gasket is removed from it. Further pressing occurs due to the compression resistance of the pressed electrode when it is pushed through the die.

At the initial moment, when the press washer is fed into the container, the sleeve is freely suspended on the axial displacement clamps 9, then the working surface of the sleeve 7 abuts against the charge and is pressed onto the housing 1 along the conical surfaces 2, 5. Due to deformation, the outer diameter of the sleeve increases, while the elastic state of its material is maintained. The maximum increase in the outer diameter of the ring can approximately reach 0.02% of the nominal size and is limited by the walls of the container. In this case, a practical choice is made of the gap between the outer surface of the sleeve and the inner surface of the matrix, which completely excludes the ingress of charge particles between them and the formation of jumpers. In this case, the movable sleeve is self-centered on the inner wall of the matrix, and the body of the press stamp on the axis of the sleeve, which ensures the accuracy of the application of the pressing forces of the electrode, and as a result, its minimal curvature. At the initial moment, pressure on the charge is carried out near the matrix walls by the working surface 7 of the movable sleeve 4, causing the charge to move into the middle part of the electrode and actively mix it. Gradually, the working surface of the conical protrusion 3 moves beyond the working surface of the sleeve 7 and mates with it, forming a common working surface. There is a redistribution of the specific pressing pressures between the outer layers and the middle part of the electrode. First they align, then in the middle of the electrode the specific pressure becomes larger. The mixture moves to the outer surface of the electrode and additionally moves under pressure. As a result, friction welding occurs and volumetric stresses are eliminated. The movement of the movable sleeve 4 is limited by a step 8, which abuts against the end face of the press stamp 12. During the reverse stroke of the press, the housing 1 and the movable sleeve 4 are easily moved relative to each other, because the angle of the conjugation cone γ is made larger than the angle of friction. A gap is formed between the die and the pressing tool, which guarantees the pressing tool from jamming and breaking of the shank of the press stamp. The movement of the movable sleeve 4 during the reverse stroke of the press is limited by the clamps 9 with the help of pins 10 and grooves 11 made in the press stamp 12. The end face of the cylindrical part 6 of the sleeve when pressing is always above the level of the charge, which ensures that the charge does not fall into the cavity formed by the surfaces of the press stamps and bushings.

A tool for compacting charge materials can also be used for pressing briquettes.

Thus, the proposed tool for compacting charge materials allows you to:

- have increased mechanical strength of the electrode (in comparison with known technologies), eliminating the possibility of breakage during transportation and its breakage during the melting process by minimizing the internal stresses of the pressed products;

- increase the accuracy of pressing products (geometric dimensions) by means of self-centering of the tool relative to the axis of the container;

- increase the density of the electrode to reduce its length and, accordingly, the height of the furnace as a result of good mixing of the charge material in the pressing process;

- increase the reliability of the pressing tool, ensuring ease of extraction of the pressing tool during the reverse stroke of the press;

- increase the maintainability of the pressing tool, compensating for the wear of the inner surface of the matrix by selecting the outer diameter of the movable sleeve.

Claims (1)

A tool for compacting charge materials, comprising a housing fixed to the press stamp with a conical protrusion coaxially arranged on the side of the working end with a working surface on which a sleeve with a working surface is mounted with the possibility of axial movement, characterized in that the inner surface of the sleeve is made with a conical and cylindrical sections, a ledge between them and located on the cylindrical section of the axial movement of the sleeve, the working surface of the conical protrusion and the movable sleeve is made curly from the condition of ensuring pairing with each other at the extreme upper position of the movable sleeve.