RU1656772C - Apparatus to produce used up electrodes - Google Patents

Abstract

FIELD: powder metallurgy. SUBSTANCE: in process of layer by layer pressing of electrode the latter is passing through first guiding bush 3 with inner ribs 4. Ribs 4 generatrix inclination angle to axis of bush 3 is in limits of 0.5 - 8 dwg and height of rib 4 lower base is equal to 0.01 - 0.08 of bush 3 hole diameter. Ribs 4 pressure makes grooves along the whole length of electrode, so increasing its strength. EFFECT: increase of electrodes strength. 3 dwg

Description

 The invention relates to powder metallurgy, in particular to a device for producing products by compaction of a granular medium consisting of metal components.

 The aim of the invention is to increase the strength of the electrodes.

 In FIG. 1 shows a device for producing consumable electrodes; in FIG. 2 - the first guide sleeve, section; in FIG. 3 - the same, with removable ribs, top view.

 A device for producing consumable electrodes consists of a container 1 in which a matrix 2 is mounted. A first guide (calibrating) sleeve 3 adjacent to the conical ribs 4 is adjacent to the lower end of the matrix 2. A second guide sleeve 5 is installed behind the sleeve 3. Pressing is carried out with a press stamp 6 .

The angle α of inclination of the forming ribs 4 to the axis of the sleeve 3 is in the range of 0.5-8 ^about . The height h of the lower base of the rib 4 is 0.01-0.08 of diameter d _{1 of the} hole of the sleeve 3, which, in turn, is no more than 5 mm larger than the diameter d _{2 of the} hole of the matrix 2.

 The device operates as follows.

 The mixture is poured into the cavity of the matrix 2 layer by layer and pressed by a press stamp 6. As the compacts pressed in the matrix move through the first guide sleeve 3 provided with inner ribs 4, the latter force smoothly push the surface areas of the compacts, forming depressions along the entire length of the electrode. In the surface layers of the recesses, the charge elements receive additional compaction and interlocking. In addition, due to the friction forces in the recesses, a certain redistribution of the charge elements occurs, and at the junction of the compacts, the surface layers of the previous compact are transferred to the next compact, increasing the adhesion forces between them and eliminating surface cracks and voids. The finished consumable electrode has concave stiffeners evenly spaced on the side surface, increasing its strength.

 The design of the ribs of the first guide sleeve cone-shaped with an increase in the cross section to its lower end causes a gradual increase in the friction and compression forces acting on the charge in the direction of pressing, which ensures the hardening process of the pressed electrode.

The optimal angle of inclination of the generatrix of the ribs to the axis lies in the range of 0.5-8 ^about . When reducing the angle ^of not less than 0.5 provides the necessary sealing surface layers formed on the electrode concave ribs. With increasing angle of more than 8 ^{on the} friction forces increase to such an extent that requires additional compressive force, leading to perepressovke material.

 The optimal height of the lower base of the ribs is 0.01-0.08 diameter of the axial hole of the sleeve. When reducing the height of the lower base of the ribs to less than 0.01 of the diameter of the sleeve bore, electrode hardening is not achieved due to the low height of the ribs, which is comparable with the difference in the diameters of the outlet of the matrix and the inlet of the first guide sleeve. When increasing the height of the lower base of the ribs more than 0.08 of the diameter of the hole of the sleeve within the specified limits of the angle of inclination of the ribs the height of its upper base goes beyond the dimensions of the outlet of the matrix, which leads to a locking effect of the process.

 The number of ribs may vary. For example, in the manufacture of electrodes of small diameters (less than 350 mm) 4 ribs are enough, in the manufacture of electrodes of medium diameters (within 350-600 mm), 6 ribs must be installed, and in the manufacture of electrodes with a diameter of more than 600 mm, 8 ribs are required. Structurally, the ribs can be removable, which allows them to be replaced when worn.

In this case, the first guide sleeve is manufactured as follows. The workpiece is bored to a diameter less than the diameter of the axial hole of the sleeve-matrix by 35 mm. In the body of the sleeve with a drill with a diameter of 10-80 mm at an angle of 0.5-8 ^about to the axis, the required number of blind holes are drilled, not reaching the lower end of the workpiece 5-30 mm, and then in the remaining jumper at the same angle with a drill with a diameter of 2- 5 less than the first, make a through hole. Bore the axial hole of the sleeve to a diameter of 5 mm larger than the diameter of the axial hole of the sleeve-matrix. Heat-treated rods, the diameter of which corresponds to the diameter of the blind hole, are inserted into the obtained nests, and they are processed flush with the upper end of the sleeve. Next, the assembly of the device for producing consumable electrodes is carried out in a known manner.

EXAMPLE 1. Pressing a consumable electrode with a diameter of 495 mm from bulk and lump components of a titanium charge is performed on a vertical specialized hydraulic press with a gain of 10,000 tons. Diameter d _{2 of the} hole of the sleeve of the matrix 2 is 495 mm, diameter d _{1 of the} hole of the first guide ( calibrating) sleeve 3 is equal to 500 mm. The first guide sleeve 3 of steel 5XHM is equipped with six conical ribs 4 made of steel SHX15. The angle α of inclination of the forming ribs to the axis is 0.5 ^about ; the height h of the base of the ribs on the lower end of the sleeve is 5 mm, which is 0.01 d ₁ . The ribs are formed by high-strength heat-treated rods with a diameter of 30 mm.

 The pressing of the electrode is carried out as follows.

 The finished electrode has six recesses on its lateral surface - “concave stiffening ribs” in the form of compacted surface sections of the charge. The strength of the obtained electrode is 1.2 times the strength of the electrode pressed on the same press using the prototype device.

PRI me R 2. The pressing of a consumable electrode with a diameter of 650 mm is performed on a press with a force of 10,000 tons (d ₂ = 650 mm; d ₁ = 660 mm). The first guide (calibrating) sleeve is equipped with eight ribs (α = 8 ^° ; h = 0.08; d ₁ = 52.8 mm). The finished electrode has 8 recesses.

 The strength of the electrode increases by 4-5 times in comparison with the electrode pressed in the prototype device, which is confirmed by a static analysis of the cases of destruction of the electrodes during the pressing process and subsequent operations associated with its melting.

PRI me R 3. Pressing a consumable electrode with a diameter of 515 mm is performed on a press with a force of 10,000 tons. The first guide (calibrating) sleeve having d ₁ = 520 mm is equipped with six inner ribs (α = 4 ^° ; h = 0.03 ; d ₁ = 15.6 mm). The strength of the electrode according to statistical data increased by 2.3 times.

 A device for producing consumable electrodes in comparison with the prototype provides an increase in the strength of the extruded electrode due to the discrete compaction of its surface layers directly during pressing, which reduces the number of scrap and breaks of the electrodes and increases the reliability of the process of their subsequent remelting in vacuum arc furnaces.

Claims (1)

DEVICE FOR PRODUCING CONSUMABLE ELECTRODES, containing a container, matrix, press stamp and a system of guide bushings, characterized in that, in order to increase the strength of the electrodes, the first guide bush is made with internal conical ribs, the angle of inclination of the generatrix to the axis of the bush is within 0 , 5-8 ^o , and the height of the ribs at the lower base is 0.01-0.08 from the diameter of the holes of the sleeve.

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