RU93712U1 - INSTALLATION FOR PRODUCING SOLID-ALLOY ELECTRODES FOR ELECTRIC SPARK ALLOYING - Google Patents

Abstract

 A device for the manufacture of electrodes for electrospark alloying containing a press, an automatic control unit, a mold, a container having a mixture cavity, a cover and an external annular stop, an initiation system, a punch, a thermally insulated guide gauge connected in the upper part with a matrix having a forming belt, characterized in that the length of the forming belt is 10 ... 20 mm, and the matrix is made of steel 45X.

Description

The utility model relates to the field of production of carbide electrodes for electrospark alloying (ESA) from refractory inorganic materials by the method of combining self-propagating high temperature synthesis (SHS) and extrusion.

A known installation for the manufacture of electrodes for spark alloying by combining SHS and extrusion, containing a press with a control system and a mold comprising a section container, a press washer, a die and a punch with an initiating device made in the form of a tungsten spiral (V.V. Podlesov , A.M. Stolin, A.G. Merzhanov, SHS-extrusion of electrode materials and their application for electrospark alloying of steel surfaces. Engineering Physics Journal, vol. 63, No. 5, pp. 636-647). The installation allows to obtain carbide electrodes for electrospark alloying from refractory inorganic materials.

The disadvantages of the known installation is the low productivity and unsatisfactory quality of the products, expressed in the heterogeneity of the properties in terms of volume (length) of the products.

The closest to the claimed utility model in technical essence and the achieved result is a device for the manufacture of long products from powder materials, which includes a press, an automatic control unit, a mold, a container having a cavity for the mixture, a lid and an external annular stop, a matrix with an angle conical part 120 ° and with forming belt, initiation system, punch, thermally insulated caliber (RU 2013186 C1, 05/30/1994).

A disadvantage of the known technical solutions is the use of a matrix with a long forming belt equal to 5 ... 7 mm, which leads to low reproducibility and lower productivity of the SHS-extrusion process, as well as poor quality of the obtained rods.

The technical result of the proposed utility model is to increase the productivity of the device, increasing the length, quality, resulting electrodes and their number in one working cycle.

The technical result is achieved in that the device for the manufacture of electrodes for spark alloying, containing a press, an automatic control unit, a mold, a container having a mixture cavity, a lid and an external ring stop, an initiation system, a punch, a thermally insulated guide gauge, in the upper part associated with the matrix having a forming belt, according to a utility model, the length of the forming belt is 10 ... 20 mm, and the matrix is made of steel 45X.

As shown by experimental studies, the length of the forming belt of the matrix L (Fig. A, b) has a strong effect on the mechanical stability of the material flow during extrusion and shaping of the product. For the prototype, at L ~ 0 ... 7 mm, the material flow through the matrix is unstable, the material is not molded and squeezed out in the form of reacted powder and individual compacted rods 20 ... 50 mm long. The reproducibility of the SHS extrusion process is low. An increase in the length of the forming belt for the claimed utility model leads to stability of the extrusion mode, surface quality and straightness of the electrodes are improved, and reproducibility of the SHS extrusion process is increased. Upon reaching some optimal value L = 10 ... 20 mm, a further increase ceases to have a noticeable effect on the length of the extruded rods. The standard length of the electrodes for ESA is 40 ... 50 mm, therefore, the yield of suitable electrodes for one working cycle of SHS extrusion for the claimed utility model is up to 5 times higher than for the prototype. By using a matrix of low alloy steel (45X steel), the cost of manufacturing electrodes is reduced.

The essence of the utility model is illustrated by the schematic diagram of the device shown in Fig., Which includes a two-layer container 1 with a top cover, where the device 2 for initiating the reaction, the press washer 3 and the initiating spiral 4 are inserted. The matrix 5 with the length of the forming belt L = is included in the design 10 ... 20 mm (for clarity, the belt 14 is highlighted separately in Fig. B) and a temperature sensor 6 (thermocouple), plugs 7, punch 8 with a guide insulating gauge 9 inserted inside it. Inside the container there is a blank 10, t insulated from the walls of the container with asbestos cloth 11. Outside the container there is an annular stop 12, on which additional loads 13 are hung, increasing, if necessary, the mass of the container.

The device operates as follows.

The preform 10, pressed from the initial charge, is coated along the edges with asbestos cloth 11, placed through an opening inside the container 1. A heat-insulating guide gauge 9 is inserted into the inner cavity of the punch 8, a matrix 5 with an integrated thermocouple 6 is placed on top, the conclusions of which are fixed to the punch. A container 1 with a blank placed inside it is put on this design so that the terminals of the temperature sensor fit into the groove of one of the exhaust channels. Previously, a lid with a fixture 2 is inserted into the container to initiate a reaction. Thus, the workpiece is loaded with the entire mass of the container, including additional rings on its outer side. After that, the control system is turned on and the exothermic mixture ignites inside the container. During combustion and after its completion, due to the mass of the container with additional weights, the workpiece is compacted to a certain porosity, the temperature of the material drops from the temperature developed during combustion to the extrusion temperature specified by the holding device. When this temperature is reached, the pressure is turned on and the press slider comes into kinematic contact with the mold cover and, at a pressure of 20-100 MPa, the combustion products are extruded into a guiding insulated caliber. The plug extends when a certain pressure is reached. At the end of the pressing time set by the control system, a command is issued to raise the plunger, and it returns to its original position. A specific installation option is based on a P6324D hydraulic press with a maximum force of 20 T. The internal diameter of the mold is 35 mm. The container is made of steel 45, the punch is made of HVG steel, the die is made of steel 45X, the plug is made of steel 3, the guiding gauge is made of steel 12X18H9T, and it is insulated with quartz glass.

The essence of the utility model is confirmed by examples.

Example 1 (prototype).

The initial mixture of powders of titanium, nickel and soot (charge) is mixed in a ball mill for 24 hours with the following ratio of components wt.%: Ti - 56; C - 14; Ni - 30.

From the resulting mixture, tablets with a diameter of 25 mm and a mass of 30 g are formed and placed in a mold, the diameter of the outlet of the matrix is 3 mm.

After initiating the reaction, passing the SHS front and holding to the desired material temperature for several seconds, the product is extruded at a given speed. Extrusion is carried out through a thermally insulated conical matrix with an angle of the conical part 120 and the length of the forming belt 5 mm.

A poorly compacted reacted powder is squeezed out and rods 20 ... 50 mm long with a scaly surface.

The number of suitable electrodes for ESA per one working cycle is 0 ... 1 pc.

An increase in the forming belt to 7 mm increases the number of suitable electrodes for ESA in one working cycle to 2 pcs.

Example 2

Under the conditions of example 1, the burnt charge is squeezed out through a thermally insulated matrix with a length of the forming belt 10 mm.

The length of the extruded rods is 120 ... 165 mm. The surface of the extruded rods is smooth.

The number of suitable electrodes for ESA in one working cycle is 4 pcs.

Example 3

Under the conditions of example 1, the burnt charge is extruded through a heat-insulated matrix with a length of the forming belt 15 mm

The length of the extruded rods is 135 ... 170 mm. The surface of the extruded rods is smooth. The number of suitable electrodes for ESA per one working cycle is 5 pcs.

Example 4

Under the conditions of example 1, the burnt charge is squeezed out through a thermally insulated matrix with a length of the forming belt of 20 mm.

The length of the extruded rods is 140 ... 170 mm. The surface of the extruded rods is smooth. The number of suitable electrodes for ESA per one working cycle is 5 pcs.

Example 5

Under the conditions of example 1, the burnt charge is squeezed out through a thermally insulated matrix with a length of the forming belt 25 mm.

The length of the extruded rods is 130 ... 170 mm. The number of suitable electrodes for ESA in one working cycle is 5 pieces, however, the press residue is difficult to extract from the matrix.

From the above examples it follows that, with values of the length of the forming belt of the matrix 10 ... 20 mm, the length of the extruded rods is 120 ... 170 mm. For small values of the length of the forming belt 5 ... 7 mm, the material is squeezed out in the form of a poorly compacted reacted powder and rods 20 ... 50 mm long with a scaly surface, which reduces the number of suitable electrodes for ESA. When the length of the molding belt is more than 20 mm, significant changes in the extruded rods are not observed, however, the matrix is clogged with material, which leads to its failure.

Properties of the obtained electrodes: resistance to oxidation of 2.0-2.2 mg / cm ² ; hardness 78-80 HRA; the average grain size is 1-3.5 microns. Properties of alloyed metal surfaces: 75-90% continuity, coating thickness 20-45 microns, wear resistance increases 2-5 times. The yield of rods increases 4-5 times relative to the prototype.

Claims (1)

A device for the manufacture of electrodes for electrospark alloying containing a press, an automatic control unit, a mold, a container having a mixture cavity, a cover and an external annular stop, an initiation system, a punch, a thermally insulated guide gauge connected in the upper part with a matrix having a forming belt, characterized in that the length of the forming belt is 10 ... 20 mm, and the matrix is made of steel 45X.