RU2801506C1 - Casting tools for manufacturing rods for argon-arc surfacing - Google Patents

Abstract

FIELD: foundry and welding production.

SUBSTANCE: casting equipment for the manufacture of rods for argon-arc surfacing comprises a flask, moulding sand and a pattern kit. The model kit comprises a metal disc (1), a threaded ring, a metal rod and a core box. Guide holes (2) and a threaded blind hole are made in the metal disk intended for forming the casting mould gating system (4) in the moulding sand. The threaded ring interacts with the blind hole of the metal disc. The metal rod forms working cavities for casting the rod for argon-arc surfacing when it is driven into the moulding sand through the guide holes of the metal disk. The core box is intended for the formation of the overlap of the core mixture, which is installed in the mould.

EFFECT: making rods for argon-arc surfacing with a diameter of 4-5 mm and a length of 250 to 500 mm by casting in a sand-clay mould without using difficult-to-manufacture tooling and without subsequent machining of the rods.

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Description

The invention relates to foundry and welding production and can be used in the manufacture of rods for argon-arc surfacing with a diameter of 4 to 5 mm and a length of 250 to 500 mm by casting in a sand-clay mold.

A chill mold for the manufacture of dimensional blanks is known (patent RU No. 2620231), containing two forming parts, along the planes of which segments of the forming cavities and the profitable part are made, which ensures the formation of castings of a predominantly cylindrical shape with a diameter of 20-30 mm and a length of 200-220 mm.

Due to the fact that the mold is made of copper, it is impossible to obtain bars from high-alloy alloys, since the melting point of copper is much lower than the melting point of iron-carbon alloys. Based on this, one of the disadvantages of this method is the very low resistance of the mold at its high cost. The second disadvantage of this method is the impossibility of obtaining rods of small diameters (up to 5 mm).

A known method of manufacturing by pressing ceramic-metal tubes and rods from metal powders (ed. St. USSR No. 109279). In order to increase the strength properties, the bars after pressing are subjected to sintering, which is carried out in an electric furnace with a protective atmosphere, for two hours at a temperature of 1200°C. Depending on the composition of the alloy, sintered rods have satisfactory strength and can be welded together by flash butt welding. Before use, they must be calcined to remove moisture.

The disadvantage of this method is that the bars made by pressing followed by sintering have low welding and technological properties and require expensive sintering equipment. When surfacing samples or experimental parts with sintered rods, significant spattering of metal and adhesion of splashes of molten metal to the tungsten electrode occur, resulting in the phenomenon of "wandering" of the arc and instability of its combustion, and also the burner nozzle is clogged. All this leads to the appearance of pores and tungsten inclusions in the weld metal, which reduces the quality of parts.

A known method of manufacturing cast blanks of antifriction bronze (patent RU No. 2762956), including melting and continuous casting of blanks with a diameter of 10 to 50 mm. The formation of a cylindrical billet in a water-cooled metal mold does not require the use of expensive molding materials, it has a sufficiently high productivity, uniformity of the chemical composition and dimensions of the billet.

However, this method cannot simultaneously produce a batch of bars, and it also excludes the possibility of manufacturing bars with a diameter of up to 5 mm from iron-carbon alloys. This is due to the high thermal conductivity of the alloy, the temperature of which during drawing is kept at the level of the melting point, while the fluidity of the alloy is very low. Also, when bars are obtained by this method, an oxide film is formed on the surface of the bar, which contributes to the formation of gas defects during surfacing of parts.

The prototype of the invention is a method for manufacturing cast rod blanks from nickel-based heat-resistant alloys (patent RU No. 2714788) having a diameter of 20-50 mm and a length of 150-250 mm.

The disadvantages of this method are the impossibility of obtaining rods with a diameter of up to 5 mm, the high cost and complexity in the manufacture of technological equipment, the use of expensive molding materials, as well as machining after melting of the rods.

The objective of the invention is the manufacture of rods for argon-arc surfacing with a diameter of 4 to 5 mm and a length of 250 to 500 mm.

The technical result of the invention is to obtain a batch of bars with a diameter of 4-5 mm without the use of difficult to manufacture and expensive technological equipment, more expensive molding materials, as well as avoiding subsequent machining of the bars.

The technical result is achieved by the fact that the foundry equipment for the manufacture of rods for argon-arc surfacing consists of a flask, characterized in that it additionally contains a molding sand, a pattern kit (a metal disk with holes and a gating system, a threaded ring, a core box, a metal bar).

In FIG. 1 shows a metal disk with holes and a gating system (top view).

In FIG. 2 shows a metal disk with holes and a gating system (in section).

In FIG. 3 shows a threaded ring.

In FIG. 4 shows a metal bar.

In FIG. 5 shows the core box (top view).

In FIG. 6 shows a core box (in section).

In FIG. 7 shows a mold for pouring metal (in section).

Casting equipment for the manufacture of rods consists of a metal disk 1 with 64 holes 2, which serve as guides when forming a cavity in the mold with a metal rod 3 with a diameter of 4 to 5 mm. On the inside of the metal disk 1 there is a gating system 4 and a sump 5. To extract the metal disk 1 after molding, a threaded ring 6 is provided, which is screwed into a blind hole with a thread 7. A core box 8 is provided for the manufacture of the ceiling 13.

The casting mold 18 for pouring metal consists of a metal flask 9, which holds the molding sand 15 (quartz sand - 92%, clay - 2%, dextrin - 2%, water - 4%), two pins 10 and holes 11 through which gas when pouring metal into a mold. The elements of the gating system 4 are: gating cup 12, installed on the floor 13 with holes 16 to control the level of the metal; a riser 14 for supplying molten metal from the gating bowl 12 to the gating system 4 and the working cavity of the mold 17; sump 5, necessary to soften the impact of a jet of molten metal during pouring.

The manufacture of rods for argon-arc surfacing is carried out as follows.

The mold 18 is made on a molding machine. A metal disk 1 is laid flat on the under-model plate of the molding machine, and a metal flask 9 is installed. The metal disk 1 must be dusted with graphite, filled with molding sand 15 and compacted by shaking and pressing. Remove the casting mold 18 from the molding machine using a crane beam and turn it over 180°. Create a working mold cavity 17 by driving metal bars 3 with a hammer through the guide holes 2 into the compacted molding sand 15, followed by the extraction of metal bars 3. Screw the threaded ring 6 into a blind hole with a thread 7 and remove the metal disk 1.

To make the floor 13, it is necessary to wipe the inner surface of the core box 8 with a rag soaked in kerosene, fill the core box 8 with a cold-hardening core mixture and compact it, remove excess mixture from the surface. Turn the core box 8 over 180° and by tapping on the surface of the core box 8 with a wooden hammer separate the cover 13 from the core box 8. Dry the mold 18 and the ceiling 13 in a drying oven.

After drying, the floor 13 is placed in the seat of the mold 18, and the gating cup 12 is installed on the floor 13. The prepared mold 18 is placed on a flat surface for pouring metal melted in the induction furnace. The melt prepared in this way is poured into the pouring ladle and poured through the gating cup 12 into the mold 18.

After cooling the poured metal, the casting is removed by destroying the casting mold 18. Then the bars are cleaned from the molding sand 15 and the gating system 4 is cut off.

It is most rational to use casting equipment to produce small batches of bars with a diameter of 4 to 5 mm. To do this, use a sand-clay casting mold with a working cavity with a diameter of 4 to 5 mm.

It is practically impossible to make a casting mold with a working cavity with a diameter of less than 4 mm, since the molten metal, getting into the cavity, solidifies instantly, and the bars are short.

An example of the implementation of the invention

Manufactured mold for the production of rods with a diameter of 5 mm and a length of 300 mm in accordance with the claims. Smelted iron-carbon alloy PNL-04Kh27N7M3D2B (C - 0.02-0.06%; Si - 0.2-0.8%; Mn - 0.5-1.2%; Cr - 25.0-29.0% ; Ni - 5.0-8.0%; Mo - 2.5-3.5%; Cu - 1.25-2.5%; Co - 0.15-0.4%; Ti - 0.25 -0.5%; Ce - 0.01-0.1%; N - 0.05-0.3%; Fe - the rest) in an induction furnace and poured into a ladle. The temperature of the molten metal during pouring it into the mold was 1550°C. After the final crystallization and cooling of the bars, the casting mold was destroyed on the knockout grid, the resulting bars were subjected to shot blasting from the molding sand, and then the gating system was cut off from them. The resulting 64 bars were then subjected to surface quality control and dimensioning. The finished bars had a diameter of 5 mm and a length of 300 mm. The surface of the bars had no traces of molding sand and casting skin.

Thus, the proposed foundry tooling for the production of rods for argon-arc surfacing will make it possible to obtain rods with a diameter of 4-5 mm, use a cheaper molding sand, and use a model set that is easier to manufacture and does not require large expenditures as technological equipment.

Claims (1)

Casting equipment for the manufacture of rods for argon-arc surfacing, containing a flask, a molding sand and a pattern kit, characterized in that the pattern kit contains a metal disk with guide holes and a blind hole with a thread, made with the possibility of forming a casting mold gating system in the molding sand, moreover, the ring with a thread is made with the possibility of interacting with a blind hole of a metal disk, a metal rod configured to form a working cavity for casting a rod for argon-arc surfacing when it is driven into the molding mixture through the guide holes of the metal disk, and a core box for forming an overlap from the core mixture made with the possibility of installation in a mold.

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