RU2103110C1 - Sand mold for production of castings - Google Patents

Abstract

FIELD: foundry, in particular, sand mold for production of small and medium castings. SUBSTANCE: sand mold has inserts with thermit or with surface-alloying material located in mold or cores. Inserts are made of cardboard and in the form of cylinder, cube, parallelepiped, plate, rings. To increase thermal stability, inserts are impregnated or coated with inorganic and organic materials. EFFECT: higher yield of cast materials and its quality, and saved exothermic materials. 3 cl, 5 dwg

Description

 The invention relates to foundry, in particular, to molds for producing dense castings from ferrous and non-ferrous alloys. The invention is also applicable to the production of individual bimetallic or surface-alloyed surfaces in castings.

 Known sand casting mold containing cores, a working cavity and a gate-feeding system, having a profit, heated by exothermic material [1].

 The aim of the invention is to increase the yield of casting, mainly of small and medium castings, improving the quality of castings, saving exothermic material, obtaining surface-alloyed and bimetallic surfaces.

 In FIG. 1 - shows an example of using a rectangular insert for heating profits; in FIG. 2 - the same, section aa (figure 1); in FIG. 3 is an example of using a cylindrical liner; figure 4 - casting of the casing of pipe fittings; figure 5 is the same, a section bB (figure 4).

 The liners are made of cardboard of a square shape or in the form of a parallelepiped, cylinder, disk and other shapes, the inner volume of the liner (box) is filled with exothermic material, termite when using liners to obtain bimetallic surfaces on the casting or filled with material for surface alloying, which will save exothermic material, to exclude the use of foil, polyethylene and other synthetic materials for heating profits, to ensure reliable operation of the heated profit, minimum 's dimensions of 30 mm ⌀.

 For large castings, in order to increase the resistance of the liner from premature failure during the casting process, the cardboard box can be impregnated with both organic and inorganic materials, for example, liquid glass, resins.

 In the case of using a rectangular insert (Fig. 1, 2) on the thermal unit of the casting 1 set profit 2.

 In order to reduce the mass of profit, increase the density of the casting in the ledge of profit 2 installed liners 3 with exothermic material and liner 4 with heat-insulating.

 To fix the liner in the molding mixture, the liner is 5-15 mm longer than the profit width.

 After filling the mold with alloy, ignition starts from the angle of the liner 4, in the central profit zone, since the angle of the liner quickly heats up to the temperature at which the exothermic reaction begins.

 After the reaction, the exothermic mixtures in the liner can retain their shape and can melt. Termite mixtures after the reaction are in a liquid state. After the liner mixture is melted, the overheated thermite metal recovered from oxides will enter the inner part, additionally increase the metal volume and heat the upper and central part of the profit, providing dense castings.

 For casting the gate 5 for heating the profit 6, an insert 7 was used in the form of a cylinder 7 (Fig. 3).

 Insert 7 is placed in the ledge of profit 6.

 The liner on both sides is covered by the alloy, and the axis of the liner will be located in the hottest area of the profit.

 The length of the liner is taken more than the length of the profit section. The protruding ends of the liner is fixed in the molding mixture during the manufacture of the mold. This design slows down the incubation period of the onset of ignition of the exothermic material of the liner, however, it is more acceptable for mass production.

 On the flat surfaces of the casting, liners 8 with an alloying composition are installed. To hold the liners in shape, they can be glued.

 Cylindrical liners can be used both for profits of small sizes with a diameter of about 30 mm, and for heating large profits up to 200 mm.

 For the manufacture of castings 9 of the body of the pipe fittings (Fig. 4), the mold is used with a vertical connector.

 Exothermic liners 10 in this form can be installed in profit 11 during the assembly process as rods. The mold is poured through the sprue system 12. An insert 14 with a thermite or other mixture is installed in the shaft 13 to obtain a bimetallic saddle with a wear-resistant, corrosion-resistant surface of the locking part of the housing.

Claims (3)

 1. A sand casting mold for producing castings, mainly small and medium, containing rods, a working cavity and a gate-feeding system having profits with inserts with exothermic material, characterized in that it is additionally equipped with inserts with termite or with surface-alloying material, placed in the form or rods, while the liners are made of cardboard that retains its shape.  2. The shape according to claim 1, characterized in that the liners are made in the form of a cylinder, parallelepiped or with a section in the form of a square.  3. The mold according to claim 1, characterized in that the inserts made of cardboard are impregnated with inorganic and organic materials.

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