SU479560A1 - Mold for casting with crystallization under pressure - Google Patents

Description

one

The invention relates to the field of foundry and is intended for the manufacture of castings of various metals and alloys.

For the manufacture of castings with high dimensional accuracy on the machines for injection molding (LPD), molds consisting of fixed and movable half-molds are used. In the fixed half-form, which is fixed on the fixed cross-bar of the LPD machine, a part of the cavity forming the casting (outer surface) and the bushing hole are made through which liquid metal is injected from the press chamber of the LPD machine into the cavity of the mold. In the movable part of the mold, which is fixed on the movable traverse of the LPD machine, a part of the cavity that forms the casting (inner surface) is made, various devices for pushing the casting out of the half-mold and returning these devices to their original position.

The disadvantage of these molds is the inability to manufacture in them castings with variable cross sections and sufficiently massive nodes of increased density and mechanical properties, since shrinkable defects are formed in the massive nodes that harden the last one. portion of the metal during the period of crystallization and linear shrinkage of the metal poured into the mold. In addition, due to the fact that the liquid metal is poured first into the press chamber of the LPD machine, and then under pressure from the pressure plunger and with greater speed it is distilled into the cavity of the mold, the liquid metal is mixed with air, as a result of which In castings, porosity is formed, which prevents their heat treatment and welding.

The aim of the invention is to improve the feeding of castings.

The described mold differs from the known ones in that its pressing element is designed as a system of floating pistons placed on a distribution plate for differential compaction and forced feeding of massive casting units with an additional portion of the metal during the period of crystallization and linear shrinkage freely poured directly into the working cavity of the press forms of liquid metal. Forced feeding of massive casting assemblies is carried out at the expense of liquid metal of profitable volumes performed in technologically necessary casting sites.

To seal the metal in the closed volume of the working cavity, the mold is provided with a knife gate, which is placed in the slot made between the sprue pan and the outer surface of the mold and fixed on the distribution plate.

This embodiment of the fixed part of the mold provides movement and operation of all the mechanisms of the mold through only one effort of the pressing mechanism of the LPD machine, as well as guaranteed overlapping of the gate by gate-zero ohm before compaction-pressing the molten metal filled in the formula.

These design differences allow to significantly expand the range of parts cast on the machines, significantly increase their mechanical properties and produce heat treatment of castings.

FIG. 1 depicts the proposed mold (view of the connector on the movable part); in fig. | 2 - section A-A in FIG. one; in fig. 3 is a section along BB in FIG. one.

The mold consists of movable (Fig. 1) and fixed (Fig. 2) parts, which are fixed with each other in the direction of yush, with their pins 1 and fixed on the cross-bars of the LPD machine: fastening plate 2 - on the movable traverse, fastening plate 3 - on a fixed traverse. On the movable and fixed parts of the mold, at the level of the plane of the connector, for example, are mounted on the side of the half of the sprue bowl 4 and 5, in which the receiving funnel 6, the sprue 7 and the through groove 8, where the gate-knife 9 is placed Part of the sprue 7 and the feeders 10 are made on the connector of the mold.

In the fixed part of the mold, two support beams 12 are installed and secured between the fastening plate 3 and the pressure plate 11, and a distribution plate 14-17 is mounted on the columns 13 (Fig. 3) in the window thus formed to fix and move. The height of the support bars 12 is made on the basis of placement in the window of the distribution plate 14-17 and ensuring the size of C G + D (Fig. 2). Size is the part of the path that the distribution plate 14-17 passes as it moves from right to left to ensure that the gate 7 is blocked by the knife blade 9 before the pistons 18-20 begin to interact with the distribution plate 14-17 and seal the liquid metal with them. Size - the maximum allowable depth of penetration of the pistons 18-20, for example, in the profitable part E of the casting during the compaction of the metal by pressing.

The right end of the knife blade 9 is rigidly connected to the distribution plate 14, 17, and the left is inserted into the groove of the halves of the sprue bowl 4 and b. In the knife gate 9, a hole 21 is made, in shape and size equal to the gate hole and located opposite the gate 7, when the distribution plate 14-17 is in the right extreme position. Hole 21 is tapered (5-15 °) to facilitate removal of the cut portion of the sprue after opening the mold.

The distribution plate is made of a composite plate 14, in which a slot is made for, for example, a T-shaped connection with the stem 22 of the intermediate plate 15, in which a cavity is made for pouring pressure-reducing compositions and evenly transmitting pressure to it. or formoplast SM, and a guide plate 17 in which holes are made -directions with stops for the flanges of the pistons 18- (20. The number of pistons and their total cross-sectional area, depending on the melt being poured, are chosen taking into account and transferring pressure to the molten and crystallizing metal of the casting, in technologically necessary places within kgf / cm.

0 In the presser plate 11 and the die 23, holes are made-directions for the working parts of the pistons 18-20. By means of the rod 12, the pressing force of the LPD machine is transmitted to the distribution plate 14-17, for which it

5 is rigidly connected to it. For this purpose, for example, a threaded hole is made at the right end of the stem 22, and a T-shaped shank, for example, is formed at the left end. The mold is mounted, for example, on an LPD machine with a horizontal compression chamber using known techniques. Before mounting the mold, the pressure piston of the LPD machine is removed and the stem 22 is installed in its place. The stem 22 is connected to the pressure plate

5 14-17 by turning the rod through 90 °.

The initial position of the working parts of the mold is shown in FIG. 2. In this case, the distribution plate 14-17 with pistons and blade-knife 9 must be located in

0 extreme right position and hole 21

against the gate hole 7 (Fig. 1).

The mold works as follows.

In the assembled mold (Fig. 2) through

sprue 6, sprue 7 and runners

5 10 (fig. 1) pour liquid metal. Filling is carried out freely and smoothly enough, with speeds that allow to achieve complete removal of air from the working cavity of the mold, which allows you to fully

0 eliminate the formation of gas and air porosity. After that, the liquid metal poured into the working cavity of the mold is compacted by the method of direct pressing by pistons 18–20. To do this, the pressing mechanism of the LPD machine is activated, which through the rod 22 acts on the distribution plate 14-17, moves it from right to left and transmits the pressing forces of the LPD machine to the knife-blade 9 and the piston 18-20. In the process

0 the displacement of the distribution plate 14--17 is first cut by a gate-knife 9 a sprue 7) And reliably overlap it (Fig. 3), and then the pistons 18-20 seal the metal in the closed volume of the working mold of the mold 5 until it is completely crystallized . Wherein

compaction and feeding of massive casting units with an additional portion of metal in the process of crystallization and linear shrinkage is performed differentially due to profitable volumes E made in the fixed part of the mold and the use of floating pistons.

The stroke of the rod 22 and the distribution plate 14-17 from left to right return the surfaces 18-20 and the gate-knife 9 to its original position. This operation, depending on the adopted technological mode and the setting of the LPT machine, is carried out before or after opening the mold. The cast is ejected from the movable part of the mold by known methods.

Subject invention

A mold for casting with crystallization under pressure, containing a movable half-form, a fixed semi-form with a pressing element and a knife gate, characterized in that, in order to improve the feed of the casting, the pressing element is made in the form of floating pistons placed on a distribution plate, blade-knife is installed in a fixed half-form and fixed on the distribution plate.

Figure 1: Podgidnaya part Acqua 7 / / / 5 f