SU789236A1 - Unit for low pressure die casting - Google Patents

Description

one

This invention relates to a foundry; namely, controlled filling of casting molds with an alloy.

A known installation comprising a sealed pneumocamera, inside of which there is a crucible with a heating element and a metal conduit. A metal mold is installed on the outer side of the pneumatic chamber cover. The installation also includes a control system 13.

However, the design has a number of significant drawbacks, namely:

when casting aluminum alloys 15, the steel metal pipe dissolves in the alloy and goes out of order, which leads to the need for its frequent replacement;

the use of Karami-20 forms is difficult, due to the difficulties of providing a pressure-tight connection of this form to the metal conductor. The leakage of the connection between the mold and the metal pipe causes a 25 air leak in the mold, which leads to a marriage;

the possibility of crimping castings in ceramic molds with high pressure (4.06 O atmospheres) is practically excluded;

the alloy in the crucible is contaminated with oxides and non-metallic inclusions when the melt is drained from the metal conduit;

when the alloy is raised in the form of a steel metal, it cools it, which leads to uncertainty about the pouring temperature.

A low pressure casting installation is also known, comprising a crucible for a melt placed in a sealed pneumatic chamber with a lid, a ceramic mold, a heating element, a guide column and a control system 2.

The disadvantages of this installation are poor quality casting and unreliable operation.

The purpose of the invention is to eliminate these disadvantages.

The goal is achieved by the fact that the form is fixed inside the pneumocamera by means of a fork clamp and a stem with a drainage hole, and a rod with a spiral thread; traverses and bushings with a drive with a guide column. FIG. 1 shows the installation, a longitudinal section; in fig. 2 casting unit; in fig. 3 (FORK clamp, bottom view. The installation consists of a sealed pneumatic chamber 1 with a lid 2 having an opening 3 with water-cooled seals 4 (the water-cooling system is not shown in the drawing), in which the rod 5 is located with the possibility of movement in the axial direction. The rod 5 is connected by means of the crosspiece 6 with two screw elevators 7 mounted on the lid 2. A drainage hole is made inside the stem 5, in which the rod 8 is arranged with spiral threading. At the upper end of the rod 8 protruding from the drainage channel of the rod An annular groove 9, into which a stopper 10 with a handle 11 rotating about a vertical axis XX is inserted, is formed. The lower part of the drainage hole is made in the form of an expanding cone. Seat 12 for installing the ceramic form 13 on the rod 5 is made in the form The tapering cone is concentric with the drainage hole. The mold 13 is attached to the rod 5 by means of a fork clamp 14, which holds it with a spring 15. The cover 2 of the pneumocamera 1 is connected to the sleeve 17 with the aid of an electric mechanism 18 to move along the guide column 19. In order to install the mold 13 on the installation, it is necessary by means of an electromechanism 18 to lift the lid 2 of the pneumatic chamber 1 along the guide column 19. In the upper position of the lid, the ceramic form 13 is mounted on the seat 12 of the rod 5 and with the help of a fork clamp 14 with a spring 15 is fixed on it. The cover 2 is then lowered and fixed to the pneumatic chamber by means of hinged bolts. With the help of screw lifts 7, the rod 5 (and the mold 13 with it) is lowered until the lower part of the mold 13 is immersed in the alloy that is in the crucible. The cavity of the mold 13 at the same time communicates with the atmosphere through the screw rod 8 located in the drainage hole of the rod 5. Then, according to a predetermined program, the hermetic pneumatic chamber 1 is supplied with a gas (e.g. argon), under the action of which the alloy rises along the ceramic mold 13 up to her full; When the alloy reaches the drain hole in the rod 5 and the rod 8, it starts intense from the heat from the alloy and the latter, having completed one or two turns of spiral cutting, crystallizes. Due to the large temperature gradient between the upper and lower parts of the mold 13, the crystallization has a directional character (from top to bottom), which contributes to obtaining a material of castings with high mechanical properties. . For elimination of defects — in the form of micropores of shrinkage origin, molding of the casting with an excess pressure of 4.0-6.0 atm. can be performed. and since the spiral cutting of the rod 8 and the lower part of the conical drainage hole is filled with the crystallized metal, the alloy does not pour out through the drainage hole while the metal crystallizing in the mold 13 is compacted by high overpressure. After the alloy has completely crystallized, the gas pressure in the pneumatic chamber 1 is relieved and the mold 13 with the rod 5 is lifted out of the spl-ava using screw lifters 7. Then cover 2 by means of an electromechanism 18 under-. It is connected along the guide column 19, since the lid is connected to the sleeve 17 by means of the crosspiece 16. The filled ceramic mold 13 is kept on the seat 12 of the rod 5 mainly due to the metal crystallized in the first and second coils of the spiral cutting of the rod 8, and not due to the force of the fork clamp 14, which is selected from the condition of reliable fastening of the ceramic mold 13 before pouring, i.e. it is small that the claim soils the possibility of the mold 13 being destroyed by the clamp 14. In the upper position, the lid 2 rotates about the ZZ axis of the guide column 19. The stopper 10 rotates about the X-X axis with the handle 11 and goes out of engagement with the annular groove 9, after which the rod 8 is easily knocked out of the drainage hole of the rod 5 together with the filled ceramic mold 13. The rod 8 is removed from the body of the casting by turning and is used in subsequent pourings. Thus, the proposed installation has a number of advantages: it allows the use of ceramic casting molds and the molding of casting; there is no metal pipe, which provides a longer turnaround time of the installation and a lower heat loss of the alloy when lifting to the form; due to the absence of the metal conductor, the alloy in the crucible is not contaminated with oxides and non-metallic inclusions when draining the melt from the metal conductor and does not require additional heat

to heat the cooled drain metal;

the realization of crystallization directivity is provided (from top to bottom);

allows you to simplify the control system by eliminating the need to adjust the gas supply program to the pneumocamera as the crucible alloy is consumed (due to the fact that the shape can be moved vertically with the help of screw lifts).

Claims (2)

Invention Formula A low pressure casting installation containing a crucible for a melt placed in an airtight pneumocamera with a lid, a ceramic mold, a heating element, a guide column, and a control system that, in order to improve the quality casting and installation reliability in operation, the form is fixed inside the pneumocamera by means of a fork clamp and a rod with a drainage hole, and a rod with a spiral thread, while the rod is installed with axial displacement and provided with a seal on the pneumocamera cover and a screw lift, and the pneumatic chamber cover by means of traverses and bushings with a drive with a guide column. Sources of information taken into account in the examination 1, Bedel V.K. Casting under low pressure. Mashgiz, 1961, p. 69 five 2. Timofeev G.I. and Filatov V.Ya. Technological features pour under low pressure in the form of different cooling capacity. Sat, New in low pressure casting, Kiev, Naukovadumka, 1971, 0 s. 177-179. . fig.g