RU1787066C - Method of die casting of aluminum alloys with crystallization - Google Patents

Abstract

SUMMARY OF THE INVENTION: a method of molding with crystallization under pressure includes pouring the melt into the die, forming a high-pressure die casting, supplying a cutting fluid at a pressure of 0.4-0.5 MPa after the formation of the casting is completed at the time of the removal of the punch over time, removable from a ratio of 0.6 VnT- where m is the mass of the casting in grams; 0.6 - empirical coefficient; pushing and removing the casting from the mold, returning the push rod of the press to its original position. 1 ill.

Description

. The invention relates to the field of foundry and can be used for the manufacture of mainly body parts. Known methods of cooling molds with water, which is brought as close as possible to the outer surfaces of the mold, and the main purpose when supplying cutting fluids is to cool the mold and protect the working surfaces of the mold parts from the influence of melt, weld on the walls of the mold .

Under the most severe conditions, die casting under crystallization (LCD) provides a matrix due to the filling of any irregularities with metal under the action of high pressing pressure (200-500 MPa). In order to reduce the loss of the working pressure of the pressing by friction (30%) and eliminate the welds during LCD, the matrix is abundantly lubricated before each pressing cycle and a suitable part is obtained, which leads to a deterioration in its appearance due to casting defects of a gas nature, and the mechanical finishing operation is performed. An insufficient degree of lubrication leads to bulging of the casting.

As a prototype, the well-known LCD method was chosen, including the supply of coolant before pouring into the matrix, pouring the melt into the matrix, forming a high-pressure casting, cooling the casting and matrix.

The disadvantages of this casting method are:

the difficulty of applying the optimal amount of coolant to the walls of the matrix, as a result of H

ABOUT

0h

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with

why gas shells can occur (with an excess of lubricant) or liquid metal bricks on the matrix walls (with a lack of lubrication);

-the duration of the application of anti-seize lubricant and coolant to the walls of the matrix; ..

- the duration of the cooling time of the casting after the formation of the high pressure casting is completed.

The aim of the invention is to remedy these drawbacks, namely improving the quality of the outer surface of the casting, increasing the productivity of the casting process.

The method of injection molding aluminum alloys by crystallization under pressure includes the injection of a lubricant-cooling fluid into the mold, pouring the melt into the die, forming a high-pressure die casting, withdrawing the die and removing the casting from the mold. The supply of cutting fluid is carried out after the formation of the casting is completed at the time of removal of the punch for a time determined from the ratio

, 6Vm, where t is the time in, s;

m-weight of the cast, g

The drawing shows a fragment of the mold.

The mold contains a punch 1, a die 2, a pusher 3, a spray gun 4. casting 5, a thermocouple 6.

The SOIS is supplied by the spray gun at the moment of the release of the mold punch 1 from the matrix 2, while the solid components of the lubricant are fed into zone h and the gap between the casting 5 and matrix 2. The formation of a gap of 0.1-0.3 mm occurs due to intensive cooling of the casting 5 than of the massive matrix 2 for the entire period of SOIS supply .-;

Example 1. A body was made of 049 x 60, weighing 200 g, by a piston-piston pressing system on a DB 2432 hydraulic press from aluminum alloy D1 b GOST 4784-74. The traditional injection technology was as follows: after lubricating the matrix and punch with anti-seize lubricant Aluminol MG-2, cooling the matrix with water-emulsion lubricant. Elitol E13M1C with the ratio of water to elitol. 20: 1 for 25 s, casting, pressing and crystallization of the high-pressure casting (200 MPa) were performed for 25 s, the slider was raised and the casting was cooled by compressed air under a pressure of 0.4 MPa in

25 s, ejection, removal of casting, return of the pusher within 5 s. In total, the technological cycle was carried out for 80 s, there were casting defects on the castings due to the uneven application of anti-seize lubricant.

In the manufacture of a part according to the claimed method, LCD produced:

- lubrication of the punch with Aluminol MG-2 for 5 s;

- pouring the melt into a matrix, pressing under pressure and crystallization under a pressure of 200 MPa for 30 s;

- raising the press slider and supplying the coolant with an injection-type spray gun under a pressure of 0.5 MPa, cooling the casting and die with a temperature of 160 ° C to 120 ° C for 10 s (g 0.6 V2QO 9 s);

- ejection and removal of the casting, return of the pusher within 5 s.

In total, the technological cycle is carried out for 50 s. Consequently, labor productivity is increased by 38%. The punch and die were heated by 3-4 fillings with the traditional grease system Aluminol MG-2, applied with a brush.

EXAMPLE 2 A body was made of 092 x 160 mm, weighing 1.8 kg, by a puncheon pressing system on a DB 2432 hydraulic press from D16 alloy.

Traditional technologists:

- lubrication of the matrix and punch with Aluminol MG-2 for 25 s;

- cooling of the matrix with Elitol E13M1S water emulsion lubricant by spray gun under a pressure of 0.5 MPa for 10 s;

-filling, pressing, crystallization under a pressure of 200 MPa for 40 s;

- raising the slider and cooling the casting with compressed air for 30 s;

- ejection and removal of the casting, return of the pusher within 10 s.

Total: 115s. There are defects on the outer surface such as delaminations, neslin, roughness R2 5 ... 20 microns.

In the manufacture of a part according to the claimed LCD method:

- lubrication of the punch with Aluminol MG-2 10 s;

- pouring, pressing, crystallization under a pressure of 200 MPa for 30 s;

- lifting the press slider and supplying the coolant with a spray gun under a pressure of 0.5 MPa, cooling the casting and die from 200 to 1.80 ° C for 25 s (g 0.6 V1800 25);

- ejection and removal of the casting, return of the pusher within 10 s.

Total: 75 sec.

Consequently, labor productivity is increased by 34%. The roughness of the outer surface of the casting was R2 2 ... 5 μm.

Thus, the use of the claimed LCD method allows to increase labor productivity by 35-40%, to eliminate casting defects of a gas nature: non-slit, nadir, to increase the surface cleanliness by reducing the roughness from R2 15 ... 20 to R2 2 ... 5; refuse to introduce technological allowance for machining on the outer surfaces of the casting.

Claims (1)

The claims A method of injection molding aluminum alloys by crystallization under pressure, including supplying a lubricant-cooling fluid to a mold under pressure, pouring the melt into the die, forming a high pressure die casting, removal of the punch and extraction of the casting from the mold, with the exception of the fact that, in order to improve the quality of the casting and the productivity of the process, the supply of cutting fluid is carried out after the formation of the casting is completed at the time of removal of the punch for a time determined from the ratio fifteen 6Vrr7; where r is time, s; m is the mass of the casting.