SU1219244A1 - Mould for making castings by directional solidification - Google Patents

Description

I

The invention relates to foundry-Nfy production, in particular, to casting molds mainly for the manufacture of permanent magnets by directional solidification, and can be used in industries related to casting.

The purpose of the invention is to increase the yield from metal loaders.

FIG. 1 shows the proposed mold, vertical section; in fig. 2 is a section a-a ka of fig. I.

The mold contains working cavities for castings 1, formed by partitions 2 of molding material and located above the metal cooler 3, runner bowl 4 and non-metal parts 5-7, forming one hundred to eight, profitable cavity 9 and heating cavity in the form of a channel 10 surrounding Peripheral the partitions and connected to the stand by means of gates 11, ac by a profitable cavity — a slit feeder 12. The channel of the heating cavity is made in cross sections tapering downwards and increasing in height in direction the effects of gating moves. The partitions of the working cavities are prevented from moving during the process of casting with the help of rods-struts 13.

The metal to be poured through the sprue cup 4, one hundred to eight and the sprue gates 11 fills the channel of the heating cavity 10 and comes into contact with peripheral partitions 2. Since the channel 10 is made in the direction away from the sprue codes, the peripheral partitions are heated approximately to the same temperature required for unidirectional solidification of the castings, then through the slit feeder 12 the metal fills the working cavities 1 and last of all the profitable cavity 9. Since the channel 10 is full in cross section with x-sectional tapering downwardly, the heat content of elementary volumes of the heating of the metal increases continuously in the direction prodvizhni solidification front, which provides conditions of forming the columnar structure oriented Jotlivkah S surrounded by this ka9244 2. ,

cash The dimensions of the cross sections of the channel of the heating cavity, located at different distances from the gate passages, depend on the type of alloy,

5 the temperature of the mold before pouring tcp, the temperature of the liquid metal in the furnace before being discharged into the ladle Tj, the height h and the thickness of the partitions of the working cavities.

0 It has been experimentally established that, for example, for hard magnetic alloys such as UNDK25BA and UNDK35T5BA at tq, 20-30 0, T „1710-1740 С, h 50 mm and about 4-5 mm

15 of the lower base A of any cross section of the channel heated by thickness varies in the range of 0.4-0.7 from the size of the upper base B of the same section. Upper

20 limit A is intended for casting molds containing relatively high partitions, and the lower - low. The height of the channel in cross section, located near the gating

5 strokes, H, fluctuates in the range (0.6-0.7) h. In the direction from this walk, the height of the channel is continuously increased to H and in a cross section located at the maximum

away from the gating run, is equal to (0,8-0,9) H. In this case, the lower limits of H and H are intended for casting molds containing relatively high partitions of working cavities, while the upper ones are low.

In cases of A 0.4 V and / or H, 0.6 h, and / or H 0.8 h, the crystallization of the casting process may be disturbed, surrounded by.

By the channel of the heating cavity, due to insufficient heating of the partitions, and in cases AO, 7 V and / or, 7h, and / or H 0.9h, the consumption of the liquid metal for heating the partitions increases, and a deterioration in the conditions of unidirectional heat removal from the liquid metal to the refrigerator due to increased heating

0 solidified lower casting zones,

Samples of castings of permanent magnets were obtained by directional solidification under the following conditions: magnetic alloy - UN14DK25BA; method of alloy smelting - in an open induction furnace with an acid lining T 1720 + 10 ° С, t 25 ± 5 С, h 36 mm; cS 4.0-4.5 mm. Geomet5

The traditional shape and size of the cross-section of the channel heating cavity

a) in a known mold, all cross sections in the shape of a rectangle having a width of 20 mm and a height of 32 mm;

b) in the proposed casting mold - all cross sections in the form of rectangular trapeziums, facing downwards with smaller bases and having a larger base equal to 20 mm, and the smaller - equal to 9-12 mm height of the trapezium are made continuously increasing along the channel length.

2192444

direction from gating moves from 22-25 to 30 mm.

The table shows the results of comparative tests, 5 From these comparative tests it can be seen that the proposed design of the casting mold provides approximately 1.3 times the yield of metal slabs compared to the known construction by reducing the casting rejects from 42.6 to 30.5% and a reduction in the metal filling from 22.1 to 20.5 kg per mold.

Claims (1)

CASTING FORM FOR PRODUCTION- LIABILITY CASTING DIRECTED HARDENING, containing the inner * part in the form of cells installed on the refrigerator with the formation of working cavities, a profitable cavity located above the working cavities, heating the cavity located around the perimeter of the inner part and connected to the riser with gate runways, characterized in that In order to increase the yield, the heating cavity is made expanded upward and in length in the direction from the gateways and the bottom, respectively, due to the slopes of its outer walls and bottom. Figure 1