SU599911A1 - Casting mould for turbine diaphragm manufacture - Google Patents

Description

form from the height of the cavity of the outer rim.

The mold contains the lower 1 and upper 2 half-molds in which semi-annular cavities 3 and 4 are made to form the pair and inner rims. The cavities are formed by means of a rod 5, in which blades 6 with variable thickness in transverse section are molded. Cavities 3 and 4 communicate with each other by means of bypass channels 7 located on the end sections of the cavities at the level of the input edges of the blades 6.

Gating system form is made of rain, providing a separate supply of metal by means of feeders 8 and 9, respectively, in the polostp of the outer and outer rims.

In this case, the total area of the cross sections of the feeders connected to the cavities for the outer and inner rims is related by the ratio

i; f ,,

1.5-9.0.

 R

- uh

The capacity of the feeders 8 is somewhat larger than the feeders 9.

The die casting is carried out as follows.

The normal metal from the bucket through the feeder 8 enters the cavity 3 and simultaneously through the feeders 9 into the cavity 4. At the same time, due to the greater throughput of the feeders 8, a certain excess of hot metal enters the cavity 3 as compared with cavity 4.

When the level of the metal in cavity 3 reaches the blade-shaped entrance edges of the blades (the thickest section of the blade), the excess of this excess through channels 7 from cavity 3 to cavity 4 begins until the metal in cavity 3 reaches the level of the ends of the blades that are poured in cavity 4 ( of the output edges of the blades bj. After this, an oratoric bypass of the colder metal from the cavity 4 into the cavity 3 occurs until the form is completely filled, i.e. the form is filled in zones (see Fig. 2):

Zone A - to the level of the input edges of the blades;

Zone B - including blades;

Zone B is the fall level of the exit edges of the rifles.

It was established experimentally that with the specified ratio of the total areas of the sections of the feeders, uniform heating of the ends of the tarpaulin through the thickness of the section of each blade is ensured.

In zone L, with separate filling of cavities 3 and 4, the velocity V in cavity 3 is greater than in cavity 4.

In zone B, in the process of bypass, the velocity V drops to a critical one, at which no junctions or torsions form at the casting ends of the blades.

In zone B, speed V increases.

The average lifting speed of the metal in the mold is 4-b mm / s (9-11 mm / s).

At the same time, for castings weighing from 300 to 5000 kg, the amount of metal transferred from the cavity of the outer rim into the cavity is internal and is approximately 50-60 kg.

When using nastotel blades in zone B, the average lifting speed of the metal in the mold is 9-11 mm / s and for castings weighing from 1000 to 3000 kg, the amount of metal transferred from the cavity of the vaporous rim to the cavity of the inner plumba is 5 - 300-350 . Due to the indicated change in velocity over zones and the provision of a specified amount of unbreakable metal, the blades in thicker sections are heated more intensively than in thin ones, which eliminates the formation of gaps between the remaining blades and the cast-iron rim body.

In thin sections of the blades, the heating is reduced, thereby eliminating the height of the thin exit edges with their crushing phenomena, i.e., each blade in the section is uniformly heated.

one

9.0

With respect

proV P

  B1I

the height of the thin exit edges of the ends of the blades, poured into the cavity of the outer rim, and insufficient heating of the thickened input edges of the ends of the blades, poured into the cavity of the inner rim.

Conversely, with a ratio of 1.5

V p

 extra

there is insufficient heating of the ends of the blades, poured into the core of the outer rim, and overheating of the ends of the blade, poured into the cavity of the inner rim.

F o rm} l and inventions

A mold for the manufacture of a turbine diaphragm reinforced with paddles contains: and cavities for the outer and inner diaphragm body, a paddle with blades and a gating system, including cavity feeders for the steam and inner rims and bypass channels connecting the said cavities, characterized by

the fact that, in order to control the transfer of metal between the cavities to increase the strength of the connection between the ends of the balance sheet and the metal to be poured, the total cross-sectional area of the feeders for external and

the inner rims are in the following ratio:

 1.5-9.0.

- -tRM

Metal lifting speed in cpopMe, Mft / f,

I I11111р1

10 ZD 30 0 50 SO 70 Duration of filling the form, with

Rig.2