RU2558698C2 - Gating system for rotary shaped casting with vertical axis of revolution - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Gating system comprises central riser with diverging lower part, horizontal runners, vertical runner, runner feeders, central metal intake and horizontal circular collector. Central metal intake is composed of a square located at the runner lower part. Angles of central metal intake accommodate horizontal runners connected with vertical runner. Gating system comprises four runner feeders arranged in horizontal plane at 90-0 degrees relative to the mould centrifugal rotation speed vector.

EFFECT: higher quality of metal intake capacity and melt unobstructed flow.

8 dwg, 2 tbl

Description

Technical field

The invention relates to the field of metallurgy, in particular to a method for producing thin-walled castings of large diameters, for example, from titanium and heat-resistant alloys, with annular surfaces differently spaced from the axis, interconnected by radial elements, centrifugally filled in a vacuum with a vertical axis of rotation.

State of the art

Closest to the proposed invention is: a sprue system containing a central riser with an expanding lower part, a divider with blades made with variable curvature, and sprue passages connected to the forms by feeders (see Moiseev BC and other RF Patent No. 2058849, 27.04. 1996). The specified configuration of the gating system due to the use of deaf, not communicating volumes formed by the blades, significantly reduces the slipping of the melt in the metal receiver, increasing the throughput of the gating system. However, the positive effect of this method does not extend to the transfer of the melt to the inner annular surfaces of the castings, the filling of which obeys only the laws of centrifugal forces. This does not take into account the dependence on the direction of rotation and the distance from the axis of rotation to the point of entry of the metal into the body of the casting. In this case, it is not possible to fully realize the production of high-quality (dense) thin-walled castings.

Disclosure of invention

The basis of the invention is the task of developing a new gate system (using graphical and calculation methods for supplying metal to various casting zones) to ensure sufficient supply of thin-walled elements and preserving the continuity of the flow to obtain high-quality casting material in all sections.

The problem is achieved by the fact that the gating system for producing thin-walled castings of large diameters from titanium and heat-resistant alloys by centrifugal shaped casting in vacuum with a vertical axis of rotation of the mold and the upper supply of the melt, containing a central riser with an expanding lower part, a central metal receiver, horizontal gateways , vertical runner, horizontal annular collector, gating casting feeders, characterized in that in the lower part of the gating system The central metal detector is made in the shape of a square, in the corners of which are located the horizontal gateways connecting to the vertical gateway, while the gate system contains at least 4 gate gates of the casting located in a horizontal plane at an angle from 90 to 0 degrees relative to the vector centrifugal rotation speed of the mold.

The technical result achieved from the invention is to improve the quality of castings by improving the quality of the throughput of the metal receiver. This gating system ensures the flow of the melt flow in pressure mode, without turbulence, inversion and has a high throughput.

The technical result is achieved as follows.

The gating system for producing thin-walled castings of large diameters from titanium and heat-resistant alloys by centrifugal shaped casting in vacuum with a vertical axis of rotation of the mold and the upper supply of the melt contains a central riser with an expanding lower part, horizontal gating gates, vertical gating gates, gating casting feeders. The gating system further comprises a central metal receiver, a horizontal annular collector, the central metal receiver being made in the form of a square and located in the lower part of the gating system, in the corners of which there are horizontal gating gates connecting to the vertical gating gates, while the gating system contains at least not less than 4 sprue casting feeders located in a horizontal plane at an angle of 90 to 0 degrees relative to the centrifugal velocity vector rashchenija form.

The invention is illustrated in the drawing, where in FIG. 1 shows a diagram of a gate system, FIG. 2 shows a graph constructed according to table 1, in FIG. 3 shows the angular arrangement of the horizontal gateways, which provides the maximum flow rate, in FIG. 4 shows the direction of rotation of the mold in a clockwise direction, in FIG. 5 shows melt transfer to a horizontal annular collector; FIG. Figure 6 shows the effect of forces on a material point "M" located on a circle of radius r, m, rotating at a speed of n revolutions per minute under the action of force F.

Fц - centrifugal force directed along the radius of rotation from the axis (center).

F is the centripetal force that balances and holds our point.

The segment MM1 characterizes the resultant of these forces.

F _K - Coriolis force, or Coriolis acceleration, trying to reset our point to the right. This is hindered by the proposed mold. In FIG. 7 shows the location of the tilt angles of the feeders for castings in the range of radii 0-1.2 meters, with a centrifugal table rotational speed of 100-400 rpm, the feeder tilt angle will be from 90 ° to the position tangent to the outer surface of the casting, in FIG. Figure 8 shows a casting that has two annular surfaces r1 = 1 m and r2 = 1.2 m. The product according to the formula will be equal to 9 and 12.96, respectively, when the angle of inclination is 60 ° and 90 ° to the graph.

In FIG. 1 shows a sprue system, where the positions indicated the following.

1. The metal receiver.

2. Horizontal runner (4 pcs.).

3. Vertical runner (4 pcs.).

4. A casting consisting of two conical surfaces interconnected by blades.

5. The gate run to the inner cone at an angle of 45 ° (4 pcs.) (Section BB).

6. Ring collector.

7. The gate run to the outer cone rod angle of 30 ° (4 pcs.) (Section CC).

8. Gating to the lower flange of the outer cone at an angle of 30 ° from the annular collector (8 pcs.) (Section D-D).

SUMMARY OF THE INVENTION

The essence of the invention lies in the fact that the proposed invention provides uniform filling of the mold due to the constant pressure of the melt, excluding spatter and rupture of the metal during its movement. This allows you to get high-quality (dense) castings of large diameters with low casting properties.

The rationale for the proposed gate system is given below.

The movement of metal into the mold cavity begins after filling the vertical gate or ring collector, since the action of centrifugal forces prevents this. The force acting on the metal can be determined by the formula (derived according to Newton’s law F = m · a).

where P is the pressure in pascals, or force,

n is the number of revolutions of the centrifugal table per minute,

10 ⁵ - 1 kg / m ² expressed in pascals,

K = 2.24, in this case, the reduced coefficient obtained as a result of recalculation of the following values: specific gravity of the alloy (in this case, titanium alloy - 4.5 tons per meter per cube), 2π (6.28), and angular translation speeds from "radians" per second to revolutions per minute, the acceleration of gravity 9.8 m / s ² .

Consider the effect of forces on a material point located on a circle of radius r, m, rotating at a speed of n revolutions per minute (Fig. 5).

According to the theory of centrifugal rotation, the system we adopted rotates together with the globe rotating around its axis, and our point will try to go to the left (Coriolis acceleration acts on it), this force is greater, the greater the radius and number of revolutions. “In the northern hemisphere, this refers to bodies rotating clockwise, and in the southern hemisphere counterclockwise.”

, поставив в это выражение численные величины, в пределах имеющихся возможностей оборудования получаем таблицу №1.If we consider the formula (1), then it depends on the product

By putting numerical values in this expression, within the limits of the available equipment capabilities, we obtain table No. 1.

Having chosen the angles of inclination 90 °, 60 ° and 30 °, we build a graph.

Recommended plot of the angle of the feeder to the angular velocity vector. At small values of n and r, the angle tends to 90 ° and the metal is fed against centrifugal forces along the radius. If the casting consists of several annular surfaces, then the transfer of metal from one surface to another is carried out according to the above recommendations (Fig. 8). The arrows indicate the rule for using the chart.

, произведение определяет габариты отливки и скорость вращения центробежного стола. На фиг. 2 показан график, построенный по таблице 1, где А-В-С рабочая часть графика для рекомендаций по выбору угла наклона «δ» (предлагаем).Calculation formula

, the product determines the dimensions of the casting and the rotation speed of the centrifugal table. In FIG. 2 shows a graph, constructed according to table 1, where A-B-C is the working part of the graph for recommendations on choosing the angle of inclination "δ" (offer).

угол δ может равняться 90°, т.е. идти по радиусу против действия центробежных сил, развиваемое давление Р не в состоянии разорвать поток металла.1. When

the angle δ can be 90 °, i.e. to go along the radius against the action of centrifugal forces, the developed pressure P is not able to break the metal flow.

величина угла δ стремится → 0, т.е. металл рекомендуем подавать по касательной к поверхности отливки (Фиг. 7).2. When

the value of the angle δ tends to → 0, i.e. metal is recommended to be fed tangentially to the surface of the casting (Fig. 7).

The square shape of the metal receiver in the lower part of the gating system (Figure 3. The angular location of the horizontal gateways provides the maximum flow rate) and the angular exit of the melt into the horizontal gateways (Figure 4. The direction of rotation of the mold clockwise) are used to transfer the melt to the vertical gate, with subsequent redistribution of the metal in the horizontal annular collector, this ensures the smoothness of the melt (its flow) without breaking the flow, eliminating its pulsation w and slippage, and the angular location of the horizontal runner passages provides maximum flow rate. In addition, the angular exit of the melt into the horizontal gateways provides forced metal capture and axis displacement relative to the axis of rotation of the mold when the melt is fed into the vertical gate, increasing the pressure head of the melt flow. At the same time, at least 4 feeders must be equidistant and made at an angle (δ) from 90 to 0 degrees (Figure 7. Dependence of the angle of direction of the feeders (δ) on the distance to the rotation axis) relative to the centrifugal rotation velocity vector, depending on the dimensions the resulting casting (table 2), to prevent metal spatter.

Claims (1)

A gating system for producing thin-walled castings of large diameters from titanium and heat-resistant alloys by centrifugal shaped casting in vacuum with a vertical axis of rotation of the mold and the upper melt supply, containing a central riser with an expanding lower part, horizontal gating gates, vertical gating gates and gating casting feeders, characterized the fact that it further comprises a Central metal detector, a horizontal annular collector, while the Central metal detector is located in the lower part of the gating system and has a cross-sectional shape in the corners of which are located horizontal gating gates connecting with the vertical gating gates, while the gating system contains at least 4 gating casting feeders located in a horizontal plane at an angle from 90 to 0 degrees relative to the centrifugal rotation speed vector of the form.

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