RU177992U1 - GAS CENTRIFUGAL CASTING SYSTEM WITH VERTICAL ROTATION AXIS - Google Patents

Abstract

Usage: the utility model relates to foundry, namely to centrifugal casting of complex profile shaped castings from reactive titanium and any other alloys. Technical result: increased flow characteristics when pouring metal and uniform metal feed into radial metal wires, improving the quality of castings. : The presence of a central riser, at the base of which is located a divider. The divider distributes the liquid metal in two, and, if necessary, in two additional metal wires with a curved initial section, which provides a smooth, almost circular path change in the direction of flow from vertical to horizontal.

Description

The utility model relates to foundry, namely to centrifugal casting of complex profile shaped castings from reactive titanium and any other alloys.

A well-known gating system (RF Patent No. 2402403, B22C 9/08, B22D 13/10, publ. 10/27/10) containing a metal receiver with a receiving cavity and a vertical channel passing into a horizontal channel along the radius R. The vertical channel is made in the form of a nozzle confuser or conoidal type attached to the base of the receiving cavity. The taper angle of the confuser is not more than 30 °. The ratio of the radius of curvature R of the channel to its diameter d is at least 2.0. The degree of narrowing of the nozzle h = D / d-1,5-3,0, where D is the diameter of the receiving cavity. This metal detector allows you to increase the throughput of the gating system and the melt flow rate.

The disadvantage of the analogue is that with a small structural height of its metal receiver and, consequently, a small static and dynamic pressure of the metal, the melt velocity at the entrance to the confuser nozzles will be low. Therefore, increasing the throughput of the gate system, in this case, can only be achieved by increasing the cross sections of the channels. So, for example, when large castings of titanium alloys are obtained by centrifugal method with a total mass of cast metal up to 450-500 kg, the performance of the gating system should be 50-80 kg / s and more. This will require, due to the above drawback of the analogue, an increase in the diameter of the metal detector and the curved channel associated with it, to structurally unacceptable values.

In the design of another gating system (AS USSR No. 969445, MKI B22D 13/10, publ. 10/30/82.), The metal receiver for centrifugal casting has a receiving cavity, a cone divider and horizontal channels in the bottom. To connect the receiving cavity with the outlet openings, vertical channels are provided that pass from a vertical position to a horizontal one with a transition radius defined by the formula:

,

,

where D is the outer diameter of the metal receiver;

d ₀ is the diameter of the base of the cone of the divider;

d _to - the diameter of the channel.

The disadvantage of this metal detector is that it does not completely eliminate the inertial sliding and squeezing of the metal to the wall of the receiving cavity, which negatively affects the flow characteristics of the gate system.

The closest technical solution is the gating system (AS USSR No. 1003996, B22C 9/08, publ. 15.03.83) with a vertical axis of rotation, containing a central riser, a radial metal wire, a collector with a variable cross-section, made in the area between two adjacent radial sprues, expanding in the direction of rotation, and the area of the larger section of the collector is 1.2-1.8 square of small section.

The disadvantage of the described gate system is the pressure loss in the central riser of large diameter when the flow direction changes by 90 ° (from vertical to horizontal) and the metal slips in the central riser during rotation of the mold. Another drawback of this sprue system is that even a slight displacement of the incident jet relative to the axis of the central riser leads to a violation of the uniformity of filling of the radial metal wires, and then of the molds, by the melt and, as a result, the quality of the castings.

These shortcomings are even more pronounced in the manufacture of large-sized massive castings in large-capacity melting plants, when the distance from the outlet tray to the bottom of the receiving device (metal drop height) can reach 1.0 m or more.

The objective of the utility model is to reduce the pressure loss in the gate system.

EFFECT: increased flow characteristics when pouring metal and uniformity of metal supply to radial metal wires, improved quality of castings.

The technical result is achieved by using a gating system with a vertical axis of rotation, containing a central riser, a radial metal wire, a collector with a variable cross-section, made in areas between two adjacent radial metal wires, expanding in the direction of rotation, and the area of the larger cross-section of the collector is 1.2-1.8 small cross-sectional area in which, according to a utility model, two branches of a radial metal wire with curved initial sections adjoin the base of the central riser and, and each of them has in the upper part, at the entrance to the radial metal wire, a semicircle section with a diameter d _o equal to 1.2-1.3 of the diameter of the central riser d _article ; in the lower part, at the exit from the curved section of the radial metal wire, there is a circle with a diameter d equal to 0.4-0.6 of the diameter of the central riser d _article , and the radius R _{in the} branch curvature is 3-5 diameters d of the lower part of the radial metal wire.

The essence of the utility model is illustrated by the drawing, which shows a General view of the gating system with two radial metal wires.

The gate system contains a central riser 1, at the base of which a divider 2 is located. The divider distributes the molten metal through two metal wires 3 with curved initial sections that provide a smooth, almost circular path change in the direction of flow from vertical to horizontal.

Gating system works as follows.

Liquid metal flowing out of the opening of the centrifugal melting unit's tray enters through the funnel into the central riser 1 of the form rotating at a given speed. The cross section of the outlet of the tray is determined taking into account the actual pressure of the metal in the tray and the volume flow rate of the metal required for high-quality casting. The diameter of the central riser at the junction with the funnel is chosen to be 1-1.5 cm larger than the diameter of the metal stream from the tray than its braking and spraying upon impact with the funnel are prevented and, thus, the melt pressure is maintained.

At the base of the central riser, the flow with the help of a splitter 2 is evenly distributed along two radial metal wires 3. Having entered the mouth of the radial metal wire almost parallel to the axis of the central riser, then in the curved channel with a radius of curvature equal to 3-5 diameters d of the lower part of the radial metal wire, the metal flow smoothly , practically along a circular trajectory, changes the direction of the flow from vertical to horizontal, i.e. 90 °.

This design of the metal receiver and the initial curved section of the radial metal wire allows to eliminate the slippage effect and reduce the pressure loss of the metal, due to which the flow coefficient increases by 1.5-2 times, reaching numerical values of 0.6-0.9 units.

The speed of the metal in the inlet of the radial metal wire, in this case, depends mainly on the dynamic and static pressure of the melt, determined by the height of its fall and the level of the metal in the central riser. The influence of centrifugal pressure on the dynamics of the metal flow at the inlet to the radial metal wire, due to the relatively small diameter of the central riser, is small. The value of this factor, as the melt moves along the radial metal wire, increases, and when

large distances from the axis of rotation, its role in the formation of velocity parameters of the flow in general becomes decisive.

Thus, the combination of static, dynamic and centrifugal heads and the elimination of metal slippage in the proposed gate system, the uniform distribution of the melt along the radial metal wires, can improve its flow characteristics and provide the required intensity and uniformity of filling of the forming cavities, and improve the quality of castings.

Claims (1)

A gating system with a vertical axis of rotation, containing a central riser, two radial metal wires adjacent to its base, a collector with a variable cross section, expanding in the direction of rotation, which is located between the radial metal wires, with a larger cross-sectional area of the collector being 1.2-1.8 small section, characterized in that the radial metal wires are made with a curved initial section, with each of the metal wires in the upper part, at the entrance to the curved section, has a section of a shape of a semicircle with a diameter d ₀ equal to the diameter of the central riser 1.2-1.3 d _st, at the bottom, at the outlet of the curved portion - section in the shape of a circle with a diameter d equal to the diameter 0.4-0.6 riser d _article , while the radius R _{in the} curvature of the curved section of each radial metal wire is 3-5 diameter d of its lower part.

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