RU2402403C2 - Iron receiver for centrifugal casting with vertical rotational axis - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to casting. Proposed iron receiver comprises intake chamber and vertical channel that changes into horizontal channel along radius R. Said vertical channel represents confuser- or conoid-like nozzle jointed to intake chamber. Confuser taper angle does not exceed 30°. Relation between channel radius R and channel diametre d make at least 2.0. Nozzle taper makes h=D/d - 1.5 - 3.0, where D is intake chamber diametre, d is iron receiver channel diametre.

EFFECT: higher capacity of iron receiver and melt flow rate.

1 dwg, 3 tbl

Description

The present invention relates to foundry, and in particular to devices for casting using external influences on liquid and crystallizing metal, and can be used in the design of equipment and the manufacture of castings by casting with centrifugation of the melt.

Gating systems with a central riser (round, oval, four-, six-sided, and others) with a conical divider installed in the center (and without it) and gating gates, radial or in the form of a segment of a ring, with forms connected to them using feeders are known castings [see Chistyakov V.V. Methods of similarity and dimensions in foundry hydraulics. - M .: Engineering, 1990, p. 55; Serebryakov S.P., Kolobkov Yu.A., Zarayskaya I.S. RF patent No. 2043826: 09/20/1995; Serebryakov S.P., Chistyakov V.V. USSR copyright certificate No. 1003996, BI No. 10, 03/15/83; Golovanov I.D. USSR copyright certificate No. 1323217, BI No. 26, 07/15/1987; Mirzoyan G.S., Kurshev N.N., Badalyan M.U. USSR copyright certificate No. 1675038, BI No. 33, 09/07/91; Shishkin G.V., Shomovsky S.S., Labutina N.I., Morozova TB USSR author's certificate No. 1650338, BI No. 19, 05.23.1991].

Such gating systems do not provide the necessary fillability of the working cavities of the mold in the manufacture of castings. The reason is the slipping of the melt in the metal receiver past the inlet of the radial collector, which is further enhanced as a result of the almost complete loss of the initial dynamic pressure during a sharp turn of the flow by 90 °. The indicated decrease in the transmission capacity of the gating system, especially at the initial stage of filling the mold, contributes to a significant decrease in the quality of castings.

A sprue system is known, containing a central riser with an expanding lower part, a divider with blades made with variable curvature, and sprue passages connected to forms by feeders [see Moiseev B.C., Neustruev A.A., Serebryakov S.P., Kolobkov Yu.A., Tserkovsky B.G., Fadeev A.V., Skornyakov Yu.L., Gubantsev N.V. RF patent №2058849, 04/27/1996], and also a metal detector containing a central riser, a cone divider with ribs having the profile of a centrifugal pump blade [see Golovanov I.D. USSR author's certificate No. 203842, BI No. 21, 10/09/1967].

The indicated configurations of the gate systems due to the use of deaf non-communicating volumes formed by the blades significantly reduce the slipping of the melt in the metal receiver and increase the transmission capacity of the gate system. However, the use of blades or dividers with ribs contributes to the foaming of the melt - capture by a stream of gases, the formation of metal-air mixture and the corresponding marriage of castings.

Closest to the proposed invention is a metal receiver, including a receiving cavity, a cone divider, individual vertical channels that go into horizontal channels with a transition radius R and connect the receiving cavity with the outlet openings [see Shomovsky S.S., Tonzenko V.I. USSR author's certificate No. 969445, BI No. 40, 10/30/1982].

This metal detector increases the transmittance, however, it does not significantly reduce the effect of the melt slipping past the vertical channels, the impact of the flow on the divider during pouring leads to a significant loss of the initial dynamic head, which helps to reduce the metal detector transmittance despite a decrease in further hydraulic losses due to smooth flow rotation by 90 °, and with insufficient flow rate it can lead to a pressureless melt flow in the vertical metal channel all receiver and at the exit from it, reducing the quality and marriage of castings for underfilling.

The technical effect achieved by the invention is to improve the quality of castings by increasing the transmission capacity of the metal receiver and eliminating slippage, ensuring pressure filling of the mold and a higher melt flow rate (flow rate) through the gating system channels by reducing the dynamic pressure loss in the metal receiver, eliminating vortex formation and reduce flow turbulization.

This technical effect is achieved due to the fact that in the metal receiver, including the receiving cavity and the vertical channel, turning into a horizontal one with a transition radius R, the vertical channel is made in the form of a nozzle of confuser or conoidal type, attached to the base of the metal receiver in its axial part, and the taper angle confuser α not more than 30 °, the ratio of the radius of rotation of the channel to its diameter R / d not less than 2.0, the degree of narrowing of the nozzle 1.5-3.0.

Figure 1 shows the metal detector for centrifugal casting with a vertical axis of rotation, where: 1 is the receiving cavity, 2 is a vertical channel with a nozzle of confuser type (a) or conoidal type (b).

The proposed metal detector works as follows. The melt from the casting device enters the receiving cavity 1 and then into the vertical channel 2, filling it throughout the section. The location of the mouth of the vertical channel on the axis of rotation of the mold allows you to eliminate the slippage effect and ensure stable flow of the melt from the receiving cavity into the channel. The configuration of the vertical channel, including the nozzles of the conoidal or confuser type, attached to the base of the receiving cavity in its axial part, and the rotation of the flow by 90 ° relative to the axis of rotation of the mold, ensures maximum preservation of the initial dynamic pressure at the entrance to the receiving cavity and reduces losses on hydraulic resistance in vertical channel. According to the data [see Altshul A.D., Zhivotovsky L.S., Ivanov L.P. Hydraulics and aerodynamics. M .: Stroyizdat, 1987, p.207-210, 313-316] the flow rate coefficient for the nozzle of the confuser type is 0.96, the conoidal type is 0.97-0.995, the coefficient of resistance of the nozzle is 0.01-0.1 depending on degree of narrowing, its smoothness, Reynolds number; the hydraulic loss coefficient of the channel with a flow angle of 90 ° depends on the ratio R / d of the radius of rotation to the diameter of the channel, the coefficient of hydraulic friction.

This metal receiver ensures the flow of the melt flow through the channels of the gating system in the pressure mode, without turbulence and inversion and has a high transmittance (flow coefficient 0.7-0.8).

In order to conduct comparative tests of the proposed metal detector and prototype, model studies were carried out in which the main hydrodynamic parameters of the process were determined: flow rate, flow rate. The optimal values of the main structural parameters of the metal detector (the taper angle α is not more than 30 °; the ratio of the radius of rotation of the channel to its diameter p = R / d is not less than 2.0; the degree of narrowing of the nozzle 1.5-3.0) was obtained by modeling on transparent models and confirmed experimentally upon receipt of real castings. The test results are shown in tables 1-3.

As follows from the data in Table 1, the optimal values of the flow coefficient (μ = 0.7-0.8 were obtained using a nozzle of confuser type with a taper angle α of not more than 30 °. An increase in the taper angle of more than 30 ° leads to a significant decrease in the flow coefficient , which significantly affects the transmittance of the metal detector.

As follows from the data in Table 2, an increase in the radius of rotation of the channel is proportional to an increase in the flow rate of the metal receiver, the most optimal values of the coefficient of flow µ = 0.65-0.8 are obtained with a ratio of the radius of rotation of the channel to its diameter p = R / d of at least 2, 0, however, an excessive increase in the radius of rotation leads to an unreasonable increase in the dimensions of the metal detector.

As follows from the data in Table 3, the optimal values of the flow coefficient μ = 0.7-0.8 were obtained with a degree of narrowing h = 1.5-3.0. Reducing the degree of narrowing of less than 1.5 leads to a slight increase in the flow coefficient, but contributes to an unreasonable increase in the dimensions of the metal detector. An increase in the degree of narrowing of more than 3.0 leads to a significant decrease in the flow rate (with the same volume of liquid being poured) and an increase in the metal consumption of the metal receiver (while maintaining the same pressure above the mouth of the vertical channel).

As shown by comparative tests of the present invention with the prototype, with the same structural parameters, the average value of the flow coefficient of the prototype is 1.4-1.5 times lower.

Table 1 Investigation of the effect of the taper angle of the nozzle of the confuser type on the flow coefficient at the number of mold revolutions of 100-800 rpm, the diameter of the receiving cavity D = 30 mm, the diameter of the channel 10 mm n rpm Flow coefficient µ for taper angle α, degrees 60 45 thirty fifteen 13 one hundred 0.40 0.56 0, 68 0.74 0.75 200 0.41 0.58 0.70 0.75 0.77 300 0.43 0.59 0.71 0.77 0.8 400 0.46 0.61 0.74 0.79 0.81 500 0.49 0.65 0.76 0.82 0.83 600 0.39 0.52 0.66 0.70 0.72 700 0.34 0.48 0.60 0.64 0.65 800 0.32 0.44 0.58 0.62 0.64

Table 2 Investigation of the influence of the ratio of the radius of rotation of the channel to its diameter p = R / d on the flow coefficient with the number of revolutions of the mold 100-800 rpm, the diameter of the receiving cavity D = 30 mm, the diameter of the channel 10 mm n rpm The flow coefficient µ for the radius of rotation of the channel R (the ratio of the radius of the rotation of the channel to its diameter p = R / d), mm 10 (p = 1.0) 20 (p = 2.0) 30 (p = 3.0) 40 (p = 4.0) 50 (p = 5.0) one hundred 0.48 0.59 0.63 0.65 0.68 200 0.50 0.61 0.65 0.67 0.7 300 0.52 0.64 0.67 0.69 0.71 400 0.55 0.66 0.71 0.72 0.74 500 0.58 0.60 0.72 0.75 0.76 600 0.47 0.53 0.60 0.62 0.66 700 0.42 0.48 0.56 0.57 0.60 800 0.39 0.42 0.49 0.54 0.58

Table 3 Study of the effect of the degree of narrowing on the flow coefficient at the number of mold revolutions of 100-800 rpm n rpm The flow coefficient µ with the diameter of the receiving cavity D = 30 mm for the diameter of the channel of the metal detector d (degree of narrowing h = D / d), mm 20 (1,5) 17 (1.7) 15 (2.0) 12 (2.5) 10 (3.0) one hundred 0.71 0.69 0.69 0.68 0.67 200 0.73 0.72 0.71 0.70 0.68 300 0.76 0.74 0.73 0.72 0.70 400 0.79 0.78 0.77 0.75 0.74 500 0.84 0.8 0.79 0.78 0.76 600 0.75 0.73 0.71 0.69 0.66 700 0.68 0.66 0.65 0.63 0.60 800 0.64 0.61 0.60 0.59 0.58 n rpm The flow coefficient µ at the diameter of the channel of the metal detector d = 10 mm for the diameter of the receiving cavity (degree of narrowing h = D / d), mm 20 (2.0) * 30 (3.0) * 40 (4.0) * 50 (5.0) * 60 (6.0) * one hundred 0.72 / 0.50 0.68 / 0.42 0.6 / 0.39 0.46 / 0.31 0.32 / 0.18 200 0.75 / 0.52 0.70 / 0.44 0.61 / 0.40 0.47 / 0.32 0.35 / 0.19 300 0.77 / 0.54 0.71 / 0.47 0.63 / 0.42 0.49 / 0.34 0.37 / 0.22 400 0.82 / 0.57 0.74 / 0.50 0.65 / 0.44 0.50 / 0.36 0.4 / 0.26 500 0.85 / 0.58 0.76 / 0.51 0.67 / 0.46 0.52 / 0.38 0.43 / 0.27 600 0.73 / 0.53 0.66 / 0.44 0.59 / 0.41 0.45 / 0.34 0.39 / 0.23 700 0.67 / 0.50 0.60 / 0.42 0.5 / 0.34 0.38 / 0.30 0.32 / 0.21 800 0.65 / 0.46 0.58 / 0.40 0.48 / 0.32 0.35 / 0.27 0.3 / 0.19 * the denominator shows the values of the coefficient of flow of the prototype with the same design parameters of the metal detector

Claims (1)

A metal receiver for centrifugal casting with a vertical axis of rotation, including a receiving cavity and a vertical channel passing into a horizontal channel along a radius R, characterized in that the vertical channel is made in the form of a nozzle of confuser or conoid type attached to the base of the receiving cavity, and the nozzle taper angle is no more than 30 °, the ratio of the radius R of the channel to the diameter of the channel d is at least 2.0, and the degree of narrowing of the nozzle h = D / d is 1.5-3.0, where D is the diameter of the receiving cavity, d is the diameter of the metal receiver channel a.