RU2138361C1 - Liquid cast iron modifying pouring system - Google Patents

Abstract

FIELD: foundry, in particular, production of cast iron with spheroidal, vermiculite and plated graphite. SUBSTANCE: pouring system has two mold halves, where feeding funnel with riser, reaction chamber, slag catcher, insert-rod and settling chamber are positioned and communicated one with another via running channels. Supplying and discharge channels of reaction chamber are disposed tangentially and in opposed relation one to another. Supplying channel is positioned at higher level and discharge channel at lower level relative to mold halves detachment line. Insert-rod is disposed under slag catcher and settling chamber is positioned under insert rod. Running channel of insert-rod is made in the form of annular slit partially extending along its circle. Reaction chamber is connected to slag catcher via running channel disposed in upper mold half. When cast iron is delivered into slag catcher, slags and inclusions come to surface and uncontaminated cast iron is fed into settling chamber. EFFECT: improved quality of cast iron and consequently of castings by additional cleaning, and wider operational capabilities. 2 cl, 2 dwg

Description

 The invention relates to foundry, in particular to the development of gating system designs for in-mold modification of ductile iron with spherical graphite.

 Known gating system for modifying ductile iron, containing a receiving funnel with a riser, a reaction chamber and a slag trap (see SU A.S. N 1537372, class B 22 D 27/20, 90 g). The specified gating system does not allow to obtain high quality modified cast iron.

 Known gating system for modifying cast iron, containing the lower and upper molds and placed in them a receiving funnel with a riser, a reaction chamber with inlet and outlet channels and a slag trap (see SU A.S. N 1616773, class B 22 D 27/20, 90 g.). This system also does not allow to obtain high quality cast iron.

 The closest set of essential features is the gating system for modifying molten iron, containing the lower and upper half-molds and a receiving funnel with a riser placed in them, a reaction chamber with discharge and supply tangential channels located below the level of the half-mold connector, and a slag trap (see SU a S. p. N 1792799, CL B 22 D 27/20, 93 g.). This sprue system does not allow to obtain high-quality cast iron with lamellar, vermicular and spherical graphite, since the tangential exit of molten cast iron from the reaction chamber, coinciding with the direction of rotation of molten cast iron contributes to the formation of a powerful fluid flow, which inevitably captures the insoluble particles of the modifier and its interaction products and carries them into the cavity of the mold.

 The problem to which the claimed invention is directed, is to obtain high quality cast iron with lamellar, vermicular and spherical graphite.

 The technical result is an increase in the quality of iron castings.

 The above technical result is achieved due to the fact that the gating system for modifying molten iron contains the lower and upper half-molds and they contain a receiving funnel with a riser, a reaction chamber with a discharge and supply tangential channels located below the level of the half-mold connector, as well as a slag trap.

 The proposed sprue system is characterized in that it is equipped with an insertion rod located under the slag trap and made with a sprue channel in the form of an annular gap placed on the circumference and the insertion rod, its lower end forming a recess in the lower half-mold, in which it installed, a settling chamber, while the outlet channel of the reaction chamber is located opposite its inlet channel and is connected to the slag trap by an additional gate channel located in the upper half-mold. Also, the feed channel of the reaction chamber is located in the upper half-mold. In FIG. 1 shows a sectional view of a sprue system; in FIG. 2 - section along aa.

 The gating system consists of the lower 1 and upper 2 half-forms. In these half-molds there is a receiving funnel 3 with a riser 4, a reaction chamber 5 with a discharge 6 located below the level of the half-mold connector and a tangential channel 7 located in the upper half-mold, as well as a centrifugal slag trap 8. A discharge channel 6 of the reaction chamber 5 is located opposite its supply channel 7 The sprue system also has an insertion rod 9 located under the slag trap 8. In the insertion rod 9, a sprue channel is made in the form of an annular slot 10 located on a part of its circumference. The lower end of the insertion rod forms, with the bottom of the recess in the lower half-mold in which it is installed, a settling chamber 11.

 The outlet channel 6 of the reaction chamber 5 is connected to the centrifugal slag trap 8 by an additional gate channel 12 located in the upper half-mold 2. The system can be run either directly in the gate form or outside the form in a separate flask or rod.

 Cast iron is poured through the receiving funnel 3, passes through the riser 4 and through the inlet channel 7 located in the upper half-mold 2, tangentially enters the upper part of the reaction chamber 5, into which the modifier is previously placed.

 The selection of modified cast iron from the reaction chamber 5 is carried out through a tangential discharge channel 6 made in the lower half-mold 1. Its direction does not coincide with the direction of rotation of the cast iron in the reaction chamber 5, i.e. selection of cast iron is carried out by a counterflow. Such selection of molten iron forms a discharge stream only due to the forces of metallostatic pressure and centrifugal forces and completely eliminates the effects of the dynamic forces of the rotating flow of cast iron and thereby reduces the removal of modifier and slag. From channel 6, the modified cast iron enters an additional gate channel 12 located in the upper half-mold 2 and tangentially leads the cast iron to the centrifugal slag trap 8. Cast iron in the centrifugal slag trap 8 comes into rotational motion and through the gate, made in the form of an annular gap 10 in the insertion rod 9, enters the settling chamber 11 and then goes through the channel system to the riser and the mold, if the system is installed on the mold, or directly to the castings, if the system is made directly in the mold.

 Such a sprue system allows to obtain high-quality cast iron due to the fact that the selection of cleaned cast iron is carried out from a centrifugal slag trap 8, in which slags and non-metallic inclusions are kept in the central part of the slag trap 8 and float up, and pure cast iron due to its higher density it is concentrated at the outer walls of the centrifugal slag trap 8, from where it enters the settling chamber 11. The settling chamber 11 provides additional cleaning of cast iron.

Claims (2)

 1. A gating system for modifying molten iron, comprising a lower and an upper half-mold, a receiving funnel with a riser placed in them, a reaction chamber with inlet and lower tangent channels and a slag trap, which is provided with an insertion rod installed under the slag trap in a recess made in the lower half-mold and having a sprue channel in the form of an annular gap on a part of its circumference, while between the lower end of the insertion rod and the bottom of the recess Hovhan settling chamber, and the discharge duct of the reaction chamber located opposite the raceway and coupled to shlakoulovitelem additional runner placed in the upper mold half.  2. The gate system according to claim 1, characterized in that the feed channel of the reaction chamber is located in the upper half-mold.

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