SU1379314A1 - Method and apparatus for producing high-duty cast iron - Google Patents

Abstract

The invention relates to metallurgy and foundry, in particular, to technology for producing high-strength cast iron. The purpose of the invention is to increase the stability of the mechanical properties and obtain the structure 2 / J / / high-strength cast iron without chill. The method for producing high-strength iron involves the sequential modification of gray iron with graphitizing additives in the ladle and spheroidizing additives in the reaction chamber of the gating system. In front of the reaction chamber, the melt stream is divided into two streams and 0.1-0.4 mass of the melt is directed, mine the reaction chamber, and then both streams are mixed at the outlet of the reaction chamber. A device for implementing the inventive method comprises a casting bowl 1, connected to the reaction chamber 5 by successively located columns 2 and sprues 3 and 4, an open intermediate bowl 9 connected to the shaping cavity. The reaction chamber 5 is provided with an isolated channel 8 connected to the stand 2 and an open intermediate bowl 9 connected to the reaction chamber 5, and the cross-sectional area of the isolated channel 8 is 0.1-0.4 cross-sectional area of the stand 2. 2 .P. f-ly. 1 sludge & (L bo from 00

Description

The invention relates to metallurgy and foundry, in particular, to technology for producing high-strength cast iron.

The purpose of the invention is to increase the stability of the mechanical properties and to obtain the structure of high-strength cast iron without chipping.

The drawing schematically shows an apparatus for carrying out the method for producing high-strength cast iron.

The method is carried out as follows.

When filling the pouring ladle, graphitizing additives are introduced into the jet of the melt, slag is removed from the mirror and the melt is poured into the mold through the gating system, in the reaction chamber of which the spheroidizing additives are placed in front of the melting chamber. One stream is directed above the spheroidizing additive in the reaction chamber, and the second, equal to 0.1-0, D mass of the melt, is passed through an isolated channel inside the reaction chamber. At the outlet of the reaction chamber, both melt streams are mixed and a secondary liquid graphitizing modification of the melt is carried out before it enters the mold cavity.

At the same time, the processes of spheroidizing metal modification in the reaction chamber are heated by heating the spheroidism with the additive, which ensures its complete and uniform dissolution and the secondary liquid graphitizing modification at the outlet of the reaction chamber. The melt processed in this way ensures stable mechanical properties and high-strength structure. cast iron without chill,

The device for producing high-strength cast iron consists of a casting bowl 1, stand 2, gates 3 AND A, a reaction chamber 5 in which spheroidizing canals are placed, discharge channels 6 and 7, an isolated channel 8, an open intermediate bowl 9, a stopper 10 and output stand 11,

The device works as follows.

From the casting ladle (not shown), the liquid melt enters the casting bowl 1 and then through one hundred to two, where

five

0

5 0 5

0

five

the melt is divided into two streams. One stream through gating run 3 enters the reaction chamber 5, which is loaded with spheroidizing additives. With the passage of molten iron through the reaction chamber, the additive is dissolved, which provides the effect of a spheroidizing modification. The second stream through gate 4 enters

isolated channel 8. When passing through - I

The scientific research institute of the initial melt through the passage cavity, made of heat-resistant material, heats the spheroidizing additive in the reaction chamber, which ensures complete dissolution of the additive and stable modification of the melt.

Through the discharge channel 6, the spheroidized melt at the outlet of the reaction chamber 5 is displaced with the initial melt coming from the isolated channel 8, which provides a secondary liquid graphitizing modification. The essence of the latter is that with the merging of two liquid melts, treated with spheroidizing additives and the original melt, previously treated in the bucket with graphitizing additives, in the first period of rotation, the submicroscopic heterogeneity of the melt increases and conditions are created for the formation of embryos that become painful in the microvolume of these volumes, which make it easier for germs to form in the microvolume inhomogeneity and melt. graphitization. As a result, the cast iron hardens with a given structure and mechanical properties,

The melt modified in this way fills the intermediate bowl 9. During the rise of the melt to a predetermined level, nonmetallic inclusions have time to float to the upper layers of the melt, and the metal is well mixed, which ensures uniform distribution of all elements throughout the entire volume of the metal. Thereafter, the stopper 10 is removed and the melt at stand 11 enters the mold cavity (not shown). At the end of the process of pouring, the melt from the reactor chamber through the discharge channel 7 enters the intermediate bowl. The bottom of the reaction chamber is made at an angle of 5-1P to channel 7, which allows the reaction chamber to remain empty at the end of pouring.

The cross-sectional area of the isolated channel 8 is equal to O, 1-0, A and the square of the stand 2, which ensures that the initial melt is supplied to the outlet from the reaction chamber 5 in an amount necessary to provide a secondary liquid graphitizing modification of the spheroidizing melt , and the necessary heating of spheroidizing additives located in the reaction chamber. When the passage cavity is made with a cross section of less than 0.1 of the cross-sectional area of the stand, the necessary heating of the spheroidizing additives and secondary liquid graphitizing modification and high-strength cast iron are obtained with secondary and unstable properties. When the passage cavity is made with a cross section of more than 0, A, the cross-sectional area of the standpile, a larger amount of the initial cast iron enters, as a result of which the modified cast iron hardens in the form with the formation of graphite lamellar form and has low mechanical properties. The calculation of other elements of the device is made on the basis of the equality of the duration of the filling of the form with metal C and the duration of dissolution of the required dose of the spheroidizing additive t.

PRI me R. Testing is carried out on a special casting consisting of five wedge and five step cavities connected in series with feeders. The total metal intensity of the mold is 100 kg. To obtain high-strength cast iron with a ferritic-pearlite metal base in the casting, a method for producing high-strength cast iron and a device for its implementation are used.

The device is made of a liquid-glass mixture through a COj process, followed by drying. The stopper is made of cast iron and coated with several layers of graphite paint, followed by sub-suspension. The reaction chamber of the device for producing high-strength cast iron has dimensions: height 100, length 120, width 100 mm. Section area: one hundred to 10, passage 3, the inlet of the reaction chamber 7 cm.

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about 5

0

five

The original cast iron is smelted in an induction furnace of the following chemical composition, May. : C 3.4; Si 2.5; Mp 0.5; P 0.07; S 0.03; Cr 0.2; iron else. Overheated to 1450 C. The filling is performed using a drum bucket Q 1.8 tons. When metal is fed from the furnace into the ladle, 4 kg of FS 30 FBSM ligature is produced for the stream. After removal of the slag, the starting melt is poured into the runner cup of the modifying device. In the reaction chamber of the device load 1.5 kg of ligature NiMg (Mg 10%, the rest Ni). Filling temperature 1420 С; pouring speed 4.5-5.0 kg / s. After filling the intermediate thicket, the stopper is pulled out to the level of 250 mm. Casting passes quietly without emissions and pyroeffect.

Using the proposed method for producing high-strength cast iron and a device for its implementation allows expanding the technical capabilities of the modification process with increasing mass of the melt being processed, improving the quality of castings by means of secondary liquid graphitizing modification, more complete mixing of the melt when modifying and cleaning it from non-metallic inclusions.

Claims (2)

1. A method of producing high-strength iron, including sequential modification of gray iron with graphitizing additives in a ladle and spheroidizing additives in the reaction chamber of the gating system by passing a melt stream through it, characterized in that, in order to improve the stability of the mechanical properties and obtain a structure of high-strength iron without bleaching, In front of the reaction chamber, the melt stream is divided into two streams and 0.1-0.4 mass of the melt is directed, mine the reaction chamber, and then both streams are mixed and at the exit from the reaction chamber. 2. An apparatus for producing high-strength cast iron comprising a casting cup connected to the reaction chamber by successive stowers and runner gates. 513793146 an open intermediate cup, together with an open intermediate cup, whelping with a shaping cavity adjoining the reaction chamber, characterized by the fact that the cross-sectional area the reaction chamber is equipped with an isolated isolate channel equal to 0.1-0, D A bath channel connected to the one-hundred cross-sectional area of the stand.