SU578902A3 - Method of conditioning modifier - Google Patents

Description

one

The invention relates to a material that causes the formation of spherical inclusions in molten iron, as well as a method for introducing this material into a molten iron and apparatus for carrying out the method.

The known method consists in inserting a modifying agent into the mold in the form of plates or disks obtained by compacting a mixture of powdered sponge iron and a modifying additive (inoculant). Such a modifying additive can be graphite, carbide or calcium silicide, or a ferrosilicon alloy into which various elements can be introduced, for example magnesium 1.. In such a way, cast iron can be modified to eliminate pigment-reducing carbides and to eliminate formation of spheroidal graphite in cast iron, while As a rule, the amount of modifying additives introduced is significantly lower than the amount necessary for the formation of spherical graphite inclusions.

The purpose of the invention is to increase the degree of assimilation of the modifier.

For this, the modifying reagent is briquetted in the form of plates and collected into a bag with a decrease in the content of the modifying agent from the top plate to the bottom. The package is made up of sixteen plates, one of which contains 75%, two 10%, and thirteen-5% modifying chemical reagent.

The material that causes the formation of spherical graphite inclusions in liquid iron contains pure iron and a pure modifier, both of which are in a powdery state and agglomerate with each other.

This material is evenly distributed in the cast iron, which gives the cast billets good mechanical properties and allows processing of small, small: cast iron, for example, small groups of cast iron billets with inclusions of spheroidal graphite. Most often, the material causing the formation of graphite inclusions, is agglomerated in the form of plates containing an agent (modifier) that forms inclusions.

According to another implementation principle of the proposed method, the material forming graphite including 1i is agglomerated in the form of plates of many different groups with different content of modifier (forming the inclusion of the agent). This makes it possible to achieve a considerable uniformity of the residual content in the cast iron of the agent that forms the graphite inclusions, the particular uniformity of the graphite inclusions and the uniformity of the base structure. The cast iron is poured into the fiu inside which it is in direct contact with the specified material. In this case, on the path of the cast iron, a plate group is established with a higher content of the inclusion agent (modifier), and then the plate groups are successively set as the content of modifier. The material that causes the formation of spherical graphite inclusions, corresponding to the first implementation principle of the present invention, is contained in the iron in an amount of from 0.5 to 3 wt.% Of the weight content of the iron, and consists of a mixture of the finest pure magnesium and pure iron, agglomerated. with each other in the form of records. The iron and magnesium metal powder used is a mixture comprising from up to 20% by weight (preferably 10% by weight, magnesium and from 80 to 99% by weight,% (preferably 90% by weight) of iron. The higher magnesium content in the mixture does not allow It does not achieve its even distribution in the molten metal / metal due to the rapid hlmic reaction with the cast iron. More, the low content of mag111 I.; in the mixture leads to a golden y of the E. volume of the plates ,, KjpoMe ;, d: og, b ,;, essence1 nenu ich, enie and ievt: gray: no. the composition of the powder mixture, Since in order to eliminate the formation of free protrusions, it is recommended to use as small as 1-5 grains as possible, therefore, the rpcientiometric composition of the mixture and its flow ranges from 0 to 500 microns (mostly from 100 to 300 microns) Powdered mixture of iron and magic compaction in a press under the pressure of at least one ton per square centimeter, mostly several tons per square centimeter, with the formation, for example, of dense plates or disks with a diameter ranging from 0.5 to 5 cm and also in thickness from 0.5 to 5 cm. It is also possible that seal the powder mixture to form shapes close to spheres, e.g. Toi type lollipop -berlingo whereby clutch plates is most stable when contacted with a stream of molten iron. The method of introduction of this material In; liquid iron means that the iron flows into the mold for pouring, the passage over the plates and around them. The drawing shows a mold for casting, which allows the introduction of a modifier into the cast iron. The cast iron first passes into the casting jar 1 g and then into the gating channel 2, at the bottom of which is located the Zr filter on which the plates 4 are installed. When contacted with the cast iron, the temperature of the plates rises to such that the speed of their interaction with the cast iron decreases. After passing through the filter 3, the cast iron through channel 5 is directed towards the almost vertical position of the cavities in the form of wedges C-1 ... ... C-5, which are located in a herringbone with respect to channel 5, and the shape rests on the wedge 6, installed on the side of RnHtJa, furthest from the entrance of the gate channel, .. so that the iron penetrates sequentially into each of the arranged ODI.N.SN -.-- other wedges with then into the cast. : 3ag.ot-wats in each of the indicated wedges, starting from the wedge C-1, which is located closest to the entrance wedge, the opening and thus containing the first batch of cast iron, the magnesium content is determined. Two separate tests were carried out. One with the use of a classical material, causing the formation of spherical inclusions of graphite, the other using the material according to the invention. The results obtained are presented in the table.

It should be noted that the test results presented in the table suggest that the proposed method characterizes a more uniform distribution of magnesium.

The iron powder can be replaced by a powdered ferrosilicon alloy, which has the advantage of modifying the cast iron at the same time as