SU1098970A1 - Modifying mix for cast iron - Google Patents

Abstract

MODIFIED MIXTURE FOR CAST IRON, containing graphite and a component containing silico barium, characterized in that, in order to reduce the specific consumption of the mixture, decrease its absorption temperature and increase the strength of the iron, it additionally contains aluminum powder, and ferrosilicate powder is used as a component containing silica cobalt in the following ratio of components, May.%: Graphite20-30 Aluminum powder, 2-5 Ferrosilicobarium65-78

Description

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The invention relates to foundry production and can be used for intraframe grinding of cast iron. Known graphitizing modifier for cast iron lj of the following composition, wt.%: Silikomishmetall5-25 Silikokaltiy 30-55 Silumin. 15-30 Foundry. cox10-30 However, metal overheating above 1400 ° C is required to introduce such a modifier due to the presence of refractory components in the silimeter mischmetal. The graphitizing effect is achieved at a high flow rate of the modifier (0.4-0.8 wt.%). Closest to the invention in its technical essence and achievable result is a mixture for modifying cast iron 2 containing composition, wt.%: Technical. boric acid Silicocalcium Siliko15-30 barium Graphite Else However, a modifying mixture is known that is slagged at a temperature of liquid iron below 1380 ° from the presence of calcium in it, which does not allow it to be used for internal modification of fuses with a lower pouring temperature. In addition, the consumption of the mixture is large and amounts to 0.3-0.4 wt.%. The aim of the invention is to reduce the specific consumption of the mixture, lower the temperature of its absorption and increase the strength of the iron. This goal is achieved by the fact that the modifying mixture for cast iron, containing graphite and a component containing silico barium, additionally contains an aluminum rod, and as a component containing silico barium, a ferrous nickel barium is used in the following ratio, wt.%: Graphite 20-30 Aluminum powder2-5 ferrosilicobarium65-78 The modifier is a mechanical mixture of ground ferrosilicobar (fraction less than 1 mm) with powdered graphite and aluminum puru. In the composition of the known mixture includes strong graphitizing elements. like aluminum, carbon, silicon, barium, which interferes with the formation of structurally free cementite in castings and evens out the size of graphite inclusions in thin and thick sections of the casting, which ultimately results in the leveling of the strength of the metal in these sections. The mixture is not slagged upon contact with liquid iron and is completely absorbed at a melt temperature above 1,300 ° C, which does not require additional overheating of the metal above the mold pouring temperature. Example. The effectiveness of the modifying mixture is evaluated by intraform processing of gray cast iron when casting samples of 3.15 and 40 mm stepped thickness and wedge samples for chill. The area of the reaction chamber is 18.0 cm, the specific consumption of metal through the chamber is 0.2 kg / s-cm, the duration of pouring is 9s, the metal intensity of the form is 32.5 kg. Cast iron smelted in an IST-0.16 induction furnace contains, wt%: carbon 3.34, silicon 1.67, manganese 0.82 phosphorus 0.11, sulfur 0.09, chromium 0.08, nickel 0, 05 The metal is poured at 1300-1320 ° C. In the study using modifiers, the composition of which is given in table. 1. The research results are shown in Table. 2 and 3. For comparison, a study was conducted on a known compound 2, containing May. %: technical boric acid 3, silicocalcium 35, silicobarium 22, graphite 30 As can be seen from the table. 2 compositions 2-4 proposed modifying mixture | At a flow rate of 0.1-0.15 wt.% Prevent chill in the sharp edges of the wedge samples. In addition, as a result of the stabilization of the sizes of graphite inclusions during the modification of cast iron with the proposed mixture, the strength in various sections of castings is increased. The use of the proposed modifying mixture in comparison with the known ones provides the following advantages: to assimilate the modifier, liquid iron does not require overheating above the temperature regulated by the fluidity of the melt, which reduces energy consumption for smelting, stabilizing the size of graphite inclusions in thin and thick sections of castings improves the performance characteristics of cast parts the modifier consumption is reduced by a factor of 2-3, which reduces the cost of iron casting, while at the edges and thin sections x castings prevented the possibility of occurrence of structurally free cementite. The economic effect from the introduction of the invention exceeds 63 thousand rubles. in year.

1098970

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Cast iron

one

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Continued table. 2

Claims (1)

A MODIFICATING MIXTURE FOR PIG IRON containing graphite and a component containing silicobarium, characterized in that, in order to reduce the specific consumption of the mixture, lower the temperature of its absorption and increase the strength of cast iron, it additionally contains aluminum powder, and use as a component containing silicobarium ferrosilicobarium in the following ratio, May.%: Graphite 20-30 Aluminum wye powder ^2-5 Ferrosily cobarium 65-78