SU1548240A1 - Briquette for inoculating iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in pig iron processing. The purpose of the invention is to improve the mechanical and technological properties. New briquette for modifying pig iron contains, in wt.%: Silicobarium 7-26

iron-silicon-magnesium-calcium ligature 35-55

yttrium 13-18

manganese nitrides 3-10

ferrosilicocyrconium 3-7

aluminum 3-20. An additional input of the preform yttrium, manganese and nitrides ferrosilikotsirkoni allowed by treating iron enhance its mechanical properties: σ _in at 1,03-1,08 times

δ 3-3.5 times

XI in 1.46-1.5 times, as well as technological properties: L in 1.13-1.18 times. 2 tab.

Description

The invention relates to metallurgy, in particular, to the development of briquette compositions for the modification of pig iron.

The purpose of the invention is to improve the mechanical and technological properties of cast iron.

The required effect of modification and improvement of the technological properties of cast iron is achieved at a concentration of ferrosilicon zirconium in the briquette from 3 to 7 wt.%. When the content of ferrosilicon zirconium is up to 3% by weight, its modifying effect is low, the dispersion of the cast iron structure is insufficient, the mechanical, technological properties of the cast iron and its stability are reduced. With an increase in the concentration of ferrosilicon zirconium more than 7 wt.%, The heterogeneity of the structure, the instability of the technological and mechanical properties of the modified cast iron are observed, and the content of vermicular graphite in the structure increases.

Entering yttri in the amount of 13–18 May.% Increases the spheroidization of graphite, fluidity, the number of crystallization centers during its hardening, the content of ferrite in the structure, crack resistance, which contributes to an increase in resistance under contact-shock loading and elastic-plastic properties. When the yttrium content is more than 18 wt.%, The content of non-metallic inclusions increases and the technological properties, the stability of the modification and the mechanical properties are reduced. Processing of cast iron modifying

briquettes with yttri content less than 13 wt,% are accompanied by insufficient modifying effect and instability of the obtained results, high content of vermicular graphite in the structure.

When a manganese nitride modifying briquette is introduced into the composition, its refining, modifying and deoxidizing effect is enhanced, the number of centers increases, which contributes to the refinement of the structure and increase the stability of the technological properties of the modified iron. When the concentration of manganese nitrides is up to 3% by mass, its refining and modifying effect is insufficient, and with an increase in the manganese nitride content of more than 10% by weight, a large concentration of non-metallic inclusions is obtained, no further improvement of the technological properties and their stability is achieved.

Iron-silicon-magnesium-calcium ligature (LCMK) at a concentration of 35-55 wt.% Ensures the production of iron without lamellar graphite. When the content of the LCMK ligature in the briquette composition is more than 55 wt.%, The pyro effect is enhanced and the stability of the structure and technological properties is reduced.

When the silicobar content is less than 7 wt.%, The stability of the modifying and graphitizing effect of the briquette decreases, and an increase in the silicobar content of more than 26 wt.% Increases the cost of the modification process without significantly increasing the mechanical and technological properties of their stability.

Steel shot in the briquette reduces the modifying effect and the technological properties of the modified iron and their stability, so it is excluded from the composition of the briquette.

PRI me R. Briquettes are produced in coke-gas cupolas on the charge from cast iron, cast iron scrap and return production. The bucket processing of cast iron containing, in wt.%, Is made: carbon 3.0-3.2; slope 2.2-2.3; manganese 0.5-0.6; hro up to 0.06; nickel up to 0.2; sulfur to 0.05; phosphorus 0.05-0.06; iron otal Consumption proposed brik

0

five

0

five

0

five

0

five

the modifier is 0.25% by weight of the melt.

To obtain a briquette of the proposed composition, silicobarium crushed to a fraction of 0.05-2 mm, LCKK-5 ligature of a fraction of 0.1-0.2 mm, metallic yttrium, powders of manganese nitrides and ferrosilicone zirconium fraction of 0.05-2 mm are used. Raw materials are mechanically mixed in Katkov mills and subjected to hydrostatic pressing with a specific pressure of 2000 MN / m2.

Cast technological samples from the modified cast iron are cast by a known technology. The fluidity assessment was carried out using a Keri helical test, and the crack resistance tests were carried out on a technological star sample with a height. 146 mm. Evaluation of the structure produced by the metallographic method according to known technology

Cast iron is cast into wet sandy-clay forms. Mechanical tests are performed on specimens in a cast state.

In tab. Table 1 lists the composition of briquettes for modification, and Table 2 shows the technological and mechanical properties of modified iron.

Metallographic studies have shown that the shape of graphite inclusions in cast iron is spherical and vermicular. The impact strength is determined on samples of 10 x 10 x 55 mm with a semicircular, notched on a scraper.

Claims (1)

As follows from the table. 1 and 2, the additional input of yttrium, manganese nitride and ferrosylacic zirconia into the briquette allows to increase the mechanical properties: iy 6 1.03-1.08 times, s / 1 3-3.5 times, XI in 1, 46-1.5 times, as well as technological properties: L 1.13 - 1.18 times. Invention Formula Briquette for modifying cast iron containing silicobarium, iron-silicon-magnesium-calcium ligature and aluminum, characterized in that, in order to improve the mechanical and technological properties of cast iron, the briquette additionally contains yttrium, manganese nitrides and ferrosiliconium zirconia in the following ratio of components, wt. %: Silicobarium 7–26 Yellow Calcium Magnesium Calcium ligature 35-55 t Yttrium13-18 Manganese nitrides 3-10 Ferro-glycicronium Aluminum 0.25 0.25 0.25 Note. In the known briquette, additionally contains 20% by weight. steel shot. table 2 Note. The form of graphite inclusions in the iron: W - spherical, B - Vermiculum rna. Table 1 815,835,820