RU2247170C1 - Modifying agent - Google Patents

Abstract

FIELD: metallurgy, in particular modified gray cast iron for cast shape.

SUBSTANCE: claimed modifying agent contains (mass %) ferrosilicon barium 0.5-5.0 and gypsum 25-5 %.

EFFECT: increased recovery of ferrosilicon barium and sulfur, absence of gypsum dusting formation, decreased chilling effect and improved cast mechanical properties.

3 tbl

Description

The invention relates to the metallurgy of foundry, in particular, to the development of compositions of gray cast iron for wall-mounted shaped castings.

Known modifier [1], which contains the following components, wt.%;

Ferrosilicobarium 25-75

Okshara 75-25

The disadvantage of this modifier is the instability of obtaining positive results for reducing “bleached” in castings and improving the properties of cast iron due to the unstable composition of okshara, as it is an industrial waste.

Closest to the proposed modifier in technical essence and the achieved result is a modifier [2] of the following composition, wt. %;

Ferrosilicobarium 25-75

Gypsum 75-25

The disadvantage of this modifier is the insufficient assimilation of ferrosilicobarium and sulfur and dust formation in the workshop when pulverized gypsum is introduced into incandescent ladles due to the emission (removal) of pulverulent matter by hot heat fluxes.

An object of the invention is to increase the absorption of ferrosilicobarium, sulfur and the exclusion of dust from gypsum, as well as reducing the “whitening” of “hard” cast irons and increasing the mechanical properties.

The technical problem is solved so that the modifier containing ferrosilicobarium and sulfur-containing material contains ferrosilicobaric fractions of 0.5-5.0 mm, and gypsum is packaged in waterproof bags (polyethylene or other types of waterproof material) in the following ratio of components, wt.%

Ferrosilicobarium fraction 0.5-5.0 mm 75-95

Plaster Packed in Bags 25-5

Analogues containing the distinguishing features of the proposed technical solution were not found.

At GAZ in the laboratory and in the foundry, comparative experimental melts were carried out with the modification of cast iron in the ladle with the well-known and proposed modifier.

Cast iron was smelted in an induction furnace IST-016 with acid lining. As a charge, pig-iron pig iron, cast iron return SCCH24, steel waste and ferroalloys FS65Ba4 (TU 14-5-160-84), FMn70 (GOST 4655-91) and gypsum (GOST 125-79) were used.

The metal was overheated in an oven to 1500 ° C and samples were poured: a wedge on bleached, a step wedge, blanks for mechanical properties.

Cast iron was of the following chemical composition,%:

Carbon 3.23

Silicon 1.70

Manganese 0.90

Chrome 0.15

Phosphorus 0.06

Sulfur 0.07

Examples of specific modifier compositions used and known are shown in Table 1, and the results of their use are shown in Table 2. Both modifiers were injected onto a metal stream during overflow from the furnace to the bucket.

As can be seen from table 2, the well-known modifier (1, 2, 3) fractions of 3-10 mm and the introduction of gypsum in bulk ladle absorption of silicon is 68-72% and sulfur absorption 69-72%. The mechanical properties (σ _in ) were 243-265 MPa at 20-50% of interdendritic graphite, the value bleached 1.5-2.5 mm.

In the proposed modifier (optimal properties in Convent. No. 5-7), the percentage of assimilation of FS65Ba4 increases to 88-94%, and the percentage of assimilation of sulfur from gypsum increases to 84-93%, interdendritic graphite is completely absent, and mechanical properties increase.

With the fourth composition of the modifier 70% FS65Ba4 + 30% gypsum, cast iron is obtained with whitening and low properties.

With the eighth composition of the modifier 97% FS65Ba4 + 3.0% gypsum, cast iron is obtained with bleaching, interdendritic graphite and low mechanical properties.

The ninth and tenth compositions of 75-80% FS65Ba4 with a fraction of less than 0.5 mm + 15-20% gypsum and 11.12 variants with the introduction of 15-20% gypsum in bulk + 75-80% FS65Ba4 have insufficient absorption of silicon and sulfur, bleached and low mechanical properties.

The most optimal properties of cast iron were obtained in 5-7 variants of the proposed modifier (table 2). The optimal additive of the proposed complex modifier is in the range of 0.3-0.4%.

In the GAZ foundry, production tests of the proposed modifier were carried out in comparison with the known ones. Parts such as wheel cylinders were cast, a wedge for bleaching, and blanks ⌀30 mm long for cutting samples to tensile strength. The results of the study are summarized in table 3.

Modifier with conv. 2 of the composition 75% FS65Ba4 (fractions 0.5-5.0 mm) + 25% gypsum packed in bags, in terms of the effectiveness of the reduction in bleaching, it exceeds the modifier with conv. 1 composition of 75% FS65Ba4 fraction of 3-10 mm + 25% gypsum in bulk in 3 cuts and increases the strength properties of cast iron by 15-18%.

List of references.

1. Yu.A. Zinoviev et al. “Gray cast iron modifier”. A.S. 1675376. MKI S 22 S 35/00.

2. Yu.A. Zinoviev et al. “Modifier”. A.S. 2151213. MKI S 22 S 35/00.

Claims (1)

Modifier of gray cast iron containing ferrosilicobarium and pulverized gypsum, characterized in that it contains ferrosilicobarium fractions of 0.5-5.0 mm and packaged gypsum in the following ratio of components, wt.%: Ferrosilicobarium fraction 0.5-5.0 75-95 Plaster Packed in Bags 25-5