RU2367688C1 - Modification method of grey cast iron - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes processing of cast iron melt by leaded silumin in amount 0.3-0.6% of belt mass. Strength limit of cast iron is 440-460 MPa and hardness is 490-510 HB.

EFFECT: rising of mechanical characteristics of details, manufactured by means of casting.

1 dwg, 1 tbl, 1 ex

Description

The invention relates to metallurgy of cast iron and can be used to improve the mechanical characteristics of parts manufactured by casting.

It is known to use modifying mixtures to increase the whole complex of properties, including mechanical, castings from cast iron, for example, methods for modifying gray cast iron with fluoroplastic, silicon oxide and slag from the production of synthetic silumin are known [1, 2].

Closest to the claimed is a method of modifying cast iron with a mixture of iron oxides [3].

However, the level of increasing the mechanical properties of cast iron, processed by a known method, is insufficient.

The objective of the proposed method of modification is to improve the mechanical characteristics of cast iron.

The essence of the proposed method lies in the fact that in the method of modifying cast iron, including the treatment of molten iron with an oxygen-containing component, lead silumin in the amount of 0.3-0.6% by weight of the melt is used as the latter.

Lead silumins are aluminum-based alloys containing 20-30% silicon, 1-20% lead, 1-10% aluminum oxide (Al ₂ O ₃ ).

The use of lead silumins for the treatment of cast iron

molten iron can achieve in the ultimate strength σ _in = 440-460 MPa and a hardness of 490-510 HB.

Example. The chemical composition of cast iron used as a charge is as follows, wt.%: Carbon - 4.19; silicon - 0.43; Manganese - 0.68; phosphorus - 0.13; sulfur - 0.03; iron is the rest. Molten iron was melted and the melt was treated with lead silumin in an induction furnace with a capacity of 60 kg. Batch iron was melted and the temperature was brought up to 1300-1360 ° С, after which they were modified with lead silumin in amounts of 0.3 and 0.6% of the mass of the melt. After sedimentation of the melt and removal of slag, the samples were poured into an aluminum chill with a size of 170 × 120 × 15 mm. Samples were made of samples for metallographic analysis and testing of mechanical properties. The results are shown in the drawing and are tabulated. As can be seen from the above results, small additions of lead silumins completely remove the release of graphite from cast iron (drawing), due to which the efficiency of this method of modifying cast iron is higher compared to the known method.

The proposed modification method can be used to obtain castings from cast iron at metallurgical and engineering enterprises.

Information sources

1. Lepinsky B.I. Physico-chemical laws of the modification of iron-carbon alloys. M .: - Science, 1986, p. 98.

2. Auto No. 1548213, class C21C 1/08, C22C 35/00, publ. 1990.

3. Auto No. 709691, cl. C21C 1/00, publ. 1980.

Table Modification Method The amount of modifier,% by weight of the melt Mechanical properties σ _V , MPa HB Known: a mixture containing iron oxide 45-50% calcium carbide 10-15% one 240-260 205-214 fluorspar 5-10% silicon carbide or its sludge - the rest Proposed: 0.3 441 492 leaden 0.45 448 505 silumin * 0.6 460 509 * The chemical composition of lead silumin in% (wt.): 30 Si; 1-20 Pb; 1-10 Al ₂ O ₃ ; Al is the rest.

Claims (1)

A method for modifying gray cast iron, comprising treating a cast iron melt with an oxygen-containing component, characterized in that lead-like silumin in an amount of 0.3-0.6% by weight of the melt is used as the oxygen-containing component.

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