SU910827A1 - Cast iron - Google Patents

Description

(5) CAST IRON

I

The invention relates to metallurgy, in particular to iron, with enhanced abrasion resistance and impact resistance.

tl the following chi. Known iron, wt.%: the composition, 3-3.8

Carbon

1.5-3

Silicon

0.3-1, +

Manganese

0.1-0.26

Molybdenum 0,, 1

Magnesium Else

Iron

Cast iron is suitable for the manufacture of gears and has high fatigue and contact strength.

The closest in technical essence and the achieved result to the proposed is cast iron 2 of the following chemical composition, weight.

Carbon 2.6-3.0

Silicon 2.7-3.2

Manganese 3.0-4.5

Magnesium0, 06

IronErest

As impurities, iron contains sulfur in an amount of 0.01-0.02 weight. and phosphorus 0.001-0.01 weight .. The structure of this iron consists of a perlite-martensitic metal matrix and graphite inclusions, mechanical characteristics: tensile strength (6 kg kg / mm 1.5-58.2; deflection boom. {(0.3 –0.5; hardness (HB) 290 units; toughness (a, kgm / cm) 0.12610

0.255.

The disadvantage of this cast iron is that it possesses low viscosity, as well as impact resistance and due to the fact that it has perlite-marten metallic metalic atrium and, as can be seen from the above mechanical characteristics, low values of elongation and hardness.

The purpose of the invention is to increase the impact strength of cast iron.

The goal is achieved by the fact that cast iron containing carbon, silicon, manganese, magnesium and iron is added3. 9 contains nickel in the following ratio of components, weight D: Carbon -2.5-2.8. Silicon 2.6-2.9 Manganese. 1.7-2.0 Magnesium, oij-0.06 Nickel2.0-2, t IronEstalled As cast iron, impurities contain, wt%: Sulfur0.005-0.02 Phosphorus 0.005-0.02 When introduced into nickel cast iron , along with abrasion resistance, the impact resistance of cast iron is increased due to the fact that the cast iron acquires the structure of a metal matrix consisting of austenite, tempered martensite and bainite. Low tempering of martensite occurs spontaneously during the cooling of cast iron parts in molds. Mechanical characteristics of the front cast iron: 6ts5g- 0. f 2.2-3.2 mm; a ,, 2.2-3.7 kgm / cm Hftj. ItA-it6: The limits on the content of the individual components in the iron are explained as follows. Carbon in the amount of less than 2.5 does not guarantee the receipt of gray iron. Pig iron containing less than 2.5% carbon is crystallized with chill. When the carbon content is above 2.8%, the cast iron crystallizes, but observes the coarsening of graphite inclusions. When carbon content is within 2.5 g 2.8%, cast iron crystallizes gray without chill and has graphite inclusions of medium size. When the content of iron in the iron is less than 2.6% and the content of manganese, silicon does not completely suppress the release of eutectic cementite. When containing a silicon institute with more than 2.3% of cast iron, it crystallizes completely gray, but the fraction of graphite eutectic increases, which leads to an increase in the amount of graphite and a decrease in the abrasion resistance and impact resistance of the iron. When silicon is found to be in the range of 2.6-2.9, cast iron crystallizes without chill and a fraction of graphite eutectic provides a good combination of abrasion resistance and impact resistance. Manganese at a concentration below 1.7 in cast iron and the content of other components within the specified limits 4 contributes to the formation of the pearlite structure of the metal matrix, which reduces the abrasion resistance of the cast iron. When the content is higher than 2.0, a large amount of martensite and a certain amount of perlite are formed, which leads to a decrease in resistance to impact. Within the range of 1.7-2.0, manganese contributes, along with perlite, to a certain proportion of martensite, thereby ensuring the hardness required for high abrasion resistance of the iron. Nickel at a content below 2.0% does not suppress the complete pearlite transformation. Cast iron with the specified ratio | In addition, carbon, cream, manganese, containing less than 2.0% of Nij, has a perlite-martensite-austenitic structure of the matrix and, as a result, not a sufficiently high impact resistance. Nickel with a content higher than 2% contributes to the formation of a large amount of austenite in the cast iron microstructure, which lowers the abrasion resistance of the iron. Nickel within 2, with the content of the supporting components within the proposed composition contributes to the achievement of the best martensite-bainite-austenitic structure of the metal matrix, which simultaneously provides high abrasion resistance and impact resistance of the iron. Phosphorus is allowed up to 0.02 so as not to emit a phosphide eutectic. Sulfur is allowed up to 0.01 so that sulfides are not released. Example. In 60 kg of an induction furnace, cast iron of the proposed composition is smelted and poured cold earth forms with a diameter of 60 mm into hot earth forms with a diameter of 30%. The microstructure of cast iron consists of medium-dispersed graphite and a bainite-martensite-austenitic matrix. Mechanical properties are shown in table. As can be seen from the table, the proposed cast iron has both high abrasion resistance and impact resistance. The smelting technology of the proposed pig iron does not change as compared with that used for the known.

II

CtfO S

0) I-2

a (dz

Claims (2)

crn; (1) 7 Invention Formula Cast iron containing carbon, silicon, manganese, magnesium, and iron, in order to increase toughness, it further contains nickel in the following ratio of components, weightD: Carbon 2.5-2.8 Silicon 2.6-2.9 910827 pr CL V Manganese 1.7-2.0 0.0t-0.06 Magnesium 2.0-2, Nickel Iron Else Sources of Information attention in the examination 1. Finnish patent number f9732, C 22 C 37/0, 1975. 2. Authors certificate of the USSR 92585, cl. C 22 C 37/00, 1976.