SU1583460A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the manufacture of mill rolls. The purpose of the invention is to reduce mountains of chelomkost, increase mechanical properties and wear resistance. Cast iron contains, wt% C 3.1-3.5

SI 0.2-0.60

MN 0.10-0.50

CR 0.80-1.50

NI 1,5-4,5

MO 0.2-0.6

rare earth elements 0.07-0.15

Fe - the rest. A change in the ratio of components in the iron of the proposed composition (an increase in the content of CR, NI, MO and REM, as well as a decrease in the content of SI) makes it possible to increase σ in by 1.06-1.14 times, AK by 1.09-1.13 times, wear resistance 1.02-1.11 times and hotness 1.16-1.28 times. 1 tab.

Description

The invention relates to metallurgy, in particular, to the development of a composition of cast iron for the casting of rolling rolls with a bleached working layer.

The purpose of the invention is to reduce mountains - chelomkost, increase mechanical properties and wear resistance.

The choice of the boundary limits of the content of components in the pig iron of the proposed composition is due to the following. Carbon within these limits provides the optimal amount of carbides (Cr, Fe) 7C3 in the iron structure. A decrease in carbon concentration below 3.1% leads to a decrease in the amount of the carbide phase. Increasing the concentration in excess of 3.5% reduces the thermal conductivity of iron, which increases the tendency to the formation of hot cracks.

When the silicon content is higher than 0.6%, graphite inclusions may appear in the structure of cast iron, which reduce the service properties of cast iron. Obtaining a silicon concentration of less than 0.2% is associated with the complication of melt melting technology.

The manganese content in the range of 0.1-0.5% provides the necessary degree of refinement of the molten iron. When the content is less than 0.1%, the melt is not sufficiently deoxidized and desulfurized, which increases the mountains - the chill of the cast iron. An increase in concentration in excess of 0.5% leads to a sharp increase in the amount of refractory manganese oxides, which increases the tendency of the iron to form hot cracks.

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3 Chromium is introduced within the indicated ranges as a carbide forming element. Its content is less than 0.8% does not provide a sufficient amount of the carbide phase. At concentrations above 1.5%, a coarseAntirtiated carbide mesh is formed in the cast iron structure, which reduces the service properties of the cast iron.

Nickel neutralizes the carbide-forming effect of chromium, helping to obtain rolls of the gamma of transition structures in the depth of the working layer. When the content is less than 1.5% of its effect is not pronounced. An increase in concentration above 4.5% leads to the formation of ferrite in the structure, which reduces the quality of the working layer.

Molybdenum contributes to a dense, fine-grained structure with a low mountain level. When the content is less than 0.2% of its action is unstable, in excess of 0.6% of the manifestation

with carbide-forming effect of molyb- | deden. Since chromium in the proposed non-carbide-forming element is chromium, increasing the concentration of molybdenum in excess of 0.6% is impractical.

Rare-earth metals (REM) of the cerium groups within the specified limits provide a fine-grained structure with grain boundaries that are pure in non-metallic inclusions. This reduces the mountains of iron cast iron. At a concentration of less than 0.07%, a sufficient degree of refining and dispersion of the cast iron structure are not achieved; with a content above 0.15%, complex compounds are formed on OCHO and REM in the melt, which, when crystallized, are released at grain boundaries, weakening the bonds between which leads to an increase in the mountains of iron casting.

Example, under identical conditions, a comparative analysis

60

properties of the proposed and famous cast iron (table).

The cast iron is melted in a crucible with a capacity of 60 kg of an IST-0.06 induction furnace with an acid lining. Charge materials - pig iron, steel scrap, ferroalloys. The metal is overheated in a furnace up to 1450110 ° C and released into a ladle, on which is placed a ligature FSZORMZOZA (fraction 20-30 mm) in an amount of 0.33-1.0% by weight of the metal.

The metal is poured into the sample upon reaching a temperature of 1330410 ° C. Gory chelomkost alloys estimate the load crack open on the instrument design Trubitsina.

A change in the pig iron of the proposed composition of the content of components (an increase in the content of Cr, Ni, Mo, and REM and a decrease in Si) makes it possible to increase 6B by 1.06-1.14 times; am in 1, 09 - 1.13 times, wear resistance in 1.02-1.11 times and reduce the mountain chelumosity in 1.16-1.28.

Form

la invention

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five

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Cast iron containing carbon, silicon, manganese, chromium, nickel, molybdenum, rare earth elements and iron, characterized in that, in order to reduce mountains of roughness, increase mechanical properties and wear resistance, it contains components in the following ratio, wt.% :

3.10-3.50 0.20-0.60 O, 10-0.50 0.80-1.50 1.5-4.50 0.20-0.60

Carbon

Cr

Manganese

Chromium

Nickel

Molybdenum

Rarebones

items

Iron

0.07-0.15 Else

Editor N. Rogulich

Compiled by N. Kosternoy Tehred M. Khodanych

Corrector Q. Tsiple

Order 2232

Circulation 481

VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology CQCP 113035, Moscow, Zh-35, 4/5, Raushsk nab.

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Claims (1)

Cast iron containing carbon, silicon, manganese, chromium, nickel, molybdenum, rare earth elements and iron, characterized in that, in order to reduce heat resistance, increase mechanical properties and wear resistance, it contains components in the following ratio, wt.%: Carbon 3.10-3.50 Cr 0.20-0.60 Manganese 0, 10-0.50 Chromium 0.80-1.50 Nickel 1,5-4,50 Molybdenum 0.20-0.60 Rare earth the elements 0.07-0.15 Iron Rest 5 1583460 6 Cast iron The content of elements, wt. X Property metrics FROM Si η Mp SG ΝΪ. And about Mg REM Hardness, HRC Wear resistance, g (weight loss) MPa Brittleness, kN ** Famous Proposed 3,55 2.60 0.25 0.32 0.55 0.06 0.04 0.04 53 0, 381 220 415 505 one 3.10 0.20 0, 10 0.80 1, 50 0.20 0,07 55 0.377 240 440 590 2 3.30 0.40 0.30 0.15 3.00 0.40 - 0, 1 1 55 0.352 245 475 650 3 3,50 0.60 0.50 1,50 4,50 0.60 - 0.15 56 0.341 250 476 600