SU1712450A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy, in particular to gray cast iron with a plastic form of graphite for responsible friction parts of internal combustion engines, such as cylinder liners. The purpose of the invention is to improve the workability, increase the ultimate strength and deflection, corrosion resistance while maintaining wear resistance. Cast iron has the following chemical composition, May. %: carbon 3.3-3.7; silicon 2.1-2.6; manganese 0.5-0.8; copper 0.5-1.1; chromium 0.4-0.8; phosphorus 0.3-0.5; titanium 0.03-0.02; aluminum 0.01-0, -1; vanadium 0.03-0.15; lithium 0.01-0.03; iron else. Table 2. (Ls

Description

The invention relates to a foundry, in particular, cast iron with a graphite shape of graphite for important grip parts of an internal combustion engine, for example, liners and liners.

Known cast iron cylinder liners for tomobile engines of the following x | 4M sic composition, wt.%:

3.0-4.0

Cast iron 2.0-2.5

Silicon 0.5 -1.0

Manganese 0.4-0.8

Chrome 0.2-1.0

Nickel 0.4-1.2

Copper 0.1-0.3

Phosphorus 0.07-0.2

Titanium

Bor0.008-0.2

IronErest

However, the corrosion resistance of this

GO 4 SL Ogun low.

Also known cast iron of the following chemical composition, wt.%:

Carbon 3.0-3.6

Silicon1.5-2.4

Manganese 0.5-2.1

Chrom0.1 -0.4

Phosphorus 0.06-0.25

Nickel0.1 -1.0

Boron 0,003-0,012

Titanium0.005-0.05

Nitrogen0,006-0,012

IronErest

However, this cast iron does not have sufficient corrosion resistance, workability, uniformity of hardness in the cross section of a centrifugal casting.

Known cast iron following chemical composition, May. %:

Carbon2.0-3.6

Silicon0.05-2.5

Manganese 0.2-1.5

Copper0.01 -1.0

Vanadium 0.05-2.0

Phosphorus1.0-4.0

Titanium0.005 - 0.7

Aluminum0.050 - 2.0

Iron Else

However, with a sufficiently high wear resistance of cast iron, it has unsatisfactory machinability.

The purpose of the invention is to improve the machinability of cutting cylinder liners, to obtain the same hardness over the liner section while casting by the centrifugal method while maintaining a sufficiently high level of wear resistance,

To achieve this goal, chromium and lithium are additionally added to cast iron containing carbon, silicon, manganese, copper, vanadium, phosphorus, titanium, aluminum, and iron in the following ratio, wt.%;

Carbon3.3-3.7

Silicon2,1-2,6

Manganese 0.5 - 0.8

Copper 0.5-1.1

Chrom0.4-0.8

Phosphorus 0.3 - 0.5

Titanium0.03-0.2

Aluminum0.01-0.1

Vanadium 0.08-0.15

Lithium0.01 - 0.03

IronErest

As an impurity, cast iron may contain sulfur up to 0.1%.

The lower and upper limits of the carbon content are 3.3–3.7%, silicon 2.1–2.6%, aluminum 0.01– 0.1%, and titanium 0.03–0.2 are selected to produce cylinder liners in castings. an optimal amount of graphite and preventing chill of their outer surfaces. When the content of these elements is below the specified limits, the total amount of graphite decreases and the tendency of the pig iron to chill increases during centrifugal casting of the sleeves.

Increasing the amount of carbon, silicon, aluminum and titanium over 3.7, respectively; 0.1; 2.6 and 0.2% leads to a deterioration in the machinability of cast iron cutting,

The alloying of cast iron with 0.5–1.1% copper improves the shape of graphite, contributes to its uniform distribution in the microstructure, which, in turn, allows

improve the antifriction properties of cast iron, reduce the wear of the mating surfaces of the piston ring with it.

The content in the iron is 0.5–0.8% manganese and 0.4–0.8% chromium favorably affects the wear resistance of the iron.

The presence of 0.3 - 0.5% phosphorus in the cast iron ensures the formation of the optimal amount of phosphide ztektica.

Introduction to Vanadium Cast Iron within

5 0.08 - 0.15% allows to increase the corrosion resistance, improve machinability, leads to a uniform distribution of hardness over the cross section of the centrifugal casting.

0 The increase in corrosion resistance is associated with the crushing of eutectic grains and the strong segregation of vanadium into the phosphide eutectic.

The vanadium content of less than 0.08% increases the corrosion resistance is not enough, and its content above 0.15% impairs the machinability of cast iron by cutting. Improved machinability is associated with the formation of complex inclusions of phosphide eutectics instead of structurally free carbides.

The uniformity of hardness over the cross section of the casting is achieved due to the fact that vanadium, having a higher atomic mass than

5 bor. less eliminates on the inner (working) surface of the centrifugal casting. Lithium at a content of 0.01 - 0.03% modifies the solid solution, grinds the structure of cast iron in castings, improves the shape of graphite and phosphide eutectic. To obtain the proposed iron, four mixtures of the ingredients of the intended composition were smelted, four mixtures of compositions with an extremely high content of elements, and one mixture of known iron. Melting of cast iron was carried out in an induction furnace IST-16 with the main lining. Ferroalloys of alloying elements were introduced at 1380 - 1420 ° C in the molten iron,

0 Aluminum, copper and lithium in the form of a ligature of lithium and calcium (30% lithium and 70% calcium with a melting point of 560 ° C) were injected directly into the ladle. The chemical composition of the smelted iron

5 is presented in Table II, and data on their operational and technological properties is given in Table. 2

Friction wear tests with lubricant containing abrasive were carried out on a friction machine with reciprocating movement of a sample cut from a piston ring against a sliding sample made from a cylinder liner. A 10% abrasive was added to the lubricant. Corrosion resistance was determined by holding samples in a sulfuric electrolyte. The relative resistance of the cutting tool is determined for carbide drills.

Claims (1)

Cast iron can be melted in induction, arc and plasma electric furnaces. Formula of the invention: Cast iron containing carbon, silicon, manganese, copper, chromium, phosphorus, titanium, aluminum, iron, tl and h and n and so with, in order to improve workability cutting, increasing the ultimate strength and deflection, corrosion resistance while maintaining wear resistance, it additionally contains vanadium and lithium at the following ratio of components. wt.%: Carbon3.3-3.7 Silicon2,1-2,6 Manganese 0.5-0.8 Copper0,5-1,1 Chrom0.4-0.8 Phosphorus, ZCH), 5 Titanium0.03-0.2 Aluminum0.01-0.1 Vanadium 0.08-0.15 Lithium0.01-0.03 IronErest t. a b l and c a. one