SU1285047A1 - High-strength cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the manufacture of thin-walled casts. The purpose of the invention is to increase the wear resistance, tensile strength and reduce the tendency to bleach. New cast iron contains, wt%: carbon 3.2-3.9; silicon 0.8-1., 2; manganese 0.005-0.03; phosphorus 0.15-0.60; cerium 0.002-0.006; aluminum 0.005-0.01; hafnium 0.05-0.1; tin.0.03-0.08 and iron else. The addition of Hf and Sn to the cast iron, as well as its carbon and phosphorus content, provided an increase in wear resistance by 1.5–2.2 times, an increase in tensile strength from 720 to 730–750 Mlla, as well as a decrease in the chipping iron tendency to I2 up to 1-3 mm (wedge test). Table I w

Description

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about

The invention relates to metallurgy, in particular to the development of cast iron compositions, and can be used for the production of thin-walled products, pins.

The purpose of the invention is improving wear resistance, tensile strength and reducing the tendency to bleaching.

Additional introduction of hafnium iron into the composer leads to grinding of the eutectic grain and a significant increase in the number of spheroidal graphite inclusions. Phosphorus forms a phosphide eutectic, which in the process of contact with the conjugate material absorbs the main loads. The combined input of hafnium and phosphorus crushes the inclusions of phosphide eutectics, which is associated with the grinding of eutectic grains along the boundaries of which it is located. Tin increases the degree of doping of the metal base, the hardness of cast iron, prevents the formation of ferrite annealing around graphite inclusions in the process of cooling in the process of casting.

The limits of the content of components are set on the basis of obtaining a beneficial combination of properties and structure of cast iron. The carbon content (3.3–3.9 wt.%) And silicon (0.8–1.2: May.%) Should ensure the production of pearlitic metal bases, taking into account the additional introduction of tin without inclusions of structurally free cementite. An increase in crass more than H, 2 wt.% Worsens the shape of graphite, and, as a result, worsens the nonchanical properties of cast iron. Margane is a byproduct containing. in metallized okatkgg. H value of manganese more than 0.03 wt. leads to the formation of ferrite around graphite inclusions, which adversely affects the mechanical properties and wear resistance of cast iron.

Phosphorus forms a wear-resistant eutectic. The minimum content (about 15 wt.% P) provides a marked increase in wear resistance. With a phosphorus content of more than (0.6 wt.%), The phosphide eutectic can form a grid, which, under microplastic deformations of the surface and shock loads, can dye and disturb the geometry of the contacting surfaces.

Aluminum (0.02–0.01 wt.%) Serves to deoxidize the melt. The concentration of aluminum was chosen experimentally. The increase in aluminum more than 0.01 wt.% Affects the size, shape and distribution of inclusions of graphite in a metal base.

Cerium in the alloy is a sulfur bonding element that crushes the eutectic grain of the structure and reduces the chill iron's tendency to chill.

Tin is introduced into the composition of cast iron as a perlitizing additive. The minimum tin content of 0.03 wt,% significantly reduces the adhesive interaction of the surfaces. An increase in the tin content of more than 0.08 wt.% Leads to the formation of ledeburite in the iron of a given chemical composition and will increase the tendency of the alloy to become white.

Hafnium (0.05-0.12 wt.%) Ensures the stability of obtaining spherical graphite uniformly distributed in the metal matrix, which ensures satisfactory lubrication of the polished surfaces. Increasing hafnium more than 0.12 wt.% Is not economically feasible.

The optimal composition of cast iron contains, wt%: carbon 3-p5 silicon 1.0; manganese 0.018: / ser a, 0.04; phosphorus 0,35; cerium is 0.004; aluminum 0.0075; hafnium 0.09, tin 0.05 iron - ostapnoe.

In order to study the structure and properties of the proposed material, cast irons containing the main components at different levels, as well as a known alloy with an average level of ingredients, were melted. The tendency of iron to chill is studied on the wedge sample. Testing fta wear is performed under friction friction conditions. The contact surfaces are lubricated from cast iron graphite. A sample with a diameter of 10 mm is moved along the surface of the counterbody of steel 45 with a hardness of 50 llRf., Wear is assessed by a weighing method after 6 hours of testing. The load is 6 kgf / cm.

The test results and chemical compositions of cast iron are presented in the table,

As follows from the table, the additional input of hafnium and tin into the composition of the proposed iron, as well as an increase in its content of carbon and phosphorus, makes it possible to increase the wear resistance in 1.5 tons from 720 to 7.30-750 MPa and a decrease in chill from 12 to 1-3 mm

the following ratio of components

May.%:

Claims (1)

The claims j High-strength cast iron containing carbon, silicon, manganese, phosphorus, cerium, aluminum and iron, which includes the following: · In order to I) increase wear resistance, tensile strength and reduce tendency to bleach, it is complemented with Carbon Silicon Manganese Phosphorus Cerium Aluminum Hafnium Tin Iron 3.2-3.9 0.8-1.2 0.005-0.03 0.15-0.60 0.002-0.006 0.005-0.01 0.05-0.12 0.03-0.08 Rest Cast iron (gp Content Elements wt.X Xie OH p; - | Fe The magnitude of otg is white, mm Tensile strength, _and O, MPa Wear, g R Mp ^s Ivestny 2.6 1,2 0.019 0.10 0.45 0.003 ' 0.0075 - Rest 12 720 0.934 Proposed zg 0.8 0.005 - 0.15 0.002 ' 0.005 0.05 0,03 4 730 0.601 3,5 1,0 0.018 - 0.35 0.004 0.0075 0.09 0.05 1 750 0.497 3.9 1,2 0,03 - 0.6 0.006 0.01 0.12 0.08 3 740 0.412 3.0 0.7 0.003 - 0.01 0.001 0.003 0.04 0.02 5 725 0.705 4.0 1.4 0.05 - 0.65 0.007. 0.015 0.14 0.1 6 690 0,501 3,5 1.0 0.018 - 0.35 0.004 0.0075 0.09 - 4 735 0.731 3.5 1,0 0.018 - 0.35 ' 0.004 0.0075 - 0.05 6 700 0 ^ 500