SU1027266A1 - Cast iron - Google Patents

Abstract

CAST IRON, carbon, silicon, manganese, chromium, nickel, calcium, magnesium, rare earth metals, copper and iron, characterized in that, in order to improve the strength and hardness in the cast state in castings with wall thickness from 150 to 300 mm, it additionally contains vanadium in the following ratio of components, wt.%: Carbon 3.3-3., 6 Silicon 2.0-2.8 1.2-1.5 Manganese Chromium 0.05-0.2 Nickel 0.8% -1.5 Calcium 0.01-0.05 Magnesium 0.04-0.07 Red-earth0, 01-0.05 solid metals 1.1-1.5 Copper Vanadium 0.2-0.4 Iron Else

Description

YU

14D

A: Yes The invention relates to magic, in particular to finding iron ores in possession of high strength and hardness. condition. Cast iron 1 is known, contained components at the next stage, wt ,,%: 2.92-3.48. Carbon 1.67-2.25 Kre14ny 0.59-1.10 Nickel 0.35-0.86 Manganese 0.036- 0.052 Magnesium 0.025-0.03 Calcium Rare-earth metals (RZK) 0.03-0.10 0.058-0.092 Aluminum 0.011-0.057 Tin Else, Iron The closest in technology and reach to the invention to the invention is the iron-burning components at the COOT shed load SRI, wt.%: - Carbon 2.6-4.5 Silicon 1.0 t4.0 Manganese 0.1-1.2 Chromium 0.01-0.5 Nickel 0.01-1.0 Copper 0.01- 1.0 Magnesium 0.015-0.1 Calcium 0.015-0.06 REM 0.005-0.15 Aluminum 0.005-0.4 Iron Rest As cast iron impurities contain sulfur in The amount of O, 03 May.%, phosphorus is up to 0.2 ma. This alloy due to its strong perlithisation of soda in it (copper, manganese and nickname within the specified limits ensures high strength in walls up to 100 mm thick. and the hardness of the composition is drastically reduced, which leads to the rejection of castings with chemical properties. The aim of the invention is the strength and hardness of the state in castings with a thickness of from 150 to 300 NBM. This goal is achieved that cast iron containing carbon, manganese, chromium, nickel, magnesium, rare-earth metals, copper and iron. It contains vanadium, with a ratio of components of 3.3-3.6 Carbon 2.0-2.8 Silicon 1.2-1.5 Manganese 0.05-0.2 0.8-1.5 Nickel 0, , 05 Calcium 0.04-0j07 Magnesium 0.01-0.05 copper 1.1-1.5 Vanadium 0.2-0.4 Iron Else As impurities, cast iron can contain phosphorus up to 0.1 wt.% And. sulfur to 0.04 wt.%. Carbon in the range of 3.3-3.6 wt.% Provides horsai casting and mechanical properties. The lower limit of carbon to 3.3 wt.% Is due to the need to exclude structurally free carbides in the alloy. The increase in the concentration of carbon viiii 3.6 wt.% Worsens the form of inclusions of graphite .. -,. The concentration of silicon (2.0 to 2, 8 wt.%) Provides the best combination of plastic and strength properties of cast iron, as well as high hardness in thick-walled casting. The lower limit for silicon (2, мас wt.%) Is set on the basis of the requirement to exclude chill in the castings. The upper limit (wt.%) Is set on the basis of the requirement for obtaining a pearlitic metal matrix. To obtain a high strength of the alloy (complete perliteration of the matrix), provided that the occurrence of structurally free cementite is encountered, the manganese content in it is from 1.2 to 1.5 wt.%. The lower limit (1.2% by weight) of the manganese content is due to the need to obtain high strength in thick-walled casting. The upper limit of 41.5 wt.% Is limited by the increase in the tendency of iron to chill and a sharp decrease in ductility. Chromium contributes to an additional perlite structure. In order to exclude the occurrence of structure-free cementite, the concentration of such a strong carbide-forming element, which is chromium, is set in the range of b, O 5 to 0.2 wt.%. To obtain high strength and hardness of high-strength cast iron in combination with satisfactory ductility in thick-walled casting, the concentration of alloyed copper and nickel elements is chosen in the range 1.0-1.5 and 0.8-1.5 wt%, respectively. Copper and nickel ZTs are strong perlitizing elements, while they do not increase the tendency to crystallization of the alloy according to the metastable diagram. The lower limits (1.0 and 0.8 wt.%, Respectively) are selected on the basis of the requirement to obtain a fully pearlitic metal material, the upper limit. , (1.5 wt.%) - based on the fact that at these concentrations nickel and copper the best mechanical properties are achieved, a further increase

the content of these elements is inefficient and impairs the efficiency of the alloy.

The calcium content (0.01-0.05 wt.%) In the alloy contributes to the improvement of the shape of the globular G11afit and to the increase in the degree of melt purity with respect to impurities.

Magnesium in the above concentrations provides nodular graphite and high mechanical properties. When the content of magnesium is less than 0.04 wt.%, Inclusions of lamellar and vermiele graphite are observed in the structure of cast iron even in low-sulfur cast iron (sulfur and 0.02 May,% Magnesium intake more than 0.07 wt.% Is inappropriate, as the shape of phyta, the tendency to chilling increases (effect of modification), the modifier consumption increases.

Introduction to the composition of the alloy of rare-earth metals in the amount of 0.01-0.05 May.% Helps to obtain the correct spherical shape of rafit.

The vanadium introduced into high-strength cast iron with the aim of exploring strength and hardness in the range of 0.2–4 May.% Has a strong perliterative effect on the structure of cast iron (due to stabilization of perlite cementite) to increases the dispersion of this structural component. The lower limit (0.2 wt.%) Is chosen on the basis of the need for any significant perlitization effect, the upper limit, 4 wt .-%) is based on the requirement to exclude the possibility of structural free cementite and from economic considerations.

Concentrations of harmful impurities in amounts of sulfur up to 0.04 and phosphorus up to 0.1 wt.% Were determined on the basis of the need to provide spherical shape of graphite and to obtain high mechanical properties of cast iron during heavy casting.

The structure of the proposed cast iron has a pearlitic metal matrix and spherical-correct inclusions of graphite.

PREMIER Comparative tests of the mechanical properties of the proposed and known alloys in the cast state were carried out. For the lower, middle and upper limits of the concentration of ingredients with a wall thickness of castings from 150 to 300 mm. Melting was carried out in 50 kg of an acid-lined induction furnace. The alloy after melting was overheated to 1420-1440 ° C. Foundry iron LKZ, steel scrap, copper, nickel, ferrovanadium, ferrocerium and the LCKK-1 ligature were used as charge materials.

The technology for producing high-strength cast iron for comparative tests included finishing the cast iron by chemical composition in a furnace with appropriate ferroalloys after overheating.

The consumption of ferrovanadium {35 wt.% Vanadium, the rest is iron) for obtaining the boundary limits of its concentration in the iron was 0.61, 2 kg, respectively.

Additive Md, Ce iCa- (in the form of master alloys were made to the bottom of the casting ladle before filling it with iron. Plate thickness was 150, 200 and 300 mm. To compare the properties, castings with such thicknesses were made of iron of known composition. The composition and structure of cast iron are presented in Table 1.

Mechanical properties of cast iron are presented in table. 2

As follows from Table 2, the cast iron of the proposed composition provides for the enhancement of tensile strength and hardness and stabilizes them in sections of castings with a thickness of 150-300 mm.

The economic effect from the introduction of pig iron on the proposed 1 H composition for the production of the bandaged rolls will be 48 thousand rubles. in year.

table 2

KnownMedium 510-540 N ote.

190-200 482-500 190-202

195-206 490-510 In the numerator, the largest and the smallest values of the mechanical properties in the castings are given; in the mean, the average values of the execution were carried out on three samples,

Claims (1)

'' CAST IRON containing carbon, silicon, manganese, chromium, nickel, calcium, magnesium, rare-earth metals, copper and iron, characterized in that, in order to increase the strength and hardness in the cast state in castings with wall thicknesses from 150 to 300 mm , it additionally contains vanadium in the following ratio of components, wt.%! Carbon 3.3-3.6 Silicon 2.0-2.8 Manganese 1.2-1.5 Chromium 0.05-0.2 Nickel 0.8-1.5 Calcium 0.01-0.05 ' Magnesium 0.04-0.07 Rare earth metals 0.01-0.05 Copper 1.1-1.5 Vanadium 0.2-0.4 S ' Iron Rest KJ 3 s yu yes yes