SU1096299A1 - Cast iron - Google Patents

Abstract

CAST IRON containing carbon, silicon, manganese, chromium, nickel, molybdenum, copper, titanium, vanadium, phosphorus and iron, characterized in that, in order to improve mechanical properties, wear resistance and increase thermal conductivity, it contains components in the following ratio, wt.%: 2.8-3.6 Carbon 1.8-2.6 Silicon 0.4-0.9 Manganese 0.05-0.25 Chromium 0.1-1.0 Nickel 0.1-0, 5 Molybdenum and 1.0-3.5 Copper 0.03-0.15 Titanium (L 0.05-0.30 Vanadium 0.1-0.60 Phosphorus Iron Else

Description

with

O5 N5

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I

The invention relates to the field of metallurgy, in particular to the search for wear-resistant cast iron with high thermal conductivity, used in various areas of mechanical engineering for parts operating under sliding friction conditions at high temperatures, urah (200-1000 o), especially for diesel engine liners with air cooling, parts of pumps, guide glasses, etc.

Known cast iron {containing components in the following ratio, wt.%:

Carbon3.0-3.4

Silicon .1.8-2.3

Manganese 0.5-1.2

Chrome 0.05-0.25

Nickel0.1-0.3

Copper0,1-0,4

Vanadium 0.1-0.4

Molybdenum 0,1-0,9

PhosphorO 1-0.5

IronErest

This cast iron is characterized by low hardness and increased wear.

The closest to the proposed technical essence and the achieved result is cast iron 2j of the following composition, weight,%:

Carbon 3.0-3.9

Silicon1.8-3.1

Manganese 0.4-1.2

Chrome .0.05-0.35

Nickel0.25-0.9

Molybdenum 0.1-1.2

Copper0,01-0,55

Titanium0.05-0.2

Vanadium0.001-0.4

Phosphorus 0.1-0.8

IronErest

However, this cast iron is characterized by high (98-102NB) hardness, especially at high temperatures with wear resistance up to 50-150 microns, as well as low thermal conductivity.

The purpose of the invention is to improve the mechanical properties, wear resistance and the increase in thermal conductivity.

This goal is achieved by the fact that cast iron containing carbon, silicon, manganese, chromium, nickel, molybdenum, copper, titanium, vanadium, phosphorus and iron contains components in the following ratio, wt%:

Carbon2.8-3.6

Silicon158-2 6

Manganese0.4-0.9

096299

0 „05-0„ 25

0,1-, 0

0.1-0.5

n

1.0-3.5

0.03-0.15

0.05-9.30

uh

0.1-0.6

Rest

The composition of the impurities is sulfur 0.01-0.08%,

The proposed cast iron fits cj-syschuyuschimy physics-mechanical -; and properties:

Tensile strength

for stretching, eg, kgf / mm 29-40

Tensile strength

for bending, kgf / mm

Hardness

198-260 Vrinnell, HB

The coefficient of linear expansion, o tgrad-- (12.3-15.1) -10 °

Liquid EC at its temperature

zashgaki 1 360-1380 ° С

on spiral test, i-m800-1250

The modulus of elasticity E, kgf / mm 14000-15200

Thermal conductivity, I, W / m K34.3-54.3

Wear, mkm10-15

For example, specific formulations of the proposed cast iron, as well as the prototype, will be tested. Cast iron is produced by smelting in an IST-016 induction furnace with an acid lining. the melt temperature is 15001520 ° С. Before shaking, crushed 75% ferrosilicon is introduced into the ladle. The casting is done in one-off forms at 1360-1420 ° C.

In tab. t are given for comparison alloys with different content of ingredients; in tabl 2, the physicochemical properties of the resulting composition of cast irons.

The wear tests are carried out on a friction machine with a reciprocating displacement of a counterbody with a force of 500–1750 kgf / cm for 8 hours. Durability S hardness J thermal conductivity and other properties are determined by conventional methods 3 The alloying of gray iron with chemical elements physico-mechanical PROPERTIES leads to a significant increase in wear resistance, especially when working in the field of high temperatures. The increase in wear resistance of cast iron is achieved due to the effect of alloying elements on the nature of carbides. to the size and nature of any distribution of graphite inclusions and carbides, as well as the metal substrate. Manganese, which has a deoxidizing and desulfurizing ability, serves to refine the melt and increase its mechanical properties. The introduction of manganese to the upper limit leads to an increase in the effect of carbides, i.e. manganese acts like a usor radical cooling. Entering manganese below its lower limit is not sufficient to deoxidize the iron, and therefore, to achieve a positive effect on the properties of the liquid iron. Reducing the carbon and silicon content leads to the bleaching of cast iron and the deterioration of the machinability of castings. An increase in their content above the upper limit increases not only the quantity, but also the size of platelet-shaped graphite inclusions, and also violates the structure homogeneity (ferrite appears), which ultimately reduces wear resistance. Chromium doping of sero pig iron results in a relatively homogeneous structure (more complete perlitetization of the metal base) and, consequently, an increase in strength properties. The introduction of chromium is less than its lower limit, and has no effect on the properties of the iron. However, the introduction of it more than the upper limit can lead to the release of eutectic chromium carbides, .- which causes a decrease in wear resistance of cast iron. The addition of titanium (0.03-0.15%) leads to deoxidation and the formation of finely dispersed titanium nitrides, which helps to improve the properties of cast iron, such as fluidity and conditions of crystallization, while increasing the physical and mechanical properties, namely strength, ductility, coefficient of linear expansion, etc. The introduction of titanium 9 4 above the upper limit increases the content of non-metallic inclusions and contributes to the enlargement of titanium nitrides, which reduces not only the strength properties of cast iron, but also wear resistance. For the durability of cast iron, a small amount of nickel is introduced into it, which contributes to the formation of a homogeneous structure of the metallic base — pearlitic. As a result, it stabilizes the properties of cast iron under mechanical and thermal effects. Nickel addition less than the lower limit, like chromium, does not affect the process of cast iron crystallization and, therefore, its properties. The content of this element more than the upper limit is economically inexpedient, since the strength properties and wear resistance of cast iron increase slightly. Complex doping with vanadium and molybdenum significantly increases at high temperatures (200–900 ° C) static strength, elasticity, hardness and, as a result, wear resistance. The number of these elements (each separately) in the cast iron below the lower limit does not provide an increase in heat resistance (cast iron resistance to temperature during friction) gray cast iron, and their content above the upper limit leads to an increase in hardness, therefore, a decrease in workability, although wear resistance increases. The introduction of copper crushes the eutectic grain, thereby increasing strength, as a result of which the thermal effect on the friction surface is significantly reduced, leading to a decrease in wear. There is a definite relationship between thermal conductivity and dispersion. The thermal conductivity of cast iron to a greater extent than other physical properties depends on the structure, its dispersion, the smallest contaminants, the amount, shape and distribution of graphite, the degree of doping, etc. Elements that prevent graphitization and increase the dispersion of perlite reduce thermal conductivity. Copper in the range of up to 1% reduces the thermal conductivity of cast iron with an intensity of approximately two

times smaller than silicon. This explains the choice of the lower limit for copper. A higher copper content significantly increases the thermal conductivity due to the separation of the independent phase with high conductivity. The addition of phosphorus improves the wear resistance and fluidity, but the introduction of it more

0,6% increases the porn content of cast iron and sues its strength characteristics.

The proposed product possesses high thermal conductivity and wear resistance and can be used in the manufacture of parts: eH5. designed to work under conditions of sliding at high temperature:

T a b l and c a

0.5

0.3

Oi

on th

0.15

2.0

0.3

2.5

0.5 P5 3.5

0.25

Continued table.

0.2

0.3

Rest

0.08

O.J

0.09

0.03 0.5

0.05 0.1

0.3

0.15

oh a

0.15 0.12

0.20

0, (

table 2

Claims (2)

CAST IRON containing carbon, silicon, manganese, chromium, nickel, molybdenum, copper, titanium, vanadium, phosphorus and iron, characterized in that, in order to improve mechanical properties, wear resistance and increase thermal conductivity, it contains components as follows ratio, May.%; Carbon Silicon Manganese Chromium Nickel Molybdenum Copper Titanium Vanadium Phosphorus Iron 2.8- 3.6 1.8-2.6 0.4-0.9 0.05-0.25 0.1-1.0 0.1-0.5 1.0-3.5 0.03-0.15 0.05-0.30 0.1-0.60 Rest SU.,., 1096299 eleven