SU1375675A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy, in particular to the search for wear-resistant cast irons with enhanced physical and mechanical properties, used in various engineering fields for parts operating under elevated temperatures, alternating loads and sliding slip. The purpose of the invention is to increase the tensile strength and flexural strength, hardness, thermal conductivity, wear resistance and stabilization of the modulus of elasticity at 20-800 ° C. The proposed cast iron contains, in wt.%: carbon 3.2 - 4.0; silicon 2.3-2.8; manganese 0.3-0.8; phosphorus 0.1-0, -5; chromium 0.05-0.30; titanium 0.05-0.30; nickel 0.1-0.5; molybdenum 0.1-0.7; copper 0.6-1.2; antimony 0.1-0.4; lanthanum 0.01-0.03; iron - the rest. Cast iron of the proposed composition can be used to manufacture the piston rings of internal combustion engines. 2 tabl „i k

Description

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The invention relates to metallurgy j, in particular, to the search for wear-resistant cast irons with physical and mechanical properties applied in various engineering fields for parts operating under conditions of increased temperatures, alternating loads and friction sliding, for example, for piston rings.

The aim of the invention is to increase the tensile strength and bending strength, hardness, thermal conductivity, wear resistance and stabilization of the elastic modulus at 20-800 ° C.

The proposed cast iron contains, wt,%;

Carbon

Silicon

Manganese

Phosphorus

Chromium

Titanium

Nickel

Molybdenum

Copper

Antimony

Lanthanum

Iron

3.2-4.0

2.4-2.8

0.3-0.8

0.1-0.5

0.05-0.30

0.05-0.30

0.1-0.5 0.1-0.7 0.6-1.2 0.1-0.4 0.01-0.03 Else

The introduction of carbon and silicon less than the lower limit leads to the bleaching of cast iron and the deterioration of workability. The content of these elements in the cast iron above the upper limit increases not only the quantity, but also the size of the inclusions of graphite, and also a ferritic structural component appears, which leads to a decrease in the modulus of elasticity and wear-resistance. details

The addition of manganese and chromium less than their lower limit leads to the release of ferrite in the cast iron structure, which promotes seizure and tearing, and consequently, an increase in wear. The introduction of these ingredients to the upper limit contributes to bleaching, the formation of unstable chromium carbides and a sharp deterioration in machinability.

 Fysfor increases the fluidity and wear resistance, However, the introduction of it above the upper limit leads to porosity and, consequently, an increase in scrap and a decrease in strength properties.

Titanium is used to deoxidize liquid iron and as nitride-like 0

five

0

five

0

50

5 n

element. Its addition below the lower limit has practically no significant effect on the state of the melt. The titanium content above the upper limit leads to an increase in the release of the spike, which creates additional difficulties in obtaining high-quality castings.

The addition of nickel below the lower limit does not have a sufficient effect on the structural iron. With an increase in its concentration, the metallic base of cast iron becomes more uniform and more resistant to the effects of high temperatures, and the inclusions of graphite become optimal in size. However, the nickel content above the upper limit leads to a change (enlargement) of inclusions of graphite, i.e. increased jr-graphitization, which adversely affects thermal conductivity.

Molybdenum is used to improve the mechanical properties at high temperatures, hardening the solid solution by forming fine carbides, which stabilize the grain boundaries. The addition of molybdenum below the lower limit does not affect the properties of the cast iron and the wear resistance. When its content is watered, the upper limit leads to an increase in hardness in the cast state, thereby deteriorating the machinability of the castings.

The alloying of cast iron with copper contributes to perlitization, an increase in strength properties and thermal conductivity. The addition of this element below the lower limit does not affect the thermal conductivity, although the strength properties increase. The copper concentration above the upper limit leads to an increase in hardness and a change in the shape of graphite inclusions and their distribution, and consequently, a decrease in thermal conductivity. It is likely that this is directly related to the effect of antimony on the metallic base of gray iron.

The addition of antimony within the specified limits leads to the stabilization of perlite in the iron, increase the hardness and increase wear resistance. The content of antimony above the upper limit leads to a decrease in thermal conductivity and deterioration of processing. Additive of this element less than the lower limit does not provide full perlititization; in the cast iron structure, there are occurrences of the ferrite component, which has a negative effect on the wear of the part.

The introduction of lanthanum within the specified limits leads to the refining of molten iron, changing the shape of nonmetallic inclusions and reducing their number in a metal base. This leads to an increase in strength, toughness and elastic properties of the iron, and hence the wear resistance of the parts in the friction units.

Example. Iron smelting is performed in an IST-016 induction furnace with an acid lining. Alloying elements are introduced into the molten iron at 1480–1500 ° C: copper, nickel, ferromolybdenum, ferrophosphorus, ferrotitanium, ferromanganese, and antimony.

Before pouring, crushed ferrosilicon — FS-75 and lanthanum were introduced into the ladle. Filling into single forms was carried out at 1420-1360 ° C.

The chemical composition of the cast iron is given in the table, and on the physical and mechanical properties after the test are given in table.

The test results showed that the proposed cast iron possesses more

more high physicomechanical properties, it can be used for the manufacture of, for example, piston rings of internal combustion engines.

Claims (1)

Invention Formula Carbon-containing cast iron, cream, scientific research institute, manganese, phosphorus, chromium, titanium, nickel, molybdenum, copper and iron, characterized in that, in order to increase the tensile strength and bending strength, hardness, thermal conductivity, wear resistance and stabilization of the module elasticity at 20-800 ° C, it additionally contains antimony and lanthanum in the following ratio, wt.%: 0 Carbon Silicon Manganese Phosphorus Chromium Titanium Nickel Molybdenum Copper Antimony Lanthanum Iron 3.2-4.0 2.3-2.8 0.3-0.8 0.1-0.5 0.05-0.3 0.05-0.3 0.1-0.5 0.1-0.7 0.6-1.2 0.1-0.4 0.01-0.3 Rest oosh cm-CV) oooh ". "CHAM oooh about o} - o with h about go cm “Ъ go || to and & X 3 " Pq co uo w o about OS about -. "H - f tchp oh oh go BUT about g BUT about to BUT about about g o see about g about 00 about sh about 1L sh about o - about about CS1 about with w o about go about Yu - about CS) about LO h about with ъ about with " about R BUT about with about cm 4h about 1L "H about g "H about 00 h about VO h about 00 about 41ts (N 1L cm tА cm 00 "N 00 CV) g 4h with 4D h th oo go about Cg about g to t 3 " but) § l p. РЗ С ea 230 250 281 358 380 343 314 270 330 340 401 512 543 490 450 412 Tav Kaa 2 50 10850 8950 6600 11,000 12300 13000 13450 12950 12200 12000 9150 10300 POOO 114ba 11000 10300 9900 6800 8400 8800 9000 S800 8500 7100 42.0 30.0 10.0 7.5 6.0 8.0 7.0 .20.0