SU1366547A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the production of iron castings operating under conditions of wear at temperatures. The purpose of the invention is to increase the wear resistance at temperatures of -60 ° C. New cast iron contains components in the following ratio, mAco%: C 3,2- 3.8; Si 2.2-3.0-. MP 0.2-0.8; Mg 0.04-0.07; Ca 0.015-0.04; Ce 0.01-0.03; Si 0.5-1.0; Mo 0.2-0.55; W Oh, 2-0,65; boron nitride 0.02-0.10 and Fe else. The addition of boron nitride to cast iron increases wear resistance by 1.27 - 2.8 times. 1 tab. i (L

Description

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The invention relates to metallurgy, in particular to the development of cast iron compositions for castings operating under conditions of increased wear at a low temperature o

The purpose of the invention is the increase in wear resistance at temperatures of -60 ° C

The choice of the content of the boundary limits of the components included in the pig iron, the proposed composition is caused by the following.

Entering into the composition of the alloy of boron nitride in the amount of 0.02-0.10% promotes the formation of fine nitrides and carbonitrides, which, evenly located in the cast iron matrix, increase its wear resistance, especially at low temperatures. At the same time, the alloy is not prone to embrittlement when the test temperature drops to -60 ° C. The presence of Ca and Ce in the alloy provides high purity in non-metallic inclusions.

Carbon and silicon are determined, on the basis of providing the required graphitization of the alloy. Their lower content (C 3.2% 5 Si 2j2%) is determined from the time of reception of the detection in a slug. when the upper content of carbide-forming elements is not more than 20% of structure-free carbides, the upper limit (C 3.8%, Si 3.0%) is a decrease in wear. resistance to copper, molybdenum, tungsten and boron nitride levels

Manganese - a permanently present element in the cast iron composition. The manganese content in tuna of this composition should not exceed 0.8%. With its higher content, the pig iron's tendency to chill increases. The lower limit for manganese is determined by its content in the original raw materials. spherical shape of graphite GF 12 GF 13 o When the content of magnesium is below the lower limit (0.04% Mg), graphite forms the shape of GF 10 o Exceeding the upper limit of 70.07% is accompanied by spherical shape grafitaoKaltsy cerium and iron in the composition of the refined metal sulfur and dissolved gases (H), preventing the formation of nonmetallic inclusions, which ultimately

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prevents cast iron from embrittlement at low temperatures

Copper is injected into cast iron to increase the physical and mechanical properties and, in particular, ductility and toughness at low temperatures.

When the copper content is less than 0.5%, it has little effect on the microstructure and

10 properties of the metal, and its input over

1.0% slightly worsens the shape of graphite inclusions

Entering into the composition of cast iron molybdenum and tungsten is intended for increasing the strength properties in cast and

heat-treated condition, as well as to ensure high wear resistance at low temperatures. The lower limit for molybdenum and 20 tungsten (0.2% Mo and 0.2% w) was established, based on the required margin of safety and wear resistance. The upper limit (0.55% Mo and 0.65%) is due to the danger of a strong bleaching effect. cast iron, as well as economically impractical due to the small increase in the increase in wear resistance

The content of boron nitride at the lower limit (0.02%) was established, the outcome

30 of the specified wear resistance at the test temperature — ° C. The upper limit (0.10% boron nitride) is established due to a small increase in the increase in wear resistance with a further increase in the boron nitride content.

An example, shpavka alloys of the proposed composition can be carried out both in the arc and in

40 induction electric furnaces. In a concrete example, a high-frequency crucible induction furnace LPZ-6.7 was used. Metallized ores containing 82.0%, 75jO%, 2.0% C return of own production, which is a Fe-C alloy, smelted from oats and containing 3.5-4.0%, were used as charge materials. WITH,

gQ electrode and crystalline silicon, ferroalloys and boron nitride

Boron nitride is injected into the cast iron through a plasma torch (PN) with a capacity of 1000 K W, a voltage

gg 250 W Argon was used as a carrier gas. The fractional composition of boron nitride is 0.05-0.2 mm. The absorption coefficient of boron nitride is 75%.

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As a spheroidizer of graphite, a complex magnesium-containing ligature served. Melting is carried out on the charge from the metallized pellets, then the slag is loaded and the return is loaded into the liquid bath. After melting the charge of finishing the alloy in chemical composition and overheating to 1460-1480 C, the cast iron is released from the furnace. The modification is carried out in a casting ladle using the sandwich method. The chemical compositions of cast iron are known and proposed on the lower, middle and upper, and 3665474

temperature is maintained. Wear is assessed by the size of the wiped hole in (mm) for I h tests using a micrometer.

The tests carried out show that the pig iron of the proposed composition due to the introduction of boron nitride has a higher wear resistance at a temperature than the known one.

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Claims (1)

Invention Formula 2 3 Famous 3.5 2.6 0.5 3.8 3.0 0.8 tal 0.055 0.0275 0.02 0.75 0.3750.425 0.06 T0 0.75 0.07 0.040.03 1.0 0.55 0.65 0.10 0.5 3.5 2.3 0.055 0.04 0.02 Editor I. Seglnik Compiled by N Kostornaya Tehred M. Didyk. 0.0275 0.27 0.325 0.03 1.4 Proofreader M Sharoshi pointy 0.0275 0.27 0.325 0.03 1.4 Proofreader M Sharoshi