SU1723175A1 - Alloying composition for cast iron - Google Patents

Abstract

This invention relates to ligatures for treating cast iron with increased frictional heat resistance. In order to improve the mechanical and operational properties of cast iron, the master alloy contains, in May,%: copper 6-, 11; aluminum 7-10; manganese 15-19; molybdenum 6-10; cerium 8-12; lanthanum 3-7; bismuth 1-5; nitrogen 2-5; titanium 0.2-1; boron 1.2-3.5 and iron else. The frictional heat resistance of cast iron is 371-384 cycles, the operational resistance is 1760-1980 hours. Table 2.

Description

This invention relates to metallurgy, in particular to complex ligatures for the treatment of cast iron with increased frictional heat resistance.

Known ligature, containing, wt.%; Aluminum30-70

Manganese10-30

Chrome 10-25

Rare earth

metals2-35:

IronErest

Known ligature does not provide a significant increase in wear resistance and frictional heat resistance.

Also known ligature of the following chemical composition, wt.%:

Silicon 6-85

Rare earth metals15-70

IronErest

High silicon content reduces the hardness and performance properties of cast iron.

Closest to the offer is the master alloy of the following chemical composition, wt.%:

Copper12-20

Aluminum7-12

Manganese 12-70

Phosphorus 10-16

Molybdenum6-10

Cerium8-12

Nitrogen2-5

IronErest

The friction heat resistance of the pigmented iron alloyed by this ligature is 184-198 cycles; relative wear resistance - 2.05-2.3; Flexural strength is 710–830 MPa and flexural endurance is 270–310 MPa.

The lack of known ligatures low mechanical and operational properties.

The purpose of the invention is to improve the mechanical and operational properties of micro alloyed iron.

The goal is achieved by those. that a ligature containing copper, aluminum,

(L

WITH

four

GO

with

but

Vj

(L

manganese, molybdenum, cerium, nitrogen and iron, additionally contains lanthanum, boron, bismuth and titanium in the following ratio of components, wt.%:

Copper6-11

Aluminum7 -.

Manganese 15-19

Molybdenum6-10

Cerium8-12

Lanthanum 3-7

Bismuth1-5

Nitrogen2,6-5,0

Titan0,2-1

Bor1,2-3,5

IronErest

Significant differences in the proposed technical solution are the introduction of lanthanum, bismuth, boron and titanium, which significantly improves the mechanical and operational properties of wear-resistant cast iron,

Lanthanum has a refining effect and modifies the structure of cast iron, reduces the thermodynamic activity of carbon, the degree of spheroidization of graphite and non-metallic inclusions, and the hardness of cast iron, which increases the mechanical and operational properties. When the concentration of lanthanum is up to Zmas.%, Its modifying effect and the operational properties of cast iron are low, and with an increase in its content of more than 7% by mass, burns and pyro effects are increased during the processing of cast iron, and the stability of the structure, mechanical and operational properties are reduced.

Titanium is introduced as a micro-alloying and graphitizing component, contributing to the improvement of frictional heat resistance, plastic and technological properties of cast iron. At a concentration of more than 1.0% by weight, the amount of non-metallic inclusions at the grain boundaries increases, the compactness of graphite and the technological and operational properties decrease. At a concentration of up to 9.2 wt.%, Thermal resistance, resistance to frictional wear, impact resistance, and frictional heat resistance are insufficient.

Bismuth was introduced into the proposed ligature in the amount of 1-5 wt.% As an effective modifying and bleaching additive for cast iron, which increases the homogeneity of the structure, the stability of mechanical properties and eliminates the formation of interdendritic graphite, which contributes to an increase in the isolation and compactness of other components of the structure and to an increase in the mechanical characteristics of cast iron in castings. When the concentration of bismuth is up to 1 wt.%, The modifying effect is weak, the mechanical and operational properties of cast iron in the castings are low, and with increasing bismuth concentration more than 5 wt.%

the stability of the modifying effect, the number of non-metallic inclusions increase and the ductility and mechanical properties of cast iron, the durability of cast parts and their wear resistance decrease.

0 Boron in the amount of 1-3.5 wt.% Significantly crushes the structural components, reduces gas porosity and increases the uniformity of the modification, cleans the grain boundaries, increases the strength of the ligature by the molten metal and the duration of preservation of the modifying effect of the ligature, which provides increased endurance limit, strength and toughness of cast iron in castings; At a boron concentration up to 1.0 wt.%, the refinement of the structure and improvement of mechanical properties is insufficient, and with an increase in the boron concentration of more than 3.5 wt.% shaets snizhayut5 metal intoxication and with uniformity of structure, mechanical and performance properties in iron castings.

Cerium strengthens and modifies the structure of cast iron, increases the degree of spheroidization of graphite and non-metallic inclusions, and the hardness of cast iron, which increases the mechanical and operational properties. When cerium concentration is up to 8 wt.%, Its modifying effect and operating properties of cast iron are low, and as its content increases to more than 12 wt.%, The pyro effect is enhanced when cast iron is processed, and the stability of the structure, mechanical and performance properties is reduced.

0 Molybdenum in the composition of the alloy provides increased strength, hardness, heat resistance and wear resistance of cast iron. Its effect begins to manifest itself with a concentration of 6 wt.%, And with an increase in concentration of more than 10 wt.%, The content of carbides in the structure increases, the absorption of the ligature by the cast iron deteriorates, the plastic properties and the flexural strength limit decrease,

0

Manganese has an austerizing effect, increases strength and performance properties, its content is increased to 15-19 wt.%. Strength and

5 operational properties with a content of up to 15 wt.% Insufficient. Increasing the manganese content of more than 19 wt.% Reduces the plastic properties, the limit of bending endurance and frictional properties,

The copper content in the ligature is reduced in accordance with the experience and their content in the ligatures used to modify cast iron with enhanced performance properties. The effective copper content in the ligature is 6-1.1 wt.%. Such a concentration of graphitizing components with the exception of phosphorus increases the uniformity and stability of the modification of cast iron, contributes to the improvement of mechanical properties. When the phosphorus content is reduced plastic properties. Increasing the copper concentration of more than 11 wt.% Increases the segregation and reduces the performance properties.

The presence in the ligature of 7-10 wt.% Aluminum contributes to the stability of the modification and mechanical properties. With an increase in the aluminum concentration of more than 10.0 wt.%, The ligature of the alloy is reduced, the homogeneity of the structure decreases, and at a concentration of up to 7 wt.%, The stability of the modification is low, the operational properties, fatigue resistance and frictional heat resistance decrease.

Ligatures are obtained in open induction furnaces by fusion of an AMT alloy (TU 48-4-365-76) with metallic manganese (GO.ST 6008-82), copper M1, ferroboron FB13 and other metals and ferroalloy- iHn. First, metal manganese is fused with ferroborne FB13 (TU 15-4-14-72) and aluminum-molybdentitanium alloy at 1530-1570 ° C. Then the melt is flushed with nitrogen for 2-5 minutes and copper M1 and the cerium mixture CerM-3 (TU 48-4-216-72), lanthanum J LaM-2 (TU 48-4- 218-72) are introduced and Bi2 Bi2 (GOST 10924-84). The casting is made into flat metal molds and crushed before use to a fraction of 0.1-5 mm. In tab. 1 shows the compositions of the ligatures

experienced heats.

In tab. 2 shows the mechanical and operational properties of wear-resistant cast iron.

Ligatures are used in the smelting of wear-resistant white cast iron, containing, wt.%: Carbon 2.35; silicon 0.5; manganese 0.8; phosphorus 0.06; chromium 3,5; nickel 0.8; sulfur 0.03; calcium 0.02; nitrogen 0.03 and iron else. Ligature prisatiyut at 1450-1470 ° C in the amount of 0.7% by weight of the melt.

The frictional heat resistance is determined at the UMT-1 friction test installation on ring specimens in accordance with the method of GOST 23.210-80.

As can be seen from the table. 2, the proposed ligature provides higher characteristics of the frictional heat resistance, wear resistance and the bending endurance limit compared to the known.

The use of the proposed ligature to modify wear-resistant cast iron provides a higher increase in mechanical and performance properties compared to the known.

The economic effect of using the proposed ligature for the microalloying of cast iron is 64 thousand rubles. in year.

Claims (1)

Formula and inventions The master alloy for cast iron, containing copper, aluminum, manganese, molybdenum, cerium, nitrogen and iron, is characterized in that, in order to improve the mechanical and operational properties of cast iron, it additionally contains lanthanum, boron, bismuth and titanium in the following ratio components, thias.%: Copper6-11 Aluminum7-10 Manganese15-19 Molybdenum6-10 Cerium8-12 Lanthanum 3-7 Bismuth1-5 Nitrogen2-5-5 Titan0,2-1,0 Bor1,2-3.5 IronErest Table Note. The ligature of composition 6 additionally contains 10% by weight of phosphorus. Table 2