SU1701753A1 - Cast iron for rolls - Google Patents

Abstract

The invention relates to metallurgy and can be used for the production of mill rolls. The purpose of the invention is to increase the mechanical properties, wear resistance, as well as reduce mountains. New cast iron contains, wt%: C 2.8-3.5; Si 0.5 - 1.8; t 0.15-0.6; ct 0.5-1.5; Ni 2 4.5; Mo 0.1-1.0; Si 0.5-2.5; REM 0.06-0.20 and Fe else. The change in the proposed cast iron content. W and vanadium extraction from it allowed to increase GU by 1.14-1.16 times, HB by 1.05-1.14 times, wear resistance by 1.11-1.26 times, and also reduce mountains - by 1 block. , 02-1.12 times. 1 tab.

Description

; . The invention relates to metallurgy, in particular to the development of cast iron compositions for the manufacture of rolls,

The purpose of the invention is to increase the mechanical properties, wear resistance, as well as reduce the mountains.

The invention is illustrated by examples of specific applications.

The choice of the boundary limits of the content of the components. In the iron of the proposed composition is due to the following.

Carbon at concentrations in the range of 2.8-3.5% provides the required. Parameters of the structure and properties of cast iron. When its content is less than 2.8%, the casting properties of cast iron deteriorate, in particular, the shrinkage increases, which increases the likelihood of hot cracking. With a content of over 3.5% in the structure of the pig iron, an excess of the carbide phase appears, the thermal conductivity of the pig iron decreases, which also increases the tendency to hot cracks.

Silicon within the claimed limits provides the optimal combination of structural components of cast iron. With a content of less than 0.5%, the tendency of the iron to form hot cracks increases. Increasing the silicon content in excess of 1.8% dramatically reduces the performance of castings,

Manganese within the specified concentration limits provides a sufficient degree of deoxidation and desulfurization of pig iron, which makes it possible to optimize the concentration of modifying elements (REM). When the content is less than 0.15%, the degree of deacidification and desulfurization is insufficient, which leads to an increased consumption of modifiers. With

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with

With a content of more than 0.6% in the melt, the amount of refractory manganese oxides increases, which increases the hot meltness of the iron.

When the content is in the range of 0.5 - 1.5%, chromium forms stable carbides, provides the required performance properties. With a content of less than 0.5%, its action is unstable, and more than 1.5%, the release of the carbide phase reduces the rheological indices of the iron and increases its hotness,

Nickel neutralizes the carbide-forming effect of chromium, provides a wide range of structures over the cross section of the casting. With a content of less than 2.0%, its action is not sufficiently effective; with a content of more than 5%, residual austenite is formed, which reduces the operational durability of the casting;

Molybdenum contributes to the formation of a dense fine-grained structure, an increase in the contact intergranular surface, which provides a high degree of intergranular communication, which reduces the height of cast iron. With a content of less than 0.1%, the action of molybranum is ineffective at concentrations above 1.0%, its carbide-forming effect is manifested. Since chromium plays the role of a carbide-forming element in the cast iron, the use of molybdenum as a more expensive and scarce element is not advisable.

Copper within the specified limits increases the degree of dispersion of austenite transformation products. A content of less than 0.5% does not significantly affect structural transformations. The copper content of more than 2.5% leads to its release in the structural-free state.

Rare-earth metals (REM) have a modifying effect on the structure of cast iron, provide half of

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20

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thirty

35

40

45

Example. The cast iron was melted in a crucible with an acid lining with a capacity of 60 kg of an induction furnace IST-0.06. The quality of charge materials was pig iron, steel scrap, ferroalloys, granulated nickel, and electrolytic copper. Rarely, land metals were introduced into the blast with a ligature of FSZO RZM 30 (contained REM 35.5% / GU Y-5-136-81), which was placed on the bottom of the ladle before launching metal heated to 1 50 -60 СС, ligature flow with thavil 0.35-1.0% of the mass of the metal (the coefficient of mastering the ligature 40

Chemical analysis was performed according to standard procedures, sampling for analysis according to GOST 7565-81. The hardness of the samples was measured firmly with Brinell by pressing the ball according to GO 9012-59. The test of the samples was carried out according to GOST. And the resistance was determined by the loss of sa when testing samples with a cross section of 10 x 10 mm under conditions of friction with slippage according to art. Zs with a load of 100 g and cooling in flowing water on an MI-1 unit. From the weight difference of the samples was determined before and after the tests. The samples were weighed on dumping scales with an accuracy of three marks. The mountains were evaluated at the load to open the cracks in the assembly at the installation of the Trubitsyn construction with fixation on the two-coordinate flatbed potentiometer PDS-021. The modulus of elasticity was determined by the ultrasonic method on an UZIS-LETI device by comparing the time it takes for the sound to pass through the sample and the sample.

As follows from the table, the proposed composition of the Ni content in the cast iron was changed, and the removal of V from its composition made it possible to improve the mechanical properties (ju 1, J-1,1b for HB 1.05-1.1 times, reduce

Claims (1)

bone 1.02-1.12 times, claims plate ledeburite and gra-50 nose in 1, c-1.2b times and mountains of cilomephitis of spherical or vermicular form. Concentrations of rare-earth metals less than 0.05% are ineffective, an increase in the content in excess of 0.20% is impractical, since graphite degeneration is observed, 55 a further increase in the number of lamellar ledeburite does not occur, Cast iron for mill rolls containing carbon, silicon, margan chrome, nickel, molybdenum, copper, red earth elements and iron, or 0 five 0 five 0 five 0 five Example. The cast iron was melted in a crucible with an acid lining with a capacity of 60 kg of an induction furnace IST-0.06. Pig iron, steel scrap, ferroalloys, granulated nickel, and electrolysis copper were used as charge materials. Rare-earth metals were introduced into the melt with a ligature of FSZO RZM 30 (content of REM 35.5% / GU Y-5-136-81), which was placed on the bottom of the ladle before the metal was heated up to 1 50-Y 60IS, the ligature consumption was 0 , 35-1.0% of the mass of the metal (coefficient of mastering the ligature 40%). Chemical analysis was performed according to standard procedures, sampling for analysis according to GOST 7565-81. The hardness of the samples was measured on a Brinel hardness tester by pressing a ball in accordance with GOST 9012-59. The bend test of the samples was carried out in accordance with GOST. Wear resistance was determined by weight loss when testing specimens with a cross section of 10 x 10 mm under conditions of rolling friction with slippage under art. A load of 100 g and cooling in running water on the MI-1 unit. Wear and tear were determined from the difference in weight of the samples before and after the tests. The samples were weighed on a damper scale with an accuracy of three marks. Chelomkost mountains were evaluated by the load to open the cracks in the casting at the installation of the Trubitsyn construction with fixation on the two-coordinate flatbed potentiometer PDS-021. The modulus of elasticity was determined by an ultrasonic method on an UZISETI device by comparing the time it took for the sound to pass through the sample and the standard. As follows from the table, the change in the pig iron of the proposed composition of Ni content, as well as the removal of V from its composition, made it possible to increase the mechanical properties (ju by 1, Y-1.1b by HB by 1.05-1.1 times, reduce from 0 nose by 1 , ts-1,2b times and mountains chel- 5 bone 1.02-1.12 times, claims nose in 1, c-1,2b times and the mountains chel- nose in 1, c-1,2b times and the mountains chel- Rolling iron for rolling rolls containing carbon, silicon, manganese, chromium, nickel, molybdenum, copper, rare earth elements and iron, or in order to improve mechanical properties, wear resistance, as well as reduce. mountains chelomkost, it contains components in the following ratio, wt.%: Carbon 2.8-3.5 Silicon 0.5-1.8 flaxes 0.15-0.60 0.5-1.5 2.0-4.5 0.10-1.0 0.5-2.5 0.05-0.20 Else gun The content of the elements is us. % „- ---- ---- -1 - t-1r -G Cr I Hi Mb Sy VPZI I F "solid- i "Stop .... IL.L..L..1.LJULl WITH  I and dost, HB Famous 3.5 3.0 1.5 0.5 0.5 0.3 1.0 1.75 0.75 Ostal - “81 0, 1310 168 a little Note, by weight loss, g, crack load, kN. Properties (j0, fla  AND. | mountains pelon- .. 572