SU1293241A1 - Grey wear-resistant cast iron for castings - Google Patents

Abstract

The invention relates to metallurgy, in particular to the search for gray antifriction cast irons for the manufacture of massive parts of metal-cutting machines, working in conditions of sliding friction. The purpose of the invention is to increase the stability of anti-4FICTION properties in castings with wall thicknesses from 30 to 200 mm. The proposed cast iron contains components in the following ratio, May.% J C 2.7-3.6, Si 1.3-2.1; Mp 0.7-1.5; Ti 0.3-0.8; 0.2-0.5; zr 0.1-0.3; Ca 0.02-0.07; REM 0.02-0.1; Mb 0.12- 0.4; Sb 0.07-0.20; Pb 0.05-0.1; Fe rest. In addition, niobium, antimony, and lead are added to the cast iron to increase the hardness, build-up, and wear resistance of the structure comminution matrix. Cast iron has the following properties: t j when stretching 457-565 MPa; HB in castings with wall thickness: 30 mm 245-259; 100 mm 241-255,200 mm 235-249. The stability of the coefficient of friction when the thickness of the walls of castings: 30 mm 88-98; 100 mm 84-96; 200 mm 78-91. Wear at the thickness of the walls of castings, µm / h 30 mm 0.42-0.34; 100 mm 0.47-0.37; 200 mm 0.58-0.42. Time to scrape against wall thickness, h: 30 mm 21.4-27.8; 100 mm 19.6-24.7, 200 mm 17.5-21.6. 2 tab. (L с: д о 9 э tib

Description

The invention relates to metallurgy, in particular to the search for gray antifriction cast irons for the manufacture of massive parts of metal-cutting machines operating under conditions of friction rubbing.

The purpose of the invention is to increase the stability of anti-friction properties in castings with wall thicknesses from 30 to 200 mm.

The goal is achieved by the fact that gray wear-resistant cast iron containing carbon, silicon, manganese, titanium, zirconium, copper, calcium, rare earth metals and iron, additionally contains niobium, antimony and lead in the following ratio of components, May. %:

Carbon Silicon Manganese Titanium Copper Zirconium Calcium Rare earth metals Niobium Antimony Lead Iron

2.7-3.6 1.3-2.1 0.7-1.5 0.3-0.8 0.2-0.5 0.1-0.3 0.02-0.07

0.02-0.10 0.12-0.40 0.07-0.20 0.05-0.10 Else Additional introduction of niobium in an amount of 0 to 12-0.40 wt.% Micro-alloy and strengthen the metal The base j crushes graphite, increases crack resistance and blocks crystal structure defects, increases the stability of the structure and mechanical properties, which provides increased wear resistance, tearing of the core and other antifriction properties in castings with a wall thickness of 30–200 mm. At a niobium concentration of up to 0.12 wt.%, The microalloying effect is weak, the metal base is not significantly strengthened, and the nose stability is low in the castings. When the concentration of nibi is more than 0.40 wt.%, Liquation increases and the stability of the mechanical and antifriction properties of cast iron in thick-walled castings decreases,

The introduction of antimony in the amount of 0 (, 2 wt.% Increases the hardness, resistance to wear and durability of the matrix, its stability in casting

five

0

five

with a wall thickness of 30 to 200 mm, which reduces wear and increases anti-friction properties. The antimony content is taken from a concentration (0.07 wt.%), From which there is an increase in the stability of hardness and wear resistance in castings with wall thicknesses from 30 to 200 mm, and is limited by the concentration of O, 2 may.%, Above which a decrease in the solubility of antimony is noted. in the metal base and the reduction of dynamic strength and stability of the mechanical and anti-friction properties of cast iron.

The introduction of lead in an amount of 0.05–0.1 wt.% Is due to its effective effect on reducing the coefficient of training and grinding the structure in thick-walled castings, on increasing the dyspersity of perlite and graphite, which leads to an increase in the stability of wear resistance and other anti-friction properties. The lead concentration was determined experimentally, with the lower limit (0.05 wt.%) Being recommended for castings with a wall thickness of 30 mm, and the upper limit of the lead content (0.1 wt.%) For castings with a wall thickness of 200 mm. When the lead concentration is more than 0.1 wt.% Chill occurs, which reduces the stability of the structure and anti-friction properties.

The content of the main components (carbon 257-3 6 wt.%, Silicon 1.3-2.1 wt.% And manganese 0.5 - 1.5 wt.% Determined based on the practice of production of antifrictional iron for thick-walled cast parts of machine tools With a decrease in carbon content of less than 2.7 wt.% And silicon below 1.3 wt.% And an increase in the manganese concentration of more than 1.5 wt.% In chilled castings, chill increases and the stability of the structure and properties decreases, and at a carbon concentration of more than 3 , 6 wt.%, Silicon more than 2.1 wt.% And manganese less than 0.7 wt.% Pearlite structure in castings with a thickness of Nki 30 - 200 mm becomes coarse, durability and stability of antifriction properties are reduced.

The content of alloying additives (titanium 0.3-0.8 wt.%, Copper 0.2-0.5 wt.%, Zirconium 0.1-0.3 wt.%) Was determined experimentally and limited to the limits below which the other 0

0

five

0

five

312

Bone and antifriction properties are insufficient, and a-above which stability of the structure and antifriction properties in castings with wall thickness from 30 to 200 mm is reduced.

Calcium (0.02–0.07 wt.%) And heavy-earth metals (0.02–0.1 wt.%) Are effective modifying agents that refine the structure and increase mechanical properties and wear resistance due to improved graphite shape factor. When concentrating them to 0.02 wt.%, The modifying effect is weak, and when calcium concentration is more than 0.07 wt.% And rare-earth metals more than 0.1 wt.%, It does not dissolve completely in the matrix, the concentration of inclusion increases and. heterogeneity of the structure, which leads to a decrease in the stability of the antifriction properties of cast iron in castings with a wall thickness of 30 to 200 mm.

Example. Experimental smelting of cast iron was carried out in a coke-gas cupola using cast iron cast iron of grades LK-3, LK5 (GOST 4832-80), limiting cast iron PL-1, gr. IV, cl. A, cat. 1 (GOST 805-80), iron scrap 17A (GOST 2787-75), silico-manganese CMN-17 (GOST 4756-77), antimony SuOO (GOST 1089-73), niobium NbZ (GOST 16099-70), antimony lead SS1, ferrosilicon and other ferroalloys. Pig iron from the cupola is poured into the mixer and overheated to 1653-1693 K and micro-alloyed. The treatment with antimony and modifying additives is carried out in buckets and autoclaves. Cylindrical specimens with a diameter of 30 mm, technological step samples with wall thickness are cast from cast iron

3,72,7. 3.23.6

1.71.31.92.1

1.20,71,21,5

0.30.20.30.30

14

up to 200 mm and casting workpieces pol-. Zunov, cylinders and beds of machine tools.

In tab. 1 shows the chemical composition of the cast iron experienced bottoms, and table. 2 their mechanical and anti-friction properties.

The tensile strength was obtained by testing cylindrical 30 mm specimens, and the hardness and antifriction properties were obtained on specimens from stepped process samples and castings with wall thicknesses of 30, 100, and 200 mm.

Claims (1)

The formula of the invention or Sery wear-resistant cast iron for castings, containing carbon, silicon, manganese; titanium, 11: irconium, copper, calcium, rare earth metals and iron, characterized in that, in order to increase the stability of antifriction properties in castings with wall thickness from 30 to 200 mm, it additionally contains niobium, antimony and lead in the following ratio of shock May %: 35 thirty 35 40 3.8 2.3 1.7 0.7 Components Content, May. Z ({famous cast iron Cast Iron Offered spruce 0.2 0.2 0.1 0.1 0.3 0.02 0.050.02 0.12 0.07 0.05 Rest Strength at stretching, MPa Hardness, HB, in castings with a thickness of steel, mm: 30 100 200 The stability of the coefficient of friction at the thickness of the walls of castings, mm: thirty 100 200 Continuation of table 1 Gray wear-resistant cast iron I five 0.3 0.8 0.07 0.10 0.40 0.20 0.10 0.07 0.17 0.01 0.01 0.07 0.02 0.02 0.4 0.9 0.1 0.12 0.50 0.23 0.15 Else Else Else table 2 521 565 262 396 94 91 85 98 96 91 71 83 58 79 54 71 1293241 8 Continued table. 2 Indicators Properties of gray wear-resistant cast iron at Image: 1.20 2.92 3.18 8.7 5.3 2.4 Editor A.Dolinich Compiled by G. Dudik Tehred L. Serdyukova Corrector I. Erdeyi 350/29 Circulation 605 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 0.38 0.42 0.49 0.34 0.37 0.42 1.17 0.51 2.88 0.69 3.07 0.82 25.2 23.0 20.8 27.8 24.7 21.6 9.1 17.4 5.7 15.2 3.1 13.7