SU1663040A1 - Cast iron alloying additive - Google Patents

Abstract

The invention relates to metallurgy, in particular to compositions of master alloys for wear-resistant cast irons of the hypoeutectic composition. The goal is to reduce wear under conditions of semi-dry friction and increase the operational durability of cast iron. The master alloy contains copper, aluminum, phosphorus, carbon, chromium nitrides, titanium carbonitrides, magnesium, beryllium and iron in the following ratio of components, wt.%: Copper 12 - 15

aluminum 6 - 8

phosphorus 5 - 10

carbon 0.07 - 0.3

chromium nitrides 22 - 27

titanium carbonitrides - 10 - 15

magnesium 6 - 11

beryllium 0,2 - 0,7 and iron the rest. The addition of chromium nitrides, titanium carbonitrides, magnesium and beryllium to the ligatures provides an increase of 20–30% in the performance characteristics of cast iron due to the complex modifying and microalloying action. 2 tab.

Description

The invention relates to metallurgy, in particular, to a composition of a ligature for the production of wear-resistant cast iron.

The purpose of the invention is to reduce wear under conditions of semi-dry friction and increase the operational durability of cast iron.

The goal is achieved by the fact that a master alloy containing copper, aluminum, phosphorus, carbon and iron additionally contains chromium nitrides, titanium carbonitrides, magnesium and beryllium in the following ratio of components, wt.%:

Copper

Aluminum

Phosphorus

Carbon

Chromium nitride

Titanium carbonitride

Magnesium

Beryllium

Iron

12-15 6-8 5-10 0.07-0.3 22-27 10-15 6-11 0.2-0.7 Else

The addition of chromium nitrides to the composition of ligatures provides an increase in the stability of the structure and coefficient of friction, hardness and strength properties, which contributes to an increase in the operational characteristics of cast iron. When the concentration of chromium nitrides is up to 22 wt.%, Wear resistance under semi-dry friction conditions and operational properties are insufficient, and the upper limit of their concentration (27 May.%) Is due to an increase in the content of non-metallic inclusions at the grain boundaries and a decrease in the operational properties of cast iron.

Magnesium modifies the structure of cast iron, which increases its mechanical and operational properties. When the concentration of magnesium to b May. % its modifying effect and operating properties are low, and with an increase in its content of more than 11 wt.%, the pyroeffect is enhanced in the processing of cast iron, decreases

ABOUT

about with about

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stability of structure, mechanical and operational properties.

Beryllium crushes and bleaches the structure, increases the content of granular perlite, mechanical and operational properties, but when its concentration is more than 0.7 wt.%, The content of cementite increases, which reduces the flexural strength and operational properties. When its content is up to 0.2 wt.%, The ferrite content increases, the hardness, wear resistance and performance properties of cast iron decrease.

Titanium carbonitrides increase the stability of the structure and coefficient of friction, which increases wear resistance and performance properties. The microalloying effect of titanium carbonitrides and the increase in frictional properties are noted by their minimum concentration in the ligature of 10 wt.%, And with an increase in their concentration of more than 15 wt.

The concentration of aluminum is reduced to 6–8 wt.% And copper to 12–15 wt.%, Since at higher concentrations, the segregation processes increase and the instability of the structure increases, which reduces the flexural strength, wear resistance and performance properties. When their concentration is less than the lower limits, the technological properties deteriorate, the cast iron structure and operational properties become larger.

Phosphorus in the composition of the ligature increases the degree of perlite structure and hardness and wear resistance, its content is left in the same range. The upper limit of the carbon content is limited to 0.3 wt.%, Above which the amount of ferrite in the iron structure increases, its hardness, wear resistance and performance properties decrease. The lower limit of concentration (0.07 wt.%) Is due to a decrease in technological, mechanical and friction properties at lower concentrations.

Example. For the production of ligatures, carbonitrides of titanium FT and 1H, ground to a fraction of 0.1-2 mm, are ground; chromium nitrides in C2 powder (11.8% nitrogen) in accordance with Specification 6-09-03-45-75; magnesium powder Mg1; crushed to a fraction of 0.1-3 mm alloy AB-2; copper in accordance with GOST 859-78 mark M1; beryllium Be1 crushed to a fraction of 0.1-3.0 mm, grade 1, TU48-103-72; phosphorus powder F1. The ligature fraction of 10-40 mm is introduced in the amount of 0.6% by weight of cast iron.

For smelting ligatures of optimal composition (composition 2, Table 1) use the mixture,

containing 26 kg of copper, 17 kg of alloy AB-1; 16 kg of phosphorus; 20 kg of magnesium; 46 kg of chromium nitrides and 21 kg of titanium carbonitrides. Magnesium is introduced as a mechanical mixture along with chromium nitride powder,

0 titanium carbonitrides with a fraction of 0.1-2 mm and crushed aluminum-berillium alloy AB-2. Loss of magnesium 17-19%.

Experimental melting ligatures held in open induction furnaces capacity

5 150 kg. The melting of the mixture was carried out in the following sequence. First, copper M1 (GOST 859-78) is melted in an induction furnace under a layer of charcoal and deoxidized with ferrophosphorus. Then, alloy AB-2 (GOST 23911-79), chromium nitrides, magnesium, and titanium carbonitrides FT and 1H (TU 6-09-112-85) are introduced. After mixing and aging for 2–3 min at 1180–1200 ° C, the ligature is poured into flat metal molds.

Table 1 shows the chemical compositions of ligatures of the experimental bottoms.

Cast iron was melted in a DC-1.5 electric arc furnace and produced in foundry

0 buckets at 1470-1490 ° C. When the ladle is filled 1/2 of its height, ligatures of compositions 1-6 of a fraction of 10-40 mm in an amount of 0.6% by weight of molten metal are seated. Chemical content of iron before microalloying, wt.%: Carbon 2.6-2.7; silicon 1.2-1.3; manganese 0.6-0.7; phosphorus 0.04-0.06; Nickel 0.20-0.22; Chromium 0.12-0.13; sulfur 0.05-0.06; iron else.

0 The study of the microstructure and mechanical properties was carried out on cylindrical 10 mm samples in accordance with GOST 3443-87, GOST 9012-59 and GOST 1497-84. The wear rate is determined by

5 on the ring samples of 15-0.2 mm in accordance with GOST 23210-80. and wear resistance under semi-dry friction conditions - according to the VNIINMASH method.

The corrosion fatigue limit is determined on samples of type U111 on the basis of 10 cycles of testing, and operational durability is determined on inertial test benches according to the scheme a stationary block of material 6KX-1B is a rotating cylinder

5 60 mm from the studied micro-alloyed cast iron.

Table 2 presents data on the mechanical and performance properties of micro-alloyed wear-resistant cast irons known and proposed by ligatures.

As can be seen from the data of Table 2, the use of the proposed ligature for the micro-alloying of wear-resistant cast iron provides an increase in the limit of corrosion fatigue, friction wear resistance and performance properties to a greater extent than the ligature is known. The form / m of the invention of a master cast iron, containing copper, aluminum, phosphorus, carbon and iron, is characterized in that, in order to reduce wear under conditions of semi-dry friction and increase operational

the resistance of cast iron, it additionally contains chromium nitrides, titanium carbonitrides, magnesium and beryllium in the following ratio of components, wt.%:

Copper .12-15

Aluminum, 6-8

Phosphorus 5-10

Carbon0.07-0.3

Chromium nitrides22-27

Titanium carbonitrides10-15

Magnesium6-11

Beryllium 0.2-0.7

Iron Else.

Table 1

table 2

Claims (1)

Claim Ligature for cast iron, containing copper, aluminum, phosphorus, carbon and iron, characterized in that, in order to reduce wear under conditions of semi-dry friction and increase the operational stability of cast iron, it additionally contains chromium nitrides, titanium carbonitrides, magnesium and beryllium in the following ratio components, wt.%: Copper 12-15 5 Aluminum 6-8 Phosphorus 5-10 Carbon 0.07-0.3 Chromium nitrides 22-27 Titanium carbonitrides 10-15 10 Magnesium 6-11 Beryllium 0.2-0.7 Iron Rest. Table 1 Ligature The content of components in the ligatures, wt. ^ Copper Aluminum Phosphorus Carbon ........ Chromium nitrides Magnesium Titanium carbonitrides Beryllium 1 12 6 5 0,07 22 6 10 0.2 2 thirteen 7 - 8 0, 12 25 9 12 0.5 3. fifteen 8 10 0.3 27 eleven fifteen 0.7 4 10 5 4 0.02 21 5 9 0.1 5 6 (of 16 7 6 0.5 28 12 16 .0.8 known) 35 21 9 0.3 - - - - table 2 Ligature Bending strength MPa Hardness, HB Fatigue limit, MPa Wear rate, Ih 10 The limit of corrosion fatigue, MPa Semi-dry friction wear, mg / cm ² Operational Resistance, h 1 1015 296 235 0.525 475 4.3 832 2 1360 330 248 0.460 520 3,7 880 3 1290 322 242 0.485 491 3.8 865 4 625 240 '198 0.608 453 5.1 786 5 6 (of 870 295 215 0.568 468 4.8 805 known) 481 220 185 0.630 450 5.3 760