RU2365657C1 - Heat-resistant nickel-base wrought alloy and article made from this alloy - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention related to metallurgy, namely to heat-resistant nickel-base wrought alloys and the articles manufactured from these alloys and can be used to manufacture disks of the turbines of gas-turbine engines and other units and parts operating at temperatures up to 800°C in all climatic conditions. The alloy and an article manufactured from it has the following compolsition, wt %: cobalt 9.5-16.0; chromium 9.0-11.0; tungsten 2.5-3.4; molybdenum 3.5-4.8; aluminium 3.4-4.0; titanium 2.3-3.5; niobium 4.1-4.8; vanadium 0.2-0.8; carbon 0.04-0.10; boron 0.007-0.02; lanthanum 0.003-0.06; cerium 0.003-0.02; magnesium 0.003-0.02; scandium 0.003-0.05; silicon 0.005-0.3; the rest is nickel. The alloy may additionally contain 0.05-2.0 wt % of tantalum.

EFFECT: increased heat-resistance at temperatures up to 800°C, plastic fatigue strength, strength at room temperature and reduction in the rate of sulphide-oxide corrosion.

3 cl, 2 tbl, 4 ex

Description

The invention relates to the field of metallurgy of heat-resistant wrought nickel-based alloys and products made of these alloys for aircraft, engineering and other sectors of the national economy, and can be used for the manufacture of turbine disks for gas turbine engines and other components and parts operating at temperatures up to 800 ° C in all climatic conditions.

Alloys are multicomponent systems based on nickel, hardened by ~ 50% of the γ′-phase - intermetallic Ni ₃ (Al, Ti, Nb), carbides and borides.

The main requirements for this class of materials are: a high level of strength characteristics in the range of operating temperatures for short, long and cyclic tests, high corrosion resistance. This ensures reliable operation of products from the proposed alloys, will increase their resource and weight return.

Known heat-resistant nickel-based alloy for heavily loaded parts of the hot gas turbine engine, including for turbine disks, the following chemical composition, wt.%:

Cobalt 16.0-22.4 Chromium 6.6-14.3 Tungsten 1.9-4.0 Molybdenum 1.9-3.9 Rhenium 0-2.5 Aluminum 2.6-4.8 Titanium 2.4-4.6 Niobium 0.9-3.0 Tantalum 1.4-3.5 Carbon 0.02-0.10 Boron 0.02-0.10 Zirconium 0.03-0.10 Nickel Rest

(Patent EP No. 1201777).

Also known alloy containing, wt.%:

Cobalt 14.0-16.0 Chromium 9.0-11.0 Iron 0.001-1.0 Tungsten 5.2-6.8 Molybdenum 3.0-3.9 Aluminum 3.2-4.5 Titanium 3.0-3.9 Niobium 1.2-2.4 Carbon 0.02-0.1 Boron 0.005-0.05 Zirconium 0.001-0.05 Hafnium 0.05-0.5 Magnesium 0.001-0.05 Manganese 0.001-0.5 Silicon 0.001-0.5 Nickel Rest

(RF patent No. 2294393).

These alloys do not possess the set of properties necessary for the material of the parts of the hot path of the turbine, including disks, promising new generation gas turbine engines: a high level of strength, low-cycle fatigue resistance combined with heat resistance. To work in difficult climatic conditions, for example, in the presence of chlorine and sulfur ions in the atmosphere or in the products of fuel combustion, their corrosion resistance is insufficient. They do not provide the necessary level of reliability and resource.

Known heat-resistant wrought alloy on a nickel basis for turbine disks and other components and parts of the hot gas turbine engine of the following chemical composition, wt.%:

Cobalt 14.0-15.9 Chromium 9.7-12.0 Tungsten 1,5-3,5 Molybdenum 3.5-4.5 Rhenium 0.5-2.5 Aluminum 3,5-4,2 Titanium 2.5-3.5 Niobium 2.5-4.0 Vanadium 0.4-0.7 Carbon 0.04-0.10 Boron 0.007-0.014 Lanthanum 0.005-0.015 Cerium 0.003-0.010 Magnesium 0.004-0.015 Scandium 0.003-0.015 Nickel Rest

(RF patent №2280091).

The alloy has high heat resistance in the temperature range from 650 to 850 ° C, strength at room temperature. However, the resistance to sulfide-oxide corrosion of the alloy is insufficient for promising new generation engines. Furthermore, the high cost of rhenium leads to a considerable (up to 2 ^times) rise in price of the alloy as compared to similar purpose serial materials, which restricts its practical use in a new generation of products.

The closest in composition and purpose to the proposed is an alloy with the following content of components, wt.%:

Cobalt 13.0 ÷ 15.0 Chromium 8.5 ÷ 9.5 Tungsten 5.3 ÷ 6.5 Molybdenum 3.0 ÷ 3.5 Aluminum 3.6 ÷ 4.0 Titanium 2.5 ÷ 2.9 Niobium 3.2 ÷ 3.8 Vanadium 0.1 ÷ 0.6 Carbon 0.08 ÷ 0.14 Boron 0.008 ÷ 0.02 Zirconium 0.01 ÷ 0.06 Lanthanum 0.005 ÷ 0.012 Cerium 0.005 ÷ 0.03 Magnesium 0.003 ÷ 0.1 Nickel Rest

(RF patent №2022044).

The disadvantages of this alloy are insufficiently high strength characteristics, heat resistance, low-cycle fatigue and resistance to sulfide-oxide corrosion. The properties of the alloy presented in the patent were obtained after a special thermomechanical treatment, as a result of which a “necklace” structure was formed. Products from this alloy with such a structure have limited resource and reliability values at temperatures above 700 ° C.

The technical task of the invention is the development of a heat-resistant wrought nickel-based alloy having a high complex of properties: long-term strength at temperatures up to 800 ° C, strength at room temperature, high low-cycle fatigue resistance and sulfide-oxide corrosion resistance, which ensures the use of this alloy in products new generation.

To solve this problem, we propose a heat-resistant wrought nickel-based alloy containing cobalt, chromium, tungsten, molybdenum, aluminum, titanium, niobium, vanadium, carbon, boron, lanthanum, cerium, magnesium, characterized in that it additionally contains scandium and silicon at the following ratio of components, wt.%:

Cobalt 9.5-16.0 Chromium 9.0-11.0 Tungsten 2.5-3.4 Molybdenum 3.5-4.8 Aluminum 3.4-4.0 Titanium 2,3-3,5 Niobium 4.1-4.8 Vanadium 0.2-0.8 Carbon 0.04-0.10 Boron 0.007-0.02 Lanthanum 0.003-0.06 Cerium 0.003-0.02 Magnesium 0.003-0.02 Scandium 0.003-0.05 Silicon 0.005-0.3 Nickel Rest

and an article made from it.

For products operating for a long time at temperatures of 750 ÷ 800 ° C, tantalum is additionally introduced into the alloy in an amount of 0.05 ÷ 2.0 wt.%.

The introduction of silicon, scandium, as well as an increase in the content of niobium in the alloy of the proposed composition simultaneously increases strength, heat resistance, resistance to low-cycle fatigue, and reduces the rate of sulfide-oxide corrosion. This is due to the formation of stable primary and secondary carbides, the binding of fusible impurities along grain boundaries, and the formation of an oxide film with a greater protective ability on the surface of the part.

The content of silicon and scandium is less than the specified amount - inefficient, more - reduces the manufacturability of the alloy during smelting and deformation.

An additional introduction to tantalum alloy is effective for products that have been operating for a long time (more than 100 hours) at temperatures of 750 ÷ 800 ° C. Tantalum contributes to the formation of more thermodynamically stable carbides and particles of the strengthening γ′-phase. It increases the strength properties and corrosion resistance of the alloy. The addition of less than the specified amount of tantalum leads to a decrease in the properties of the alloy during prolonged operation at temperatures of 750 ÷ 800 ° C, more - to a decrease in manufacturability during smelting and deformation.

Implementation example

For the practical implementation of the invention in laboratory conditions, five vacuum induction melts of the proposed alloy, (examples 1-4) and prototype alloy (example 5) were smelted (table 1).

The metal was melted in round metal molds. The obtained ingots were turned “as clean”, and then cut into billets. Billets for deformation of ⌀100 mm and a weight of ~ 22 kg were obtained by remelting by the method of high-speed directional crystallization.

Further, the workpieces were repeatedly deformed. As a result, we obtained model stampings of discs -3200-300 mm, 50-25 mm high, from which blanks were cut for samples.

Heat treatment - hardening and double aging.

The obtained samples were tested for long-term and short-term strength, low-cycle fatigue, corrosion resistance in the presence of chlorine and sulfur ions at temperatures of 650 and 750 ° C.

The test results are presented in Table 2.

The proposed alloy surpasses the prototype alloy in the whole range of properties: in terms of strength at short-term rupture at 20 ° С - by more than 11%, long-term strength at 800 ° С ~ by 8%, low-cycle fatigue at 750 ° С - by more than 9% , sulfide-oxide corrosion resistance - at 650 ° С - more than 55%, at (750-800) ° С - more than 10 times.

Thus, the use of the proposed alloy will improve the set of properties of the parts of the hot gas turbine engine, increase the resource and reliability of promising engines. In addition, higher corrosion resistance will allow the use of products from this alloy without protection in all climatic conditions and when using fuels with a high sulfur content.

Table 1 The chemical composition of the experimental heats of the proposed alloy and prototype alloy No. of swimming trunks Chemical composition, wt.% Co Cr W Mo Al Ti Nb V C B Zr La Ce Mg Sc Si Ta Ni one 16,0 9.0 2.5 3,5 3.4 3,5 4.8 0.8 0.04 0.007 - 0.003 0.02 0.02 0.05 0.3 - 2 14.9 10.0 3.2 4.8 3,7 2.5 4.4 0.6 0,07 0.012 - 0.010 0.007 0.008 0.009 od - Rest 3 9.5 11.0 3.4 4.4 4.0 2,3 4.1 0.2 0.10 0.02 - 0.06 0.003 0.003 0.003 0.005 0.05 four 15.0 9,4 2.5 3,5 3,5 2,3 4.1 0.5 0.06 0.012 - 0.010 0.007 0.010 0.009 0.1 2.0 5 14.0 9.0 5.9 3.3 3.8 2.7 3,5 0.4 0.11 0.015 0.04 0.009 0.018 0.007 - - -

table 2 The results of comparative tests of experimental swimming trunks of the proposed alloy and prototype alloy (average values) The properties T σ _in ²⁰ σ _0.2 ²⁰ δ ₅ ²⁰ σ ₁₀₀ MCU based on 10 ⁴ c, smooth samples The speed of sulfide oxide corrosion, g / m ² · h No. pl. ° C MPa % MPa MPa % one twenty 1608 1198 15.3 - 1360 - 650 1570 1100 13,2 1090 1280 -0.20 750 - - - 720 1150 -0.45 800 - - - 510 - -0.64 2 twenty 1625 1215 14.0 - 1370 - 650 1570 1110 13.0 1085 1300 -0.22 750 - - - 710 1150 -0.35 800 - - - 510 - -0.43 3 twenty 1630 1220 13.8 - 1360 - 650 1560 Fine art 12.9 1085 1300 -0.29 750 - - - 720 1160 -0.52 800 - - - 520 - -0.67 four twenty 1657 1273 15,2 - 1380 - 650 1570 1100 13.5 1095 1300 -0.15 750 - - - 730 1150 -0.23 800 - - - 530 - -0.37 5 twenty 1450 1100 14.8 - 1360 - 650 1400 1060 18,4 1030 1100 -0.45 750 - - - 686 1060 -6.7 800 - - - 460 - -7.1 T - test temperature, σ _in - ultimate strength; σ _0.2 - yield strength δ - elongation; σ ₁₀₀ is the limit of hourly long-term strength; MTSU - low-cycle fatigue.

Claims (3)

1. Heat-resistant wrought nickel-based alloy containing cobalt, chromium, tungsten, molybdenum, aluminum, titanium, niobium, vanadium, carbon, boron, lanthanum, cerium, magnesium, characterized in that it additionally contains scandium and silicon in the following ratio of components , wt.%:
Cobalt 9.5-16.0 Chromium 9.0-11.0 Tungsten 2.5-3.4 Molybdenum 3.5-4.8 Aluminum 3.4-4.0 Titanium 2,3-3,5 Niobium 4.1-4.8 Vanadium 0.2-0.8 Carbon 0.04-0.10 Boron 0.007-0.02 Lanthanum 0.003-0.06 Cerium 0.003-0.02 Magnesium 0.003-0.02 Scandium 0.003-0.05 Silicon 0.005-0.3 Nickel Rest 2. The heat-resistant wrought nickel-based alloy according to claim 1, characterized in that it additionally contains tantalum 0.05 ÷ 2.0 wt.%. 3. A product of a heat-resistant wrought alloy based on nickel, characterized in that it is made of an alloy according to claim 1 or 2.