RU207259U1 - Blade of the second stage of the turbine DG-90 - Google Patents

Abstract

The utility model relates to the field of mechanical engineering, namely, to the blades of power and transport turbines, and, in particular, gas turbines with heat-resistant coatings. Blade of the second stage of the turbine DG-90 with a heat-resistant coating, made of a nickel-based alloy containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron, niobium, cerium, yttrium, titanium, hafnium, manganese, zirconium, silicon, nitrogen , iron, copper and nickel, characterized in that said alloy additionally contains lanthanum and ytterbium. The heat-resistant coating is made with a thickness of 50 to 60 microns from an alloy of the composition, wt%: Si from 4.0 to 6.0; Y 1.0 to 2.0; Al the rest, and the mass of the blade is 0.27 kg, and the overall dimensions are 136.0 × 65.0 × 26 mm.

Description

The utility model relates to the field of mechanical engineering, namely, to the blades of power and transport turbines, and, in particular, gas turbines with heat-resistant coatings.

Gas turbine units and engines are increasingly used in modern technology: marine gas turbine engines, power gas turbine turbine units (GTU) and gas pumping units.

The main details that determine the reliability, efficiency and resource of their work are the turbine rotor blades. Long-term operation of the turbine blades is possible only if the rotor blades are made of heat-resistant alloys on a nickel or cobalt base. Heat-resistant alloys on a nickel and cobalt base used for the manufacture of blades make it possible to ensure the operability of the turbine blades.

In particular, the DG-90 engine is used as a part of gas turbine units intended for natural gas transportation at compressor stations. One of the urgent tasks of increasing the reliability of the specified engine DG-90 is to increase the service life of the rotor blades of the 1st and 2nd stages of a gas turbine, made of ChS-88U-VI with a heat-resistant coating. It is known that an increase in the resource of the rotor blades of a GTE turbine is achieved by improving the composition of the heat-resistant alloy and the use of heat-resistant coatings.

Known high-temperature alloy based on nickel for the manufacture of gas turbine blades, containing about 6.0 wt.% Aluminum; about 6.5 wt.% tantalum; about 4.5 wt.% chromium; about 5.0 wt.% tungsten, about 2.5 wt.% molybdenum, about 4 wt.% rhenium; about 12 weight percent cobalt, about 0.2 to about 0.6 weight percent hafnium, about 0.01 to about 0.03 weight percent carbon; about 0.002 to about 0.006 weight percent boron; and the balance of nickel and incidental impurities (US patent No. 8858876).

Also known is a nickel-base heat-resistant alloy containing Cr 3.0-5.0 wt%, Co 5.0-10.0 wt%, Mo 0.5-3.0 wt%, W 8.0-10.0 wt%, Ta 5.0-8.0 wt%, Nb 3.0 wt% or less, Al 4.5-6.0 wt%, Ti 0.1-2.0 wt%, Re more than 3.0-4.0 wt%, Ru 0.2-4.0 wt%, Hf 0.01-0.2 wt%, and the balance being Ni and unavoidable impurities (US patent No. 8852500 ).

Gas turbine rotor blades made of known alloys do not have a sufficiently high heat resistance, since their composition is aimed at simultaneously increasing heat resistance and heat resistance. The need to increase the corrosion resistance and oxidation resistance of the blades under the influence of an aggressive environment due to suboptimal ratios of alloying elements leads to a decrease in the heat resistance. In addition, gas turbine blades made of a known alloy have an increased volume of the non-equilibrium eutectic γ'-phase.

The known alloy includes carbon, chromium, cobalt, tungsten, molybdenum, aluminum, tantalum, rhenium, boron, niobium, cerium, yttrium, lanthanum, neodymium and nickel in the following ratio of components, wt%: carbon 0.05-0.12; chromium 5.0-6.0; cobalt 8.0-10.0; tungsten 6.5-7.5; molybdenum 0.8-1.5; aluminum 5.5-6.0; tantalum 4.4-5.4; rhenium 3.8-4.6; boron 0.001-0.02; niobium 0.6-1.0; cerium 0.005-0.10; yttrium 0.0001-0.002; lanthanum 0.001-0.05; neodymium 0.0005-0.01; nickel the rest (RU 2148099, C22C 19/05, published 04/27/2000).

The closest in technical essence is a high-temperature alloy based on nickel for the manufacture of rotor blades of gas turbines (TU 14-1-4828-90: KhN57KVYUTMBRL (ChS88U)), containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron, niobium, cerium, yttrium, titanium, hafnium, manganese, zirconium, silicon, nitrogen, iron, copper and nickel, with the following ratio of components, wt%:

carbon 0.06-0.12 chromium 15.00-16.20 cobalt 10.00-11.50 tungsten 4.70-5.90 molybdenum 1.60-2.30 aluminum 2.60-3.30 boron 0.010 niobium 0.10-0.30 cerium 0.020 yttrium 0.030 titanium 4.20-5.00 hafnium 0.30-0.60 manganese ≤0.30 zirconium 0.030 silicon ≤0.30 nitrogen ≤0.010 iron ≤0.50 copper ≤0.10 nickel the foundation

However, this known alloy has insufficiently high heat resistance.

During operation, the blades are exposed to increased mechanical stress, high temperatures and aggressive media. The result of such a complex effect on the part is its rapid failure, which does not provide the required resource of the product as a whole. To solve the problem of increasing the efficiency of turbine blades, various effective protective coatings are used [Chemical and thermal treatment of heat-resistant steels and alloys / NV Abraimov, Yu.S. Eliseev. - M .: Intermet Engineering, 2001. - 622 p.].

The heat-resistant coatings used to protect the blades, with their sufficient stability under operating conditions, can significantly reduce the processes of destruction of the base material of the part and ensure its performance at high temperatures.

The most promising materials used for the formation of heat-resistant coatings are alloys of the systems: Me-Cr-Al-Y, where Me is Ni, Co or their combination, as well as alloys combining Ni, Cr, Al, Si, Y, B. [Muboyadzhyan S.A., Kablov E.N., Budinovskiy S.A. Vacuum-plasma technology for producing protective coatings from complex alloyed alloys, MiTOM. 1995, No. 2, pp. 15-18]. Both single-layer [US Pat. No. 4,475,503] and two-layer coatings are used, for example, with an outer layer based on nickel aluminides [US Pat. No. 4,080,486].

Known heat-resistant coating composition NiCrAlY, which is applied in vacuum [Muboyadzhyan SA, Kablov EN, Budinovsky SA. Vacuum-plasma technology for producing protective coatings from complex alloyed alloys, MiTOM. 1995, No. 2, pp. 15-18].

The disadvantage of the known blades with heat-resistant coatings is the intense diffusion exchange between the MeCrAlY layer and the base material of the part, which leads to a decrease in the operational properties of the turbine blades of GTE and GTU.

The closest in technical essence is a turbine blade for a gas turbine engine, with a heat-resistant coating, [RF Patent No. 2441102. IPC S23S 30/00. A method of obtaining a heat-resistant coating on turbomachine blades, publ. 2012]. The known blade contains a heat-resistant coating of the composition Si 4.0-4.5%, Y 1.6-2.0%, Al the rest, or Si 4.0-12.0%, Y 1.6-2.0%, Al the rest, or Si 4.0-12.0%, Y 1.6-2.0%, Al the rest, with layers of borides.

The main disadvantage of the prototype is low heat resistance and insufficient endurance and cyclic strength, i.e. parameters that must be ensured during the operation of blades of gas turbine engines and installations.

The technical result of the claimed utility model is to increase the heat resistance and heat resistance of the blade while increasing its endurance and cyclic strength.

The technical result is achieved by the fact that the blade of the second stage of the turbine DG-90 with a heat-resistant coating, made of a nickel-based alloy containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron, niobium, cerium, yttrium, titanium, hafnium, manganese , zirconium, silicon, nitrogen, iron, copper and nickel, characterized in that said alloy additionally contains lanthanum and ytterbium in the following ratio of components, wt%:

chromium 15.50-16.00 cobalt 11.00-12.00 tungsten 5.50-6.00 molybdenum 2.00-2.50 aluminum 2.80-3.50 boron 0.010 niobium 0.20-0.40 cerium 0.020 yttrium 0.030 titanium 4.50-5.00 hafnium 0.30-0.60 manganese ≤0.30 zirconium 0.030 silicon ≤0.30 nitrogen ≤0.010 iron ≤0.50 copper ≤0.10 lanthanum 0.015 ytterbium 0.015 nickel the foundation,

moreover, the heat-resistant coating is made with a thickness of 50 to 60 μm from an alloy of the composition, wt%: Si from 4.0 to 6.0; Y 1.0 to 2.0; Al the rest, and the mass of the blade is 0.27 kg, and the overall dimensions are 136.0 × 65.0 × 26 mm.

In the proposed nickel-based alloy, the amount of the strengthening γ'-phase (Ni ₃ Al) is about 55-60 at.%, Which provides high heat resistance: 350-360 MPa for 10 ³ hours at a temperature of about 850-900 ° C.

The content of tungsten and tantalum gives an increased heat resistance of the cast alloy, however, a further increase in their total content causes a significant increase in the temperature of dissolution of the γ'-phase, which is compensated by the increased content of cobalt.

Hafnium in combination with niobium in the stated concentrations provides sufficient ductility of the cast alloy for a long service life and stabilization of carbides.

At the same time, the claimed ratios of the components in the alloy exclude the appearance of embrittling phases during production and limit the release of the nonequilibrium eutectic γ'-phase, which provides a reduced volume of gas-shrinkage porosity and increases the product's resistance to cracking.

To obtain cast rotor blades of a gas turbine from the proposed alloy, known methods and devices for casting turbine blades from heat-resistant alloys with monocrystalline, directional and equiaxed structures are used. Heat treatment of cast billets includes homogenizing annealing at a temperature of about 1260 ° C for 3-10 h.

The achieved increased resistance to aggressive environmental influences of the proposed blade made of the proposed alloy (in comparison with the known analogue) makes it possible to increase the operational reliability and service life of the products.

High strength characteristics of such alloys are achieved due to a significant amount of the strengthening γ'-phase (Ni ₃ Al), alloyed with niobium, titanium, tantalum, etc., as well as hardening of the solid solution (γ-phase) with cobalt, chromium, molybdenum and tungsten. ... Increased corrosion resistance, as well as resistance to oxidation at elevated ones, are provided by a high content of chromium and aluminum and tantalum in the surface layer of the blade, as well as by applying a heat-resistant coating.

The additional introduction of lanthanum and ytterbium makes it possible to strengthen the grain boundaries of the heat-resistant alloy.

To assess the durability of the known and proposed gas turbine blades, comparative tests were carried out, showing the following results.

The thicknesses of the heat-resistant coatings were:

according to the prototype method, the coating thickness is from 50 microns to 60 microns;

according to the proposed method, the thickness of the coating is from 50 microns to 60 microns.

As a result of the tests for heat resistance, the following results were obtained: the long-term strength of nickel alloy blades, on average, compared with the prototype, is:

1) at a temperature of 600 ° C, a load of 1000 MPa is:

prototype: 370-380 h;

according to the proposed technical solution: 505-520 h;

2) at a temperature of 800 ° C, a load of 500 MPa is:

prototype: 415-430 h;

for the proposed technical solution: 525-554 h;

3) at a temperature of 900 ° C, a load of 250 MPa is:

prototype: 370-380 h;

according to the proposed technical solution 420-435 h.

The endurance limit of nickel alloy specimens, according to the proposed option, exceeds those obtained from the prototype by an average of 7.6-8.3%.

Thus, the proposed blade made of a nickel-based alloy with a heat-resistant coating makes it possible to achieve the technical result of the claimed utility model - increasing the heat resistance and heat resistance of the blade while increasing its endurance and cyclic strength.

Claims (3)

Blade of the second stage of the turbine DG-90 with a heat-resistant coating, made of a nickel-based alloy containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron, niobium, cerium, yttrium, titanium, hafnium, manganese, zirconium, silicon, nitrogen , iron, copper and nickel, characterized in that said alloy additionally contains lanthanum and ytterbium in the following ratio of components, wt%: chromium 15.50-16.00 cobalt 11.00-12.00 tungsten 5.50-6.00 molybdenum 2.00-2.50 aluminum 2.80-3.50 boron 0.010 niobium 0.20-0.40 cerium 0.020 yttrium 0.030 titanium 4.50-5.00 hafnium 0.30-0.60 manganese ≤0.30 zirconium 0.030 silicon ≤0.30 nitrogen ≤0.010 iron ≤0.50 copper ≤0.10 lanthanum 0.015 ytterbium 0.015 nickel the foundation, moreover, the heat-resistant coating is made with a thickness of 50 to 60 μm from an alloy of the composition, wt%: Si from 4.0 to 6.0; Y 1.0 to 2.0; Al the rest, and the mass of the blade is 0.27 kg, and the overall dimensions are 136.0 × 65.0 × 26 mm.