RU208686U1 - Block of three hollow turbine guide vanes for gas turbine engines and power plants - Google Patents

Abstract

The utility model relates to the field of mechanical engineering, namely to blocks of guide vanes of power and transport turbines, and, in particular, blocks of blades of gas turbines of gas turbines and gas turbine engines with heat-resistant coatings. The block contains an external heat-resistant coating on the outer surface of the feather and an internal heat-resistant coating on the inner surface of the blade cavity, the block being made of a nickel-based alloy containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron, niobium, titanium, hafnium, manganese , zirconium, silicon, nitrogen, iron, copper and nickel. The alloy additionally contains cerium, yttrium and hafnium. The outer heat-resistant coating with a thickness of 10 µm to 15 µm is made by slip aluminosilicization at a content in the coating, wt. %: Al - from 26% to 32%; Si - from 3.0% to 4.7%; Ni is the rest, and the internal heat-resistant coating with a thickness of 10 µm to 15 µm is made of an alloy of composition, wt %: Cr - from 4.0% to 8.0% and Al - from 15.0% to 25.0%, Ni - the rest, with a thickness of 10 microns to 15 microns. The mass of the blade unit is 2.8 kg, and the overall dimensions are: 252 mm × 80.5 mm × 130 mm.

Description

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

Gas turbine plants and engines are increasingly used in modern technology: marine gas turbine engines, power gas turbine turbine units (GTU) and gas compressor units. Turbine blades are the main details that determine the reliability, efficiency and resource of their work. Long-term operation of the turbine blade apparatus is possible only if the working blades are made of heat-resistant nickel- or cobalt-based alloys. Nickel- and cobalt-based heat-resistant alloys used for the manufacture of blades make it possible to ensure the performance of turbine blades. At the same time, trends in the improvement of turbomachines lead to the tightening of these operating conditions and to an increase in the cost of parts. All this requires the use of more effective protective coatings on turbine blades.

Guide vanes of GTE and GTU turbines during operation are exposed to significant dynamic and static loads, high and rapidly changing temperatures, as well as corrosion and erosion destruction. Based on the requirements for the manufacture of gas turbine blades, heat-resistant and heat-resistant nickel and cobalt alloys such as TsNK-7, TsNK-21, FSX-414, ZhS-6, ZhS-6U, EI-893, U-5000, etc. are used.

The increase in the operational properties of the blades is due, in particular, to the fact that the replacement of damaged turbine blades is a laborious and expensive undertaking, since it requires removing them from the rotor, acquiring new blades, installing them on the rotor, and so on. [Gonserovsky F.G., Silevich V.M. Feasibility study of a method for repairing erosion-worn steam turbine blades in power plants. // Heavy engineering. - 2001. - No. 9. - S. 21-22]. In this regard, the development of new ways to improve the performance of turbine blade units is an urgent task.

Known high-temperature nickel-based alloy 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 wt.% cobalt, from about 0.2 to about 0.6 wt.% hafnium, from about 0.01 to about 0.03 wt.% carbon; from about 0.002 to about 0.006 wt.% boron; and a balance of nickel and incidental impurities (U.S. Patent No. 8,858,876).

Also known is a nickel-based 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 mass%, Ta: 5.0-8.0 mass%, Nb: 3.0 mass% or less, Al: 4.5-6.0 mass%, 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 rest - Ni and inevitable impurities (US patent No. 8,852,500).

Gas turbine blades made from known alloys do not have sufficient 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 non-optimal ratios of alloying elements leads to a decrease in heat resistance. In addition, gas turbine blades made from a known alloy have an increased volume of non-equilibrium eutectic γ'-phase.

Known alloy includes carbon, chromium, cobalt, tungsten, molybdenum, aluminum, tantalum, rhenium, boron, niobium, cerium, yttrium, lanthanum, neodymium and Nickel in the following ratio, 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 nickel-based heat-resistant alloy for the manufacture of gas turbine blades (TU 14-1-4828-90: KhN58KTVYUMBL-VI (ChS104-VI)), containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron , niobium, titanium, hafnium, manganese, zirconium, silicon, nitrogen, iron, copper and nickel, in the following ratio of components, wt.%:

carbon 0.06-0.12 chromium 20.00-21.80 cobalt 10.30-12.00 tungsten 3.00-4.00 molybdenum 0.30-0.90 aluminum 2.10-2.90 boron 0.015 niobium 0.15-0.35 titanium 3.10-3.90 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 does not have sufficiently high rates of heat resistance and heat resistance.

During operation, the blades are exposed to high temperatures and aggressive environments. The result of such a complex impact 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 the turbine blade unit, various effective protective coatings are used [Chemical-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 destruction of the base material of the part and ensure its performance at high temperatures.

The most promising materials used to form heat-resistant coatings are alloys of the systems: Me-Cr-Al-Y, where Me is Ni, Co or a combination thereof, as well as alloys combining Ni, Cr, Al, Si, Y, B. [Muboyadzhyan S.A., Kablov E.N., Budinovsky S.A. Vacuum-plasma technology for obtaining protective coatings from complex alloys, MiTOM. 1995, no. 2, p. 15-18. Both single-layer [US Patent No. 4475503] and two-layer coatings are used, for example, with an outer layer based on nickel aluminides [US patent No. 4080486].

It is also known a heat-resistant coating containing a heat-resistant coating on the front and the shelf of the blade, consisting of a lower heat-resistant layer and an external heat-resistant layer deposited on it [RF Patent No. 1658652. IPC S23S 14/00. The method of obtaining a combined heat-resistant coating, publ. 2000]. The known blade contains a heat-resistant coating obtained by vacuum deposition of a nickel-based alloy coating layer containing cobalt, chromium, aluminum and a rare earth element, followed by deposition of an outer coating layer of an aluminum-based alloy containing nickel as an alloying additive, with a content in each from layers of aluminum in the amount of 20-80 g/m ² and the thickness of the inner layer of the coating 30-100 microns and subsequent vacuum annealing.

It is also known heat-resistant coating composition NiCrAlY, which is deposited in a vacuum [Muboyadzhyan S.A., Kablov E.N., Budinovsky S.A. Vacuum-plasma technology for obtaining protective coatings from complex alloys, MiTOM. 1995, No. 2, pp. 15-18].

Also known are heat-resistant coatings obtained by aluminosiliconing (for example, RF patent No. 2032764, IPC 23C 10/52 - "Suspension for aluminosilicizing metal parts"). The process of aluminosiliconation includes: preparation of an aqueous suspension, which includes phosphates and chromates, filler - aluminum and silicon powders, colloidal silicon oxide powder (aerosil); part surface preparation and painting; heat treatment.

The main disadvantage of the prototype is low heat resistance and insufficient endurance and cyclic strength, ie. parameters that must be ensured during the operation of the blade assembly 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 block of blades while increasing its endurance.

The technical result is due to the fact that a block of three hollow turbine guide vanes for gas turbine engines and power plants, containing an external heat-resistant coating on the outer surface of the feather and an internal heat-resistant coating on the inner surface of the blade cavity, moreover, the said block is made of a nickel-based alloy containing carbon, chromium, cobalt, tungsten, molybdenum, aluminum, boron, niobium, titanium, hafnium, manganese, zirconium, silicon, nitrogen, iron, copper and nickel, in contrast to the prototype said alloy additionally contains cerium, yttrium and hafnium, with the following ratio of components, wt.%:

carbon 0.06-0.12 chromium 20.00-22.00 cobalt 10.30-12.00 tungsten 3.00-4.00 molybdenum 1.10-1.90 aluminum 2.40 – 3.30 boron 0.015 niobium 0.25 - 0.40 cerium 0.025 yttrium 0.025 titanium 3.20-4.00 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

Moreover, the outer heat-resistant coating with a thickness of 10 μm to 15 μm is made by slip aluminosilicization at the content in the coating, wt.%: Al - from 26% to 32%; Si - from 3.0% to 4.7%; Ni is the rest, and the internal heat-resistant coating with a thickness of 10 µm to 15 µm is made of an alloy of composition, wt %: Cr - from 4.0% to 8.0% and Al - from 15.0% to 25.0%, Ni - the rest, with a thickness of 10 microns to 15 microns.

The technical result is also achieved by the fact that the mass of the blade unit is 2.8 kg, and the overall dimensions are 252 mm × 80.5 mm × 130 mm.

In the proposed nickel-based alloy, the amount of the strengthening γ'-phase (Ni3Al) is about 55-60 at. %, which provides high heat resistance: 350-360 MPa in 103 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 dissolution temperature of the γ'-phase, which is compensated by an increased content of cobalt.

Hafnium in combination with niobium in the stated concentrations, as well as additives of cerium and yttrium, provide sufficient ductility of the cast alloy for a long service life, contribute to the stabilization of carbides in the alloy, and also improve the performance of the blade under high temperatures and aggressive environments.

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

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

Achievable increased resistance to aggressive environments of the proposed blades of the proposed alloy (compared to the known analogue) can increase the operational reliability and service life of products.

High strength characteristics of such alloys are achieved due to a significant amount of the strengthening γ'-phase (Ni3Al) 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 under increased exposure to high temperatures and aggressive environments, is 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.

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

The coating thicknesses were:

according to the prototype method:

outer coating: heat-resistant layer - from 10 microns to 15 microns thick;

an internal covering - from 10 microns to 15 microns thick.

according to the proposed method:

outer coating: heat-resistant layer - from 10 microns to 15 microns thick;

an internal covering - from 10 to 15 microns thick.

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

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

prototype: 360-380 hours;

according to the proposed technical solution: 490-510 hours;

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

prototype: 410-430 hours;

according to the proposed technical solution: 510-530 hours;

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

prototype: 360-370 hours;

according to the proposed technical solution: 410-418 hours.

The endurance limit of nickel alloy specimens, according to the proposed variant, exceeds similar indicators obtained by the prototype by an average of 6.7-8.4%.

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

Claims (2)

1. A block of three hollow turbine guide vanes for gas turbine engines and power plants, containing an external heat-resistant coating on the outer surface of the feather and an internal heat-resistant coating on the inner surface of the cavity of the blades, and said block is made of a nickel-based alloy containing carbon, chromium, cobalt , tungsten, molybdenum, aluminum, boron, niobium, titanium, hafnium, manganese, zirconium, silicon, nitrogen, iron, copper and nickel, characterized in that said alloy additionally contains cerium, yttrium and hafnium in the following ratio, wt.% : carbon 0.06-0.12, chromium 20.00-22.00, cobalt 10.30-12.00, tungsten 3.00-4.00, molybdenum 1.10-1.90, aluminum 2.40 –3.30, boron 0.015, niobium 0.25–0.40, cerium 0.025, yttrium 0.025, titanium 3.20–4.00, hafnium 0.30–0.60, manganese ≤0.30, zirconium 0.030, silicon ≤0.30, nitrogen ≤0.010, iron ≤0.50, copper ≤0.10, nickel is the base, and the outer heat-resistant coating with a thickness of 10 microns to 15 microns is made of slip aluminum plating at the content in the coating, wt %: Al - from 26% to 32%; Si - from 3.0% to 4.7%; Ni - the rest, and the internal heat-resistant coating with a thickness of 10 microns to 15 microns is made of an alloy of composition, wt%: Cr - from 4.0% to 8.0% and Al - from 15.0% to 25.0%, Ni - the rest, with a thickness of 10 microns to 15 microns. 2. Block according to claim 1, characterized in that the weight of the block of blades is 2.8 kg, and the overall dimensions are 252 mm × 80.5 mm × 130 mm.