SU1719451A1 - Nickel base alloy - Google Patents

Abstract

The invention relates to metallurgy and concerns the development of a nickel-based alloy used for casting parts, in particular gas turbine blades, working in the corrosive environment of combustion products of gas turbine fuel. The goal is to increase the heat resistance while maintaining the level of corrosion resistance. The alloy contains, wt%: carbon 0.005-0.12; chromium 11.5-13.0; cobalt 8.0-10.0; tungsten 6.2-8.0; niobium 0.7-12; titanium 4.1-5.2; aluminum 3.5-4.5; boron 0.001-0.015; cerium 0.001-0.02; nickel is the rest, and the ratio of the amount of titanium to aluminum in the alloy is 1.05-1.40. The alloy has the following properties; AV at 293К 1170-1230 MPa, OB at 1123К 923-955 MPa; the limit of long-term strength for 103 h at 1123 K 330-350 MPa; the limit of long-term strength for 10% at 1123К 225-266 MPa; corrosion resistance at 850 ° C in the environment of the products of combustion of natural gas (1.6-1.8) U 2 g / cm3 2 table.

Description

The invention relates to metallurgy and concerns the development of a nickel-based alloy used for casting parts, in particular gas turbine blades, working in the aggressive environment of combustion products of gas turbine fuel.

The aim of the invention is to increase the heat resistance while maintaining the level of corrosion resistance.

The proposed ratio of titanium to aluminum in the range of 1.05-1.40 provides a minimal discrepancy between the lattice parameters of the y and y phases at the interfacial y / y boundaries and the formation of y-g phase particles with an average size close to

to a critical degree of dispersion. With a Ti: AI ratio of less than 1.05, the corrosion resistance of the cast alloy is reduced due to a decrease in the deterrent effect of titanium on sulphide formation. With a ratio of more than 1.40, the heat resistance decreases due to an increase in the y-phase lattice parameter.

Example. Samples of the proposed and well-known alloys were obtained by the method of directional solidification on a vacuum melting and casting plant PNP-2.

The chemical composition of the alloys is given in table 1.

YU

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ate

Short-term strength tests were carried out in accordance with GOST 1497-73, GOST 9651-73 on samples with a working part diameter b mm and a calculated length of 30 mm; for heat resistance - in accordance with GOST 10145-62 and OST 108.901.102-78 at AIMA-5 installations on cylindrical samples with a working part diameter of 6 mm and an estimated length of 30 mm.

The corrosion resistance tests were carried out at 850 ° C in an environment simulating the combustion products of natural gas under the conditions of contact of samples with aggressive coating components, containing, in wt.%: NaCI 3; No. 2804 40; ReaOz 5; CaO 10; MDO 3.5; 3.5; SI02 35. The evaluation was carried out on the weight loss of the samples after testing.

The test results are given in table. 2

As can be seen from the data table. 2, the proposed alloy is characterized by higher rates of heat resistance at

0

five

0

equal values of corrosion resistance.

Claims (1)

Alloy based on nickel containing carbon, chromium, cobalt, tungsten, niobium, titanium, aluminum, boron, cerium, characterized in that, in order to increase heat resistance while maintaining the level of corrosion resistance, it contains components in the following ratio, wt. %: Carbon0.005-0.12 Chrome 11.5-13,0 Cobalt8.0-10.0 Tungsten6,2-8,0 Niobium 0.7-1.2 Titan4.1-5,2 Aluminum 3.5-4.5 Bor0.001-0.015 Cerium0,001-0.02 Nickel Else, moreover, the ratio of the content of the amount of Gitan to aluminum in the alloy is 1.05-1.40. Table Table. 2