RU2285059C1 - Nickel-base heat-resistant alloy and article made of this alloy - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to nickel-base heat-resistant weldable alloys. Proposed nickel-base heat-resistant weldable alloy has the following chemical composition, wt.-%: carbon, 0.03-0.10; chrome, 20.0-32.0; molybdenum, 10.5-18.0; niobium, 2.5-4.5; aluminum, 1.0-1.0; tungsten, 0.3-3.0; vanadium, 0.1-1.0; boron, 0.0001-0.006; magnesium, 0.001-0.05; lanthanum, 0.001-0.10; cerium, 0.001-0.06, and nickel, the balance. Invention provides high indices of strength, ductility, thermal resistance and heat-resistance of alloy in combination with good values of weldability and deformability.

EFFECT: improved and valuable properties of alloy.

3 cl, 2 tbl, 1 ex

Description

The invention relates to the field of metallurgy of heat-resistant welded alloys based on nickel of the Ni-Cr-Mo system and products made from these alloys for aircraft, engineering and other sectors of the national economy and can be used for the manufacture of flame tubes6, cases, casings, screens and other welded assemblies and parts operating in the temperature range of 20-1000 ° C.

Creating an alloy that is operable in the entire temperature range from 20 to 1000 ° C and is intended for a wide range of welded assemblies and parts operating in a wide range of operating conditions and, accordingly, presenting various requirements for the material, allows to unify and reduce the number of alloys in the product, but at the same time it requires from the proposed alloy a number of high-level properties for nickel-based materials.

The main requirements for such an alloy is a combination of high strength, ductility, heat resistance and heat resistance with good weldability and deformability for operating temperatures of 20-1000 ° C.

Known nickel-based alloys of the following chemical composition (wt.%):

1. Chrome 4 ÷ 16

Molybdenum 9 ÷ 20

Aluminum 0.2 ÷ 1.0

Titanium 1 ÷ 4

Iron <10

Carbon <0.1

Niobium <6 and / or tantalum <12

Titanium + _^1/2 Nb + _^1/4 Ta - 2 ÷ 5

Nickel - the rest

(Japan Application No. 6004900 Bulletin "Inventions of the World" No. 9-1996).

2. Carbon - max 0.10

Chrome - 16.0 ÷ 24.0

Molybdenum - 7 ÷ 12

Niobium - 2 ÷ 6

Aluminum - 0 ÷ 1

Titanium - 0.5 ÷ 2.5

Boron - max 0,02

Cobalt - max 5

Tungsten - max 4

Zirconium - max 0,5

Silicon - max 1

Phosphorus - max 0,03

Sulfur - max 0,03

Copper - 0-3

Iron - max 20

Nitrogen - max 0,04

Manganese - max 5

Nickel - the rest

(US Patent No. 5,556.594)

These alloys have underestimated values of ductility characteristics (short-term, long-term and technological), and weldability, relative to the requirements for materials of aircraft.

At the same time, the high alloying of alloys with elements with a high number of electronic vacancies leads to the release of topological close-packed phases that wrap the material during operation.

These factors significantly increase the complexity of manufacturing flame tubes, housings, casings, screens and other welded assemblies and parts from these alloys, and also reduce their reliability and performance in operation.

The closest in composition and purpose to the proposed alloy is an alloy based on Nickel of the following chemical composition (wt.%):

Carbon - 0.05 ÷ 0.10

Chrome - 26.0 ÷ 30.0

Molybdenum - 6.0 ÷ 10.0

Niobium - 1.5 ÷ 4.5

Aluminum - 0.8 ÷ 2.0

Boron - 0.003 ÷ 0.01

Magnesium - 0.005 ÷ 0.03

Yttrium - 0.005 ÷ 0.03

Lanthanum - 0.01 ÷ 0.10

Nickel - the rest

(RF patent No. 1746733)

This alloy has high plasticity and weldability characteristics, has sufficient structural stability, and is not prone to isolating topological close-packed phases.

At the same time, for products of gas turbine engines, such as welded bodies, casing, etc., higher characteristics of strength (both short-term and long-term) and ductility are required.

The technical task of the invention is the development of a heat-resistant alloy based on nickel and products made of it, combining high temperatures, strength, ductility, heat resistance and heat resistance with good weldability and deformability for operating temperatures of 20-1000 ° C.

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

Carbon - 0.03 ÷ 0.10

Chrome - 20.0 ÷ 32.0

Molybdenum - 10.5 ÷ 18.0

Niobium - 2.5 ÷ 4.5

Aluminum - 1.0 ÷ 1.8

Tungsten - 0.3 ÷ 3.0

Vanadium - 0.1 ÷ 1.0

Boron - 0.0001 ÷ 0.006

Magnesium - 0.001 ÷ 0.05

Lanthanum - 0.001 ÷ 0.10

Cerium - 0.001 ÷ 0.06

Nickel - the rest

and an article made from it.

The proposed alloy, a significant proportion of the strength is provided due to the formation of thermally stable zones of pre-allocation of reinforcing phases. Of the alloying elements in the formation of such zones, the leading role belongs to chromium and molybdenum, therefore, an increase in the molybdenum content in the proposed alloy can significantly increase the number of precipitates and thereby increase the strength of the alloy. Since there is no clear phase boundary between the pre-allocations and the matrix, this type of hardening does not lead to any significant decrease in ductility.

The introduction of tungsten increases the interatomic bonding forces in the matrix, which increases the heat-resistant properties of the alloy, especially in the upper region of operating temperatures.

Vanadium improves the weldability of the alloy and its heat-resistant properties at temperatures up to 800-850 ° C. The introduction of cerium reduces the defectiveness of the grain boundaries, whereby the whole complex of its mechanical properties is improved, and the heat resistance of the material is increased.

Unlike yttrium, which is part of the γ phase of the prototype, cerium is located mainly along the grain boundaries and thereby more effectively reduces the degree of their defectiveness, and also contributes to the formation of oxides with better heat-resistant properties.

The use of the proposed alloy as the material of flame tubes6, cases, casings, screens and other welded units and parts of aircraft products, engineering and other sectors of the national economy will reduce their weight by increasing specific strength, increase resource and reliability, and significantly reduce the range of materials, used in the manufacture of products.

EXAMPLE FOR CARRYING OUT THE INVENTION:

In laboratory conditions, four vacuum induction melts of the proposed alloy and prototype alloy were smelted. Table 1 presents the chemical compositions of the alloys, where examples 1-3 of the proposed composition, example 4 is an alloy prototype.

The metal was melted in round metal molds. The obtained ingots were forged into small stones, which were then hot rolled onto sheets of 2 mm thickness with a heating temperature of 1120 ° C.

Hot-rolled sheets were annealed at a temperature of 1020 ° С, then they were rolled into cold sheets onto sheets with a thickness of 1.2 mm.

Samples were made from cold-rolled sheets for testing for mechanical properties, heat resistance, and weldability.

Since there are no cracks and other violations of the integrity of the material on the cold-rolled sheets of the proposed alloy, and their surface condition meets the whole range of requirements for a cold-rolled sheet of heat-resistant nickel-based alloys, the conclusion about its good deformability is logical.

The test results of the properties presented in table 2 indicate that the proposed alloy has high strength and plastic properties both short and long, in the temperature range from 20 to 1000 ° C, significantly exceeding the level of properties of the prototype.

The proposed alloy has better weldability (V _cr ) than heat of the prototype, heat resistance, and such characteristics as heat resistance, which is most important for flame tubes (the number of cycles before cracking).

Thus, the use of the proposed alloy will reduce the weight of the products, as well as increase their resource, reliability and operating temperature, unify and reduce the number of alloys used in the product.

Table 1 The chemical composition of the experimental swimming trunks of the proposed alloy, and the prototype alloy (wt.%). Chem. el No. pl. FROM Cr Mo Al Nb W V at Mg La Xie Y Ni one 0,03 20.0 10.5 1.0 2.5 0.3 0.1 0.0001 0.001 0.001 0.001 - Ost. 2 0.06 26.0 14.1 1.4 3.5 1,6 0.6 0.003 0,03 0.05 0,03 - Ost. 3 0.10 32.0 18.0 1.8 4.5 3.0 1,0 0.006 0.05 0.10 0.06 - Ost. four 0.06 27.0 7.5 1.35 3.1 - - 0.001 0.01 0.006 - 0.01 Ost.

Claims (2)

1. A heat-resistant nickel-based alloy containing carbon, chromium, molybdenum, aluminum, niobium, boron, lanthanum, magnesium, characterized in that it additionally contains tungsten, vanadium and cerium with the following components, wt.%: Carbon 0.03 ÷ 0.10 Chromium 20.0 ÷ 32.0 Molybdenum 10.5 ÷ 18.0 Niobium 2.5 ÷ 4.5 Aluminum 1,0 ÷ 1,8 Tungsten 0.3 ÷ 3.0 Vanadium 0.1 ÷ 1.0 Boron 0.0001 ÷ 0.006 Magnesium 0.001 ÷ 0.05 Lanthanum 0.001 ÷ 0.10 Cerium 0.001 ÷ 0.06 Nickel Rest 2. A product of a heat-resistant nickel-based alloy, characterized in that it is made of a heat-resistant nickel-based alloy according to claim 1.