RU2341576C2 - Casting copper-bearing alloy based on nickel - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: casting copper-bearing alloy based on nickel contains wt %: copper 26-32, carbon 0.03-0.09, aluminium 1.2-2.2, titanium 1.5-2.0, niobium 1.2-2.3, vanadium 0.1-0.6, zirconium 0.05-0.1, cerium, lanthanum or dysprosium 0.01-0.2, nickel - the rest.

EFFECT: increasing of alloy mechanical properties, decreasing of porosity, increasing of surface condition and providing of performance featheredge at mold castings, improving of grain boundary structure with keeping high strength and thermal conduction of molding material.

1 tbl

Description

The invention relates to the field of metallurgy, in particular to casting alloys based on nickel, and can be used for the manufacture of castings with improved mechanical properties, for example, for body parts of units for supplying liquid rocket engines (LRE).

Known alloy based on Nickel, containing copper, carbon, aluminum, titanium, niobium, vanadium, zirconium in a certain ratio of components (copyright certificate No. 1492751, IPC C22C 19/00, 1987). The alloy refers to high-strength powder alloys.

A disadvantage of the known nickel-based alloy when used for the manufacture of shaped castings is increased porosity, contamination of grain boundaries in the structure of the material of castings with oxysulfides and carbonitrides, a low level of mechanical properties, low surface quality and poor filling of thin edges during casting. The objective of the invention is to eliminate these drawbacks of the known alloy and obtain a casting alloy on a nickel basis with improved mechanical characteristics, reducing porosity, improving the quality of the surface, making thin edges during shaped casting, improving the grain boundary structure while maintaining high strength and thermal conductivity of the casting material.

The problem is achieved due to the fact that the casting alloy based on Nickel, containing copper, carbon, aluminum, titanium, niobium, vanadium, zirconium, according to the invention additionally contains rare earth elements: cerium, lanthanum or dysprosium in the following ratio of components (wt.%) : copper 26-32; carbon 0.03-0.09; aluminum 1.5-2.2; titanium 1.5-2.0; niobium 1.2-2.3; vanadium 0.1-0.6; zirconium 0.05-0.1, cerium, lanthanum or dysprosium 0.01-0.2; nickel - the rest.

A decrease in copper content to 26-32 wt.% Helps to reduce the porosity of the material of the castings.

The increase in nickel content to 60-70 wt.%, Niobium to 1.2-2.3 wt.%, Titanium to 1.5-2.0 wt.% And aluminum to 1.2-2.2 wt.% Contributes to increase its strength at low and high temperatures, since these elements are part of the main hardening γ'-phase type Ni ₃ (Al, Ti, Nb).

The vanadium content limits are expanded to 0.1-0.6 wt.% Of a strong carbide-forming element. By binding carbon to stable VC carbides located in the grain body, vanadium helps to clean grain boundaries from carbide precipitates.

Zirconium is stored in the alloy as a microalloying element for modifying grain boundaries.

Rare earth elements (cerium, lanthanum or dysprosium) in an amount of 0.01-0.2 wt.% Are introduced into the alloy to improve the filling of thin edges, modify the structure as elements that contribute to supercooling of the alloy during crystallization by suppressing crystallization centers, and also globularization of inclusions along grain boundaries and suppression of the harmful effect of impurities (sulfur) on the mechanical properties of the alloy.

Alloys were obtained by smelting in a vacuum installation with pouring the shapes of sample blanks for mechanical tests and body parts for LRE feed units obtained by investment casting.

The surface quality of the castings is satisfactory, edges with a radius of 0.2 mm are successfully filled, the grain boundaries in the structure of the material of the castings are less contaminated than the grain boundaries of the prototype alloy.

Of the cast samples and parts after high-temperature gas-static and heat treatment, samples were made for mechanical tests, the comparative results of which are given in the table. It presents the results of mechanical tests of the casting variant of the prototype alloy at 20 ° C and the test results of the proposed alloy at temperatures of 20, 540 and 600 ° C.

Analysis of the results of the mechanical tests presented in the table shows that, in comparison with the prototype, the strength properties of the cast alloy are improved with a slight decrease in ductility. Moreover, the level of mechanical properties at room and elevated temperatures corresponds to the level of properties of high-strength nickel alloys.

Example The composition of the alloy, wt.% Results of mechanical tests at temperature Nickel Copper Carbon Aluminum Niobium Vanadium Zirconium Cerium, Lanthanum or Dysprosium Iron 20 ° C 540 ° C 600 ° C σ _in , MPa σ _0.2 MPa δ ₅ % Ψ% σ _in , MPa σ _0.2 MPa δ ₅ % Ψ% σ _in , MPa σ _0.2 MPa δ ₅ % Ψ% Foundry alloy prototype * Suggested Alloy ** The ranges of values of the results of chemical analysis and mechanical testing of the material are given:
* - four swimming trunks.
** - six swimming trunks.

Claims (1)

Nickel-based foundry copper-containing alloy containing copper, aluminum, titanium and a rare earth element, characterized in that it additionally contains carbon, niobium, vanadium and zirconium, and as a rare earth element it contains cerium, lanthanum or dysprosium in the following ratio of components, wt .%: copper 26-32 carbon 0.03-0.09 aluminum 1.2-2.2 titanium 1.5-2.0 niobium 1.2-2.3 vanadium 0.1-0.6 zirconium 0.05-0.1 cerium, lanthanum or dysprosium 0.01-0.2 nickel rest