A service damage recovery method for precipitation-strengthened polycrystalline cast nickel-based alloys

A nickel-based alloy, precipitation strengthening technology, applied in the field of metallurgy, can solve the problems of different chemical composition service history and damage mechanism, it is difficult to determine the recovery heat treatment parameters of alloy materials, and the reference value of specific alloy recovery is not high, and achieve a wide range of heat treatment temperatures , Overcome the initial melting behavior and improve the effect of high temperature performance

Active Publication Date: 2019-10-11
XIAN THERMAL POWER RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for the precipitation-strengthened polycrystalline cast superalloy materials used in the high-temperature components of gas turbines, there are often creep holes or casting shrinkage cavities, as well as damage forms of γ′ phase coarsening and rafting, and hot isostatic pressing and heat treatment alone Difficulty restoring damaged tissue and performance to pre-service conditions
In addition, this alloy material generally contains a large amount of grain boundary strengthening elements, which is prone to incipient melting behavior, and it is difficult to determine the recovery heat treatment parameters of the alloy material
Due to the diverse microstructure, chemical composition, service history and damage mechanism of superalloys, the reported recovery heat treatment processes are different, and the reference value for the microstructure and performance recovery of specific alloys is not high.

Method used

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  • A service damage recovery method for precipitation-strengthened polycrystalline cast nickel-based alloys
  • A service damage recovery method for precipitation-strengthened polycrystalline cast nickel-based alloys
  • A service damage recovery method for precipitation-strengthened polycrystalline cast nickel-based alloys

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Experimental program
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Effect test

Embodiment 1

[0038] Use clamps to fix the turbine blades after service, then place them in the heat preservation area of ​​the high-pressure vessel of the hot isostatic press, vacuumize, fill the pressure vessel with argon, repeat 2 to 3 times to ensure that the air inside the high-pressure vessel is exhausted, and then Under the action of inert gas, the internal pressure of the high-pressure container is kept at 100MPa, the temperature is raised to 1200°C, kept for 4 hours, and the furnace is cooled; exhausted to normal pressure, the temperature is raised to 1120°C, kept for 2 hours, and air-cooled; the temperature is raised to 920°C, kept for 1~ 4 hours, air cooling; heat up to 850°C, keep warm for 12-36 hours, air cooling.

Embodiment 2

[0040] Use clamps to fix the turbine blades after service, then place them in the heat preservation area of ​​the high-pressure vessel of the hot isostatic press, vacuumize, and fill the pressure vessel with helium, repeat 2 to 3 times to ensure that the air in the high-pressure vessel is completely exhausted, and finally Under the action of inert gas, the internal pressure of the high-pressure vessel is kept at 100MPa, the temperature is raised to 1190°C, kept for 4 hours, and the furnace is cooled; exhausted to normal pressure, the temperature is raised to 1130°C, kept for 2 hours, and air-cooled; the temperature is raised to 1050°C, kept for 1~ 4 hours, air cooling; heat up to 840°C, keep warm for 12-36 hours, air cooling.

[0041] image 3 and Figure 4 Respectively, the metallographic structure and γ′ phase microstructure of GTD111 alloy material, Figure 5 and Figure 6 They are the microstructure of IN738 alloy material and the microstructure of γ′ phase (the turbine...

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Abstract

The invention belongs to the technical field of metallurgy, and provides a service damage recovery method of a precipitation strengthening type polycrystal cast nickel-based alloy. The method mainly comprises the processes of hot isostatic pressing, solid solution and aging. Hot isostatic pressing is used for overcoming hole and loose defects in an alloy material, meanwhile dissolving part of coarsened or nodulized gamma' and ensuring that incipient melting does not happen to the alloy material. Solid solution testament is used for dissolving residual coarsened or nodulized gamma' phases formed in the service process of the alloy material. Aging treatment is used for adjusting the form and size of gamma' so as to obtain optimal matching of strength and plasticity, and finally the nickel-based alloy material without hole defects and with large-size square gamma' and small-size point-like gamma' coexisting is obtained. After recovery treatment, the high-temperature endurance performance of the alloy material can be close to the level before service. According to the service damage recovery method, operation is simple, the production efficiency is high, the economic benefits are high, and universality, generality and adaptability are high; and the requirements for repair and life prolonging of gas turbine high-temperature components can be met.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a service damage recovery method for precipitation-strengthened polycrystalline cast nickel-based alloys. Background technique [0002] Turbine blades, guard rings, flame tubes, and transition sections, as the core components of gas turbines for energy conversion, are subjected to high temperature, high stress, and harsh oxidative corrosion environments during service. With the increase of gas turbine inlet temperature, higher requirements are put forward for the materials of high temperature components. [0003] Precipitation-strengthened nickel-based superalloys can obtain austenite γ+γ′ phase structure under appropriate heat treatment conditions. The γ′ phase is the main strengthening phase of precipitation-strengthened nickel-based superalloys, and its size, form and volume fraction determine its high-temperature creep resistance. Because nickel-based superal...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/10
Inventor 唐文书肖俊峰高松南晴高斯峰李永君张炯
Owner XIAN THERMAL POWER RES INST CO LTD
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