Rapid heat treatment method of high-strength nickel-based superalloy for power station

A technology of nickel-based superalloy and rapid heat treatment, which is applied in the field of alloy materials and can solve complex problems

Active Publication Date: 2022-01-21
CHINA HUANENG GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a rapid heat treatment method for high-strength nickel-based superalloys used in power stations. Higher problems, improve the overall performance of the alloy, and facilitate the service of subsequent materials

Method used

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  • Rapid heat treatment method of high-strength nickel-based superalloy for power station
  • Rapid heat treatment method of high-strength nickel-based superalloy for power station
  • Rapid heat treatment method of high-strength nickel-based superalloy for power station

Examples

Experimental program
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Effect test

Embodiment 1

[0020] Example 1: The experimental materials are smelted according to the following proportions, mass percentage Cr: 15% to 18%, Co: 15% to 20%, Ti: 0.5% to 1.5%, Al: 3.5% to 4.5%, W: 8.5% % to 10%, Si: ≤0.5%, Mn: ≤0.5%, Nb: 0.5% to 1.5%, C: 0.03% to 0.085%, and the balance is Ni. After casting, the finished product is obtained after homogenization and hot rolling.

[0021] The nickel alloy of this embodiment has undergone traditional solution + aging treatment, that is, the rolled alloy is kept at 1120° C. for 4 hours for solution treatment, and after air cooling to room temperature, it is kept at 760° C. for 8 hours, and then heated to 860° C. for 2 hours. hours, then air-cool to room temperature. Such as figure 1 Shown is the scanning electron micrograph of the processed tissue, grain boundaries figure 1 a shows that the grain size is about 70-120 μm, and there are discontinuous carbides, figure 1 b shows that there are a large number of dense precipitates in the crysta...

Embodiment 2

[0022] Example 2: The method provided by the present invention is used for the alloy of Example 1 to carry out single-step rapid treatment of different processes on the nickel alloy, solid solution at 1180 ° C for 2 hours and air cooling, followed by 1020 ° C for 2 hours and directly cooling at about 80 ° C / min to Room temperature, according to this example, the morphology of the tissue after rapid processing is as follows: figure 2 . according to figure 1 and figure 2 It can be clearly found in the displayed microstructures before and after homogenization that after the treatment formulated by the present invention, the morphology and quantity of the carbides at the grain boundaries and the precipitation strengthening phases in the grains of the two are similar. Table 1 is a comparison table of the tensile properties at room temperature of the traditional solid solution + aging three-step heat treatment and the rapid heat treatment of this example. It can be seen that t...

Embodiment 3

[0025] Example 3: The method provided by the present invention is used for the alloy of Example 1 to perform single-step rapid treatment of nickel alloys in different processes, solid solution at 1180°C for 2 hours and air cooling, and then directly cool to room temperature at 3°C / min after holding at 1020°C for 2 hours , according to this example, the tissue morphology after rapid processing is as follows image 3 . Table 2 is a comparison table of the tensile properties at room temperature of the traditional solid solution + aging three-step heat treatment and the rapid heat treatment of this example. It can be seen that its strength and plasticity are superior to the traditional heat multi-step treatment process. At the same time, for large parts, due to the lack of rapid cooling, the internal stress generated during the cooling process can be greatly prevented from initiating cracks, which will eventually lead to cracking.

[0026] Table 2 Example 1 and Example 3 Room Tem...

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Abstract

The invention discloses a rapid heat treatment method of a high-strength nickel-based superalloy for a power station, and belongs to the technical field of metal materials. The alloy comprises the following basic components: 15%-18% of Cr, 15%-20% of Co, 0.5%-1.5% of Ti, 3.5%-4.5% of Al, 8.5%-10% of W, less than or equal to 0.5% of Si, less than or equal to 0.5% of Mn, 0.5%-1.5% of Nb, 0.03%-0.08% of C and the balance of Ni. The treatment method comprises the following steps: loading the nickel-based alloy into a heat treatment furnace at a charging temperature of less than or equal to 600 DEG C; heating to 1170-1190 DEG C, controlling the heating speed to be 5 DEG C / min, keeping the temperature for 2 hours, then carrying out air cooling, heating to 1020 DEG C, keeping the temperature for 2 hours, carrying out solid solution heat treatment, and not carrying out cooling after solid solution treatment so as to be matched with subsequent heat treatment operation; and selecting the cooling speed based on Jmat pro software, directly cooling a 1020 DEG C heat preservation sample to the room temperature at the speed of 3-80 DEG C / min. The method can obtain better strength and plasticity matching compared with traditional heat treatment by adjusting and controlling the cooling speed, different strength and plasticity matching can be obtained within a certain range, and the heat treatment time and flow are effectively shortened.

Description

technical field [0001] The invention belongs to the technical field of alloy materials, and in particular relates to a rapid heat treatment method for a high-strength nickel-based superalloy used in a power station. Background technique [0002] Due to the abundant coal resources and special energy structure in my country, coal-fired thermal power plants provide about 70% of electric energy in China, and coal-fired power will still occupy a dominant position in the future. In response to the current demand for energy saving and emission reduction, improving the parameters of thermal power units and adopting high-parameter ultra-supercritical thermal power units is the main development direction at this stage. Therefore, extremely high performance requirements are put forward for the service materials of the units, especially for high-parameter units. Over / reheater tubes are required to withstand multiple factors such as high temperature creep, thermal fatigue, oxidation and ...

Claims

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Application Information

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IPC IPC(8): C22C19/05C22C30/00C22F1/10
CPCC22C19/056C22C30/00C22F1/10
Inventor 李沛谷月峰袁勇杨征严靖博鲁金涛
Owner CHINA HUANENG GRP CO LTD
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