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A ferrite-based high-strength corrosion-resistant dual-phase alloy and its preparation method

A dual-phase alloy and ferrite technology, which is applied in the field of high-temperature alloy steel, can solve the problem that it is difficult to meet the high-temperature strength of the alloy hot-end parts of the unit, the resistance to steam oxidation and corrosion, the corrosion resistance and oxidation resistance cannot be effectively guaranteed, The problems such as the decline of the peak-shaving operation ability of the boiler to achieve the effect of promoting carbide growth, excellent strength performance, and improved dispersion and precipitation

Active Publication Date: 2022-06-21
HUANENG POWER INT INC +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, with the further improvement of steam parameters, the existing commercial ferritic heat-resistant steels are difficult to meet the performance requirements of the hot-end parts of the unit for alloy high-temperature strength, steam oxidation resistance, and corrosion resistance (small tubes). Currently, the widely used 9- The recommended operating temperature of 12Cr and improved ferritic heat-resistant steel is generally not higher than 620°C
The strength performance of the alloy is effectively improved by adding Cu element in G115 alloy, but the corrosion resistance and oxidation resistance of the alloy under higher temperature service conditions cannot be effectively guaranteed because the content of Cr element does not exceed 9%.
Austenitic heat-resistant steels with higher heat-resistant strength, such as Super304H and HR3C, have higher thermal expansion coefficients and poor heat transfer efficiency, making them more sensitive to temperature fluctuations, which can easily cause problems such as thermal fatigue damage, resulting in Decreased boiler peak shaving operation capacity

Method used

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  • A ferrite-based high-strength corrosion-resistant dual-phase alloy and its preparation method
  • A ferrite-based high-strength corrosion-resistant dual-phase alloy and its preparation method
  • A ferrite-based high-strength corrosion-resistant dual-phase alloy and its preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The high-strength corrosion-resistant alloy material of this embodiment includes, by mass percentage: C: 0.08%, B: 0.005%, Cr: 18%, Ni: 8%, Co: 0.5%, Mn: 10%, Si: 0.4%, Nb: 0.5%, Mo: 0.5%, W: 1.0%, Ti: 1.4%, Al: 1.2%, and the balance is Fe.

[0038] The preparation method of this embodiment comprises the following steps:

[0039]1) Raw material preparation: The ingredients include by mass percentage: C: 0.08%, B: 0.005%, Cr: 18%, Ni: 8%, Co: 0.5%, Mn: 10%, Si: 0.4%, Nb: 0.5% , Mo: 0.5%, W: 1.0%, Ti: 1.4%, Al: 1.2%, and the balance is Fe.

[0040] 2) Smelting and forming: The alloy is smelted by vacuum, and the pouring temperature of the alloy is controlled to be 1600 ℃. After completion, the ingot was homogenized at 1000°C for 16h. The alloy is processed and deformed by hot rolling, the rolling temperature is 1000 °C, the final rolling temperature is 700 °C, and the deformation amount in a single pass is 30%.

[0041] 3) Heat treatment: The alloy is solution-treated...

Embodiment 2

[0043] The high-strength corrosion-resistant alloy material of this embodiment includes, by mass percentage: C: 0.08%, B: 0.005%, Cr: 18%, Ni: 8%, Co: 0.5%, Mn: 10%, Si: 0.4%, Nb: 0.5%, Mo: 0.5%, W: 1.0%, Ti: 1.4%, Al: 1.2%, and the balance is Fe.

[0044] The preparation method of this embodiment comprises the following steps:

[0045] 1) Raw material preparation: The ingredients include by mass percentage: C: 0.08%, B: 0.005%, Cr: 18%, Ni: 8%, Co: 0.5%, Mn: 10%, Si: 0.4%, Nb: 0.5% , Mo: 0.5%, W: 1.0%, Ti: 1.4%, Al: 1.2%, and the balance is Fe.

[0046] 2) Smelting and forming: The alloy is smelted by vacuum, and the pouring temperature of the alloy is controlled to be 1600 ℃. After completion, the ingot was homogenized at 1000°C for 16h. The alloy is processed and deformed by hot rolling, the rolling temperature is 1000 °C, the final rolling temperature is 700 °C, and the deformation amount in a single pass is 30%.

[0047] 3) Heat treatment: The alloy is solution-treate...

Embodiment 3

[0049] The preparation method of this embodiment comprises the following steps:

[0050] 1) Raw material preparation: The ingredients include by mass percentage: C: 0.07%, B: 0.007%, Cr: 17%, Ni: 10%, Co: 0.5%, Mn: 12%, Si: 0.2%, Nb: 0.8% , Mo: 0.3%, W: 1.5%, Ti: 1%, Al: 1%, and the balance is Fe.

[0051] 2) Smelting and forming: the alloy is smelted by vacuum, the vacuum degree is not higher than 0.5Pa, and the pouring temperature of the alloy is controlled to be 1620℃. After completion, the ingot was homogenized at 1000°C for 24h. The alloy is processed and deformed by hot rolling, the rolling temperature is 1000°C, the final rolling temperature is 700°C, and the deformation amount per pass is 30%.

[0052] 3) Heat treatment: The alloy is solution-treated at 1000°C, holding time for 1.5h, and water-cooled after the treatment is completed. The aging treatment temperature is 650°C, the holding time is 12h, and the water is cooled after the treatment is completed.

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Abstract

The invention belongs to the field of materials, and specifically relates to a ferrite-based high-strength corrosion-resistant dual-phase alloy and a preparation method thereof, which meet the following range requirements in terms of mass percentage: C: 0.07-0.1%, B: 0.003-0.007%, Cr: 17-0. 19%, Ni: 7-10%, Co: 0.5-1.0%, Mn: 7-12%, Si: 0.2-0.5%, Nb: 0.3-0.8%, Mo+W: 1.0-2.0%, Ti+Al : 2.0 to 3.0%, the balance being Fe. The alloy of the present invention is prepared by vacuum smelting and hot rolling. After the heat treatment, the alloy matrix is ​​composed of two phases of austenite and ferrite. Among them, the granular NiAl phase is dispersed and distributed inside the austenite grains. The average diameter does not exceed 150nm. The thermal expansion coefficient of the alloy is between ferritic steel and austenitic steel, and has good room temperature and high temperature mechanical properties.

Description

technical field [0001] The invention belongs to the field of high-temperature alloy steel, in particular to a ferrite-based high-strength corrosion-resistant dual-phase alloy and a preparation method. Background technique [0002] Efficient and clean high-parameter ultra-supercritical coal-fired power generation technology is one of the main development trends of clean coal-fired power generation technology in the world today. The thermal efficiency of the 700°C advanced ultra-supercritical (A-USC) coal-fired power generation system currently under development can exceed 50%, and the coal consumption for power supply is lower than 240G / KW. But the commercial value of the A-USC technology will depend on many variables: coal prices, the cost of nickel-based alloys (about 20 times the cost of high-grade ferritic steel), and carbon taxes, among others. The thermal efficiency of 650℃ and its secondary reheating unit can exceed 50%, and the coal consumption for power supply is lo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/54C22C38/52C22C38/58C22C38/02C22C38/48C22C38/44C22C38/50C22C38/06C21D8/00
CPCC22C38/54C22C38/52C22C38/58C22C38/02C22C38/48C22C38/44C22C38/50C22C38/06C21D8/005C21D2211/005C21D2211/001
Inventor 严靖博谷月峰袁勇于在松杨征张醒兴
Owner HUANENG POWER INT INC