Nickel-based alloy for tubes of boiler of ultra-supercritical power station and preparation method thereof

A technology for nickel-based alloys and power plant boilers, which is applied in the field of nickel-based alloys and preparations for advanced ultra-supercritical power plant boiler tubes, can solve problems such as tissue instability, and achieve excellent mechanical properties, high tissue stability, and high surface quality. Effect

Active Publication Date: 2014-08-20
TAIYUAN IRON & STEEL GROUP
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  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

Under advanced ultra-supercritical conditions, traditional ferritic, austenitic heat-resistant steels and nickel-based alloys can no longer meet the requirements, requiring higher durable strength, good oxidation resistance, coal ash corrosion resistance, higher microstructure Stable precipitation-strengthened nickel-based superalloys to meet superheater and reheater material requirements for advanced ultra-supercritical generator sets
[0005]Inconel 740H alloy is one of the main candidate materials for 700℃ advanced ultra-supercritical utility boiler superheater / reheater, although the alloy has excellent high-temperature durable strength, Steam oxidation resistance and coal ash corrosion resistance, etc. However, experts from the Iron and Steel Research Institute found that during the long-term aging process at 750°C, cellular carbides were found at some grain boundaries in Inconel 740H. The research team also found that the alloy produced a needle-like η phase during the long-term aging process at 760°C, that is, Inconel 740H still has the problem of structural instability
In addition, for this kind of precipitation-strengthened nickel-based superalloy seamless pipe, it is quite difficult to consider from the perspective of pipe smelting, hot working, cold working and heat treatment.

Method used

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  • Nickel-based alloy for tubes of boiler of ultra-supercritical power station and preparation method thereof
  • Nickel-based alloy for tubes of boiler of ultra-supercritical power station and preparation method thereof
  • Nickel-based alloy for tubes of boiler of ultra-supercritical power station and preparation method thereof

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Embodiment 1

[0042] The composition mass percentage ratio of the nickel base alloy seamless pipe of the present embodiment is:

[0043] 24.2% Cr; 20.0% Co; 1.53% Al; 1.25% Ti; 1.36% Nb; 0.45% Mo; 0.04% C; 0.0035% B; 0.052% Zr; 0.22% Si; 0.35Mn; ; 1.0% Fe, the balance being Ni and unavoidable impurity elements. Ti / Al=0.82, Al+Ti=2.78%.

[0044] A preparation method of a nickel-based alloy seamless pipe, the process steps are:

[0045] Batching→vacuum induction smelting (VIM)→die casting→electroslag remelting (ESR)→special homogenization treatment→forging billet opening→tube billet preparation→ring furnace heating→primary induction heating→hole expansion→secondary induction heating→heating Extrusion→solution treatment→straightening→finished pipe, inspection, grinding→flat head→cold rolling→degreasing→sawing→solution + aging heat treatment→straightening→pickling→flat head→non-destructive testing (hydraulic, ultrasonic, Eddy current) → measurement → weighing → printing → packaging.

[0046...

Embodiment 2

[0053] The composition mass percentage ratio of the nickel base alloy seamless pipe of the present embodiment is:

[0054] 23.9% Cr; 21.3% Co; 1.65% Al; 1.29% Ti; 1.42% Nb; 0.41% Mo; 0.035% C; 0.0032% B; 0.047% Zr; 0.25% Si; 0.37Mn; ; 1.3% Fe, the balance being Ni and unavoidable impurity elements. Ti / Al=0.78, Al+Ti=2.94%.

[0055] The alloy of the embodiment of the present invention is smelted by an industrial-scale 1-ton VIM+ESR process. The special homogenization treatment process is that the temperature of the ingot is 350°C, the heating rate is 80°C / h, and the temperature is raised to 1200°C for 40h. After the heat treatment, the ingot is cast first. Rapid cooling at 60°C / h to 1000°C, then slow cooling at 20°C / h to 940°C, then furnace cooling, after furnace cooling to ≤700°C, take out and air cool.

[0056] The homogenized electroslag ingot is made into a tube blank by radial forging. The initial forging temperature is 1170°C, the final forging temperature is 940°C, an...

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Abstract

The invention provides a nickel-based alloy for tubes of a boiler of an ultra-supercritical power station and a preparation method thereof and belongs to the field of metallurgy. The nickel-based alloy comprises the following chemical components in percentage by weight: 23.5-25.5% of Cr, 19.0-23.0% of Co, 1.4-1.9% of Al, 1.05-1.4% of Ti, 1.2-1.5% of Nb, 0.3-0.5% of Mo, 0.03-0.06% of C, 0.002-0.006% of B, 0.04-0.07% of Zr, not more than 0.5% of Si, not more than 0.5% of Mn, not more than 0.003% of S, not more than 0.005% of P, not more than 4.0% of Fe and the balance of Ni and inevitable impurity elements, wherein, the amount of Al and Ti is not less than 2.45% and the ratio of Ti/Al is 0.75-0.95. The nickel-based alloy tubes obtained according to the preparation method provided by the invention can meet the requirements of using environments of boiler superheaters/reheaters of advanced ultra-supercritical power stations.

Description

technical field [0001] The invention belongs to the technical field of nickel-based alloys, and is mainly used for superheater / reheater pipes of advanced ultra-supercritical power plant boilers, and in particular relates to a nickel-based alloy for advanced ultra-supercritical power plant boiler pipes and a preparation method thereof. Background technique [0002] With the rapid development of the world economy, energy and environmental issues have become increasingly prominent. As the main form of energy, electricity is in increasing demand. At present, my country's coal-fired power generation accounts for more than 80% of the total power production, occupying a dominant position. To maintain the sustainable, rapid and healthy development of the power industry, larger-scale power construction is needed to meet the needs of my country's industrialization and modernization. Therefore, advanced ultra-supercritical (Advanced ultra-supercritical pressure) power generation techno...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C19/05C22C1/02C22F1/10
Inventor 李莎李阳王岩曾莉郝文慧
Owner TAIYUAN IRON & STEEL GROUP
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