Rare earth element-containing ultra-supercritical steam turbine blade steel and preparation method thereof

Abstract

The invention discloses a rare earth element-containing ultra-supercritical steam turbine blade steel and a preparation method thereof, and belongs to the technical field of steel. The rare earth element-containing ultra-supercritical steam turbine blade steel aims to solve the problems that hot working material forming is affected due to the fact that defects of cracks and the like are prone to occurring in the forging process of the ultra-supercritical turbine blade steel in the prior art. The rare earth element-containing ultra-supercritical steam turbine blade steel is provided, and rare earth elements are added to the ultra-supercritical steam turbine blade steel. Through the composition optimization and supplemented with the process optimization, the forging property of the steel iseffectively controlled, so that the blade steel has good forging property, the finished product annealing state flaw detection is class A qualification, and the grain size is greater than or equal tograde 5.5.

Description

technical field [0001] The invention belongs to the technical field of steel materials, and in particular relates to an ultra-supercritical steam turbine blade steel containing rare earth elements and a preparation method thereof. Background technique [0002] Ultra-supercritical steam turbine blade steel is a martensitic heat-resistant steel used in steam turbine blades, which has very high requirements on the normal temperature and high temperature performance of the steel. Moreover, this type of steel has high alloy content, high hardness, and low plasticity. During the forging process, if the forging parameters are not well controlled, defects such as cracks will appear, which will affect the thermal processing. Therefore, how to make this type of steel obtain better hot workability is very important. Rare earth elements can improve the as-cast and hot-deformed microstructure, thereby improving its forgeability. [0003] CN106011683 discloses a molybdenum-cerium compos...

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Problems solved by technology

[0004] The above method uses molybdenum-cerium composite microalloying to improve the mechanical properties and corrosion resistance of steel, but it does not involve the influence of this method on the forgeability of steel, and the content of molybdenum element in this method is 0.35% to 0.55%, which will increase the corrosion resistance of steel. Thermal strength, thereby increasing the strength of steel during forging and reducing forgeability

[0005] There are many methods of rare earth microalloying martensitic steel or heat-resistant steel at home and abroad, mainly used in vacuum induction furnace smelting, or electroslag remelting furnace smelting, but for the production of ultra-super super The smelting and production process characteristics of critical blade steel, innovation and optimization of rare earth content is still the first case

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