Method for adding rare earth to T91 and P91 steel for improving high temperature corrosion resistance

A T91, high temperature resistance technology, applied in the field of adding rare earth to improve high temperature corrosion resistance, can solve the problems of practical application limitations, difficult implementation of the inner wall of the pipeline, etc. Effect

Inactive Publication Date: 2012-01-18
NANCHANG HANGKONG UNIVERSITY
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Problems solved by technology

At present, there are two ways to improve the high temperature water vapor corrosion resistance of T91 steel: one is to apply protective layer or thermal diffusion coating by means of chrome plating, chromizing, spraying, etc., but these measures are difficult to implement on the inner wall of the pipeline. The practical application is limited; the second is to adopt a suitable surface pretreatment process to promote the preferential formation of Cr on the surface of T91 steel during the oxidation process 2 o 3 , if the inner wall is shot peened to refine the grain

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  • Method for adding rare earth to T91 and P91 steel for improving high temperature corrosion resistance
  • Method for adding rare earth to T91 and P91 steel for improving high temperature corrosion resistance
  • Method for adding rare earth to T91 and P91 steel for improving high temperature corrosion resistance

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Embodiment 1

[0017] Embodiment 1: raw material: rare earth: yttrium oxide (Y 2 o 3 ) Purity ≥ 99.00%, average particle size 15nm; T91 steel pipe.

[0018] The required T91 or P91 steel is baked in a protective atmosphere and put into an induction furnace for smelting. After the temperature rises to 1600°C, rare earth Y is added under the protection of argon. 2 o 3 , stirring, standing, pouring, and cooling to obtain T91 and P91 steels containing rare earths. After the modified sample was oxidized at a constant temperature in a water vapor environment at 650°C for 150 hours, the oxidation weight gain of the blank sample reached 8.53mg / cm 2 , while the oxidation weight gain of the sample modified by adding rare earth is only 0.12mg / cm 2 . No surface cracks and oxide film peeling were found on the surface of the sample with rare earth added. figure 1 , figure 2 For adding rare earth Y 2 o 3 The surface topography and energy spectrum analysis results of the sample oxidized in water v...

Embodiment 2

[0019] Embodiment 2: raw material: rare earth La purity ≥ 95.00%, T91 steel pipe.

[0020] Bake the required T91 or P91 steel in a protective atmosphere and put it into an induction furnace for smelting. After the temperature rises to 1600°C, add rare earth La under the protection of argon, stir, stand still, pour, and cool to obtain rare earth-containing steel. T91 and P91 steel. After the modified sample was oxidized at a constant temperature in a water vapor environment at 650°C for 150 hours, the oxidation weight gain of the sample modified by adding rare earth was only 0.23mg / cm 2 . No surface cracks and oxide film peeling were found on the surface of the sample with rare earth added. Figure 5 This is the surface topography of the sample after adding the rare earth La and oxidizing it in water vapor at 650°C for 150 hours. In the figure, it can be seen that Cr-rich oxides are formed on the surface.

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Abstract

The invention relates to a method for adding rare earth to T91 and P91 steel for improving the high temperature corrosion resistance. The method comprises steps that: during a T91 and P91 steel smelting procedure, rare earth and/or corresponding oxides of rear earth are added to the steel, such that rear earth is dispersed in T91 steel. With the steps, T91 and P91 steel containing rear earth is prepared. The technical effects of the invention are that: 1, the T91 and P91 steel with the additive provided by the invention has excellent high-temperature vapor oxidation resisting capacity, and the oxidation speed of the type of material can be substantially reduced. When oxidized for 150 hours with a constant temperature under an environment of vapor with a temperature of 650 DEG C, an oxidation mass gain of a blank sample reaches 8.53mg/cm<2>, but an oxidation mass gain of a rear-earth-modified sample is only 0.12mg/cm<2>. No surface crack or oxide film exfoliation is found on the rear-earth-modified sample. 2, with the rear-earth-modified T91 and P91 steel provided by the invention, under an environment of high-temperature vapor, an oxide layer containing a large amount of chrome and a small amount of rear earth is formed on the surface of the sample.

Description

technical field [0001] The invention relates to a method for improving high-temperature corrosion resistance, in particular to a method for adding rare earth to T91 and P91 steels to improve high-temperature corrosion resistance. Background technique [0002] With the continuous growth of electricity demand, supercritical and ultra-supercritical units with high steam parameters and high efficiency are the inevitable trend of thermal power development. Due to the increase in boiler equipment capacity and steam parameters in thermal power plants, more and more boiler tube burst accidents have occurred. Statistics show that the leakage damage of the heating surface tubes (water wall tubes, superheater tubes, reheater tubes, economizer tubes, also known as "four tubes") in power plant boiler accidents accounts for about 2 / 3 of boiler accidents. It is the main factor affecting the safe and economical operation of the generating set. Among them, the superheater and reheater, wh...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/04C22C38/18
Inventor 刘光明
Owner NANCHANG HANGKONG UNIVERSITY
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