Method for preventing internal corrosion of gas turbine by adopting aluminizing process

Abstract

The invention provides a method for preventing internal corrosion of a gas turbine combustor by adopting an aluminizing process, which comprises the following steps: S1, surface cleaning: selecting a workpiece made of ferrite alloy steel containing 0.08-0.3% by mass of Mo, and cleaning impurities on the surface of the workpiece through heat treatment at the temperature of 200-500 DEG C for 1-3 hours; performing ultrasonic cleaning on the workpiece by adopting an acid solution; s2, sample embedding: embedding the cleaned workpiece in an aluminizing agent, and then placing the workpiece in a double-layer quartz tube aluminizing high-temperature heat treatment device; the double-layer quartz tube aluminizing high-temperature heat treatment device containing the workpiece is placed in a high-temperature heat treatment furnace, the heating rate is controlled to be 30-50 DEG C / h, the temperature is increased to 700-750 DEG C, and heat preservation is conducted for 3-5 h; and then the furnace is cooled to the room temperature, the cooling rate is controlled to be 40-50 DEG C / h, and then the workpiece is taken out. The method has the beneficial effects that the aluminum coating on the surface of the product is normally coated on the basis that the performance of the raw materials is not obviously attenuated, and the coating thickness and the surface deposition rate both meet the requirements.

Description

technical field [0001] The invention relates to the technical field of metal surface protection, in particular to a method for preventing internal corrosion of a gas turbine by using an aluminizing process. Background technique [0002] Gas turbine combustors will corrode during actual operation. One possible cause of corrosion is that when the fuel is delivered to the interior of the combustor, the temperature of the fuel rises gradually and decomposes at high temperature to form gaseous hydrogen sulfide (H 2 S), hydrogen sulfide corrodes the surface of the burner inner cavity under this environmental condition, forming oxides / sulfides; another possible reason is that during the shutdown process of the gas turbine, the burner components are still in a high temperature state and are in contact with the air Oxygen (O 2 ) contact, the burner cavity is therefore oxidized. The above two reasons promote each other, especially when the base material of the burner is iron-based (...

AI Technical Summary

Problems solved by technology

Because there are many small fuel distribution holes downstream of the fuel pipeline, these fallen foreign objects can easily block the fuel distribution holes and deposit near the fuel distribution holes, resulting in uneven fuel distribution among different burners, unstable combustion, and Problems such as uneven exhaust gas temperature

The above-mentioned abnormal problems can cause unstable operation of gas turbines and a decrease in thermal efficiency of gas turbines, or cause unplanned shutdowns, damage to other components and other serious accidents.

[0004] At present, the parts in some burners are welded by corrosion-resistant stainless steel materials, but stainless steel materials still have a series of disadvantages, such as: stainless steel materials can also cause slight corrosion, and because stainless steel materials contain a higher content of nickel (Ni ), chromium (Cr) and other elements, these elements are not conducive to the welding of burner parts, and are prone to cracks and other abnormal conditions; in addition, products made of stainless steel will generate high thermal stress during operation, which is not conducive to burner The safety of the component itself

[0005] At high temperature, the performance of products made of ferritic alloy steel has obvious attenuation, which is not conducive to the implementation of aluminum coating

However, the traditional aluminizing process has high temperature requirements. If the treatment temperature is too low, it will not be conducive to the diffusion of aluminum powder into the ferrite matrix. In some cases, a large amount of aluminum powder cannot be deposited on the surface due to the large amount of diffusion, so that effective protection cannot be formed in the later stage. coating

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