Method for improving wear-resistant anti-corrosion property of coating of heating surface of boiler

Abstract

The invention relates to a method for improving wear-resistant anti-corrosion property of a coating of a heating surface of a boiler. A shot blasting technology is adopted for carrying out shot blasting treatment on a metal coating or a metal ceramic coating for obtaining a compact coating, porosity is reduced, permeability of corrosive atmosphere is reduced, and bonding strength, corrosion resistance and wear resistance of the coating are improved. The method for improving the wear-resistant anti-corrosion property of the coating of the heating surface of the boiler comprises the following steps: ash removal is carried out on the heating surface of the boiler sprayed with the coating by adopting compressed gas, and the surface of the coating is maintained to be clean; steel shots are adopted for carrying out shot blasting pretreatment on the surface of the coating by utilizing a sand blasting machine, large weakly bonded particles caused by poor atomization effect in a surface spraying process are removed; shot blasting treatment is carried out on the surface of the coating by adopting the sand blasting machine, and compaction is carried out on the coating, and the method for improving the wear-resistant anti-corrosion property of the coating of the heating surface of the boiler has the characteristics that a technology is simple and performance is obviously improved. Compared with the traditional electric arc spraying coating, a metal coating or a metal ceramic coating treated by adopting the method provided by the invention has low porosity and high bonding strength, and corrosion prevention and wear-resisting properties of the coating are improved.

Description

technical field

[0001] The invention relates to the technical field of wear-resistant and anti-corrosion coatings on boiler heating surfaces, in particular to a method for improving the performance of wear-resistant and anti-corrosion coatings on boiler heating surfaces. Background technique

[0002] The fuel used in coal-fired power plant boilers is mainly coal. The harmful components in the flue gas and fly ash in the furnace will chemically react with the boiler tube metal, causing corrosion, making the tube wall thinner and reducing its strength. In the furnace flame, the sodium in the minerals is volatilized and sublimated, and the potassium in the non-volatile aluminum silicate is released through the replacement reaction, and the sodium, potassium and SO in the flue gas 3 The reaction produces sodium sulfate and potassium sulfate, which condense on the tube wall. Alkali metal oxides condensed on the tube wall and SO in the surrounding flue gas 3 The gas reacts to fo...

Examples

Embodiment Construction

[0020] The present invention will be further described in detail below in conjunction with specific implementation examples.

[0021] 45CT coating was sprayed on the surface of 20g steel by electric arc spraying, and the coating thickness was 0.28mm. After spraying, the porosity was 2.47% through metallographic analysis. The average bonding strength by tensile test is 51.3±7.4MPa. At 700°C, O 2 -1.5% (SO 2 +SO 3 ) atmosphere, the surface exists (0.9Na,0.1K) 2 SO 4 After being corroded for 100 hours under the condition of salt film, the weight loss rate per unit area is 9.24mg / cm 2 . After 45g, 100M brown corundum 90° erosion test, the average weight loss of the coating is 0.0376±0.0012g, and the coating surface has a rough surface caused by poor droplet atomization effect during the spraying process. The steel shot with an average diameter of 0.63mm is used for pre-peening, the shot-peening gas pressure is 0.3MPa, the gas flow rate is 800SLM / min, the shot-peening mechan...

technical field

[0001] The invention relates to the technical field of wear-resistant and anti-corrosion coatings on boiler heating surfaces, in particular to a method for improving the performance of wear-resistant and anti-corrosion coatings on boiler heating surfaces. Background technique

[0002] The fuel used in coal-fired power plant boilers is mainly coal. The harmful components in the flue gas and fly ash in the furnace will chemically react with the boiler tube metal, causing corrosion, making the tube wall thinner and reducing its strength. In the furnace flame, the sodium in the minerals is volatilized and sublimated, and the potassium in the non-volatile aluminum silicate is released through the replacement reaction, and the sodium, potassium and SO in the flue gas 3 The reaction produces sodium sulfate and potassium sulfate, which condense on the tube wall. Alkali metal oxides condensed on the tube wall and SO in the surrounding flue gas 3 The gas reacts to fo...

Examples

Embodiment Construction

[0020] The present invention will be further described in detail below in conjunction with specific implementation examples.

[0021] 45CT coating was sprayed on the surface of 20g steel by electric arc spraying, and the coating thickness was 0.28mm. After spraying, the porosity was 2.47% through metallographic analysis. The average bonding strength by tensile test is 51.3±7.4MPa. At 700°C, O 2 -1.5% (SO 2 +SO 3 ) atmosphere, the surface exists (0.9Na,0.1K) 2 SO 4 After being corroded for 100 hours under the condition of salt film, the weight loss rate per unit area is 9.24mg / cm 2 . After 45g, 100M brown corundum 90° erosion test, the average weight loss of the coating is 0.0376±0.0012g, and the coating surface has a rough surface caused by poor droplet atomization effect during the spraying process. The steel shot with an average diameter of 0.63mm is used for pre-peening, the shot-peening gas pressure is 0.3MPa, the gas flow rate is 800SLM / min, the shot-peening mechan...