采用外壁喷涂与内壁喷丸方法提高锅炉高温受热面管抗高温腐蚀性能的试验

Investigations on outer thermal spraying and inner shot blasting on boiler tube to promote high-temperature corrosion resistance

针对锅炉高温受热面管子运行中产生的锈层引起管子超温过热的问题,采用外壁电弧和棒材火焰喷涂N iCrA l、FeCrA l等耐高温烟气腐蚀涂层,并与内壁喷丸的方法相结合,对π11(12Cr3M oVSiTiB)材料的锅炉对流过热器管进行了复合处理,经实际运行20000h后割管取样,进行表层横截面扫描电镜分析。结果表明:外壁火焰棒材喷涂N iCrAl(DCP)涂层并以W T-600+Al2O3封闭涂层孔隙,可完全防止烟气对管壁的腐蚀损伤,并明显减轻管子表面的粘灰;在此基础上附以内壁气动喷丸处理,可有效减轻水蒸气对管子的高温氧化,内壁氧化膜厚度可减小至未处理管子的1/3以下,提高内外壁抗高温腐蚀性能总有效率为4倍以上。该复合处理方法的综合成本仅为更换新管的1/4。

As scales on heating surface caused tubes overheated, outer thermal spraying with NiCrAl, FeCrAl etc. high-temperature corrosion-resistant coatings, combined with inner shot blasting, was used to treat super-heater tubes of material ?仔11(12Cr3MoVSiTiB). After 20,000-hour's operation, the cross-section was analyzed by scanning electron microscope (SEM). The result shows that outer thermal spraying with NiCrAl (DCP) coating and sealing the coating aperture with WT-600+Al2O3 can prevent boiler tube from flue gas corrosion and alleviate ash deposit remarkably. Combined with outer thermal spraying, inner shot blasting can relieve high-temperature oxidation of steam to tubes efficiently, reduce the inner scale thickness to less than 1/3 of that of the untreated boiler tube, raise the total efficiency of both inner and outer high-temperature corrosion-resistance to 4 times more of that of the untreated boiler. The cost of the combined treatment is only 1/4 of that of changing the tubes with new ones.