正压水煤气余热锅炉防磨瓦腐蚀失效分析

1Cr20Ni14Si2不锈钢防磨瓦在水煤气余热锅炉中运行被腐蚀甚至断裂,对正压水煤气立式余热锅炉过热器不锈钢防磨瓦断裂失效进行研究。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电子能谱分析仪(EDS)设备对锅炉1Cr20Ni14Si2不锈钢失效防磨瓦的表面腐蚀褐色粉末、不锈钢表面和人为断面成分进行测试。XRD测试结果表明表面褐色粉末存在多种金属氧化物和硫化物；EDS实验检测结果表明：不锈钢表面含大量S和O。这说明1Cr20Ni14Si2不锈钢在焦化炉中易被S腐蚀而失去不锈钢特性。EDS结果分析发现不锈钢Ni含量明显低于国标要求含量,降低了不锈钢韧性并降低其防腐蚀性能。烟气中S、C和O经腐蚀孔隙进入材料内部加速不锈钢内部腐蚀。研究结果对水煤气余热锅炉防磨瓦材料选型和防磨结构优化具有指导意义。

Corrosion Failure Analysis of Anti-wear Bearing of Positive Pressure Water Gas Vertical Waste Heat Boiler

1Cr20Ni14Si2 stainless steel anti-wear pad is corroded or even fractured in the operation of water gas waste heat boiler. In this paper, we studied the fracture failure of stainless steel anti-wear tile in vertical waste heat boiler with positive pressure water gas. X-ray diffractometer (XRD), scanning electron microscope (SEM) and electronic energy spectrum analyzer (EDS) equipment were used to test the corrosion brown powder on the surface of 1Cr20Ni14Si2 stainless steel, the composition of stainless steel surface and artificial section. XRD results show that the brown powder contains several oxides and sulfides.EDS results show that the surface of stainless steel contains a lot of S and O. This shows that 1Cr20Ni14Si2 stainless steel is easily corroded by S in the coking furnace and loses the characteristics of stainless steel. EDS results show that the Ni content of stainless steel is obviously lower than the national standard, which reduces the toughness of stainless steel and accelerates corrosion. S, C and O in the flue gas enter into the material through corrosion pores to accelerate the internal corrosion of stainless steel. The research results can be used to guide the selection and optimization of anti-wear tile materials for water gas waste heat boilers.