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近几年来,一些电厂的高温高压锅炉,经常发现高温段铬钼钒钢过热器管外壁产生纵向和纵横交叉的裂纹,同时大量的氧化皮脱落,管壁减薄。管壁裂纹在高温下氧化并扩展到金属内部,进一步降低了管子的强度,引起爆管事故。为了找出管壁产生裂纹的原因,我们对唐山发电厂~*3炉、北京热电厂~*5炉和高井电站~*2炉的管壁产生裂纹的过热器管进行了显微组织观察、电子显微观察、高、常温机械性能试验、电子探针试验,对碳化物进行了成份及X 射线结构分析等,通过上述试验,初步分析了产生裂纹的原因。
In recent years, some high-temperature and high-pressure boilers in power plants often found cracks in the longitudinal and longitudinal cracks on the outer wall of the chrome molybdenum-vanadium steel superheater tube in the high-temperature section. At the same time, a large amount of scale was shed and the wall was thinned. Wall cracks at high temperature oxidation and expansion to the metal interior, further reducing the strength of the tube, causing a squib accident. In order to find out the cause of cracks in the pipe wall, we observed the microstructure of cracked superheater tubes in Tangshan Power Plant ~ * 3 furnaces, Beijing Thermal Power Plant ~ * 5 furnaces and Gaojing Power Station ~ * 2 furnaces. The electron Microscopic observation, high and normal temperature mechanical properties test, electronic probe test, composition of the carbide and X-ray structure analysis. Through the above experiments, the causes of the crack were analyzed preliminarily.