关键词: 　低温过热器, 　分析, 　爆裂

Abstract: Through experimental detection methods of macro inspection, chemical composition analyzing , mechanic performance testing , micro metallog raphy analyzing and X ray diffraction, the blow out reasons of low - temperature superheatertube were analyzed in the process of boiler operation. The results show that the fracture of a broken tube is a kind of expansion form and a typical ductile fracture, and has instantaneous overheat blow out characteristic under the high temperature. Structure sizes of super heater tubes and inside resistance coefficients as well as imbalance thermal lo ads will result in the rmal deviation. The difference of heated area be tween tubes is very small, so the thermal deviation mainly results from inhomog eneous endo therm and flux . Throughverifying , the reexist strong bonding force oxide attached on inside and outside wall of low - temperature superheater tubes, and ashes are deposited be tween tubes, which result in producing thermal deviation. Once tube wall is overheated, oxidation corrosion rate is not only accelerated , but also the tube performance is rapidly deteriorated. At the same time , low - temperature super heater keeps on running under the high temperature for long time , micro structure appears globular car bide configuration , and bearing capacity of materials at high temperature declines.When tube wall strength can not bear inner steam pressure in the tube , blowout of low - temperature tube occurs.

Key words: Low - temperature supe rheater , Analysis , Blowout