ANALYSIS OF THE REASONS FOR CRACKING PIPES OF THE BOILER OF THE RECOVERY

8-381X  Abstract. Formulation of the problem. One of the main tasks of production is reliable and trouble-free operation of equipment. In the oxygen-envelope process, when cast iron is purged, a large amount of carbon monoxide CO is emitted in the converter, which has a high temperature of more than 1 700 °С of the outgoing gases. The envelope gases in the waste heat boiler are cooled. Converter gas output is characterized by cyclic unevenness In this case, uneven heating of the walls of the boiler pipes occurs. By circulation pumps, chemically purified water is supplied for forced cooling of the boiler walls. When raising the outgoing gases, the cooling water is converted to pars by its subsequent supply to the consumer. The study is dedicated to solving the scientific and applied problem for the reasons for the formation of defects and the identification of cracks in the pipes of the recovery boiler.The purpose of the work. To investigate the causes of the development of transverse cracks in the pipelines of the recovery boiler by various methods of non-destructive testing, to use the methods of scanning microscopy to analyze the microstructure, mechanical tests, and the magnetic properties of structural carbon steel. Conclusions. One of the main reasons for the appearance of massive cracks in the pipes of cylindrical caissons is thermal fatigue caused by high thermal loads. Transverse cracks have the character of thermal fatigue failure, which is confirmed by changes in the ferrite-pearlite structure of the metal, resulting from uneven local cooling of the walls of the caisson. The reasons for the violation of the water circulation in the boiler are the pressure drop in the boiler and a sharp discharge, the load is the release of water from the boiler.