Features of siliconizing of pipe steel X12CrNi25-20 with various term of operation in the conditions of the reactionary furnace

Most refinery and petrochemical reaction furnaces are operated under harsh conditions characterized by high pressures, temperature, and aggressiveness of the process environment. The high temperature and features of the heated raw material contribute to the formation and deposition of coke on the surface of the furnace pipes, which through adhesion and diffusion phenomena has a negative effect and reduces the operational reliability of the entire furnace, causing such a negative phenomenon as carburization of the metal. Carburization contributes to a significant limitation of the ductility of the metal and increases brittleness, which leads to the formation of various unacceptable defects, in particular the formation of brittle cracks. The occurrence of defects of this type inevitably leads to the depressurization of the coil and, as a result, to the occurrence of emergency situations and emergency shutdown for repair. The problem of carburizing a metal can help solve the silicization of its surface layers, since silicon can serve as an effective protection for active saturation of the metal with carbon. In this regard, a relevant topic is the study of the features of the formation of a modified silicon-based surface layer in the coil tubes of a reaction furnace of steel X12CrNi25-20 with a different operating life in order to increase the reliability and reliability of the furnace during operation.