Study On Cladding Procedures For 2.25Cr-1Mo Steel Bended Pipes In Hydroprocessing Reactors

For hydroprocessing reactors used in petrochemical industry, it is difficult to provide high quality cladding in the inboard wall of bended pipes. Traditional manufacture method make bended pipe to cut into three parts, before putting these parts into a whole, cladding layer must be cladded in the pipe. This method's working procedure are more, including processing, molding, cladding, assembly, welding and so on. In addition, its efficiency is low and welding quality is difficult to guarantee. For these reasons, there is a new method that is to cladding in pipe before the pipe is bended. But there is a question in this method, Wether does the cladding layer's capability can meet technology's require in chemical composition, mechanical properties, resistance to intergranular corrosion, and so on. So, we adopt the method that is cladding on the board before bending to simulate the making course of the bending pipe, try to find out the rule of this kind of manufacture method, in order to reduce too many returning working procedure.This thesis shows that:①The E309L+E347 caldding layer on 2.25Cr-1Mo steel has cold bending crack sensitivity after heat bending, quaching and tempering, Max PWHT. The crack sensitivity is from segregation of crystal.②Using this cladding method and technology can make the cladding layer have the resistance to intergranular corrosion and even chemical composition.③It should adopt water quenching and tempering with high temperature in the heat treatment of performance, in order to guarantee to obtain the micro-organization with the best impact toughness, and avoiding the section of 475- 650℃sensitization temperature to stainless steel.Up to now, there is no report on this new method of hydroprocessing reactors's bending pipe. The result of study has offered the scientific data for the method amelioration of hydroprocessing reactors's bending pipe and established the solid foundation.