On Application And Quality Control Of Strip Overlaying Welding In Petrochemical Device-hydrogenation Reactor

Hydrogenation reactor is the core equipment of petrochemical plant, under high temperature and pressure, and run in the medium with the hydrogen, the main material is21/4cr-1mo steel。and to improve the abrasion resistance, in the actual production the21/4cr-1mo+overlaying welding technology to manufacture hydrogenation reactor. Overlaying welding is by welding method in surface of workpiece to overlay a layer which has a certain performance to make the parts surface wear resistance, heat resistance, corrosion resistant and other special properties In actual production the automatic welding technology is widely used in the inner wall required large area of surfacing welding. Automatic welding with band strip is high efficiency, quality uniform inside and surfacing welding surface is smooth。 And due to the low dilution rate, the combination of surfacing welding metal and base material is not easy to produce welding defects and quality problems.See From the welding method, overlay welding with band strip can be divided into automatic submerged arc welding and surfacing electro slag welding。 By doing this study with a hydrogenation reactor wall stainless steel welding experiment, mastered the influence mechanism for parameter of overlaying welding materials, process and construction factors and master the general knowledge of welding qualification. Through the analysis of test results of the research, found the electroslag surfacing welding with welding fusion depth, low dilution rate, layer surface more smooth. But due to the welding depth, large amount of heat input, the vessel when running, the probability of overlaying layer to produce hydrogen stripping is more chances。 In order to ensure the quality of overlaying welding layer and the operation of the vessel works well, when large size band strip is used, the transition layer is using the submerged arc automatic welding. And for the surfacing layer surface is smooth, surface surfacing by electroslag welding. This conclusion has certain guiding significance to practical production.