Investigation and analysis of weld failure in the China hat equipment ofthe steel direct reduction furnace

In this case study, the aim was to do a failure analysis of the welds in the China hatequipment. The China hat is installed in direct reduction furnaces working with PEREDtechnology. It causes disturbances in the gas flow and, as a result, increases the rate ofmass transfer in the PERED furnace. China hat is made of AISI ۳۱۰s steel. ۳۱۰s steel is awear and corrosion resistance steel suitable for uses in high temperatures and it is weldedby ER-۳۰۹L filler metal. In order to analysis this failure to prevent them from happeningagain, a microstructural investigation and analysis of related diagrams were done. Theresults showed that according to the working conditions of the China hat and thesensitivity of ۳۱۰s steel to cracking, using high quality sheets that ensures the correctpercentage of elements is necessary. if possible, adding a small amount of La or Ti and aconsiderable amount of Mn (more than normally contained). also according to theScheffler diagram ER-۳۰۹L electrodes do not tolerate these working conditions, andthere is a possibility of failure due to the penetration of carbon and brittle elements intothe interface. For these welds ER-۳۱۰ electrodes are more Suitable alloys

کلیدواژه ها:

Fracture ، Welding ، Stainless Steel ، PERED Direct Reduction Furnace ، Filler MetalE۳۰۹L.