窄间隙焊接用EH11K焊丝及配套焊剂研制OA

To break the import monopoly of submerged arc welding consumables for narrow-gap welding of shielded nuclear main pump motors and achieve localized replacement,the research and development of EH11K submerged arc weld-ing wires and their matching SJ11HR fluxes was carried out.Aiming at the stringent requirements of the nuclear main pump's service conditions on the compositional purity,narrow-gap process adaptability,and low-temperature toughness of welding consumables,a fluoro-alkaline flux slag system was selected.By adjusting the ratio of flux components,the core process is-sues of slag adhesion and difficult slag removal under narrow-gap preheating conditions were effectively solved.To address the shortcoming of insufficient low-temperature toughness of the deposited metal at-40℃,a multi-element microalloying scheme was applied to the EH11K welding wires,which significantly enhanced the low-temperature anti-brittle fracture ca-pacity of the deposited metal.Test results showed that during narrow-gap welding,the optimized combination of EH11K wires and SJ11HR fluxes achieved automatic detachment of the slag crust,with smooth weld bead formation and excellent inter-layer fusion.For the undiluted deposited metal prepared by this consumable combination,the room-temperature tensile strength reached 540 MPa,the yield strength was 428 MPa,and the elongation after fracture was 33％.The average impact absorption energy was 166.5 J at-12.2℃ and 125.9 J at-40℃,and no fracture occurred in the drop-weight test at-40℃.All performance indicators fully met the technical requirements of the nuclear main pump project.The successful develop-ment of this localized welding consumable provides key technical support for the localization of the entire industrial chain of shielded nuclear main pump motors.