haynes 230？ is a nickel-based superalloy which possesses an outstanding mechanical response at high temperatures and an excellent stability in severe environments (oxidation and corrosion processes). its applications (aerospace sector, heat treatment industry？) cover components that require in-service temperatures up to 1150oc. however, the remarkable characteristics of this superalloy can be deteriorated when it is subjected to a welding process. this process can change the mechanical response of the material due to the formation of microcraks in the fusion zone or the appearance of cracks during solidification. in this work the microstructure of welded haynes 230？ sheets is analysed. then, the mechanical strength and stability are evaluated by means of tensile and creep tests at high temperatures. finally, a fractographic study of the tested specimens is carried out to identify the micromechanisms of failure.