BOLT-JOINING METHOD FOR CREEP-DEFORMABLE MATERIAL AND BOLT-JOINING WASHER

摘要

PURPOSE:To effectively control compressive deformation caused by creeping to maintain frictional joining force for a long term by increasing the distribution of thickness of material to be joined at its contacting portion with a washer in a direction corresponding to the diametral direction of the washer. CONSTITUTION:A contacting portion of the bolt hole of an austenitic stainless steel member with a washer is formed with a tapered part so as to increase the distribution of thickness of the steel member in a direction corresponding to the diametral direction of the washer. Thus, high compressive force in a direction of plate thickness acts on a portion separating from the inner surface of the bolt hole to restrain material near the bolt hole for increase in radial compressive stress. Deviating stress is thereby sharply reduced to maintain high frictional joining strength for a long term.