STUDY ON MECHANICAL BEHAVIOR OF WELDMENTS OF TYPE 304SS UNDER CREEP-FATIGUE LOADING

摘要

In this paper the creep-fatigue evaluation method of type 304 ss welded joint under cyclic thermal loading is investigated. For a study the strain concentration factor: K ε, which is derived from the generalized elastic follow-up concept as the plastic strain redistribution, is referred, and the metallurgical discontinuity is evaluated. The elastic follow-up increment factor for weldment q{sub}w value in the equation of K ε is equal to 2 under uniaxial mechanical loading. And under biaxial thermal loading in shell structures, it is clarified that 1.5 of the q{sub}w value specified for the longitudinal welded joint with longitudinal temperature gradient can be applied to the circumferential welded joint with temperature gradient in thickness. As for the creep damage estimation, the simplified procedure is discussed, and it is investigated whether the creep damage of weldment can be evaluated by using mechanical properties of base metal and a strain range derived from the K ε factor.