EFFECT OF GROOVE PROFILES ON CREEP STRENGTH OF MODIFIED 9CR-1MO STEEL WELDED JOINT

摘要

The pressurized components for fossil power plants operating at high temperature and stress are often manufactured with Mod. 9Cr-1Mo steel. In this paper, the creep behaviour for the welded joints of this material has been evaluated analytically for several groove profiles. The groove profiles are I-type, V-type, and X-type. For V-type and X-type joints, groove angles are 10 degree and 30 degree each. The analytical models consist of three materials parts, the base metal, and the softened metal at the heat affected zone (HAZ), and the weld metal. The maximum equivalent creep strain yields near the surface of HAZ softened region on all type of the joints. In I-type joint its value shows the smallest and the largest in V-type joint. On X-type and V-type joints, its value becomes larger as the groove angle increases. From the results of these analysis, it is shown that the groove profile is an important parameter on the practical design for the creep strength of welded joints.