FAILURE ANALYSIS ON SUPPORT FRAMES MADE OF ODS SUPERALLOY SERVICED IN 1050°C FURNACES FOR PORCELAIN BAKING

摘要

Frames made of ODS ferrous alloy X 3 CrAlY 20 4 meant for transportation of raw porcelain products through a tunnel furnace experienced temperatures far above 1050°C and failed after only ca. 1000 h of exposure, in spite of very successful small scale experiments undertaken before. Combined metallurgical failure analysis and non-linear FEM aided engineering design verification recognised that a too less detailed stress analysis neglected during dimensioning several severe stress peaks in transient behaviour and an underestimation of the extreme stress sensitivity of the used alloy at highest temperatures (16000 h/5 MPa) could be deemed as main failure cause, rather than the not ideal metallurgical correspondence of the material to its supplier declared specification.