Research and Development > JFE TECHNICAL REPORT >JFE TECHNICAL REPORT No.20 March 2015 - Special Issue on “Steel Plates” and “Welding and Joining” > Effect of Microstructure on Fatigue Crack Growth Rate

No.20 March 2015 - Special Issue on “Steel Plates” and “Welding and Joining”

Effect of Microstructure on Fatigue Crack Growth Rate

IGI Satoshi      SADASUE Teruki      OHMORI Akio

Abstract

Recently various trials to reduce life cycle cost (LCC) by the improvement of fatigue life of welded steel structures were performed actively by heavy industrial fabricators. JFE Steel has developed the excellent fatigue resistant steel plate “AFD^TM” which reduces the fatigue growth rate with a half level to that of conventional steels. In the AFD^TM, uniformly and finely dispersed perlite in ferrite matrix contributed to achieve good fatigue properties, however the detailed mechanism has not been fully understood yet. In this paper, investigation results on the relationship between fatigue growth rate and perlite morphologies using fatigue testing equipment in the scanning electron microscope (SEM) which enables in-situ observation is introduced.

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