Embrittlement of alloy 625 and effect of remedial treatments

Abstract

This study investigated the susceptibility of alloy 625 to embrittlement in the temperature range 600-800 C using simulated thermal treatments, specimens from ex-service petroleum industry components and subsequent remedial heat treatment. Embrittlement was quantified by conducting impact testing using the Charpy V-notch method and the results discussed in terms of precipitate formation and ageing. The results of annealing the exposed samples at high temperature are presented, demonstrating that embrittlement is most detrimental at intermediate temperatures (i.e. 650 C). The study confirms that a 24-h remedial heat treatment of embrittled alloy 625 leads to significant recovery of impact energy on ex-service samples.