Fatigue Properties of a 420 MPa Structural Steel at Low Temperature

摘要

The exploration of oil and gas fields in the arctic brings severalchallenges in the use of structural steels concerning their lowtemperatureproperties. Among others, fatigue behavior needs also tobe considered for arctic applications, despite little attention to fatigue atlow temperature has been given so far. This paper summarizes a set offatigue crack growth rate tests performed both at room temperature andat -60 ˚C, with the latter representing the possible design temperaturerelevant for the most extreme arctic areas. Accordingly, the materialunder investigation is a 420 MPa structural steel, one of the probablecandidate materials to be used for structural purpose here.Since weldments are the most susceptible to fatigue failures, the fatiguecrack growth measurements have been performed not only on parentmetal, but they have been extended also to weld thermal simulatedCoarse Grained Heat Affected Zone (CGHAZ) and IntercriticallyReheated Coarse Grained Heat Affected Zone (ICCGHAZ). Theresulting fatigue crack growth curves are compared to the fatigueassessment curves indicated in BS 9710:2013. Data indicates that, forall the material under investigation, the fatigue properties are improvedat -60 ˚C when compared to room temperature.