Cole, I. S.Andenna, C.2026-06-112026-06-118756-758XORCID:/0000-0001-6582-1457/work/217149628https://hdl.handle.net/1885/733810637Abstract— The susceptibility of an X65 line pipe steel to hydrogen‐induced stress corrosion cracking (SCC) is investigated. SCC tests on the steel are carried out in three environments of different aggressivity based on a NACE TM‐01‐77 solution with dissolved gaseous H2S. The threshold stress intensity factor is calculated for each environment using the multiple specimen technique. The steel is tested in the as‐received condition and after homogenisation. Permeation tests are carried out on specimens of the same steel in the same environment. The relationship between threshold stress intensity factor and hydrogen concentration is obtained. The results from these studies are used to generate the parameters in the micro‐mechanic model of Akhurst and Baker. The validity and physical significance of the model is assessed.11en199410.1111/j.1460-2695.1994.tb00228.x0028396869