Capacity of pitting corroded pipes under hydrogen assisted cracking

Steel pipes used in the oil and gas industry when subject to corrosion pitting may fail as a result of internal pressure and metal cracking influenced by hydrogen embrittlement. The progressive shape of the crack, including at the instant of failure, is predicted under increasing internal pressure. It is proposed that when hydrogen-assisted cracking (HAC) is involved the shape of the crack front may be estimated from a parallel numerical analyses in the absence of HAC. The theory for this is outlined and an example given.