Objectif The development of steels for oil and gas pipelines designed to convey aggressive (i.e. H2S-contaminated) fluids and the forecasting of their in-service behaviour are topics of increasing importance for both steel producers and users. The situation regarding SSCC (sulphide stress corrosion cracking) is, however, fairly unclear, since it has not so far been finally determined when and how such a phenomenon can occur in the pipeline or what mechanism causes it at microscopic level. SSCC has been studied above all in high-strength steels (for geothermal applications, for example), in which a fairly clearly defined phenomenology has been observed: surface cracks propagating in the thickness perpendicular to the direction in which the load is applied. Various mechanisms have been put forward to explain the hydrogen embrittlement that takes place at the apex of the crack. A different phenomenology has been observed on a laboratory scale in steels for oil and gas pipelines, in which there is typically a complex interaction between a HIC phenomenon, modified by the presence of loading, and the subsequent propagation of internal cracks by SSCC. Furthermore, it is possible that yet another situation arises in the case of welded joints, for which adequate information is not available. Lastly, the problem is further complicated by the discovery that the actual mechanism at work in the field depends on specific interactions between the metallurgical, environmental and stressing conditions, which has cast serious doubts on the adequacy of the usual methods for evaluating in the laboratory the resistance to HIC and SSCC of steels for oil and gas pipelines. Programme(s) ECSC-STEELRES 7C - Medium-term guidelines (ECSC) "technical steel research", 1986-1990 Thème(s) F2 - Corrosion Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur CENTRO SVILUPPO MATERIALI SPA Contribution de l’UE Aucune donnée Adresse Via di Castel Romano 100/102 00128 ROMA EUR Italie Voir sur la carte Coût total Aucune donnée
