DURABILITY OF THE OIL PIPELINE SYSTEMS UNDER ENVIRONMENTAL EFFECTS

Abstract

Recent discoveries of petroleum and gas reserves in environments with severe operational conditions metallic materials, carbon and low alloy steels, have pushed and prompted the need to find alternatives. The presence of gaseous hydrogen may cause the suffering of hydrogen damage and embrittlement. The effect of hydrogen and temperature on fatigue life properties, have pushed the utilization of steel procurement specification even stricter than they used to be. The main modifications concern the mechanical resistance, toughness at low temperatures weld ability and resistance to embrittlement related to hydrogen. Aiming to enhance the reliability and operation of pipelines system, a study based on the elastoplastic fracture was carried out to determine high level prediction for the fatigue life, as well as to evidence the toughness resistance of the used materials. The materials tested here are API 5L X70 and X100 micro alloyed steels. Hydrogen had affecting the material properties, which are reducing the toughness and an influence spotted in Charpy tests.

Keywords

• Charpy impact
• Durability
• Fracture Toughness
• Pipeline steel
• Temperature