Effect of Sandblasting on Tensile Properties, Hardness and Fracture Resistance of a Line Pipe Steel Used in Algeria for Oil Transport

Transport of oil and gas through pipelines in the harsh conditions of the Algerian desert, results in erosion of the pipeline materials. Erosion is a mechanical process that causes a loss of wall thickness, damage and residual stresses on the surface of a pipe due to shocks between sand particles and structure surface. Damage manifests by spalling craters of different shapes and depths. The evaluation of tensile properties and hardness after sandblasting for different durations has been performed on API 5L X70 pipeline steel. Particular attention has been paid to fracture resistance after sandblasting to provide the necessary data for defect assessment, specially the effect of sandblasting on the Material Failure Master Curve (MFMC). The results demonstrated that the sandblasting has slightly increased the yield stress, the ultimate strength and the fracture toughness and, at the same time, had an adverse effect on elongation, young’s modulus, hardness and thickness of the tested pipeline.