Comparison between a predicted and an experimentally measured residual stress field generated by side-punching of API X65 steel

A residual stress field was generated by a circular, flat-ended, rigid punch indenting a thick test specimen extracted from X65 grade-controlled-rolled pipeline steel. Laboratory X-ray diffraction was used to measure residual stress field the near-surface, whereas the contour method and neutron diffraction were used to quantify the through-thickness residual stress field. A numerical method was proposed to account for gauge volume variation which allowed a direct comparison of the Finite Element prediction with the experimental measure-ments. A good agreement between the measurements and prediction was observed, showing that the through -thickness compressive residual stress reaches the highest magnitude in the centre of the specimen. The vali-dated results can be used with confidence for residual stress-crack interaction studies in single-edge notched bend SEN(B) and single-edge notched tension SEN(T) fracture specimens which are common in the oil and gas industry due to the inherited close level of constraint experienced in a pipe.

Automated summary

A study was conducted to investigate the residual stress field in X65 grade-controlled-rolled pipeline steel. Experimental results and numerical simulations showed that the highest compressive residual stress is located in the center of the specimen. These validated results are crucial for studying residual stress-crack interaction in typical fracture specimens used in the oil and gas industry.