Proceedings of the Third International Conference on Metals & Hydrogen K03

Fracture toughness measurement of carbon steels with different directions of crack growth

Abderrazak Traidia (1)1 , Elias Chatzidouros (2)2 , Mustapha Jouiad (3)3 , Dimitrios Pantelis (4)4

  • (1) 1

    Research & Development Center, Saudi Aramco, PO Box 62, Dhahran, Saudi Arabia

  • (2) 2

    Engitec Systems International Ltd (ESI), Chrysanthou Business Center, PC 3083, Limassol, Cyprus

  • (3) 3

    MASDAR Institute, PO Box 54224, Abu Dhabi, United Arab Emirates

  • (4) 4

    National Technical University of Athens, Athens, Greece


In an effort to characterize the fracture toughness of carbon steels, susceptible to sour service Hydrogen-Induced Cracking (HIC), in the ST and SL directions, a new design of a W-shaped single edge bending (SEB) specimen was developed and validated in this work. The specimen topology was optimized using finite element simulations and validated experimentally against standard ASTM E1820 SEB specimens extracted from a flat FCA (Fatigue Crack Arrest)  steel plate. The new specimen design was then used to compare the fracture toughness parameters (KQ and CTOD) of an API-5L-X65 pipeline steel in two different directions; SL (crack plane parallel to the pipe wall) and LT (crack plane perpendicular to the pipe wall). Experimental results show an approximate 20% increase in the maximum CTOD measured in the SL direction as compared to the value measured in the LT direction. This new specimen design can be used to measure the fracture toughness of steels in hydrogen environment with different crack growth directions. Such experimental results are important to integrity engineers, as they constitute critical inputs for accurate fitness for service assessment and remaining life prediction of HIC damaged assets.


  • fracture toughness
  • parallel direction
  • hydrogen-induced cracking
  • sour service.