Skip to main navigationSkip to main content
The University of Southampton
Rifi An Enterprise Consultancy Unit

Case Study: Failure investigation of sleeve and cage components from a subsea choke valve

Objective: To provide an informed opinion on the original condition / composition of sintered carbide materials from which the choke valve was manufactured and identify the mechanism of failure.

Situation

  • Choke valves were failing below the designed service life.
  • The failure of the valves was causing major delays during production.
  • There were concerns about the metallurgical properties of the materials used for the manufacture of the choke valves.
  • It was imperative to establish the mechanism causing the failure of the valves: was it material dependent or due to operational inconsistencies?
  • What we did

  • Detailed visual assessment of the damaged inner walls of the sleeve was conducted.
  • Samples were examined using both optical and scanning electron microscopes, including energy dispersive X-ray analysis.
  • It was demonstrated that failure of the subsea choke valves was material related and resulted from subsurface cracks in the tungsten carbide (WC-Co) matrix, causing the sleeve to delaminate and fracture.
  • Impact

  • The findings of this study have led the client to consider alternative materials for the manufacture of the subsea choke valves.
  • According to the client, the potential cost saving to their business by the recommendation of this work is in the region of £1M - £2M per day avoiding unnecessary shut downs.
  • SEM image of choke valve
    SEM image of choke valve
    Damaged choke valve
    Damaged choke valve

    We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

    ×