Hydrogen-Induced Stress Cracking (HISC) of Duplex Stainless Steels

Qualification: PhD

Department: School of Engineering

Application deadline: 22 September 2020

Start date: 1 October or as soon as possible after

Overview

Supervisor

Project description

Background

Duplex stainless steels (DSSs) are widely used in oil and gas subsea applications, such as pipelines, and manifolds and risers in production systems, due to their superior properties. In these environments, DSS components are often connected to ferritic steel components, which necessitate the application of cathodic protection (CP) as a means of corrosion prevention. Whilst successful in preventing degradation of the ferritic parts, CP can generate hydrogen at the bare surface of the subsea structures, whereupon, it can be absorbed into the alloy and cause embrittlement. Cracking of this embrittled material is known as hydrogen-induced stress cracking (HISC) and is recognised as a major cause of catastrophic failures in service, which are of significant fatal and financial losses. However, there are currently no established/standardised guidelines for evaluating resistance to cracking of DSSs in such environments, in a quantitative manner and against any established acceptance criterion. 

Project outline

The main objectives of this PhD project are to develop an in-depth insight to the cracking behaviour of DSSs once exposed to hydrogen, and provide new, quantitative methods for assessing and designing against HISC, as well as providing data to enable production of more reliable assists. This also helps risks of HISC to be managed, and therefore increase safety and reduce the operation costs and issues associated with, potentially fatal, catastrophic failures. A series of experimental and modelling tasks (but not limited to the following items), will be undertaken:

  • Advanced microstructural characterisation of a few DDS product forms (and weldments);
  • Modelling  of test specimen geometries, and numerical calculation of strain/stress distributions along the stress raiser to be incorporated in those specimens; 
  • Mechanical and environmental  testing of a number of specimens with different geometries (size, notch acuity); 
  • Post characterisation of tested specimens using metallography and fractography ; 
  • Data analysis and interpretation of the findings obtained.

About University/School

Leicester is a leading University committed to international excellence, world-changing research and high quality, inspirational teaching. We are strongly committed to inclusivity, promoting equality and celebrating diversity among our staff and students. You will develop your career in a supportive and collaborative academic environment in one of the world’s leading research-intensive universities; elite in the excellence of our research, yet distinctive for the genuine synergy between our research and teaching.

About NSIRC

NSIRC is a state-of-the-art postgraduate engineering facility established and managed by structural integrity specialist TWI, working closely with a number of academic partners and universities and a number of leading industrial partners. NSIRC aims to deliver cutting edge research and highly qualified personnel to its key industrial partners.

Funding

Funding

This project is funded by the University of Leicester, Lloyds Register Foundation and TWI.

The funding covers the cost of Home/Overseas tuition fees and a standard tax-free UKRI stipend of £15,285 per year for three years.

Entry requirements

Entry requirements

Candidates should have a relevant degree at 2.1 minimum, or an equivalent overseas degree, in a Materials or Mechanical Engineering field.

English language requirement if applicable is IELTS 6.0 or other acceptable English test/qualification as detailed on our English Language web page.

Informal enquiries

Informal enquiries

For informal inquiry, please contact Professor Dong.

Application enquiries to be emailed to engineeringpgr@le.ac.uk.

How to apply

How to apply

Please use the Apply button at the bottom of the page to start your online application and select September 2020 entry.

In the funding section of the application please indicate you wish to be considered for the Eng TWI Dong 2020 studentship.

In the proposal section please provide the name of the supervisors and project title  (a proposal is not required).

With the application, please include:

  • CV
  • Personal statement explaining your interest in the project, your experience and why we should consider you
  • Degree Certificates and Transcripts of study already completed and if possible transcript to date of study currently being undertaken
  • Evidence of English language proficiency if applicable
  • In the reference section please enter the contact details of your two referees in the text boxes provided or upload letters of reference if already available.

Eligibility

Eligibility

This PhD studentship is available to UK/EU and International students.