Influence of Surface Properties On The Tightness of - Valenciennes, France - Université Polytechnique Hauts-de-France

Description

• Réf

• Sujet de Thèse 11/07/2023
• Cifre
• Université Polytechnique HautsdeFrance
• Lieu de travail
• Valenciennes
• Les Hauts de France
• France
• Intitulé du sujet
• Influence of surface properties on the tightness of metal spans
• Champs scientifiques
• Matériaux
• Mots clés surface morphology; sealing
  Description du sujet:

• Vallourec, one of the world leaders in seamless tubular solutions, supplies the most demanding industries. It offers innovative global solutions, tailored to the energy challenges of the 21st century, specifically for the lowcarbon energy industry (such as hydrogen).
• One of the major challenges is to ensure the tightness of junctions in transportation and storage systems, especially in the field of hydrogen.

• Therefore, it is necessary to understand the role of surface properties and their evolution in relation to sealing.

• What are the surface morphological parameters that influence sealing?
• What is the effect of lapping, and what is the evolution of asperities?
• Is it possible to link surface properties obtained from _in situ_ tests (production line) and laboratory tests (bench tests)? Is it possible to define a multiscale model (fractal, statistical or other) to ensure the sealing function of this joint?

• It is necessary to target the type of steel, grade and the surface treatment configuration (grease or specific coating).
• Compare the sealing behavior for different types of surfaces (_e.g_. by studying the effect of machining parameters).
• Depending on operating conditions, is it possible to reproduce scaleddown tests to generate controlled levels of galling that will be associated with leakage levels?
• Generate calibrated leak defects on surfaces (smallscale and fullscale).

• The experimental part comprises two test sections:
• A part at a reduced scale.
• A part at full scale (connection).
• The same experimental conditions must be respected: same parameters at both scales, same roughness, same machining process (turning), same materials, and coatings.
• Part 1: Generation and control of surfaces after machining, at both scales of the study.
• Part 2: What is the evolution and modification of asperities during screwing? What is the state of the surface after friction?
• Part 3: Description and understanding of the tribosystem.
• Part 4: Impact on sealing: how do surface conditions, material mechanical properties and the tribosystem affect sealing? Identification of the parameters that need to be controlled to achieve optimum behavior (_i.e. _leakfree).

• Cifre

• Remuneration of 2700€/month gross

• Université Polytechnique HautsdeFrance

• Université Polytechnique Hauts de France
  Ecole doctorale:
• Ecole Doctorale Polytechnique HautsdeFrance (ED PHF n°635)