Development of heat resistant alloys for optimal creep performance

Nowak, Igor Mateusz (2015). Development of heat resistant alloys for optimal creep performance. University of Birmingham. Eng.D.

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Abstract

Heat resisting centrifugally cast tubes of HP micro alloy (25/35 Cr/Ni, 0.4C), are extensively used in steam reforming, which is currently the dominate technology for hydrogen generation. High pressure of the reacting gases inside the tubes generates high hoop stress in the tube wall and together with the temperature exposure of 900-1050°C causes the tubes to creep along the circumferential direction. The alloy's ability to successfully withstand the severe operating condition is highly dependent on its high temperature creep-rupture behaviour.

In recent years a number of manufactures have introduced higher creep-rupture strength versions of the heat resisting HP micro alloy. As a consequence they are able to offer the centrifugally cast tubes in thinner walls. Therefore, there is a need to enhance the creep-rupture strength of the alloy produced by Doncasters Paralloy. The immediate objective of this research project is to establish the mechanisms that govern the creep process in this alloy system. Once these mechanisms are better understood further alloy development within the present alloy composition can be achieved. The advanced stages of the project specifically involve studying the influence of microstructure in relation to creep resistance as a function of compositional modifications.

Type of Work:

Thesis (Doctorates > Eng.D.)

Award Type:

Doctorates > Eng.D.

Supervisor(s):