Properties, Performance, Characteristics and Improvements of Structural Materials: Alloys, 1988-1991Project ID: 2367
Properties, Performance, Characteristics and Improvements of Structural Materials: Alloys, 1988-1991
Total cost:Not available
EU contribution:Not available
Objective of the work To study the performance and deterioration of materials in simulated industrial environments and contribute to physically based modelling with experimental verification to predict behaviour in service. To develop advanced test and assessment methodologies suitable for R industrial needs.
Progress to end 1990
1. Power Engineering Alloys
The corrosive degredation of 4 candidate heat exchanger alloys has been monitored using laboratory studies in comparison with the behaviour observed after in-plant exposures in a coal gasifier. Characterisation of the creep/microstructure relationship in MA760 has continued at temperatures above 1000C. The degradation mechanisms in selected heat resistant steels have been investigated in increasingly complex environments with and without superimposed stress. Multiaxial stress tests on tubular ferritic and austenitic alloy steels have allowed the determination of controlling criteria for application in component design models. Creep crack growth measured in tubular components could be related to that observed for conventional tests, as required for lifetime prediction analysis. The measurement of LCF and TMF properties of MA 760 has started. Most of this work forms part of 3 integrated Work Packages within COST 501, a programme which is strongly supported and led by European industry. In addition WP 5 with 30 participants is managed by our scientists. The remaining activities described above are carried out in collaboration with ad-hoc groupings in European industry.
2. Test and Assessment Methodologies
Techniques for testing and examination which have been developed include: assessment of the corrosion behaviour of alloys under solid deposits and in presence of molten salts; creep testing of very thin samples with high accuracies in aggressive environments; creep testing in high pressure hydrogen environments; in - situ assessment of damage on high temperature mechanical test samples. Lack of resources prevented the planned construction of a high temperature thermal gradient test rig. Other developments include: Phase II of the expert system "Artic" which relates to residual lifetime in headers; validation procedures for an internal pressure testing code of practice. The work on technique development has been conducted for use with third party contracts. 9 publications, 10 papers, on conference proceedings.
Detailed description of work foreseen in 1991 (expected results) .SP0
1. Power Engineering Alloys:
The investigative programmes will continue in the directions described above, particularly for laboratory/in-plant corrosion studies; creep/microstructure/environment interaction in M.A. alloys and their study under LCF/TMF conditions; models and data for lifetime prediction of multiaxially loaded components, with and without defects.
2. Test and Assessment Methodologies:
Facilities for creep testing intermetallics followed by procedure development; high pressure H2 creep crack growth; high temperature thermal gradient testing; complex mechanical testing in aggressive gases. Other developments will include the standardisation of corrosion assessment techniques and image analysis software for in-situ analysis of mechanical damage.
Short description of evolution of work in 1992
The work will evolve in an organic manner, responding to the future needs of European industry for H.T.Alloys and an ability to handle complex stress/environment situations.
1755 ZG PETTEN
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