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European Creep
Collaborative Committee
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Description of the
Working Groups, Their Role and
Materials Being Studied |
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WG1
This working group is
studying data generation, analysis, exchange and assessment procedures used
by various European experts. Based on these studies WG1 makes recommendations
and produces guidelines for best methods of testing, electronic data
collation and assessment practices to be used by the ECCC ‘Data Working
Groups’ (i.e. WG3A, 3B, 3C and 4) and for use in the current and future
European research projects and testing laboratories etc. WG1 produces
guidelines and procedures, which are then published by WG2 (dissemination
Working Group run by the secretariat). In particular, WG1
examines he modelling of creep behaviour and develops guidelines for the
generation of creep data to form the basis of model equations which may
subsequently be used for the finite element analysis of components. WG1.1
This is a sub-group and is overseen by
WG1. It considers information dealing with post exposure testing for existing
materials. WG1.1 aims to improve the credibility and reliability of remaining
life assessment (RLA) and life extension procedures used to predict the
performance of existing/old plants. It envisages to propose refining of
available methods and experiences by: · The use of experimentally sound creep data,
derived from material of the component under investigation and checked
against recommended minimum acceptability criteria, · The use of post exposure
creep data from different sources but on the same material to obtain a larger
data set which will be used to validate the RLA methods. WG1.2
This is the second
sub-group responsible to WG1. It evaluates data and issues of creep crack
initiation in the presence of design allowable or in-service defects and its effect
on creep life. It is studying the comparison of various existing assessment
procedures with the aim of making recommendations for the harmonisation of
these. WG2
This group's tasks are as
follows: Information
Dissemination: The group publishes
an annual newsletter, and organises Information Days, Conferences and
Training Courses on the work and finding of ECCC, although the conferences
welcome international contributions from others working in the filed. This WG
has the responsibility for dissemination of information produced by ECCC. Data
Working Groups
WG 3A, B, C shown below,
deal with the projects involved in creep data electronic exchange, and
assessment, including creep strength at various levels of strain. These WGs
also review European data on creep ductility, multi-axial test data, creep
strain, notch ductility and rupture strength. European data, where necessary,
is re-analysed according to the guidelines provided by WG1. Working groups
WG3A, WG3B, and WG3C make their recommendations available to European design
codes and standards committees and provide assessed data sheets. WG3A
This working group is
responsible for dealing with data on ferritic steels. The steels being
studied include in particular those used for bolts, piping and tubing
applications within the chemical, process, oil refining, power generation and
nuclear plant. This WG covers all types of existing and new alloy steels such
as 1Cr0.5Mo, 2.25Cr1Mo, 0.5Cr0.5Mo0.25V, 5Cr1Mo, 9Cr1Mo and 12CrMoV
materials, which have been used extensively in modern plant. The work in
particular covers new advanced materials such as P91, P92, E911 and HCM12A,
T23 and T24 steels. The products considered may include parent, welds,
castings, virgin and post-exposure materials. WG3B
This working group is
responsible for dealing with data on austenitic stainless steels in a
manner similar to WG3A. Austenitic steels are the alloy grades particularly
applicable to chemical plant for pipework and reactor vessels, fossil power
plant boiler applications and for heat exchangers generally in nuclear plant
and advanced (supercritical) fossil plant. The products considered include
parent, welds, castings, virgin and post-exposure materials. WG3C
This working group deals
with data on turbine materials and in particular nickel based alloys,
used mainly in gas turbines, but also being considered as new materials for
use in future high temperature steam turbines. Nickel based alloys are
used extensively in the manufacture of gas turbines and as new materials in
advanced plant steam turbines. Material development for industrial gas
turbines has progressed more rapidly than the development of boiler materials
largely due to significant increases in efficiency that may be achieved with
better blading and disc materials. Rapid expansion in the use of industrial
gas turbines, and the interest by steam manufacturers in using nickel-based
alloys for advanced designs demonstrate the industrial importance of these
materials. Due to the high cost of fully validating new materials, however,
design strengths are often based on incomplete datasets or are unnecessarily
conservative. There is therefore a strong European requirement to collaborate
on turbine materials development, providing better quality and more complete
creep data sets. WG4
This group aims to review
model component / feature test data and produce harmonised assessment
methods. It also aims to review the use of laboratory specimen data for
assessment of component behaviour, safety and life. The work of this WG
includes the study of data from bolting steels, which are often tested
in feature specimen form. WG4 aims to pool and re-analyse component
model/features test data, where necessary. In addition, multi-axial test data
and post-exposure materials test data is studied as required for the analysis
of the component model/feature tests. |
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Project Coordination and Secretariat Facilities Provided By
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