TY - BOOK
T1 - Master curve analysis of ductile to brittle transition region fracture toughness round robin data
T2 - The "EURO" fracture toughness curve
AU - Wallin, Kim
N1 - Project code: V7SU00063
PY - 1998
Y1 - 1998
N2 - Brittle fracture in the ductile to brittle transition
regime is connected with specimen size effects and - more
importantly- tremendous scatter of fracture toughness,
which the technical community is currently becoming
increasingly aware of. The size effects have the
consequence that fracture toughness data obtained from
small laboratory specimens do not directly describe the
fracture behaviour of real flawed structures. Intensive
research has been conducted in the last decade in order
to overcome these problems. Different approaches have
been developed and proposed, one of the most promising
being the master curve method, developed at VTT
Manufacturing Technology.
For validation purposes, a large nuclear grade pressure
vessel forging 22NiMoCr37 (A508 Cl.2) has been
extensively characterised with fracture toughness
testing. The tests have been performed on standard
geometry CT-specimens having thickness 12.5 mm, 25 mm, 50
mm and 100 mm. The a/W-ratio is close to 0.6 for all
specimens. One set of specimens had 20% side-grooves. The
obtained data consists of a total of 757 results
fulfilling the ESIS-P2 test method validity requirements
with respect to pre-fatigue crack shape and the ASTM
E-1921 pre-fatigue load. The master curve statistical
analysis method is meticuously applied on the data, in
order to verify the validity of the method. Based on the
analysis it can be concluded that the validity of all the
assumptions in the master curve method is confirmed for
this material.
AB - Brittle fracture in the ductile to brittle transition
regime is connected with specimen size effects and - more
importantly- tremendous scatter of fracture toughness,
which the technical community is currently becoming
increasingly aware of. The size effects have the
consequence that fracture toughness data obtained from
small laboratory specimens do not directly describe the
fracture behaviour of real flawed structures. Intensive
research has been conducted in the last decade in order
to overcome these problems. Different approaches have
been developed and proposed, one of the most promising
being the master curve method, developed at VTT
Manufacturing Technology.
For validation purposes, a large nuclear grade pressure
vessel forging 22NiMoCr37 (A508 Cl.2) has been
extensively characterised with fracture toughness
testing. The tests have been performed on standard
geometry CT-specimens having thickness 12.5 mm, 25 mm, 50
mm and 100 mm. The a/W-ratio is close to 0.6 for all
specimens. One set of specimens had 20% side-grooves. The
obtained data consists of a total of 757 results
fulfilling the ESIS-P2 test method validity requirements
with respect to pre-fatigue crack shape and the ASTM
E-1921 pre-fatigue load. The master curve statistical
analysis method is meticuously applied on the data, in
order to verify the validity of the method. Based on the
analysis it can be concluded that the validity of all the
assumptions in the master curve method is confirmed for
this material.
KW - fractures (materials)
KW - steels
KW - fracture strength
KW - ductile brittle transition
KW - brittleness
KW - statistical analysis
KW - master curve method
M3 - Report
SN - 951-38-5345-4
T3 - VTT Publications
BT - Master curve analysis of ductile to brittle transition region fracture toughness round robin data
PB - VTT Technical Research Centre of Finland
CY - Espoo
ER -