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Kurzzeitkriechverhalten von chromreichen Warmarbeitsstählen
Author(s) -
Shirani M.,
Härkegård G.
Publication year - 2011
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201100911
Subject(s) - materials science , casting , cast iron , fatigue limit , turbine , metallurgy , stress (linguistics) , structural engineering , material properties , composite material , engineering , mechanical engineering , linguistics , philosophy
Two types of EN‐GJS‐400‐18‐LT ductile cast iron were investigated in this research, clean baseline material in the shape of castings with different thicknesses and also defective material from a rejected wind turbine hub. P‐S‐N curves for baseline EN‐GJS‐400‐18‐LT specimens with different dimensions and from castings with different thicknesses at different load ratios were established. Geometrical size effect, technological size effects and mean stress effect on fatigue strength of baseline EN‐GJS‐400‐18‐LT were evaluated. Fatigue strength of baseline EN‐GJS‐400‐18‐LT was compared with that of defective material from the rejected hub. The effect of defects type, shape, size and position on fatigue strength of this material was evaluated. The hypothesis that the endurance observed in an S‐N test can be predicted based on the analysis of crack growth from casting defects through defect‐free ‘base’ material was tested for the analyzed defective material. 3D X‐ray computed tomography was use to detect defects in defective specimens and find the defect size distribution. The obtained defect size distribution for the defective material was used in random defect analysis to establish the scatter of fatigue life for defective specimens. Finally both safe‐life design and damage tolerant design of wind turbine castings were analyzed and compared.