scholarly journals Initiation and Propagation of Low-Cycle Fatigue Cracks in Fe-Ni-C Martensitic Steel

1973 ◽  
Vol 22 (233) ◽  
pp. 140-145
Author(s):  
Shin-ichiro KUMAGAI
Keyword(s):  
Martensitic Steel ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Cycle Fatigue ◽  
Initiation And Propagation

SEM Study of the Influence of Microstructure on Low Cycle Fatigue Crack Growth in Martensitic Steel I

2018 ◽  
Vol 774 ◽  
pp. 96-100 ◽  
Author(s):  
Tamaz Eterashvili ◽  
Temur Dzigrashvili ◽  
M. Vardosanidze
Keyword(s):  
Room Temperature ◽  
Martensitic Steel ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Cycle Fatigue ◽  
Slip Bands ◽  
Sem Study ◽  
Austenite Grains ◽  
Plastic Zones ◽  
The Impact

Distribution of fatigue cracks in chromium martensitic steel after low cycle fatigue (LCF) tests at room temperature has been studied using SEM, and the experimental evidences of localized plastic flow (LPF) are presented. The influence of the location of LPF and the microstructure elements on the trajectory and growth of microcracks is also considered. The dimensions of plastic zones ahead of macrocrack tip as well as at its edges were measured in the process of crack propagation inside of the sample. The processes occurring in plastic zone, particularly ahead of macrocrack tip, were analyzed. Distribution, orientation and the reasons of slip bands’ formation as well as the microstructure elements at which they were nucleated have been studied. The impact of the slip bands’ orientation on the process of macrocrack growth was also analyzed. In addition the interactions of a crack with the boundaries of former austenite grains, martensitic packets, martensitic laths, slip bands and precipitates have been discussed.

Low-Cycle Fatigue Behaviour of Gas Turbine Alloys

1974 ◽  
Vol 188 (1) ◽  
pp. 321-328 ◽  
Author(s):  
W. J. Evans ◽  
G. P. Tilly
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
High Stress ◽  
Cyclic Creep ◽  
Fatigue Curve ◽  
Fatigue Behaviour ◽  
Material Surface ◽  
Tension Stress ◽  
Cycle Fatigue ◽  
Stress Tests

The low-cycle fatigue characteristics of an 11 per cent chromium steel, two nickel alloys and two titanium alloys have been studied in the range 20° to 500°C. For repeated-tension stress tests on all the materials, there was a sharp break in the stress-endurance curve between 103 and 104 cycles. The high stress failures were attributed to cyclic creep contributing to the development of internal cavities. At lower stresses, failures occurred through the growth of fatigue cracks initiated at the material surface. The whole fatigue curve could be represented by an expression developed from linear damage assumptions. Data for different temperatures and types of stress concentration were correlated by expressing stress as a fraction of the static strength. Repeated-tensile strain cycling data were represented on a stress-endurance diagram and it was shown that they correlated with push-pull stress cycles at high stresses and repeated-tension at low stresses. In general, the compressive phase tended to accentuate cyclic creep so that ductile failures occurred at proportionally lower stresses. Changes in frequency from 1 to 100 cycle/min were shown to have no significant effect on low-cycle fatigue behaviour.

Short Crack Initiation during Low-Cycle Fatigue in SAF 2507 Duplex Stainless Steel

2007 ◽  
Vol 345-346 ◽  
pp. 343-346 ◽  
Author(s):  
M.C. Marinelli ◽  
Suzanne Degallaix ◽  
I. Alvarez-Armas
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Surface Strain ◽  
The Other ◽  
Cycle Fatigue ◽  
Cyclic Tests ◽  
Characteristic Microstructure

In this work, the formation of fatigue cracks is considered as a nucleation process due to the development of a characteristic microstructure formed just beneath the specimen surface. Strain controlled cyclic tests were carried out at room temperature at total strain ranges εt = 0.8 and 1.2% in flat specimens of SAF 2507 Duplex Stainless Steel (DSS). The results show that for this DSS, at εt = 0.8%, the correlation between phases (Kurdjumov-Sacks crystallographic relation) plays an important role in the formation of microcracks. On the other hand, at εt = 1.2%, microcracks initiate in the ferritic phase and the K-S relation does not seem to affect the formation of the cracks.

Effect of Specimen Shape on the Low Cycle Fatigue Life of Reduced Activation Ferritic/Martensitic Steel

2010 ◽  
Vol 47 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Shuhei NOGAMI ◽  
Yuki SATO ◽  
Atsushi TANAKA ◽  
Akira HASEGAWA ◽  
Arata NISHIMURA ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Martensitic Steel ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Specimen Shape

Using CFRP to Repair the Steel Pipe with Fatigue Cracks

2010 ◽  
Vol 146-147 ◽  
pp. 1086-1089 ◽  
Author(s):  
Hong Tao Zhang ◽  
Xiao Xiang Xue ◽  
Yan Zheng ◽  
Peng Feng
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Fiber Reinforced Polymer ◽  
Steel Pipe ◽  
Carbon Fiber Reinforced Polymer ◽  
Cycle Fatigue ◽  
Safe Operation ◽  
Reinforced Polymer ◽  
Pressure Pipeline ◽  
Crack Defect

This paper provides a new method to repair the steel pipe with fatigue cracks by using carbon fiber reinforced polymer (CFRP). Cracks may arise in Pressure pipeline in service because of low cycle fatigue. Crack defect is the biggest problem, because crack will gradually propagate and seriously threaten the safe operation of pipeline. This paper provides a repair and calculation method for pressure pipeline with fatigue cracks, and some specific engineering cases are given based on this method.

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