scholarly journals Fatigue fracture and probabilistic assessments of a cone and pipe welded structure of stainless steels

2021 ◽  
Author(s):  
Gyoko Oh
Keyword(s):  
Fatigue Fracture ◽  
Stainless Steels ◽  
Welded Structure

Effect of Post Weld Heat Treatment on Microstructure and Mechanical Properties of Welded 2205 Duplex Stainless Steel

2004 ◽  
Vol 467-470 ◽  
pp. 217-222 ◽  
Author(s):  
R. Badji ◽  
B. Belkessa ◽  
H. Maza ◽  
M. Bouabdallah ◽  
Brigitte Bacroix ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Post Weld Heat Treatment ◽  
Corrosion Properties ◽  
X Ray ◽  
Welded Structure ◽  
Mechanical And Corrosion Properties ◽  
Ray Methods

Duplex stainless steels 2205 are widely used in constructional and petrochemical applications because of their good mechanical and corrosion properties. The objective of this work was to study the influence of aging at high temperature on the austenite and d ferrite equilibrium. After welding by TIG process, duplex stainless steel was aged in the range of 800 – 1150 °C temperatures for 60 min. The microstructure was characterized by metallography and X-ray methods. The toughness of welded structure was also measured.

scholarly journals Fatigue fracture and probabilistic assessments of a cone and pipe welded structure of stainless steels

2021 ◽  
Author(s):  
Gyoko Oh
Keyword(s):  
Stress Concentration ◽  
Stainless Steels ◽  
Weld Interface ◽  
Fatigue Tests ◽  
Coefficient Of Determination ◽  
Opening Angle ◽  
Band Model ◽  
Initiation Point ◽  
Welded Structure ◽  
Stress Concentration Factors

Using thin-walled cone-pipe welded joints of stainless steels, fatigue tests under bending loads were carried out. The test data were statistically analyzed with the Benard’s approximation, Gaussian, 2P-Weibull, and 3P-Weibull distributions. Stress–life curves at different failure probabilities by a constant strength scatter band model were obtained. The metallographic structures were investigated, and the stress concentration states were analyzed to elucidate the causes of the strengths and scatters. In the high-cycle fatigue regime, the 2P-Weibull distribution was mostly in agreement with the Benard’s approximation, and the coefficient of determination was 0.9666. The microstructure of the weld metal with a high weld opening angle was mainly ferrite phase with 20% austenite distribution. The crack initiation point was close to the weld interface, but the propagation direction was at a right angle, and initially penetrated the heat affected zone of the cone, leading to the high fatigue strength. The stress concentration factors depended on the weld opening angles, indicating the main factor which affected strengths and scatters.

scholarly journals Fatigue Fracture Surface of Ultra-Fine Grained Ferritic Stainless Steels

2008 ◽  
Vol 57 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Yoshikazu MATSUMURA ◽  
Katsuhiro KISHI ◽  
Yasuhiro ISHIBASHI ◽  
Ryuichiro EBARA
Keyword(s):  
Fracture Surface ◽  
Fatigue Fracture ◽  
Stainless Steels ◽  
Fatigue Fracture Surface ◽  
Ferritic Stainless Steels ◽  
Fine Grained

Study on Metallography of Low Cycle Creep Fatigue Fracture of Type 316 Stainless Steels

1992 ◽  
pp. 88-93 ◽  
Author(s):  
Takanori Nakazawa ◽  
Nobuhiro Fujita ◽  
Hitoshi Kaguchi ◽  
Hideaki Kaneko ◽  
Hiroyoshi Ueda
Keyword(s):  
Fatigue Fracture ◽  
Stainless Steels ◽  
Creep Fatigue

scholarly journals Hydrogen Effect on Microstructural Alteration before Fatigue Fracture on Austenitic Stainless Steels

2021 ◽  
Vol 107 (3) ◽  
pp. 237-246
Author(s):  
Misaho Yamamura ◽  
Jun Nakamura ◽  
Tomohiko Omura ◽  
Masaharu Hatano
Keyword(s):  
Fatigue Fracture ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Hydrogen Effect

Development of Structural Steel With High Resistance to Fatigue Crack Initiation and Growth: Part 3

2005 ◽  
Author(s):  
Hiroshi Katsumoto ◽  
Noboru Konda ◽  
Kazushige Arimochi ◽  
Kazuhiro Hirota ◽  
Atsushi Isoda ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Crack Initiation ◽  
Fatigue Fracture ◽  
High Resistance ◽  
Fatigue Crack Initiation ◽  
Conventional Steel ◽  
Welded Structure ◽  
Safety And Reliability

In recent years, higher safety and reliability of steel welded structures have been required as it shows growing concern about environmental problems. To prevent fatigue fracture is one of the most important challenges to improve the safety and reliability. A lot of studies how reduce stress concentration at critical areas have been carried out from the viewpoint of structural design as prevention measures while nothing has been studied from the viewpoint of material because fatigue strength of welded joints converges in limited range regardless of material strength. On the other hand, it was found that an appropriate dual phase microstructure could reduce the fatigue crack growth rate remarkably. The newly developed steel plate with high resistance to fatigue crack growth could extend the fatigue life of structures. The developed steels have already been applied to some ships and vessels, and a new bulk carrier applied the developed steels acquired the notation and descriptive note as the valuable ship with resistance to fatigue fracture by Nippon Kaiji Kyokai for the first time in the world. From further studies, it was found the developed steels had also high resistance to fatigue crack initiation as well as the growth even in welded structure. In this study, it was clarified that the fatigue strength of HAZ, where fatigue crack generally initiates, in the developed steel was higher than that in conventional steel and the stress concentration at toe of weld in the developed steel was smaller than in the conventional steel. It was considered the mechanism of suppression of fatigue crack initiation with FEM analysis and fatigue test. The newly developed steel can effectively extend fatigue fracture life of welded structure from the viewpoint of material.

Study on Fatigue Behaviors of 0Cr21Mn17Mo2N0.83 High Nitrogen Stainless Steels

2020 ◽  
Vol 861 ◽  
pp. 89-94
Author(s):  
You Yang ◽  
Wei Feng Tang
Keyword(s):  
Solid Solution ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Fracture ◽  
Stainless Steels ◽  
Room Temperature ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
High Nitrogen

High cycle fatigue behaviors of 0Cr21Mn17Mo2N0.83 high nitrogen stainless steels at forged and solid solution state were investigated. High cycle fatigue tests were carried out up to 107cycles at a stress ratio R=0.1 and frequency of 70Hz on specimens using a high frequency fatigue machine. Fatigue fracture surfaces of specimens that in the high cycle fatigue tests were observed using a scanning electron microscope for revealing the micro-mechanisms of fatigue crack initiation and propagation. The results showed that the fatigue limit of test alloys at room temperature is 865.25 MPa (as-forged alloy) and 736.10MPa (solid solution alloy), respectively. The micro-fatigue fracture surface of the test alloys included three representative regions. These regions are fatigue initiation area, fatigue crack propagation area and fatigue fracture area. Fatigue cracks of the test alloys initiate principally at the precipitates, inclusion or uneven stress concentration sites of alloy surface, and propagate along the grain boundary. The fatigue striations of fatigue crack propagation area are very clear. The fatigue fracture of test specimens show the rupture characteristics of quasi cleavage and dimple fracture. The room temperature fatigue properties of as-forged alloy are generally higher than that of the solid solution high nitrogen stainless steel according to the S-N curves fitting results.

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