Effect of high temperature and load cycle asymmetry on the growth rate of fatigue cracks in stainless steel, nickel, and titanium alloys

1987 ◽  
Vol 19 (10) ◽  
pp. 1376-1383 ◽  
Author(s):  
V. T. Troshchenko ◽  
A. V. Prokopenko ◽  
V. N. Ezhov
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
High Temperature ◽  
Titanium Alloys ◽  
Fatigue Cracks ◽  
Load Cycle ◽  
Cycle Asymmetry

AL 453

Alloy Digest ◽  
2006 ◽  
Vol 55 (4) ◽  
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
High Temperature ◽  
Physical Properties ◽  
Rare Earth Metals ◽  
Heat Treating ◽  
Temperature Performance ◽  
Low Levels

Abstract Allegheny Ludlum AL 453 Alloy is a ferritic stainless steel with low levels of rare earth metals added to reduce the growth rate of oxides at high temperatures. The enhanced oxidation resistance makes it applicable to high-temperature applications. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and machining. Filing Code: SS-958. Producer or source: Allegheny Ludlum.

scholarly journals Characterization and modelling of both high-cycle hightemperature fatigue behaviour of Stainless Steel Grades

2018 ◽  
Vol 165 ◽  
pp. 19008
Author(s):  
Pierre-Olivier Santacreu ◽  
Cloé Prudhomme ◽  
Benoit Proult ◽  
Isabelle Evenepoel
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
High Temperatures ◽  
High Cycle Fatigue ◽  
Fatigue Cracks ◽  
Fatigue Behaviour ◽  
Cycle Fatigue ◽  
Vibration Fatigue ◽  
Steel Grades ◽  
Stress Ratios

In the same context of thermo-mechanical fatigue and high temperature applications of stainless steel, high-frequency vibration fatigue at high temperatures should be considered, in particular for automotive exhaust gas applications. In fact one of the most frequent incidents that can happen on exhaust components is an accumulation of low-cycle thermal fatigue and high-cycle fatigue. The prediction of the lifetime of a structure under such complex thermal and mechanical loading is therefore a constant challenge at high temperature due to the coupling of metallurgical, oxidation or creep effects. In order to better understand in a first approach, the high cycle fatigue of stainless steels at high temperatures, tractioncompression tests were performed on flat specimens at 25Hz, under air and in isothermal conditions from ambient temperature to 850°C. Two different stress ratios, R=-1 and 0.1, are characterized with the objective to assess a multiaxial model for high temperature. Different criteria are used to predict the ruin of a structure under high-cycle fatigue but in general for ambient-around temperatures. In particular, multiaxial and stress-based DangVan criterion is today widely used to evaluate the risk of fatigue cracks initiation and it has been implemented recently in our fatigue life processor Xhaust_Life®. Therefore the Dang Van criterion was identified from the isothermal high cycle fatigue using the 2 stress ratio and its validity is discussed especially for temperatures higher than 500°C where strain rate and creep effects have increasing influence. Results are presented for two ferritic stainless steel grades used in high temperature exhaust applications: K41X (AISI 441, EN 1.4509) and K44X (AISI 444Nb, EN 1.4521).

scholarly journals High Temperature Fatigue Crack Growth Rate Studies in Stainless Steel 316L(N) Welds Processed by A-TIG and MP-TIG Welding.

2018 ◽  
Vol 165 ◽  
pp. 21014 ◽  
Author(s):  
Manuel Thomas ◽  
Raghu V. Prakash ◽  
S Ganesh Sundara Raman ◽  
M. Vasudevan
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
High Temperature ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Base Metal ◽  
Tig Welding ◽  
Weld Distortion

Welded stainless steel components used in power plants and chemical industries are subjected to mechanical load cycles at elevated temperatures which result in early fatigue failures. The presence of weld makes the component to be liable to failure in view of residual stresses at the weld region or in the neighboring heat affected zone apart from weld defects. Austenitic stainless steels are often welded using Tungsten Inert Gas (TIG) process. In case of single pass welding, there is a reduced weld penetration which results in a low depth-to-width ratio of weld bead). If the number of passes is increased (Multi-Pass TIG welding), it results in weld distortion and subsequent residual stress generation. The activated flux TIG welding, a variant of TIG welding developed by E.O. Paton Institute, is found to reduce the limitation of conventional TIG welding, resulting in a higher depth of penetration using a single pass, reduced weld distortion and higher welding speeds. This paper presents the fatigue crack growth rate characteristics at 823 K temperature in type 316LN stainless steel plates joined by conventional multi-pass TIG (MP-TIG) and Activated TIG (A-TIG) welding process. Fatigue tests were conducted to characterize the crack growth rates of base metal, HAZ and Weld Metal for A-TIG and MP-TIG configurations. Micro structural evaluation of 316LN base metal suggests a primary austenite phase, whereas, A-TIG weld joints show an equiaxed grain distribution along the weld center and complete penetration during welding (Fig. 1). MP-TIG microstructure shows a highly inhomogeneous microstructure, with grain orientation changing along the interface of each pass. This results in tortuous crack growth in case of MP-TIG welded specimens. Scanning electron microscopy studies have helped to better understand the fatigue crack propagation modes during high temperature testing.

Effect of Mechanical Parameter Selection in Quantitative Estimation of the Growth of Environmentally Assisted Cracks at Flaws in Light Water Reactor Components With Complex Mechanical Condition

2011 ◽  
Author(s):  
He Xue ◽  
Xiaoyan Gong ◽  
Lingyan Zhao ◽  
Zhanpeng Lu ◽  
Tetsuo Shoji
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
High Temperature ◽  
Quantitative Estimation ◽  
Pressure Vessels ◽  
Parameter Selection ◽  
Mechanical Parameter ◽  
Mechanical State ◽  
Light Water ◽  
Nickel Based Alloy

To simplify the experimental process, most experiments carried out to make quantitative predictions of environmentally assisted cracking (EAC) growth rate of stainless steel or nickel based alloy are based on standard specimen in a simulated high temperature water environment in laboratories. In the other hand, the mechanical state and geometrical shape of the flaws in the components of light water reactors (LWRs) are usually more complex than the cracks in standard specimens. It is well known that the mechanical factor near to the crack tip is one of the most important factors affecting EAC growth rate in high-temperature aqueous environments. Based on an EAC experiment with a mock-up pipe specimen with two inner axial cracks and a numerical simulation by the elastic-plastic finite element method (EPFEM), it is analyzed that the effect of the different mechanical parameter selection in describing mechanical state close to the tip of EAC on quantitative estimation of EAC growth rate at flaws in nuclear pressure vessels and piping in this study. And the study is expected to form a bridge between predicting EAC growth rate in the stainless steel or nickel based alloy and evaluating EAC growth in key structural components in LWRs.

Further Understanding on Deformation-Oxidation Model in Stress Corrosion Cracking Tip Based on Meso-Scale Mechanical Field

2011 ◽  
Author(s):  
He Xue ◽  
Zhijun Li ◽  
Xiaofeng Xue ◽  
Zhanpeng Lu ◽  
Tetsuo Shoji
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
High Temperature ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Pressure Vessels ◽  
Corrosion Cracking ◽  
Quantitative Prediction ◽  
Oxidation Model ◽  
Meso Scale

Stress corrosion cracking (SCC) is a common failure in stainless steel and nickel based alloys in high-temperature oxygenated aqueous systems. Because the propagating mode and morphology is particular at the SCC tip, it is necessary to investigate and understand in detail the mechanical state close to the SCC tip for improving the prediction accuracy of SCC growth rate in stainless steel and nickel based alloys in the nuclear pressure vessels and piping. By using a sub-model technique in commercial finite element analysis code, the meso-scale stress and strain field in the SCC tip constituted by the oxide film and base metal is simulated and analyzed in this study. And reasonable and operational mechanical parameters in the prediction method of SCC growth rate based on the slip-oxidation model are also discussed. The results of the investigation provide a new insight into the quantitative prediction of SCC growth rate in nuclear structural materials in high temperature water environments.

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