scholarly journals On the Influence of Ultrasonic Surface Mechanical Attrition Treatment (SMAT) on the Fatigue Behavior of the 304L Austenitic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 100 ◽  
Author(s):  
Clément Dureau ◽  
Marc Novelli ◽  
Mandana Arzaghi ◽  
Roxane Massion ◽  
Philippe Bocher ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Fatigue Limit ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
High Stress ◽  
Fatigue Tests ◽  
Surface Mechanical Attrition Treatment ◽  
Self Heating ◽  
Mechanical Attrition

The potential of ultrasonic surface mechanical attrition treatment (SMAT) at different temperatures (including cryogenic) for improving the fatigue performance of 304L austenitic stainless steel is evaluated along with the effect of the fatigue loading conditions. Processing parameters such as the vibration amplitude, the size, and the material of the shot medias were fixed. Treatments of 20 min at room temperature and cryogenic temperature were compared to the untreated material by performing rotating–bending fatigue tests at 10 Hz. The fatigue limit was increased by approximately 30% for both peening temperatures. Meanwhile, samples treated for 60 min at room temperature were compared to the initial state in uniaxial fatigue tests performed at R = −1 (fully reversed tension–compression) at 10 Hz, and the fatigue limit enhancement was approximately 20%. In addition, the temperature measurements done during the tests revealed a negligible self-heating (∆t < 50 °C) of the run-out specimens, whereas, at high stress amplitudes, temperature changes as high as 300 °C were measured. SMAT was able to increase the stress range for which no significant local self-heating was reported on the surface.

scholarly journals Fatigue behavior of 316L austenitic stainless steel in air and LWR environment with and without mean stress

2018 ◽  
Vol 165 ◽  
pp. 03012 ◽  
Author(s):  
Wen Chen ◽  
Philippe Spätig ◽  
Hans-Peter Seifert
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Test Results ◽  
316L Austenitic Stainless Steel

The fatigue life design curves in nuclear codes are generally derived from uniaxial straincontrolled fatigue test results. Evidently, the test conditions are very different from the actual components loading context, which involves much more complex thermo-mechanical loading including mean stress, static load holding time and variation in water chemistry, etc. In this work, the mean stress and environmental effects on fatigue life of 316L austenitic stainless steel in air and light water reactor (LWR) environment were studied using hollow fatigue specimens and testing under load-controlled condition. Both positive (+50 MPa) and negative (-20 MPa) mean stresses showed beneficial effect on fatigue life in LWR environment and in air. This is tentatively attributed to mean stress enhanced cyclic hardening, which leads to smaller strain response at the same loading force. -20 MPa mean stress was found to increase fatigue limit, whereas the effect of +50 MPa mean stress on fatigue limit is still unclear. The preliminary results illustrate that the environmental reduction of fatigue life is amplified in load-controlled fatigue tests with tensile mean stress.

Effect of Roller-Working on Fatigue Strength Improvement of Notched Structural Stainless Steel

2006 ◽  
Vol 306-308 ◽  
pp. 151-156
Author(s):  
Priyo Tri Iswanto ◽  
Shinichi Nishida ◽  
Nobusuke Hattori ◽  
Yuji Kawakami
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Increase With Increase ◽  
Fatigue Strength Improvement ◽  
Rolled Specimen ◽  
Number Of Cycles

In order to study the effect of plastic deformation on fatigue behaviors of plastically deformed specimen, bending fatigue tests had been performed on notched deformed stainless steel specimens. Also pulsating fatigue tests were done on notched non-deformed specimens to evaluate the influence of mean stress on fatigue behavior of notched non-deformed specimens. The result showed that according to increase of deformation value, the fatigue limits of these specimens also significantly increase. Fatigue limit of rolled specimen does not linearly increase with increase in plastic deformation value. Based on fatigue limit diagram, the effect of compressive residual stress on fatigue limit improvement of stainless steel is higher than that of work-hardening. In case of non-deformed specimen, when the compressive mean stress increases, the fatigue limit and the number of cycles to failure increase. In case of tensile mean stress, this kind of mean stress decreases the fatigue limit.

scholarly journals Effects of Surface Softening on the Mechanical Properties of an AISI 316L Stainless Steel under Cyclic Loading

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1788
Author(s):  
Tiehui Fang ◽  
Feng Cai
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
High Stress ◽  
Sample Surface ◽  
Fatigue Tests ◽  
Aisi 316L ◽  
Homogeneous Sample ◽  
Aisi 316L Stainless Steel

The effects of surface softening on fatigue behavior of AISI 316L stainless steel were investigated. Using cold-rolling and electromagnetic induction heating treatment, a gradient structure was fabricated on AISI 316L stainless steel within which the grain size decreased exponentially from micrometers to nanometers to mimic the surface softening. Stress-controlled fatigue tests were applied to both the gradient and homogeneous structures. Compared with the homogeneous sample, surface softening had no evident effect on fatigue behavior when the stress amplitude was greater than 400 MPa, but significantly deteriorated the fatigue behavior at stress amplitude ≤400 MPa. At high-stress amplitude, fatigue behavior is dominated by crack propagation. When the stress amplitude is lowered, strength reduction and stress concentration caused by surface softening accelerate crack initiation and propagation, resulting in an inferior fatigue behavior.

Fatigue Behavior Analysis of Cruciform Welded Joints by Infrared Thermographic Method

2011 ◽  
Vol 197-198 ◽  
pp. 1395-1399 ◽  
Author(s):  
Xing Lin Guo ◽  
Jun Ling Fan ◽  
Yan Guang Zhao
Keyword(s):  
Stainless Steel ◽  
Fatigue Limit ◽  
Welded Joints ◽  
Traditional Method ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Structural Components ◽  
Structural Evaluation ◽  
Fatigue Characteristics ◽  
Good Agreement

Fatigue tests were carried out at different stress levels on cruciform welded joints made from mastensitic stainless steel. The purpose of the present paper was to verify the validity of the thermographic method and to extend its capability on welded structural evaluation, considering the real operating situations. Due to limitations of the traditional fatigue test, the infrared thermographic technique was developed to predict and assess the fatigue limit and the entire S-N (Stress-Life) curve of cruciform welded joints. Through the comparison, the predictions of the fatigue behavior by the thermographic method (TM) manifested good agreement with the traditional method. The present research paper concludes that the TM as a promising method enables us to rapidly obtain reliable fatigue characteristics of welded structural components.

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