Comparison between the improvements made to the fatigue strength of stainless steel by cavitation peening, water jet peening, shot peening and laser peening

2019 ◽  
Vol 269 ◽  
pp. 65-78 ◽  
Author(s):  
Hitoshi Soyama
Keyword(s):  
Stainless Steel ◽  
Fatigue Strength ◽  
Shot Peening ◽  
Water Jet ◽  
Laser Peening

scholarly journals Comparison between Shot Peening, Cavitation Peening, and Laser Peening by Observation of Crack Initiation and Crack Growth in Stainless Steel

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 63 ◽  
Author(s):  
Hitoshi Soyama
Keyword(s):  
Stainless Steel ◽  
Laser Ablation ◽  
Fatigue Strength ◽  
Crack Initiation ◽  
Crack Growth ◽  
Shot Peening ◽  
Stress Test ◽  
Water Jet ◽  
Laser Peening ◽  
The Impact

The traditional technique used to modify the surface of a metallic material is shot peening; however, cavitation peening, a more recent technique in which shot is not used, was developed, and improvements in the fatigue strength of metallic materials were demonstrated. In order to compare the fatigue properties introduced by shot peening with those introduced by cavitation peening, crack initiation and crack growth in specimens of austenitic stainless steel (Japanese Industrial Standards JIS SUS316L) treated using these techniques were investigated. With conventional cavitation peening, cavitation is produced by injecting a high speed water jet into water. In the case of submerged laser peening, bubbles are generated using a pulsed laser after laser ablation, and the impact produced when the bubbles collapse is larger than that due to laser ablation. Thus, in this study, cavitation peening using a water jet and submerged laser peening were investigated. To clarify the mechanisms whereby the fatigue strength is improved by these peening techniques, crack initiation and crack growth in specimens with and without treatment were examined by means of a K-decreasing test, where K is the stress intensity factor, and using a constant applied stress test using a load controlled plane bending fatigue tester. It was found that the improvement in crack initiation and the reduction in crack growth were roughly in a linear relationship, even though the specimens were treated using different peening methods. The results presented here show that the fatigue strength of SUS316L treated by these peening techniques is closely related to the reduction in crack growth, rather than crack initiation.

scholarly journals Effect of Micro-Shot Peening on the Fatigue Performance of AISI 304 Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1408
Author(s):  
Yu-Hsuan Chung ◽  
Tai-Cheng Chen ◽  
Hung-Bin Lee ◽  
Leu-Wen Tsay
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Strain Hardening ◽  
Fatigue Resistance ◽  
Shot Peening ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304

The effects of micro-shot peening on the rotating bending fatigue resistance of AISI 304 stainless steel (SS) were investigated in this study. The strain-hardening, surface roughness and induced residual stress were inspected and correlated with fatigue strength. Micro-shot peening caused intense strain-hardening, phase transformation and residual stress but was also accompanied by a minor increase in surface roughness. A nanograined structure, which was advantageous to fatigue resistance, was observed in the severe shot-peened layer. The absence of microcracks, minor increase in surface roughness, nanograined structure and induced high compressive residual stress in the shot-peened layer were responsible for the improved fatigue strength of AISI 304 SS.

scholarly journals Influence of Residual Stress on Fatigue Design of AISI 304 Stainless Steel

2011 ◽  
Vol 7 (2) ◽  
pp. 44 ◽  
Author(s):  
L. Singh ◽  
R.A. Khan ◽  
M.L. Aggarwal
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Stress Field ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Residual Stress Field ◽  
Aisi 304 ◽  
Fatigue Design

 Austenitic stainless steel cannot be hardened by any form of heat treatment, in fact, quenching from 10000C merely softens them. They are usually cold worked to increase the hardness. Shot peening is a cold working process that changes micro-structure as well as residual stress in the surface layer. In the present work, the compressive residual stress and fatigue strength of AISI 304 austenitic stainless steel have been evaluated at various shot peening conditions. The improvement in various mechanical properties such as hardness, damping factors and fatigue strength was noticed. Compressive residual stress induced by shot peening varies with cyclic loading due to relaxation of compressive residual stress field. The consideration of relaxed compressive residual stress field instead of original compressive residual stress field provides reliable fatigue design of components. In this paper, the exact reductions in weight and control of mechanical properties due to shot peening process are discussed. 

Effects of Laser Peening Treatment on High Cycle Fatigue and Crack Propagation Behaviors in Austenitic Stainless Steel

2009 ◽  
Author(s):  
Yasuo Ochi ◽  
Kiyotaka Masaki ◽  
Takashi Matsumura ◽  
Takaaki Ikarashi ◽  
Yuji Sano
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Propagation ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Laser Peening ◽  
Cycle Fatigue

Laser peening without protective coating (LPwC) treatment is one of surface enhancement techniques using impact wave of high pressure plasma induced by laser pulse irradiation. One of the effects of the LPwC treatment is expected to reduce the tensile residual stress and to induce the compressive residual stress in the surface layer of metallic materials. As a laser has no reaction force due to irradiation and also it has easy characteristics for remote control, the LPwC treatment is practically used as a technique for preventing the stress corrosion cracking (SCC) and for improving the fatigue strength of some structural materials. In this study, high cycle fatigue tests with four-points rotating bending loading were carried out on the non-peened and the LPwC treated low-carbon type austenitic stainless steel 316L in order to investigate the effects of the LPwC treatment on the high cycle fatigue strength and the surface fatigue crack propagation behavior. Two types of specimens were prepared; one was a smooth specimen, the other was a specimen with a pre-crack by the fatigue loading from a small artificial hole. As the results of the LPwC treatment, the high compressive residual stress was induced in the surface layer on the specimens, and the region of the compressive residual stress was about 1mm depth from the surface. The fatigue strength of the LPwC treated SUS316L was remarkably improved during the whole regime of the fatigue life up to the 108 cycles compared with the non-peened materials. Through the fracture mechanics investigation of the pre-cracked materials after the LPwC treatment, it became clear that the fatigue crack propagation was restrained by the LPwC treatment on the pre-cracked region, when the stress intensity factor range ΔK on the crack tip was under the value of 7.6 MPa√m.

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