scholarly journals Relationship between Damping Factor and Compressive Residual Stress for Shot-Peened Austenitic Stainless Steel

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Lakhwinder Singh ◽  
R. A. Khan ◽  
M. L. Aggarwal
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Film Surface ◽  
Damping Factor ◽  
Thin Film Surface ◽  
Deformed Layer

The mechanical properties of austenitic stainless steel are rarely improved by heat treatment. Shot peening is a well-known cold working process that affects thin surface of materials. By controlling the shot peening intensity and shot size, the variable mechanical properties film thickness was obtained from 0.05 mm to 0.5 mm. The damping factor and compressive residual stress are determined experimentally and forming a relation between them. It was found that damping factor in thin film surface increases with depth of deformed layer. An investigation was carried out, and it was found that the increase in damping factor was due to introduction of compressive residual stress and increased hardness due to shot peening. The paper discusses a model of changing damping properties with compressive residual stress and depth of deformed layer of austenitic stainless steel.

The Influence of Shot Peening Process on the Residual Stress and Microstructure in Deformed Surface Layer of S30432 Austenitic Stainless Steel

2013 ◽  
Vol 768-769 ◽  
pp. 550-556 ◽  
Author(s):  
Ke Zhan ◽  
Chuan Hai Jiang ◽  
Henry Pan
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Austenitic Stainless Steel ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Diffraction Method ◽  
Micro Structure ◽  
Near Surface ◽  
Deformed Layer

Shot peening is an important surface treatment which can induce compressive residual stress and refine micro-structure in the deformed surface layer. In this paper, the conventional shot peening, dual shot peening and triple shot peening have been applied to S30432 austenitic stainless steel. The residual stress and micro-structure in the deformed layer were investigated by X-ray diffraction method. The results revealed that a compressive residual stress field was induced in the deformed layer for all shot peening conditions. As the shot peening step increased, the compressive residual stresses increased in near surface layer, and then deceased faster in deeper deformed layer. In terms of microstructure, the domain size increased, while the micro-strain decreased with the depth increasing in the deformed layer. Compare with the effect of three different shot peening method, triple shot peenng is more effective to optimize the compressive residual stress, microstructure and micro-hardness of S30432 austenitic stainless steel.

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. 

Development of Residual Stress Improvement for Nuclear Pressure Vessel Instrumentation Nozzle Weld Joint (P-43+P-8) by Means of Induction Heating

2006 ◽  
Author(s):  
Takuro Terajima ◽  
Takashi Hirano
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Induction Heating ◽  
Weld Joint ◽  
Thermal Stresses ◽  
Pressure Vessels ◽  
Weld Joints

As a counter measurement of intergranular stress corrosion cracking (IGSCC) in boiling water reactors, the induction heating stress improvement (IHSI) has been developed as a method to improve the stress factor, especially residual stresses in affected areas of pipe joint welds. In this method, a pipe is heated from the outside by an induction coil and cooled from the inside with water simultaneously. By thermal stresses to produce a temperature differential between the inner and outer pipe surfaces, the residual stress inside the pipe is improved compression. IHSI had been applied to weld joints of austenitic stainless steel pipes (P-8+P-8). However IHSI had not been applied to weld joints of nickel-chromium-iron alloy (P-43) and austenitic stainless steel (P-8). This weld joint (P-43+P-8) is used for instrumentation nozzles in nuclear power plants’ reactor pressure vessels. Therefore for the purpose of applying IHSI to this one, we studied the following. i) Investigation of IHSI conditions (Essential Variables); ii) Residual stresses after IHSI; iii) Mechanical properties after IHSI. This paper explains that IHSI is sufficiently effective in improvement of the residual stresses for this weld joint (P-43+P-8), and that IHSI does not cause negative effects by results of mechanical properties, and IHSI is verified concerning applying it to this kind of weld joint.

Numerical Simulation of Residual Stress Field Induced by Ultrasonic Shot Peening

2008 ◽  
Vol 373-374 ◽  
pp. 832-835 ◽  
Author(s):  
Gang Ma ◽  
Xiang Ling ◽  
Yuan Song Zeng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Diffraction Method ◽  
Residual Tensile Stress ◽  
Finite Element Software ◽  
Ultrasonic Shot Peening ◽  
Stress Layer

A 3D finite element model is established to simulate the ultrasonic shot peening process by using a finite element software ABAQUS. The residual stress distribution of the AISI 304 stainless steel induced by ultrasonic shot peening (USP) is predicted by finite element analysis. Ultrasonic shot peening (USP) process can cause a compressive residual stress layer on the surface of the material. During the simulation, many factors, e.g., ultrasonic shot peening duration, initial residual stress, hourglass, etc., are taken into consideration for the purpose of optimizing the process. The simulation results show that ultrasonic shot peening can produce a compressive residual stress layer on the surface of the material even if there is initial residual tensile stress (250MPa) and the longer peening duration. The residual stress of simulation were compared with the experiment data which were obtained under the same ultrasonic shot peening parameters and have a good agreement with the measurement values by X-ray diffraction method. In conclusion, ultrasonic shot peening is an effective method for protecting weldments against stress corrosion cracking by introducing the compressive residual stress layer into the surface of stainless steel.

The Evolution of Residual Stress and Microstructure in Shot Peened S30432 Austenitic Stainless Steel at High Temperatures

2013 ◽  
Vol 768-769 ◽  
pp. 557-563
Author(s):  
Ke Zhan ◽  
Chuan Hai Jiang ◽  
Henry Pan
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
High Temperatures ◽  
Exposure Time ◽  
Shot Peening ◽  
Thermal Relaxation ◽  
Domain Size ◽  
Line Profile Analysis ◽  
Relaxation Energy

The thermal relaxation behavior of residual stress and microstructure at high temperatures in S30432 austenitic stainless steel after shot peening was investigated by X-ray residual stress analyzer. The effects of exposure time and applied temperature on the residual stress and microstructure relaxation were particularly analyzed and discussed. A significant decrease of the residual stress values were observed in the first period of exposure time, followed by slowing down and then stabilization. It was also observed that a higher applied temperature produced greater relaxation. In terms of microstructure, the domain size and micro-strain were calculated by Voigt method, the results showed that the refined domain size and high micro-strain induced by shot peening were greatly relaxed at the first stage of annealing, then stabilized. With higher annealing temperature, the recrystallization behavior in the shot peened deformed layer was more obvious. Based on the results of line profile analysis, the recrystallization activation energy and micro-strain relaxation energy were calculated, respectively.

Application of Indirect Laser Peening to SUS304 Stainless Steel

2014 ◽  
Vol 783-786 ◽  
pp. 2316-2321
Author(s):  
Hiroshi Kawakami ◽  
Akiyoshi Kondo ◽  
Muneharu Kutsuna ◽  
Kiyotaka Saito ◽  
Hiroki Inoue ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stress Distribution ◽  
Pulse Energy ◽  
Laser Power ◽  
Compressive Residual Stress ◽  
Residual Stress Distribution ◽  
Bending Test ◽  
Laser Peening

Indirect laser peening applied to the substrate of austenitic stainless steel with the sheet of similar material. Effects of indirect laser peening condition on the formation of the dimple and the residual stress were investigated in this paper. Shape of the dimple and distribution of the residual stress were measured by laser microscope and X-ray diffraction, respectively. It was observed by the microscope that clean substrate surface of as-received state kept after indirect laser peening because of protection by the sheet. However, fracture of sheet occurred slightly in high pulse energy condition. The diameter and the depth of the dimple by indirect laser peening increased with the increase of laser power. Efficiency of dimple formation decreased with the increase of pulse energy. Affective condition region of indirect laser peening with a combination between the substrate and the sheet of austenitic stainless steel may be limited below the laser power density of 10GW/cm2. It was confirmed that indirect laser peening induced compressive residual stress in the substrate. One of peak of compressive residual stress in residual stress distribution existed near the bottom of the dimple. Residual stress distribution which was produced by indirect laser peening may affect change of quasi bending modulus which was obtained by three-point bending test.

Residual Stresses in Austenitic Stainless Steel due to High Strain Rate

2011 ◽  
Vol 681 ◽  
pp. 278-283 ◽  
Author(s):  
Kenji Suzuki ◽  
Takahisa Shobu
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Rate ◽  
Compressive Residual Stress ◽  
Tensile Deformation ◽  
X Rays ◽  
Lattice Plane ◽  
Wide Range ◽  
The Difference

Austenitic stainless steel (SUS316L) was used as specimen material, and the plate specimens were deformed plastically with a wide range of strain rates (6.67×10-5~ 6.70×102/s). The residual micro-stress for each lattice plane was measured with hard synchrotron X-rays. The residual macro-stress due to tensile deformation depended on strain rate. The residual micro-stresses varied from tension to compression, depending on the diffraction elastic constant. The soft lattice plane had tensile residual stress, and the hard lattice plane had compressive residual stress. The higher the strain rate, the smaller the difference in residual micro-stresses. The residual micro-stresses of the surfaces peened with the laser-peening or water-jet-peening were examined. Both surfaces had exhibited large compressive residual stress. The residual micro-stress on the peened surfaces showed a tendency opposite to residual micro-stress due to tensile deformation.

scholarly journals Improvement of mechanical properties and fatigue life by shot peening process on ASTM A516 Grade 70 steel

2018 ◽  
Vol 14 (4) ◽  
pp. 440-442
Author(s):  
Mohd Rashdan Isa ◽  
Omar Suliman Zaroog ◽  
Kalaikathir Murugan ◽  
Sharif Osman Kabashi Guma ◽  
Fareg Saeid Ali
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Industrial Sector ◽  
Low Intensity ◽  
Before And After

ASTM A516 Grade 70 is widely used in the industrial sector as it provides very good mechanical properties in tough conditions. The main usage of this material is in moderate and low operating services. This paper focuses on the effect of shot peening process on ASTM A516 Grade 70 on improving the mechanical properties and fatigue life of the material. Samples have been shot peened with steel shot to induce compressive residual stress. Hardness, tensile and fatigue test as well as microstructure were done on the samples before and after shot peening process to study the effects on mechanical properties. The result shows that there is an increment in every test after shot peening process. There is a slight increment of 0.47% in hardness value, 0.39% increment in tensile strength and 6.78% increment in fatigue life of the material after shot peening process applied. The slight increment in every result was due to the low intensity of the shot peening process. Result also shows that the shot peening process compressed the molecules closer to each other as can be seen under SEM. Therefore it was proven that in this study, there is a very significant improvement in mechanical properties and fatigue life by shot peening process on ASTM A516 Grade 70 Steel.

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