Improvement of Fatigue Strength of Aluminum Alloy by Cavitation Shotless Peening

2002 ◽  
Vol 124 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Hitoshi Soyama ◽  
Kenichi Saito ◽  
Masumi Saka
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Shot Peening ◽  
High Speed ◽  
Bending Fatigue ◽  
Hydraulic Machinery ◽  
Bending Fatigue Test ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Cavitation Shotless Peening

Cavitation impact, which normally produces severe damage in hydraulic machinery, can be used to modify surfaces in the same way as shot peening. Cavitation impact enables the surface of a material to be peened without the use of shot, thus it is called cavitation shotless peening. As there are no solid body collisions occurring in this peening process, the roughness of the peened surface should be less than that produced by shot peening. This characteristic makes it suitable for peening soft metals. In order to demonstrate the improvement of the fatigue strength of aluminum alloy by this process, specimens were subjected to the process, and then tested in a rotating bending fatigue test. Cavitation impacts were produced and controlled by using a submerged high speed water jet with cavitation, i.e., a cavitating jet. It was revealed that the fatigue strength of an aluminum alloy specimen treated by this peening process was 50% stronger than that of a specimen without peening.

Effect of Shot Peening Coverage on Fatigue Strengths of Steels and Aluminum Alloy

2015 ◽  
Vol 1102 ◽  
pp. 33-36
Author(s):  
Junji Sakamoto ◽  
Yong Sung Lee ◽  
Seong Kyun Cheong
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Shot Peening ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Carbon Steels ◽  
Medium Carbon Steels ◽  
Negative Effect ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

The relations between shot peening coverage and fatigue strength in the quenched-tempered and annealed medium-carbon steels and aluminum alloy A7075-T6 were experimentally studied using a rotating bending fatigue testing machine. It was found that the fatigue strengths of the annealed steel and aluminum alloy were increased by shot peening. On the other hand, the fatigue strength of the quenched-tempered steel were not increased by shot peening. Same shot peening condition causes the positive effect and the negative effect depending on the type of material. Moreover, the valuable coverage might depend on the type of material. More detailed work is necessary to resolve the issue.

Improvement of Fatigue Strength of Maraging Steel by Shot Peening

2007 ◽  
Vol 348-349 ◽  
pp. 537-540
Author(s):  
Norio Kawagoishi ◽  
Takanori Nagano ◽  
M. Moriyama ◽  
Eiji Kondo
Keyword(s):  
Fatigue Strength ◽  
Maraging Steel ◽  
Shot Peening ◽  
Fine Particles ◽  
Fatigue Tests ◽  
Fracture Origin ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Points Of View

Rotating bending fatigue tests up to 108 cycles were carried out to investigate the effects of shot peening on the fatigue strength and the fracture mechanism in an 18 % Ni maraging steel by using shot particles of various sizes or hardness. Fatigue strength was increased markedly by shot peening in the wide region of fatigue life. The S-N curves showed duplex S-N properties because of the transition of fracture origin from the specimen surface in the short life region to the subsurface in the long life one. Double shot peening by using super-hard fine particles was effective to improve the fatigue strength for surface fracture, though the fatigue strength for an internal fracture was hardly influenced. These results were discussed from the points of view of effects of surface roughness, residual stress and work hardening on the fatigue strength.

Effects of an Artificial Small Defect on Torsional Fatigue Strength of Steels

1987 ◽  
Vol 109 (2) ◽  
pp. 124-129 ◽  
Author(s):  
Masahiro Endo ◽  
Yukitaka Murakami
Keyword(s):  
Fatigue Strength ◽  
Crack Propagation ◽  
Hole Diameter ◽  
Threshold Condition ◽  
Bending Fatigue ◽  
Torsional Fatigue ◽  
Small Defect ◽  
Bending Fatigue Test ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

In order to elucidate the effect of small defects on the torsional fatigue strength of steels, reversed torsion tests were carried out on the 0.46 percent C steel specimens containing a small hole. The hole diameter ranges from 40 to 500μm. The fatigue behaviors on the specimen surface and near the hole were observed with the aid of a microscope. The torsional fatigue strength of steels containing small holes can be predicted from the results of rotating bending fatigue test by considering the threshold condition for crack propagation.

Rotating Bending Fatigue Tests on Aluminum Alloy AISI-SAE 6061-T6 at High Speed (150 Hz), and Close to Elastic Limit

2009 ◽  
Vol 65 ◽  
pp. 79-88
Author(s):  
Gonzalo Domínguez Almaraz ◽  
Edgar Tapia Silva ◽  
Mauricio Guzmán Tapia ◽  
Jesús Villalón López
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Elastic Limit ◽  
High Stress ◽  
Fatigue Tests ◽  
Test Machine ◽  
General Description ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

This work deals with rotating bending fatigue tests at high speed (150 Hz), carried out on aluminum alloy AISI-SAE 6061-T6 for which the highest experimental stress inside the specimen is close to the elastic limit of material. Simulation results are obtained by Visual Nastran software in order to determine the numerical stress and strain distributions inside the specimen; then, this information is used for the experimental set up. A general description of experimental test machine and experimental conditions are developed in first sections, following section present the experimental results and discussion about the observed failure origin related to discontinuities and the associated high stress zones. A principal contribution of this work is related to the analysis of fracture surfaces and its correlation with experimental fatigue endurance: a simple model is proposed for the prediction of fatigue life of this aluminum alloy under high speed rotating bending fatigue tests, based on the surface density of associated fatigue macro-plastic deformation zones close the crack initiation.

Sign in / Sign up

Export Citation Format

Share Document