scholarly journals Fatigue limit analysis of shot peened spring steel

2021 ◽  
Author(s):  
NohJun Myung ◽  
Liang Wang ◽  
Nak-Sam Choi
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Shot Peening ◽  
High Cycle Fatigue ◽  
High Strength ◽  
Spring Steel ◽  
Cycle Fatigue ◽  
Positive Effects ◽  
Fracturing Process ◽  
Fish Eye

This paper investigated the effect of shot-peening on fatigue strength of spring steel for the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) to clarify the fatigue limit behavior of high strength spring steel during service life. Hourglass shape specimens made of spring steel (Si-Cr alloys) were prepared for the rotary bending fatigue test. Actual local stresses were quantitatively calculated to compensate for the stress amplitudes, through which it was clarified that the shot-peening had strongly positive effects on the HCF strength, but rather negative effect on the VHCF strength. The fish-eye fracturing process confirmed that most fish-eye fractures arose at sites deeper than the compressive residual stress zone, which did not prevent the creation of the fish-eye, and the fatigue strength improvement in the VHCF range could scarcely be shown as a result of the shot-peening treatment.

scholarly journals The Effect of Baking Heat Treatment on the Fatigue Strength and Life of Shot Peened 4340M Landing Gear Steel

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5711
Author(s):  
Seok-Hwan Ahn ◽  
Jongman Heo ◽  
Jungsik Kim ◽  
Hyeongseob Hwang ◽  
In-Sik Cho
Keyword(s):  
Heat Treatment ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Shot Peening ◽  
High Cycle Fatigue ◽  
Landing Gear ◽  
Cycle Fatigue ◽  
Heat Treated ◽  
Ultrasonic Fatigue

In this study, the effect of baking heat treatment on fatigue strength and fatigue life was evaluated by performing baking heat treatment after shot peening treatment on 4340M steel for landing gear. An ultrasonic fatigue test was performed to obtain the S–N curve, and the fatigue strength and fatigue life were compared. The micro hardness of shot peening showed a maximum at a hardened depth of about 50 μm and was almost uniform when it arrived at the hardened depth of about 400 μm. The overall average tensile strength after the baking heat treatment was lowered by about 80–111 MPa, but the yield strength was improved by about 206–262 MPa. The five cases of specimens showed similar fatigue strength and fatigue life in high cycle fatigue (HCF) regime. However, the fatigue limit of the baking heat treated specimens showed an increasing tendency rather than that of shot peening specimens when the fatigue life was extended to the very high cycle fatigue (VHCF) regime. The effect of baking heat treatment was identified from improved fatigue limit when baking heat was used to treat the specimen treated by shot peening containing inclusions. The optimum temperature range for the better baking heat treatment effect could be constrained not to exceed maximum 246 °C.

High Cycle Fatigue Strength of Spring Steel with Small Scratches

2017 ◽  
pp. 541-548 ◽  
Author(s):  
Yoshiro Nishimura ◽  
Masahiro Endo ◽  
Keiji Yanase ◽  
Yuichi Ikeda ◽  
Susumu Miyakawa ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Spring Steel ◽  
Cycle Fatigue

Investigations on the Fatigue Property of the High-Strength and Toughness 211Z Casting Aluminium Alloy

2013 ◽  
Vol 423-426 ◽  
pp. 197-201
Author(s):  
Xiao Min Zhang ◽  
Jian Mao ◽  
Yun Che ◽  
Zhong Ke Zhang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Testing Machine ◽  
High Strength ◽  
Cycle Fatigue ◽  
Fracture Appearance ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum ◽  
Strength And Toughness

211Z is a new type of high strength and toughness Al-Cu-Mn casting aluminum alloy. With the aid of GPS-100 high-cycle fatigue testing machine and DDL100 multifunction tensile testing machine, conventional mechanics performance tests and high-cycle fatigue tests were carried out in this paper. The conventional mechanical property results show that the tensile strength is 477.5 MPa, the theory yield strength is 397.5 MPa and the elongation is 6.625%. Fatigue experiments were performed with load control at room temperature and R =-1 in ambient air. The tensile and compression fatigue strength is 130 MPa under ten million times fatigue test, and S-N fatigue life curve of this alloy was also given in the investigations. 211Z casting aluminum alloy possessing high fatigue strength can be attributed to the fact that it owns high strength and good plasticity simultaneously. The microstructure analysis of fatigue fracture appearance shows that, the fatigue crack initiation behavior of this aluminium alloys depends mainly on the region possessing defects under the surface, there has only one crack source, which means it is belongs to low nominal stress unidirectional bending. In the crack growth stage, the width of fatigue striations decreases with the increase of stress, and a few secondary cracks were found in this stage. When cracks finally losed stability, an instantaneous fracture occured in the investigated samples. Shear lips and dimples were found in the fracture appearance and the final fracture is belongs to ductile fracture.

Very high cycle fatigue properties of high-strength spring steel 60SiCrV7

2016 ◽  
Vol 39 (9) ◽  
pp. 1081-1091 ◽  
Author(s):  
W. J. Hui ◽  
C. Zhou ◽  
Y. J. Zhang ◽  
X. L. Zhao ◽  
H. Dong
Keyword(s):  
High Cycle Fatigue ◽  
High Strength ◽  
Spring Steel ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High
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