Fully Reversed Uniaxial Tension-Compression High Cycle Fatigue Behaviour of Shot-Peened Steels

2011 ◽  
Vol 488-489 ◽  
pp. 21-24
Author(s):  
Alan Plumtree ◽  
M. M. Mirzazadeh
Keyword(s):  
Fatigue Limit ◽  
Shot Peening ◽  
Surface Hardness ◽  
Fatigue Behaviour ◽  
Cyclic Softening ◽  
Beneficial Effects ◽  
Heat Treated ◽  
Quenched And Tempered Steel ◽  
Hot Rolled ◽  
Compressive Residual Stresses

The effect of shot-peening on the uniaxial fatigue behaviour of four engineering steels, heat treated to a similar final hardness was investigated. Forged 0.39%C and 0.72%C steels, a quenched and tempered 0.51%C steel and a 0.50%C powder forged (PF) steel were fatigue tested under fully reversed (R=-1) push-pull loading conditions. Following long life (107) cycling, shot-peening had little effect on the fatigue limit of the 0.39%C and 0.72%C steels whereas the fatigue limit of the PF steel increased 10.4%. Conversely, the fatigue limit of the quenched and tempered steel decreased 12.0% after shot-peening. The results showed that the beneficial effects of shot-peening, such as compressive residual stresses and work hardening, balanced the effects of surface roughness since crack initiation tended to occur below the surface. Microhardness profiles showed that the greatest amount of cyclic softening in the shot-peened regions occurred in the hot rolled steels. Softening was accompanied by a decrease in the depth of surface hardness.

Influence of Shot Peening on the Surface Hardness of TC11 Titanium Alloy after High Cycle Fatigue Test

2016 ◽  
Vol 849 ◽  
pp. 302-308 ◽  
Author(s):  
Yi Long Liang ◽  
Li Qiong Zhong ◽  
Zhen Yan
Keyword(s):  
Titanium Alloy ◽  
Stress Intensity ◽  
Shot Peening ◽  
High Cycle Fatigue ◽  
Surface Hardness ◽  
Cyclic Softening ◽  
Cycle Fatigue ◽  
Hardness Change ◽  
Tc11 Titanium Alloy ◽  
Hardness Gradient

This paper studied the change of surface hardness after high-cycle fatigue (HCF) test of TC11 alloy with and without Shot Peening (WSP). The results showed that the surface hardness gradient of WSP specimens increased after R=-1 and R=0.1 HCF tests. It was found that the depth and magnitude of surface hardness gradient were related to the stress intensity and cyclic times of HCF, which increased with stress intensity; however, the surface hardness gradient of Shot Peening specimens after HCF maintained the same with that before HCF tests, the values of surface hardness varied slightly after HCF. According to analysis, the surface hardness change of WSP TC11 alloy is related to their surface integrity, which, during the cyclic loading, is due to the higher stress concentration generated on the original machining marks and the cyclic softening of surface layer generated by multi-directional stress.

scholarly journals Effect of Shot Peening on Mechanical Properties for Steel AISI 1008

2019 ◽  
Vol 12 (2) ◽  
pp. 54-64
Author(s):  
Mohammed Abdulraoof Abdulrazzaq
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Limit ◽  
Shot Peening ◽  
Surface Hardness ◽  
Hardness Test ◽  
Metal Resistance ◽  
Engineering Properties ◽  
Low Carbon ◽  
Steel Aisi

Residual stress has a significant effect for improving engineering properties for metals .Most of the surface treatments produce compressive residual stress at the metal surfaces, which reduce crack initiation and increasing the metal resistance to fatigue, which is shot peening process. Shot peening is usually used for this purpose for producing plastic deformations of surface of the metal which can lead to creation high residual compressive stresses at metal surface .This research include study the influence of shot peening process on fatigue resistance, surface hardness and surface roughness for low carbon steel (AISI 1008). This process accomplished with different times which were (10, 20 and 30(minutes. The result of the fatigue test showed that the fatigue limit increase when shot peening time increased and the best fatigue limit obtained when shot peening process was carried out at 30 minutes. Results of hardness test showed that surface hardness increased with increase of shot peening time. It can be seen that highest value of surface hardness is obtained from shot peening process at time (30 minutes) which is (235.1 HVN). Results of surface roughness test showed that the surface roughness of metal increased when time of shot peening increased.

Influence of the Shot Peening Process on the Fatigue Behaviour of Duplex Stainless Steel Reinforcing Bars

2007 ◽  
Vol 539-543 ◽  
pp. 4981-4986 ◽  
Author(s):  
Enrique Real ◽  
Cristina Rodríguez ◽  
A. Fernández Canteli ◽  
F.Javier Belzunce
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Shot Peening ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Reinforcing Bars ◽  
Cold Rolled ◽  
Hot Rolled

The influence of shot peening on the fatigue properties of duplex stainless steel reinforcing bars manufactured using both hot and cold rolled processes was studied. From determination of the S-N curves, the experimental results show that shot peening improves the fatigue behaviour of the re-bars, but that the improvement is much greater for the hot rolled bars. A more severe peening action capable of promoting greater plastic deformation of the bar surface needs to be used to improve the fatigue resistance of cold rolled corrugated bars.

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.

Influence of Small Surface Defects on Fatigue Limit of Nitrided and Shot Peening Steel

2009 ◽  
Vol 417-418 ◽  
pp. 57-60 ◽  
Author(s):  
Ines Fernández Pariente ◽  
Sara Bagherifard ◽  
Ramin Ghelichi ◽  
Mario Guagliano
Keyword(s):  
Fatigue Limit ◽  
Shot Peening ◽  
Surface Defect ◽  
Surface Defects ◽  
Fatigue Behaviour ◽  
Residual Stress Field ◽  
Small Surface ◽  
Bending Fatigue ◽  
Micro Holes ◽  
A Minor

Effects of surface defect size and the method used to obtain the defect itself on bending fatigue behaviour of nitrided and shot peened steel was studied. Two different series of 15 sandglass specimens with a microhole in the minimum section generated after nitriding and shot peening treatments were considered. In one series the microholes were obtained by controlled electro-erosion. In the other series microholes were obtained by indentation, much more invasive that electro-erosion, simulating a damage due to a mechanical impact or scratch on the surface material, common on real components during the life span. In both cases the microholes act as a pre-existent crack. The results show that defects obtained by indentation lead to a minor fatigue limit with respect of larger defects obtained by electro-erosion. This was interpreted as the modification of the residual stress field due to the mechanical indentation. On the basis of the results some consideration is formulated about generating micro-holes with one of the discussed ways.

Effect of Heating and Subsequent Re-Shot Peening on Surface Characteristics of Shot-Peened Carbon Steel

2011 ◽  
Vol 325 ◽  
pp. 739-744 ◽  
Author(s):  
Yasunori Harada
Keyword(s):  
Carbon Steel ◽  
Shot Peening ◽  
Cast Steel ◽  
Surface Hardness ◽  
Surface Characteristics ◽  
Heat Treated ◽  
Processing History ◽  
History Of ◽  
Type Machine ◽  
Steel Balls

The shot peening process is one of the surface treatments. In this process the peening effects are characterized by the fact that the surface layer undergoes large plastic deformation due to the collision of shots. The effects are greatly influenced by the processing history or the thermal history of material. Little is known about the relation between hardness of the shot peened surface and the processing history of materials. In the present study, the effect of heating and subsequent re-shot peening on the surface characteristics of the shot-peened carbon steel was investigated. Shot peening was performed with an air-type machine using cast steel balls. Hardness and compressive residual stress in the re-shot peened workpieces were measured. When the heat treated workpiece was re-processed by shot peening, surface hardness and fatigue life of carbon steel were improved. It was found that the surface characteristics of the peened carbon steel were improved by heating and subsequent re-shot peening.

scholarly journals Introducing gradient severe shot peening as a novel mechanical surface treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erfan Maleki ◽  
Sara Bagherifard ◽  
Okan Unal ◽  
Michele Bandini ◽  
Gholam Hossein Farrahi ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Grain Refinement ◽  
Shot Peening ◽  
Surface Hardening ◽  
Surface Defects ◽  
Critical Role ◽  
Beneficial Effects ◽  
Severe Shot Peening ◽  
Projection Pressure ◽  
Compressive Residual Stresses

AbstractShot peening is widely used for improving mechanical properties especially fatigue behavior of metallic components by inducing surface hardening, compressive residual stresses and surface grain refinement. In air blast shot peening, projection pressure and surface coverage (an index of peening duration) have been considered as major controlling process parameters; the combination of these parameters plays a critical role in the beneficial effects of shot peening. Generally in severe shot peening aimed at obtaining surface grain refinement, constant values of pressure are considered with different peening durations. Considering very high peening duration, however, the phenomenon of over shot peening, which can be identified with the formation of surface defects could occur. The present study introduces a novel shot peening treatment, here called gradient severe shot peening (GSSP) that instead of using constant projection pressure, implements gradually increasing or decreasing pressures. The gradual increase of the projection pressure acts as a pre-hardening stage for the following higher projection pressure boosting the potential of the material to tolerate the sequential impacts and thus become less prone to the formation of surface defects. The results of the experiments indicate significant fatigue life improvement obtained for GSSP treated specimens compared to the standard treatment with constant pressure. GSSP avoids the detrimental effects of over-peening, while maintaining the beneficial effects of surface nano-crystallization, surface hardening and compressive residual stresses. The notable difference in fatigue strength enhancement for GSSP treated material can be also attributed to the modulated surface morphology with lower surface roughness compared to a standard shot peening treatment with the same exposure time.

scholarly journals Influence of Shot Peening on the Isothermal Fatigue Behavior of the Gamma Titanium Aluminide Ti-48Al-2Cr-2Nb at 750 °C

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1083
Author(s):  
Christoph Breuner ◽  
Stefan Guth ◽  
Elias Gall ◽  
Radosław Swadźba ◽  
Jens Gibmeier ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Shot Peening ◽  
Elevated Temperatures ◽  
Stress Amplitude ◽  
Negative Impact ◽  
Fatigue Behavior ◽  
Surface Hardness ◽  
Fatigue Tests ◽  
Positive Effects ◽  
Isothermal Fatigue

One possibility to improve the fatigue life and strength of metallic materials is shot peening. However, at elevated temperatures, the induced residual stresses may relax. To investigate the influence of shot peening on high-temperature fatigue behavior, isothermal fatigue tests were conducted on shot-peened and untreated samples of gamma TiAl 48-2-2 at 750 °C in air. The shot-peened material was characterized using EBSD, microhardness, and residual stress analyses. Shot peening leads to a significant increase in surface hardness and high compressive residual stresses near the surface. Both effects may have a positive influence on lifetime. However, it also leads to surface notches and tensile residual stresses in the bulk material with a negative impact on cyclic lifetime. During fully reversed uniaxial tension-compression fatigue tests (R = −1) at a stress amplitude of 260 MPa, the positive effects dominate, and the fatigue lifetime increases. At a lower stress amplitude of 230 MPa, the negative effect of internal tensile residual stresses dominates, and the lifetime decreases. Shot peening leads to a transition from surface to volume crack initiation if the surface is not damaged by the shots.

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