Effect Of Shot Peening Research Articles

Comparative study of the effects of conventional shot peening and ultrasonic shot peening on very high cycle fatigue properties of GH4169 superalloy

This study investigates the effects of two different shot peening techniques, conventional shot peening (CSP) and ultrasonic shot peening (USP), on the very high cycle fatigue (VHCF) properties of the GH4169 superalloy. The study evaluates and compares surface roughness, X-ray diffraction patterns, microhardness, and residual stress in specimens treated with CSP and USP. The VHCF tests reveal that both CSP and USP treatments improve the VHCF properties of the GH4169 superalloy. However, while the USP-treated specimens have deeper work hardening and compress residual stress layers, their VHCF lives are significantly shorter than those of the CSP-treated specimens. Additionally, the study finds that the stress triaxiality, which inhibits dislocations at the crack tip, is higher closer to the center of the specimen. The transmission electron microscopy (TEM) results further confirm that the reduced dislocation density and increased stress concentration in the plastic zone of the high stress triaxiality region promote fatigue short crack propagation and reduce the fatigue properties of the material.

Effect of Shot Peening on Oxidation and Precipitation in Inconel 718

In this study, the effect of the surface state on the behaviour of Inconel 718 alloy exposed to 640 ^{circ }C and 700 ^{circ }C environments for times varying between one and one hundred hours was investigated. In particular, the focus was set on the evolution of oxidation and precipitation phenomena during thermal exposure. Three surface states were considered: two generated through shot peening treatments featuring different coverage levels, while the third condition is a non-peened one. Shot peening treatments modify the surface condition and introduce higher residual stresses and microhardness values than in the non-treated condition. The morphology of the oxides appears to be different depending on the condition observed. Regarding the kinetics, over time the oxidation process follows a parabolic trend and appears to be influenced by the surface state; in particular, severe shot peening treatment is characterized by the highest intensity of the phenomenon. However, the order of magnitude of the weight gains measured suggests that the observed variations can be neglected, and that the positive effect of shot peening can be exploited without introducing oxidation problems. From the point of view of the microstructural evolution, an increase in the coarsening kinetics of gamma” phase was observed in the shot peened layer.

Effect of High-Energy Shot Peening on Properties of High-Velocity Oxygen-Fuel Spraying

A Cr3C2-Al2O3-NiCr composite coating was prepared on an INCONEL600 alloy surface through high-velocity oxygen-fuel spraying followed by further processing through high-energy shot peening to create the composite coating. The microhardness and friction properties of the composite coating are analyzed by a microhardness tester and reciprocating friction tester. The microscopic structure and wear trace of the composite coating were analyzed by scanning electron microscope (SEM). The element distribution of the coating was analyzed by energy-dispersive spectroscopy (EDS). The porosity of the coating was detected by industrial CT. The phase and residual stress of the coating were tested by X-ray diffraction (XRD). The electrochemical corrosion and friction wear performance of the samples under different surface states were discussed. The results showed that the compactness of the coating was improved and the porosity was significantly reduced after high-energy shot peening. The high-energy shot peening did not alter the phase composition of the coating but introduced residual compressive stress. The microhardness of theCr3C2-Al2O3-NiCr high-velocity oxygen-fuel coating can reach 2.9 times that of the INCONEL600 substrate, and the hardness of the coating after high-energy shot peening can reach 3.9 times of that of the substrate. After high-energy shot peening, the corrosion resistance of the coating in HCl solution is improved. Compared with the INCONEL600 substrate, the friction coefficient and calculated wear rate of the Cr3C2-Al2O3-NiCr high-velocity oxygen-fuel coating decrease by 62.5% and 79.6%, respectively. After high-energy shot peening, the friction coefficient and calculated wear rate of the coating decrease by 75% and 98.7%, respectively.

Effect of shot peening on the surface integrity and fatigue property of gear steel 16Cr3NiWMoVNbE at room temperature

The gear steel 16Cr3NiWMoVNbE was shot peened using a range of pellet sizes and shot peeningintensities. The surface morphology, residual stress field, and cross-section microstructure were examined, and the influence of surface integrity difference on the room-temperature rotary bending fatigue performance was analyzed. The results indicate that surface roughness, the depth of maximum residual stress, and dislocation density increase as shot peening strength and projectile size increase, whereas the value of surface residual stress decreases as shot peening strength increases. By shot peening, the rotary bending fatigue life of gear steel at room temperature was enhanced by 5.03 ∼ 17.20 times. As the shot peening strength increased from 0.10mmA to 0.15mmA when AZB150 shot peening was utilised, the estimated median fatigue life of shot peening increased by 80.46%. When the shot peening strength is 0.10mmA, the estimated median fatigue life of shot peening increases by 2.02 times as the shot size increases from 0.15 mm to 0.30 mm. The actual maximum stress value taking the surface stress concentration coefficient into account was used to estimate the location of the hazardous components, which was confirmed by the fatigue source location study.

Effect of shot peening and nitrogen ion implantation on the fatigue behavior of TA15 titanium alloys

The titanium alloy TA15 was treated with SP (shot peening), followed by heat exposure at 500 °C and NII (nitrogen ion implantation) treatment at 500 °C for 5 h each. The surface topography, microstructure, micro-hardness, residual stress, and fatigue behavior were, thereafter, analyzed. The results showed that the SP and NII treatments changed the surface topography of the TA15 titanium alloy, producing a high density dislocation and a high amplitude residual compressive stress on its TA15 titanium surface. In addition, the local stress concentration on the surface was reduced, pushing the fatigue nucleation site below the surface. Also, the difficulty of crack initiation and propagation was increased. At 450 MPa, the fatigue life of the SP treated sample was increased by 23.5 times. A large amount of TiN was generated in the grains of the NII treated sample, and compared with a sample without any NII treatments, the median fatigue life was increased by 17 times. The results showed that SP can effectively improve the fatigue properties of a TA15 titanium alloy, and the NII treatment is an effective way to improve the thermal stability of the SP strengthening effect.

Competitive effect of residual stress and surface roughness on the fatigue life of shot peened S42200 steel at room and elevated temperature

The effect of shot peening (SP) on the fatigue life of S42200 steel at room and elevated temperature is investigated. The fatigue test is carried out on a high temperature rotating bending tester. Surface integrity characterization is used to study the effect of SP on surface properties. Furthermore, Finite Element Method (FEM) combined with a fatigue damage model, namely Zheng Equation, is proposed to predict the fatigue life. The results show that SP effectively improves the fatigue life of S42200 steel under all temperatures. However, at lower temperature, higher strength SP leads to higher fatigue resistance, while at higher temperature, lower strength SP leads to higher fatigue resistance. This can be explained by the competitive effect of surface roughness and compressive residual stress (CRS) relaxation on the local stress concentration. This research can be a good guide to the application of SP at different temperatures.

Effect of shot peening on electrophoretic deposition of bioactive glass coating on AISI 316L stainless steel

Bioactive glass coating of SiO2–CaO–P2O5 was synthesized and deposited on shot peened stainless steel AISI 316L substrates through electrophoretic deposition. Shot peening is known to enhance the fatigue properties of the substrate material; however, the present study aims to investigate how this prior shot peening can affect on the electrophoretic coating properties and performance. Shot peening was carried using two different sets of parameters as conventional shot peening (Almen intensity: 15A and coverage:100%), and severe shot peening (Almen intensity: 7C and coverage:1500%). The coated samples were studied regarding deposition thickness, microstructure, macrotexture and surface roughness, as well as wettability with contact angle tests. Corrosion behavior was also investigated using potentiodynamic polarization and electrochemical impedance spectroscopy in simulated body fluid solutions at 37 °C. The results confirmed that the coating thickness decreased from 55.3 μm for CNP to 27 μm and 9.5 μm for CCSP and CSSP respectively. Shot peening applied before electrophoretic deposition modulated the wettability and corrosion resistance of the coated samples through variation of roughness and the extent of grain refinement. As well as, the water contact angle of CSSP sample was equal to 15.64° which is much lower than CNP (55.3°). Also, the amount of coated samples’ corrosion rate changed by this order CCSP (1.91 × 10−2)>CNP (1.31 × 10−2)>CSSP (1.07 × 10−2). The high surface energy on shot peened samples caused the smaller BG grain size deposited on surfaces. The amount of BG grain size of each sample is as follow CNP 2.12 ± 1.6 μm, CCSP 1.34 ± 0.8 μm and CSSP 0.81 ± 0.3 μm.

Effect of Ultrasonic Shot Peening and Laser Shock Peening on the Microstructure and Microhardness of IN738LC Alloys.

IN738LC is a conventional-cast Ni-based superalloy intended for power generation and aerospace applications. Typically, ultrasonic shot peening (USP) and laser shock peening (LSP) are utilized to enhance cracking, creep, and fatigue resistance. In this study, the optimal process parameters for USP and LSP were established by observing the microstructure and measuring the microhardness of the near-surface region of IN738LC alloys. The LSP impact region (modification depth) was approximately 2500 μm, which was much higher than the USP impact depth of 600 μm. The observation of the microstructural modification and resulting strengthening mechanism revealed that the build-up of dislocations upon peening with plastic deformation was crucial for alloy strengthening in both methods. In contrast, significant strengthening via γ' shearing was observed only in the USP-treated alloys.

EFFECTS OF SHOT PENNING ON MECHANICAL PROPERTIES, MICROSTRUCTURAL EVOLUTION AND RESIDUAL STRESS OF SUBMERGED FRICTION STIR-WELDED AA6061-T6 ALLOY

The purpose of this work is to study the effect of shot peening on the mechanical characteristics of welded plates which were performed by Submerged Friction Stir Welding (SFSW) on AA6061-T6 alloy. SFSW was carried out under three cooling mediums like water, brine solution, and coolant oil at the rotational speed of 1200[Formula: see text]rpm and welding speed of 45[Formula: see text]mm/min, respectively. The welded samples from each cooling medium were subjected to a shot peening process. A tensile test was carried out on weld peened and welds unpeened joints. The hardness of the various zones of HAZ, TMAZ, and NZ was also investigated. Optical and scanning electron microscopy was used to examine the microstructures of peened and unpeened joints formed by coolant samples. Shot peening has the potential to enhance the compressive residual stress of friction stir welded joints. According to these findings, shot peening had a greater impact on the mechanical properties of welded samples than unpeened samples, including tensile strength, percentage of elongation, and hardness. The grain size was a little bit smaller than the FSW sample because the surface of the welded samples was subjected to more strain during shot peening.

Effects of Ultrasonic Shot Peening on the Corrosion Resistance and Antibacterial Properties of Al0.3Cu0.5CoCrFeNi High-Entropy Alloys

Cu-bearing high-entropy alloys (HEAs) have been proposed for use as structural materials in the marine environment due to their superior mechanical and antimicrobial properties. However, the Al, Cu-enriched precipitations in HEAs damage their corrosion resistance. In this study, we used ultrasonic shot peening (USSP) technology to solve this problem. USSP caused severe plastic deformation of the Al0.3Cu0.5CoCrFeNi HEA surface and dispersed the long-strip Al, Cu-enriched phases into scattered dots, which reduced the galvanic corrosion of the HEA and enhanced passive film formation. The Al, Cu-enriched scattered precipitations also increased the number of Cu2+ ion dissolution sites, leading to the improvement of the alloy’s antibacterial properties.

Additively Manufactured 316L Stainless Steel Subjected to a Duplex Peening-PVD Coating Treatment.

This research studies the individual and combined effects of mechanical shot peening and the deposition of TiAlCuN coating on additively manufactured 316L stainless steel. Shot peening has been found to induce a 40% increase in surface hardness, while the combined effect of shot peening and the coating produced an approximately three-fold increase in surface hardness when compared to the as-printed coupons. Shot peening reduced the surface roughness of printed metal coupons by 50%, showing that shot peening can also serve to improve the surface finish of as-printed 316L stainless steel components. The peening process was found to induce a compressive residual stress of 589 MPa, with a maximum affected depth of approximately 200 μm. Scratch testing of the printed and coated specimens showed complete delamination failure at a normal load of 14 N, when compared to hybrid treated samples which failed at 10 N. On the other hand, from the corrosion tests, it was found that the hybrid treated samples provided the optimal results as opposed to the other variables.

Effect of ultrasonic shot peening on electrodeposited Ni and Cu coatings on Cu substrate

In this study, the effect of ultrasonic shot peening (USSP) on bilayered Ni and Cu coatings on Cu substrate was studied. On the Cu substrate, Ni and Cu coatings were sequentially electrodeposited followed by ultrasonic shot peening with a varying shot diameter and peening time. Apart from phase analysis and microscopy study of the coatings (before and after peening), hardness, compressive residual stress, wear, and corrosion resistances are also examined. Improvement of surface-mechanical properties and electrochemical properties were observed in specific peening conditions. There was also a noticeable improvement in residual compressive stress as an effect of peening.

What can micromechanics tell us about the surface integrity of shot-peened materials?

Standard techniques for assessing shot peening include XRD and EBSD for measuring residual stresses and severe deformation beneath the surface; however, these techniques do not consider the localised micromechanical behaviour. Here, single-grain micropillar compression tests in a Ni-base superalloy reveal that the micromechanical effect of shot peening could be insignificant due to the machining-induced pre-strained condition of the surface. Further, it is shown that shot-peening-induced strengthened layer can extend much less (∼50%) than the depth at which compressive stresses are still present. This work highlights the need for employing micromechanics as a complementary shot peening assessment technique for machined components.

Fatigue Limit Improvement and Rendering Surface Defects Harmless by Shot Peening for Carburized Steel

Remanufacturing has become popular as a system for reducing CO2 emissions caused by the life cycle of products. Therefore, producing more components via remanufacturing is important. Shot peening can be used to render surface defects harmless owing to the compressive residual stress effects. This study investigated the effects of shot peening as a means of remanufacturing gears. In this study, carburized steel specimens containing artificial defects were used to investigate the effects of shot peening on the fatigue strength; the defect size was rendered harmless by shot peening. Shot peening was conducted after inducing semicircular slits with depths of a = 0.15, 0.20, and 0.30 mm. Subsequently, plane bending fatigue tests were carried out. A maximum compressive residual stress of 1400 MPa was induced after shot peening. The fatigue limit of the smooth specimen increased by approximately 31% after shot peening. A semicircular slit of at least 0.20 mm deep could be rendered harmless by shot peening (SP). The defect size reduced by SP was evaluated on the basis of fracture mechanics. The estimated results are consistent with the experimental results. On the basis of the results, the feasibility of shot peening as a remanufacturing method for gears is discussed.

The Effect of Shot Peening on Residual Stress and Surface Roughness of AMS 5504 Stainless Steel Joints Welded Using the TIG Method.

This article presents the influence of the Shot Peening (SP) process on residual stress and surface roughness of AMS 5504 joints welded using the Tungsten Inert Gas (TIG) method. Thin-walled steel structures are widely used in the aviation and automotive industries, among others. Unfortunately, the fatigue properties become worse during the welding process. Samples of 1 mm-thick AMS 5504 steel plates were first prepared using TIG welding and then strengthened by the Shot Peening (SP) process. The technological parameters of the SP process were changed in the range of time t from 2 min to 4 min and of pressure p from 0.4 MPa to 0.6 Mpa. The residual stresses were measured by X-ray diffraction in three zones: fusion zone (FZ), heat-affected zone (HAZ) and base metal (BM). The results showed that SP introduced compressive residual stresses in all of the zones measured, especially in the FZ. The greatest value of compressive residual stresses σ = -609 MPa in the FZ was observed for the maximum parameters of SP (p = 0.6 MPa, t = 4 min). The increase in value of residual stress is about 580% when compared to welding specimens without treatment. As a result of shot peening in the FZ, the mean roughness value Ra decreased in range 63.07% to 77.67% in the FZ, while in the BM increased in range 236.87% to 352.78% in comparison to specimen without treatment. Selected surface roughness parameters in FZ and BM were analyzed using neural networks. In FZ, it was demonstrated that the most correlated parameters with residual stresses are Rt and Rsk. On the other hand, in the BM zone, the most correlated parameters were Rv, Rt and Rq. This enables the estimation of stresses in the welded joint after SP on the basis of selected roughness parameters.

Erosion-corrosion behaviour of shot peening treated nickel-aluminium bronze in simulated sand-containing seawater

The effect of shot peening on the erosion-corrosion property of nickel-aluminium bronze was investigated. The results show that erosion-corrosion has a shot peening-like effect and thus increases the hardness and compressive residual stress. Shot peening alters the erosion-corrosion mechanism. With peening intensity increasing, the predominant reason for causing materials removal shifts progressively from ductile deformation coupled with selective phase corrosion to brittle cleavage-like fracture, highlighting the overriding role of strain-hardening capacity over hardness, compressive residual stress, and surface roughness in erosion-corrosion performance. However, the mass loss rate can be reduced by up to 30% by implementing appropriate peening intensity.

Effect of shot peening on surface characterization and cavitation resistance of nickel aluminum bronze

Nickel aluminum bronze is subjected to cavitation corrosion as propellers working in the seawater. The cavitation corrosion is dominated by the synergistic effect of corrosion and mechanical attack. Previous studies have demonstrated that shot peening (SP) could enhance surface mechanical strength through residual stress and refined grains. In this work, shot peening with Almen intensities from 30 A to 40 A is performed on the nickel aluminum bronze to investigate the effect on the corrosion and cavitation performance. After shot peening with the rough surface, the samples exhibit higher corrosion current densities due to the increased corrosion area and galvanic cells compared to the as-treated samples. Meanwhile, the samples treated by 40 A show the lowest mass loss during the cavitation test and the highest surface micro-hardness. The enhancement of the cavitation resistance is dominated by the coupling mechanism of the surface corrosion aggravation and strain strengthening. Meanwhile, the higher current intensity, the more pronounced surface strengthening enhancement due to the grain refinement's synergistic mechanism and dislocation density.

Effect of surface shot peening on the microstructure and mechanical properties of fuel cladding 1515-Ti austenitic steel

Lead-bismuth fast reactor is considered to be the most promising solution to meet the enormous energy demand in the future. The 15-15Ti austenitic stainless steel with outstanding corrosion and irradiation resistance has been proposed as main cladding candidate material for lead-bismuth fast reactor. However, the mechanical properties of 15-15Ti are weakly influenced by LBE. Shot peening as one of surface strengthening technique can efficiently improve metal mechanical properties. In this paper, shot peening (SP) treatment was applied on 15-15Ti. The microstructures and compositions were investigated using Optical Microscope, Scanning Electron Microscope and X-Ray Diffraction. It concludes that the material hardness is improved, and the residual stress induced by SP did not cause martensitic phase transformation on the sample surface. The presence of slip bands and other obstacles in the reinforcement layer improved the yielding and tensibility of the material.

Effect of shot peening on high cycle and very high cycle fatigue properties of Ni-based superalloys

In this work, the GH4169 superalloy specimens were shot-peened at two different intensities (0.15 mmA and 0.3 mmA) to improve the fatigue properties, and the fatigue behavior of the shot-peen-treated specimens was investigated in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regime. The results of the HCF and VHCF tests indicated that shot peening improved the fatigue properties of the material. In addition, it has shown that the tensile residual stresses introduced by excessive shot peening intensity reduce the benefits of shot peening in terms of improving fatigue properties.

Improving effects of cavitation peening, using a pulsed laser or a cavitating jet, and shot peening on the fatigue properties of additively manufactured titanium alloy Ti6Al4V

To demonstrate and compare the improving effects of cavitation peening and shot peening on the fatigue properties of additively manufactured metals, titanium alloy Ti6Al4V specimens prepared by direct metal laser sintering were treated by cavitation peening, using a pulsed laser or a submerged high-speed cavitating water jet, and shot peening and, subsequently, subjected to torsion fatigue tests. It was revealed that cavitation peening using a laser, shot peening, and cavitation peening using a cavitating jet prolong the fatigue life of AM Ti6Al4V at τa (applied stress) = 450 MPa by factors of 3.5, 3.2, and 1.4, respectively.