Peening Surface Treatment Research Articles

Shot Peening Effect on Sliding Wear in 0.9% NaCl of Additively Manufactured 17-4PH Steel.

The growing demand for modern steels showing corrosion and tribological resistance has led to their increased use in the production of medical devices. This study analyzed the effect of shot peening on wear resistance in 0.9% NaCl solution of 17-4PH steel produced by direct laser metal sintering (DMLS) technology. The study's novelty relies on revealing the effect of shot peening (SP) surface treatment on the wet sliding wear resistance of 17-4PH steel produced with DMLS. Moreover, in the context of 17-4PH steel application for medical devices, the 0.9% NaCl tribological environment were selected, and SP processes were conducted using steel CrNi shot and ceramic (ZrO2) beads. The up-to-date scientific literature has not identified these gaps in the research. DMLS technology makes it possible to obtain products with complex architectures, but it also faces various challenges, including imperfections in the surface layer of products due to the use of 3D printing technology itself. The chemical and phase composition of the materials obtained, Vickers hardness, surface roughness, and microscopic and SEM imaging were investigated. Tribological tests were carried out using the ball-on-disc method, and the surfaces that showed traces of abrasion to identify wear mechanisms were subjected to SEM analysis. The XRD phase analysis indicates that austenite and martensite were found in the post-production state, while a higher martensitic phase content was found in peened samples due to phase transformations. The surface hardness of the peened samples increased by more than double, and the post-treatment roughness increased by 12.8% after peening CrNi steels and decreased by 7.8% after peening ZrO2 relative to the reference surfaces. Roughness has an identifiable effect on sliding wear resistance. Higher roughness promotes material loss. After the SP process, the coefficient of friction increased by 15.5% and 20.7%, while the wear factor (K) decreased by 25.9% and 32.7% for the samples peened with CrNi steels and ZrO2, respectively. Abrasive and adhesive mechanisms were dominant, featured with slight fatigue. The investigation showed a positive effect of SP on the tribological properties of DMSL 17-4PH.

Effect of Shot Peening and Nitriding on Toughness and Abrasive Wear Resistance of Powder Metallurgic Steels Highly Alloyed with Vanadium

Böhler K390 steel is used for cold work tools, with 9% of V, made by using powder metallurgy. In this work, it has been studied the effect of shot peening and nitriding surface treatments on wear resistance and impact toughness of this type of steel. For this purpose, previous changes in several thermal processing factors related to quenching and tempering were carried out. The results allow for an increase in the hardness, impact toughness, and abrasive wear resistance of these steels. An austenitizing treatment at 1100 °C with air cooling and 3 tempering processes at 550 °C is suggested. These conditions foster a lower weight percentage of retained austenite, up to 3%, a higher carbide percentage, up to 15–16% in weight, and a greater impact toughness with no notch, of above 40 J/cm2. If this treatment is combined with further ion nitriding, the maximum level of abrasive wear resistance is reached. The only carbide type present in the microstructure is the MC type. Most of the V, Cr, and Mo contents are present in said carbides. The Co and the W tend to remain in solid solution in the matrix constituent. Both the shot peening treatment as well as ion nitriding offer a considerable increase in hardness, with values of up to 1500–1600 HV. Nevertheless, it has been confirmed that shot peening does not offer any abrasive wear resistance improvement. Such resistance may only be considerably improved by the application of an ionic nitriding treatment. The thickness of the nitrided layer fluctuates between 150 and 175 µm. The carbides are affected by nitriding, reaching levels that are higher than the atomic 10%, at an intermediate depth of the nitrided layer. These values are higher in the matrix constituent, as they are even higher than the atomic 20% in N.

Third-generation biodegradable bone implants: A novel Mg-1Zn-0.5Sc alloy treated by laser shock peening to improve its characteristics

Magnesium (Mg) and its alloys are of much interest as promising third-generation bio-materials for bone implant applications; however, challenges remain for the alloy's mechanical integrity and bio-corrosion behaviour. Therefore, appropriate alloying elements and surface-modification techniques are required to overcome these limitations. Zinc and scandium were found to possess good biocompatibility and biodegradability, in addition to magnesium. This study aims to enhance the mechanical integrity and bio-corrosion resistance behaviour of a novel Mg-1wt% Zn-0.5wt% Sc cast alloy by laser shock peening surface treatment with multiple passes (LSP-2 pass and LSP-3 pass). The microstructural and texture evolution was investigated using various techniques, including field emission scanning electron microscopy with energy-dispersive spectroscopy (FESEM-EDS), optical microscopy (OM), X-ray diffraction (XRD) analysis, electron back-scattered diffraction analysis (EBSD), as well as the surface residual stress, wettability, microhardness, tensile strength, electrochemical polarization test, and biocompatibility were analysed on as-cast, LSP-2 pass and LSP-3 pass specimens. LSP induced beneficial compressive residual stress around the surface and sub-surface region of Mg-1Zn-0.5Sc alloy due to severe plastic deformation, which led to grain refinement through the twinning mechanism of the Mg alloy. Also, the dispersion of second-phase particles (β-ScZn) was observed while analysing the XRD profiles. Strain hardening, grain refinement, and precipitate strengthening have contributed to the structure and texture evolution, which enhanced the microhardness, tensile strength, ductility, and corrosion resistance of the Mg-1Zn-0.5Sc alloy. From in vitro studies, a low rate of corrosion in simulated body fluid and less cytotoxic behaviour were observed for the LSP-3 pass Mg-1Zn-0.5Sc alloy.

Influence of Conventional Shot Peening Treatment on the Service Life Improvement of Bridge Steel Piles Subjected to Sea Wave Impact

The first goal of the current study is to estimate the fatigue life of the middle steel piles of an integrated bridge installed in water and subject to the impact of sea waves. In the following, the authors have tried to improve the service life of this critical part of the bridge, which is also the main purpose of the study. To this end, conventional shot peening, as one of the most well-known surface treatments, was used. Axial fatigue tests were performed on samples fabricated from IPE-220 steel piles in two states without and with shot peening surface treatment. Next, the modified S-N curve was entered into the finite element software to define the effect of shot peening treatment. Different analysis, including thermal, thermal-structural coupled, and transient dynamic, were performed and various outputs were extracted for the entire structure. In all these analyses, changes in air temperature have been neglected. The most important achievement of this research is the discovery that motionless water cannot cause serious damage to steel piles. Moreover, application of conventional shot peening can increase the fatigue life of steel piles, or in other words the service life of the bridge, subjected to the impact of sea waves by about 22%.

The effect of surface treatment and orientation on fatigue crack growth rate and residual stress distribution of wire arc additively manufactured low carbon steel components

The directed energy deposition (DED) processes, such as laser metal deposition or Wire Arc Additive Manufacturing (WAAM), are gradually becoming the preferred method for fabrication of large-scale components using metal additive manufacturing (AM) technology. In this work, the possibility of fatigue life enhancement in WAAM built low carbon steel components, by means of rolling and laser shock peening surface treatment techniques, was investigated. A series of fatigue crack propagation tests were performed on surface treated ER70S-6 and ER100S-1 WAAM built specimens, and the results were analysed and compared with the untreated materials tested under the same loading conditions. The obtained results were interpreted in terms of the sensitivity of the cracking behaviour to the specimen orientation and extraction location. Furthermore, the residual stress profiles were measured, before and after applying the surface treatment techniques, and the effects of locked-in residual stresses on the fatigue performance of WAAM built components were discussed. Finally, a detailed texture analysis was performed on the surface treated and untreated regions of both WAAM built materials considered in this work. The obtained results from this study provide an insight into the advantages and disadvantages of various surface treatment techniques for fatigue life enhancement of WAAM built components with the view to extend the application of this advanced manufacturing technology to a wider range of industrial applications.

The influence of laser shock peening on corrosion-fatigue behaviour of wire arc additively manufactured components

The need for increased manufacturing efficiency of large engineering structures has led to development of wire arc additive manufacturing (WAAM), which is also known as direct energy deposition (DED) method. One of the main barriers for rapid adoption of the WAAM technology in wider range of industrial applications is the lack of sufficient performance data on the WAAM components for various materials and operational conditions. The present study addresses this essential need by exploring the effects of laser shock peening surface treatment on corrosion-fatigue crack growth (CFCG) life enhancement of WAAM components made of ER70S-6 and ER100S-1 steel wires. The experimental results obtained from this study were compared with the CFCG trends from nominally identical specimens without surface treatment and prove the efficiency of the examined surface treatment method for corrosion-fatigue life enhancement and crack growth retardation of WAAM built steel components, regardless of the material type and specimen orientation. Furthermore, the residual stresses in the WAAM built specimens with and without surface treatment were measured to validate the influence of beneficial residual stresses, arising from surface treatment, on subsequent CFCG behaviour of the material. The residual stress profiles show the beneficial compressive stress fields in the surface treated areas which result in CFCG life enhancement. The results from this study make significant contribution to knowledge by evaluating the suitability of WAAM built steel components for application in offshore environments.

Effect of Ultrasonic Peening on Mechanical Properties of Low Carbon Steel AISI 1020 TIG Welding Joints Process

In this paper, the effect of ultrasonic peening surface treatment on the mechanical properties of TIG butt weld joints of low-carbon steel (AISI 1020) was studied. A single V-angle (<i>45</i>°) was made on sheets of metal used then welded at constant parameters, namely: current, voltage. Wire filler ER70S-3 with argon was used to obtain many butt welding joints. Some of them were subjected to ultrasonic peening at one, two and three passes. The micro-hardness, microstructure, tensile and bending were tested. The results show increases in the tensile strength after the welding process. The test results showed improvements in the tensile strength of the weldments in comparison to the base metal. On the other hand, the tensile strength decreased with the ultrasonic process. Nevertheless, the tensile strength increased at a high number of ultrasonic passes. On the contrary, the ultrasonic process enhanced the bending strength compared to the base metal, whereas the weldments ability to bend deteriorated.

The effects of laser peening treatment on the very high cycle fatigue properties for AA2024-T351 alloy using a crystal plasticity framework

The effects of laser shot peening (LSP) on very high cycle fatigue (VHCF) properties of AA2024-T351 alloy were investigated using the combination of experiment and modified crystal plasticity finite element (CPFE) method. The experimental observation found a contradictable result that the fatigue life decreased after laser peening with relatively high pulse energy in this work. The fatigue fracture observation shows that there are obvious facets and refined grains on the shot peening surface, which are not uniform and their aspect ratio is obviously larger than that of the matrix material. In particular, the fracture surface of the sample treated with 20 J pulse energy shows a highly distorted zig-zag crack propagation path. In order to further understand the ultra-high cycle fatigue failure mechanism of aluminum alloy treated with laser shot peening, a modified crystal plasticity (CP) model was applied to find a possible explanation for the contradictable experimental results. In this model, the critical resolved shear stress (CRSS) evolution of the deformation systems in the CP model was variable due to the refined average grain size after different laser peening conditions using the Hall-Petch type relationship. Additionally, the effects of grain morphology characterized by aspect ratio were considered after LSP of AA2024-T351. The fatigue indicator parameters (FIPs) were calculated based on the modified CPFE model under cyclic low stress amplitudes to estimate the fatigue driving force for fatigue crack initiation and microstructural small crack propagation. It is found that the LSP treatment has a beneficial effect on the fatigue properties only considering the refined influence of grain size. However, LSP has a detrimental effect on VHCF properties when considering the combined influences of grain refinement and the changing of grain aspect ratio due to the laser peening surface treatment with relative high pulse energy in this work.

Influence of surface treatment on the metal dusting behavior of alloy 699 XA

AbstractMetal dusting attack is a serious problem in processing industries using carbonaceous gases and high temperatures. Ni‐based alloy 699 XA was recently developed as an alloy for these types of environments with high resistance against metal dusting. In this study, different surface treatments of this chromium‐ and aluminum‐rich alloy are shown to have an important influence on the metal dusting onset behavior. It was found that surface treatments that are traditionally considered to be helpful for fatigue performance, for example, shot peening, and pickling were detrimental to the metal dusting performance of alloy 699 XA. Additionally, the shot peening surface treatment promoted Fe surface contamination, resulting in a negative impact on the metal dusting pitting resistance of the alloy. Deformation accompanied by apparent BCC α‐Cr precipitation in the bulk microstructure, but a comparison with cold‐rolled materials shows that the surface treatment dominates the metal dusting resistance.

Corrosion Protection on AISI 304 by Shot Peening Treatment with Variation of Particle Size and Shooting Pressure

AISI 304 is widely used as biomedical material due to its lower cost and availability, but low corrosion resistance. The shot peening method can increase the mechanical characteristics and corrosion resistance of a surface. The purpose of this study was to determine the effect of shot peening surface treatment with a combination of steel ball diameter variations and pressure on corrosion resistance of AISI 304 material. Shot peening treatment was carried out using variations of 0.2, 0.5, and 0.8 mm steel ball diameters with a hardness of around 40-50 HRC. Shot peening pressure varies from 7, 8, and 9 bar. Corrosion rate testing was carried out using bovine serum media. The results showed that the best increase in corrosion resistance was 0.117 mpy for a steel ball diameter of 0.5 mm with a pressure of 9 bar, 3 times lower than that of non-treated specimens, which was 0.378 mpy.

Laser shock wave loading of the vanadium and titanium

Measurements of the plastic wave attenuation in the material is very important for understanding Laser Shock Peening (LSP) surface treatment (Seddik et al. (2022)) mechanisms. We have tested thin disk-shaped specimens from titanium VT6 and vanadium VnP-1. Specimens were loaded by Beamtech SGR-Extra-10 Nd:YAG pulse laser. To increase the wave amplitude the front surface was covered by a thin water layer. The water layer should be thin because of the absorption of the IR radiation in the water. At provided laser energy density we did not observe any spallation. We did not observe grain fragmentation and other signs of severe plastic deformation.

Fatigue study on AISI/SAE 1015 steel with shot peening under corrosive environments

This work evaluates alternative four-point bending fatigue stress in 2 < pH < 4 corrosive media of AISI/SAE 1015 steel subjected to shot peening surface treatment. A tri factorial experimental design with replications was used. The intervening factors were: i) load levels, 0.96, 0.85, 0.73, 0.65; ii) corrosive media; pH2, pH4, ambient; iii) shot-peening surface treatment; without any shot peening, S230 shot peening and CW-41 shot peening, for which a total of 108 specimens were tested with a reliability level of 95% and a probability of failure of 3%. Tests were performed on a universal machine in a three-point bending assembly with an electro-pneumatic system. The cycle counting and control were performed by a programmable logic controller. The results of the stress-life method in each one of the scenarios show that the best condition was shown in the probes with shot peening S230 and CW-41 treatment under atmospheric conditions, where the material tends to increase its fatigue behavior; the number of cycles reached 36990 and 37773 respectively. The corrosive effect of pH2 and pH4 reduced on probes without shot peening treatment with a maximum of 9862 and 8670 cycles respectively; however, for S230 and CW-41 shots, an increase in cycle number in pH2 and pH4 was evidenced, with the best result for S230 shot at pH4 with a maximum range of 21568. Likewise, the fractography analysis shows mixed fractures with fatigue failure mechanism; the characteristics found were beach marks, secondary cracks, localized oxidation (filiform, plates, pitting, stress, and compression corrosion), nucleation, microvoids, cleavage facets, intergranular and transgranular cracks.

Cumulative Fatigue damage of AA7075-T6 under Shot Peening and Ultrasonic Surface Treatments

One of the important aspects of mechanical design is improving fatigue life.; In this work, the effect of Ultrasonic impact treatment (UIP) and shot peening (SP)on constant cumulative fatigue life and fatigue strength of AA7075-T6 were studied; The sample group was machined and primed, and some specimens were treated using ultrasonic impact therapy (UIT) with one line of peening. Fatigue experiments were conducted under constant and variable amplitude (R=-1) at ambient temperature to determine the fatigue life of the S-N curve and fatigue strength during treatment 3.46% and 8.57% at 107 cycles for (UIT) and (SP). Cumulative fatigue damage testing was carried out for two steps loading it is observed that the fatigue life for SP and UIP treated specimens was improved compared to the unpeeled results. The fatigue endurance limit was enhanced by 35% for UIT and 54% for SP. The fatigue life for both treatments was much improved compared to as-received metal. These results also show a strong tendency of increasing fatigue strength after application of (UIT) and (SP) with an increase in mechanical properties of the material used.

Influence of shot peened surfaces on friction in hot forging

Dies in hot forging operations are subjected to a complex load combination consisting of thermal, mechanical and tribological loads. Therefore, hot forging dies exhibit short service life in comparison to other forming operations. An extension of tool life represents an effective way of increasing the efficiency of hot forging operations since the dies represent a large share of the process chain’s production costs. Since there is no prior knowledge of ideal die surface properties, a shot peening surface treatment was applied in order to create enhanced tribological properties in comparison to machined die surfaces.Peening is a surface treatment procedure which enables a repeatable and accurate adjustment of topographical parameters. In this scientific contribution, the technique is investigated as a method to enhance tribological properties of hot forging die surfaces resulting in less friction and wear. Hot forging dies of AISI H11 were peened using different peening media creating die surfaces with varying topography. Tribological properties of the peened die surfaces were analysed in ring compression tests in dry and lubricated conditions using water-based graphite lubricant. The lowest friction was detected under lubricated conditions for peened surfaces with slightly increased roughness compared to the initial smooth, unpeened die surfaces.

Laser peening: A tool for additive manufacturing post-processing

Additive manufacturing (AM) is rapidly moving from research to commercial applications due to its ability to produce geometric features difficult or impossible to generate by conventional machining. Fielded components need to endure fatigue loadings over long operational lifetimes. This work evaluates the ability of shot and laser peening to enhance the fatigue lifetime and strength of AM parts. As previously shown, peening processes induce beneficial microstructure and residual stress enhancement; this work takes a step to demonstrate the fatigue enhancement of peening including for the case of geometric stress risers as expected for fielded AM components. We present AM sample fatigue results with and without a stress riser using untreated baseline samples and shot and laser peening surface treatments. Laser peening is clearly shown to provide superior fatigue life and strength. We also investigated the ability of analysis to select laser peening parameters and coverage that can shape and/or correctively reshape AM components to a high degree of precision. We demonstrated this potential by shaping and shape correction using our finite element based predictive modeling and highly controlled laser peening.

Effect of Applied Stress and Temperature on Residual Stresses Induced by Peening Surface Treatments in Alloy 600

In this study, the effects of applied tensile stress and temperature on laser shock peening (LSP) and cavitation shotless peening (CSP)-induced compressive residual stresses were investigated using neutron and x-ray diffraction. Residual stresses on the surface, measured in situ, were lower than the applied stress in LSP- and CSP-treated Alloy 600 samples (2 mm thick). The residual stress averaged over the volume was similar to the applied stress. Compressive residual stresses on the surface and balancing tensile stresses in the interior relax differently due to hardening induced by LSP. Ex situ residual stress measurements, using XRD, show that residual stresses relaxed as the applied stress exceeded the yield strength of the LSP- and CSP-treated Alloy 600. Compressive residual stresses induced by CSP and LSP decreased by 15-25% in magnitude, respectively, on exposure to 250-450 °C for more than 500 h with 10-11% of relaxation occurring in the first few hours. Further, 80% of the compressive residual stresses induced by LSP and CSP treatments in Alloy 600 were retained even after long-term aging at 350 °C for 2400 h.

Effects of low intensity shot peening treatments applied with different types of shots on the fatigue performance of a high-strength steel

The aim of this research is to study the fatigue life enhancement produced in a quenched and tempered AISI4340 steel with a tensile strength of 2000 MPa after being submitted to shot peening surface treatments. These treatments generate compressive residual stress fields in a superficial layer of the material at the same time as inducing some kind of damage on the surface. Different kind of projectiles were chosen to perform the treatment (ceramic and steel shots), studying the way these affected the fatigue life of the specimens.The surface topography of the samples was analysed using a roughness tester and by means of scanning electron microscopy (SEM). The compressive residual stress profile induced by these treatments was measured using X-ray diffraction (XRD) plus electro-polishing. The fatigue behaviour of the treated samples was subsequently studied by means of 4-point rotating bending tests and their fracture surfaces were analysed using SEM.The best fatigue performance was obtained after shot peening with ceramic beads under an 8A Almen intensity. The main difference in relation to the treatment performed under the same intensity but using steel cut wire shots was the much lower surface damage induced by the impacts with the ceramic shots compared with the cut wire projectiles, which in turn is justified by the greater geometric perfection and hardness of the former. Furthermore, fatigue specimens shot peened with ceramic beads under an 8A intensity always gave rise to internal fatigue crack initiation, which took place outside the zone subjected to residual compressive stresses. Moreover, fatigue initiation was always linked to the presence of hard and rigid alumina inclusions, which acted as microstructural stress concentrators.

Effect of Abrasive Waterjet Peening Surface Treatment of Steel Plates on the Strength of Single–Lap Adhesive Joints

Effect of Abrasive Waterjet Peening Surface Treatment of Steel Plates on the Strength of Single–Lap Adhesive Joints

Improvement of fatigue endurance of welded S355 J2 structural steel by severe shot peening

ABSTRACTThis work deals with the fatigue resistance of welded joints manufactured from EN S355 J2 structural steel and the possibility of improving fatigue characteristics by the severe shot peening (SSP) surface treatment. Fatigue testing was carried out by the rotating bending test on specimens manufactured from the base material (BM), welded material and welded material treated by SSP. Results have shown big scatter in obtained results from as-welded material and overall reduction of fatigue endurance when compared to the BM. SSP applied on the welded joints has reduced the scatter of experimental data and increased the fatigue strength. Obtained results of fatigue tests are compared, discussed and supported by correlation with results of additional experiments, e.g. metallographic analyses, microhardness tests, residual stresses measurements and surface roughness measurement.

Predictive design approach of high-cycle fatigue limit of shot-peened parts

This attempt proposes an engineering design approach to predict the high-cycle fatigue limit of shot-peened parts. The effects of the shot peening surface treatment on the high-cycle fatigue performance of Waspaloy, a nickel superalloy widely used in the airframe sector, are investigated. The proposed approach consists in (i) predicting the initial shot peening surface properties, (ii) simulating the evolution of the shot peening surface properties occurring during fatigue loading, and (iii) deducing the new fatigue limit of the shot-peened surface in the case of tensile, torsion, and combined tensile-torsion loading. The physical model is implemented and analyzed using the finite element analysis. The mathematical model sheds light on the evolution of the shot-peened surface performance. It allows determining the influence of the industrial parameters in order to optimize the shot peening process operating conditions. The prediction of the fatigue performance for different shot peening conditions leads to have physically consistent results.