Investigation of Water Cavitation Peening-Induced Microstructures and Residual Stress in the Near-Surface Spring Steel SAE 1070

2011 ◽  
Vol 299-300 ◽  
pp. 1036-1039
Author(s):  
Bing Han ◽  
H. Zhang ◽  
Dong Ying Ju
Keyword(s):  
Residual Stress ◽  
Spring Steel ◽  
Bubble Collapse ◽  
In Situ Observation ◽  
Near Surface ◽  
Influence Of Water ◽  
Observation Function ◽  
Stress Layer ◽  
Surface Morphologies ◽  
The Impact

Water cavitation peening (WCP) with aeration, namely, a new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. In this study, the influence of water cavitation peening (WCP) treatment on the microstructure of spring steel SAE 1070 was investigated. The microstructural evolution in the near-surface of spring steel SAE 1070 as a function of WCP time was characterized by X-ray diffraction (XRD), optical microscopy (OM). After WCP treatment, changes in the microstructure, as well as residual stress and surface morphologies as functions of WCP time, were recorded using a novel experimental design involving an in-situ observation function. The obtained results indicated that the refinement grains were induced by WCP in the strengthening layer. A stable compressive residual stress layer was found in the near-surface of the investigated spring steel SAE 1070.

A Method for Evaluating Intensity of Water Cavitation Peening Processing

2011 ◽  
Vol 675-677 ◽  
pp. 747-750
Author(s):  
B. Han ◽  
Dong Ying Ju ◽  
Xiao Guang Yu
Keyword(s):  
Residual Stress ◽  
Process Capability ◽  
Diffraction Method ◽  
Spring Steel ◽  
Bubble Collapse ◽  
Plastic Layer ◽  
Process Conditions ◽  
X Ray Diffraction ◽  
Near Surface ◽  
The Impact

Water cavitation peening (WCP) with aeration, namely, a new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. In this study, in order to investigate the process capability of the WCP with aeration a standard N-type almen strips of spring steel SAE 1070 was treated byWCP with various process conditions, and the arc height value and the residual stress in the superficial layers were measured by means of the Almen-scale and X-ray diffraction method, respectively. The optimal fluxes of aeration and the optimal standoff distances were achieved. The maximum of arc height value reach around 150μm. The depth of plastic layer observed from the results of residual stresses is up to 150μm. The results verify the existence of macro-plastic strain in WCP processing. The distributions of residual stress in near-surface under different peening intensity can provide a reference for engineers to decide the optimal process conditions of WCP processing.

Investigation of the Process Capability of Water Cavitation Peening and Shot Peening Processing

2011 ◽  
Vol 69 ◽  
pp. 83-87
Author(s):  
Bing Han ◽  
Chao Deng ◽  
Dong Ying Ju
Keyword(s):  
Shot Peening ◽  
Process Capability ◽  
Potential Method ◽  
Spring Steel ◽  
Bubble Collapse ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Treatment Changes ◽  
Surface Morphologies ◽  
The Impact

Water cavitation peening (WCP) with aeration is a recent potential method in the surface enhancement techniques. In this method, a ventilation nozzle is adopted to improve the process capability of WCP by increasing the impact pressure, which is induced by the bubble collapse on the surface of components in the similar way as conventional shot peening(SP). In this paper, the process capability of water cavitation peening and shot peening is investigated, The residual stresses in the near-surface and surface morphologies of spring steel SAE 1070 was characterized by X-ray diffraction (XRD), optical microscopy (OM). After peening treatment, changes in surface morphologies, as well as residual stress with the different peening duration were recorded. The obtained results indicate that the WCP processing had a better surface finish than SP processing.

Experimental Investigation on Intensity and Residual Stress in Superficial Layers Induced by Water Cavitation Peening with Aeration

2008 ◽  
Vol 373-374 ◽  
pp. 754-757 ◽  
Author(s):  
Dong Ying Ju ◽  
B. Han
Keyword(s):  
Residual Stress ◽  
Process Capability ◽  
Diffraction Method ◽  
Spring Steel ◽  
Bubble Collapse ◽  
Process Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Enhancement Method ◽  
The Impact

Water cavitation peening (WCP) with aeration is a novel surface enhancement method. A new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. In this study, in order to investigate the process capability of the WCP with aeration, a standard N-type almen strips of spring steel SAE 1070 was treated by WCP with various process conditions, and the arc height value and the residual stress in the superficial layers were measured by X-ray diffraction method. The optimal fluxes of aeration and the optimal standoff distances were achieved.

Investigation on Fatigue Crack Growth Behaviour in S45C Steel by Water Cavitation Peening with Aeration

2007 ◽  
Vol 561-565 ◽  
pp. 2485-2488 ◽  
Author(s):  
B. Han ◽  
Dong Ying Ju ◽  
Tetsuya Nemoto
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Compressive Residual Stress ◽  
Bubble Collapse ◽  
In Situ Observation ◽  
Crack Growth Behaviour ◽  
Near Surface

Water cavitation peening (WCP) with aeration is a recent promising method in the surface enhancement technique, which can induce compressive residual stress in the near surface of mechanical components by the bubble collapse on the surface of components in the similar way as conventional shot peening. In this paper, the effect of WCP on fatigue crack growth behavior was investigated in single-edge-notched flat tensile specimens of S45C steel. The notched specimens were treated by WCP, and the compressive residual stress distributions in the near surface layer were measured by X-ray diffraction method. The tension-tension (R = Smin/Smax = 0.1, f = 10 Hz) fatigue tests were conducted. A Shimadzu servo-hydraulic fatigue test machine with in-situ observation by JSM-5410LV scanning microscope was used for all testing. Compared with those without WCP treatment, WCP can induce the residual compressive stress in the near surface layer, and delay the fatigue crack initiation, and decrease the rate of fatigue crack growth.

scholarly journals Effect of Centrifugal Shot Peening on the Surface Properties of Laser-Cut C45 Steel Parts

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3635 ◽  
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Shot Peening ◽  
Experimental Studies ◽  
Combustion Products ◽  
Stress Distributions ◽  
Machining Center ◽  
Fold Reduction ◽  
Stress Layer ◽  
The Impact

This article presents the results of experimental studies of the impact of centrifugal shot peening parameters on the roughness, microstructure, and microhardness of the surface layer of laser-cut C45 steel parts. Residual stress distributions and the presence of iron oxides on the surface of these elements were also examined. Centrifugal shot peening tests were performed on an FV-580a vertical machining center while using a specially designed peening head. The parameters that were varied during centrifugal shot peening included tangential speed of the tool vg and feed rate vf. The use of centrifugal shot peening for finish machining of laser-cut C45 steel parts allowed for obtaining a four-fold reduction in the surface roughness parameters Ra and Rz. As a result of shot peening, the geometrical structure of the surface of the steel parts was modified and it acquired new beneficial features, such as large values of the rounding radii of the micropeaks and high material ratios (Rmrmax = 92%). At the same time, the surface layer was hardened (microhardness increased by 16%) and a compressive residual stress layer was produced on the surface of the workpieces. Additionally, as the shot impacted the processed surface, combustion products were “blasted” or “sheared” off it. Shot peening using the proposed technique can be successfully performed while using CNC machines.

Molecular Dynamics Simulation of Shot Peening Process and Residual Stress Generation: Effects of Particle Impact Speed and Impinging Angle

2014 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Xinnan Wang
Keyword(s):  
Molecular Dynamics ◽  
Residual Stress ◽  
Stress Distribution ◽  
Shot Peening ◽  
Md Simulation ◽  
Stress Generation ◽  
Dynamics Simulation ◽  
Surface Finishing ◽  
In Situ Observation ◽  
The Impact

Shot peening is a well-known surface finishing process that is often applied to enhance the residual stress distribution in the component surfaces. In this study, we carry out a molecular dynamics (MD) simulation study to investigate the single particle shot peening process on the (100) silicon surface at nano scale. The MD simulation enables in-situ observation and analysis of complex material deformation mechanisms in the presences of ultra-high strain rate, such as stress distribution, dislocation propagation, and particle/workpiece interface interaction. Three levels of shot speed (i.e., 200, 500, and 800 m/s) and three levels of impinging angle (i.e., 30°, 60°, and 90°) are configured in the simulation. It is found that higher shot speeds result in deeper depths of residual indentation, deeper penetration depths of residual stress below surface, and higher magnitude of maximum compressive stress. The residual stress distributions underneath the shot-peened surfaces exhibit strong anisotropic manner. Residual stress only concentrates in the area along the impact direction; and the decrease of impact angle results in shallower penetration of residual stress.

scholarly journals Numerical Investigation on the Ultimate Strength of Box Beams with Impact Damage

2020 ◽  
Author(s):  
Wei Xu ◽  
C. Guedes Soares
Keyword(s):  
Residual Stress ◽  
Ultimate Strength ◽  
Impact Damage ◽  
Ship Hulls ◽  
Four Point Bending ◽  
Impact Location ◽  
Box Beam ◽  
Box Beams ◽  
Fracture Damage ◽  
The Impact

AbstractThe objective of this paper is to study the residual ultimate strength of box beams with impact-induced damage, as a model of what may occur in ship hulls. The bottom and side plates of ship hulls can suffer denting or fracture damage due to grounding, collision and other contacts during the ship’s service life and these impact-induced damages could result in considerable strength degradation. Box beams are firstly subjected to impact loading and then four-point bending loading is imposed on the damaged structures to assess the residual strength using ANSYS/LS_DYNA. The ultimate moment and collapse modes are discussed considering the effect of impact location. The impact-induced deformation is introduced in the four-point bending simulation, and the impact-induced stress is included or not to determine the effect of residual stress and distortion after impact. It is shown that impact location has significant influence on the residual ultimate bending moment of the damaged box beam providing that the impact energy is kept constant. The collapse modes also change when the impactor strikes on different locations. Damaged hard corner and inclined neutral axes might explain the reduction of ultimate strength and diverse collapse modes. The residual stress in the box beam after impact may increase or decrease the ultimate strength depending on impact location.

Residual Stresses in Intrinsic UD-CFRP-Steel-Laminates - Experimental Determination, Identification of Sources, Effects and Modification Approaches

2015 ◽  
Vol 825-826 ◽  
pp. 369-376 ◽  
Author(s):  
Robert Prussak ◽  
Daniel Stefaniak ◽  
Christian Hühne ◽  
Michael Sinapius
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Tensile Strength ◽  
Epoxy Composite ◽  
Thermal Residual Stress ◽  
Fiber Metal Laminates ◽  
Fiber Metal ◽  
Impact Energies ◽  
The Impact ◽  
Specific Impact

This paper focuses on the reduction of process-related thermal residual stress in fiber metal laminates and its impact on the mechanical properties. Different modifications during fabrication of co-cure bonded steel/carbon epoxy composite hybrid structures were investigated. Specific examinations are conducted on UD-CFRP-Steel specimens, modifying temperature, pressure or using a thermal expansion clamp during manufacturing. The impact of these parameters is then measured on the deflection of asymmetrical specimens or due yield-strength measurements of symmetrical specimens. The tensile strength is recorded to investigate the effect of thermal residual stress on the mechanical properties. Impact tests are performed to determine the influence on resulting damage areas at specific impact energies. The experiments revealed that the investigated modifications during processing of UD-CFRP-Steel specimens can significantly lower the thermal residual stress and thereby improve the tensile strength.

scholarly journals Assessing the regional impacts of Mexico City emissions on air quality and chemistry

2009 ◽  
Vol 9 (11) ◽  
pp. 3731-3743 ◽  
Author(s):  
M. Mena-Carrasco ◽  
G. R. Carmichael ◽  
J. E. Campbell ◽  
D. Zimmerman ◽  
Y. Tang ◽  
...  
Keyword(s):  
Air Quality ◽  
Mexico City ◽  
Ozone Production ◽  
Anthropogenic Aerosol ◽  
Near Surface ◽  
Mixing Ratios ◽  
Regional Impacts ◽  
Photolysis Rates ◽  
Regional Air Quality ◽  
The Impact

Abstract. The impact of Mexico City (MCMA) emissions is examined by studying its effects on air quality, photochemistry, and on ozone production regimes by combining model products and aircraft observations from the MILAGRO experiment during March 2006. The modeled influence of MCMA emissions to enhancements in surface level NOx, CO, and O3 concentrations (10–30% increase) are confined to distances <200 km, near surface. However, the extent of the influence is significantly larger at higher altitudes. Broader MCMA impacts (some 900 km Northeast of the city) are shown for specific outflow conditions in which enhanced ozone, NOy, and MTBE mixing ratios over the Gulf of Mexico are linked to MCMA by source tagged tracers and sensitivity runs. This study shows that the "footprint" of MCMA on average is fairly local, with exception to reactive nitrogen, which can be transported long range in the form of PAN, acting as a reservoir and source of NOx with important regional ozone formation implications. The simulated effect of MCMA emissions of anthropogenic aerosol on photochemistry showed a maximum regional decrease of 40% in J[NO2→NO+O], and resulting in the reduction of ozone production by 5–10%. Observed ozone production efficiencies are evaluated as a function of distance from MCMA, and by modeled influence from MCMA. These tend to be much lower closer to MCMA, or in those points where modeled contribution from MCMA is large. This research shows that MCMA emissions do effect on regional air quality and photochemistry, both contributing large amounts of ozone and its precursors, but with caveat that aerosol concentrations hinder formation of ozone to its potential due to its reduction in photolysis rates.

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