Enhanced Surface Residual Compression of Carburized Steel Parts Using Laser Peening Process With Preload

2014 ◽  
Author(s):  
Zhichao (Charlie) Li ◽  
B. Lynn Ferguson
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Laser Peening ◽  
X Ray Diffraction ◽  
Carburized Steel ◽  
Initiation And Propagation ◽  
Quench Hardening ◽  
Enhanced Surface ◽  
Compressive Residual Stresses ◽  
Residual Compression

Residual stresses are critical to the fatigue performance of parts. In general, compressive residual stress in the surface is beneficial, and residual tension is detrimental because of the effect of stress on crack initiation and propagation. Carburization and quench hardening create compressive residual stresses in the surface of steel parts. The laser peening process has been successfully used to introduce residual compression to the surface of nonferrous alloy parts. However, the application on carburized steel parts has not been successful so far. The application of laser peening on carburized steel parts is limited due to two main reasons: 1) the high strength and low ductility of carburized case, and 2) the compressive residual stresses in the surface of the part prior to laser peening. In this paper, the carburization, quench hardening, and laser peening processes are integrated using finite element modeling. The predicted residual stresses from quench hardening and laser peening are validated against residual stresses determined from X-ray diffraction measurements. An innovative concept of laser peening with preload has been invented to enhance the residual compression in a specific region of laser peened parts. This concept is proved by FEA models using DANTE-LP.

Investigation of Residual Stresses in a Sleeve Coldworked Lug Specimen by Neutron and X-ray Diffraction

1994 ◽  
Vol 38 ◽  
pp. 455-461
Author(s):  
R. Lin ◽  
B. Jaensson ◽  
T. M. Holden ◽  
R. B. Rogge ◽  
J. H. Root
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Cracks ◽  
Fatigue Properties ◽  
Aircraft Industry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initiation And Propagation ◽  
Structural Parts ◽  
Compressive Residual Stresses

Sleeve coldworking (SCW) is a mechanical process used in the aircraft industry to strengthen fastener holes of structural parts. By cold-expanding the holes, compressive residual stresses and a high dislocation density are introduced around the holes, the effect of which is to counteract the initiation and propagation of fatigue cracks and thus increase the fatigue life of the parts. The knowledge of residual stress due to SCW is therefore crucial for assessing the fatigue properties of a treated part. In this study, residual stresses were investigated, by employing neutron and X-ray diffraction methods, in a lug specimen that was sleeve coldworked and fatigued. The specimen had been used for testing the influence of the SCW process on fatigue life and crack propagation behaviour under constant amplitude or variable amplitude cyclic loading.

scholarly journals Effect of Laser Peening with a Microchip Laser on Fatigue Life in Butt-Welded High-Strength Steel

2021 ◽  
Vol 2 (4) ◽  
pp. 878-890
Author(s):  
Tomoharu Kato ◽  
Yoshihiro Sakino ◽  
Yuji Sano
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
High Strength Steel ◽  
Welded Joint ◽  
Base Material ◽  
High Strength ◽  
Microchip Laser ◽  
Laser Peening ◽  
Near Surface ◽  
Compressive Residual Stresses

Laser peening introduces compressive residual stresses on the surfaces of various materials and is effective in enhancing fatigue strength. Using a small microchip laser, with energies of 5, 10, and 15 mJ, the authors applied laser peening to the base material of an HT780 high-strength steel, and confirmed compressive residual stresses in the near-surface layer. Laser peening with a pulse energy of 15 mJ was then applied to fatigue samples of an HT780 butt-welded joint. It was confirmed that laser peening with the microchip laser prolonged the fatigue life of the welded joint samples to the same level as in previous studies with a conventional laser.

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

Influence of Milling Parameters on Surface Residual Stresses of 7050-T7451 Aluminum Alloy

2012 ◽  
Vol 723 ◽  
pp. 208-213 ◽  
Author(s):  
Yi Wan ◽  
Chen Li ◽  
Zhan Qiang Liu ◽  
Shu Feng Sun
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Orthogonal Direction ◽  
Mechanical Coupling ◽  
Surface Residual Stresses ◽  
Compressive Residual Stresses

Residual stresses generated in milling process affect the performance of machined components. Milling residual stresses correlate closely with the cutting parameters. In this paper, the generation and distribution of surface residual stresses in milling of aluminum alloy 7050-T7451 was investigated. The cutting speed changes from 300m/min to 3000m/min. In the experiments, the residual stresses on the surface of specimen are detected by X-ray diffraction technique. The result shows that compressive residual stresses are generated when cutting speed is under 500 m/min. In feed and its orthogonal direction, the effect of cutting speed and feed rate on residual stresses is similar. The formation of the residual stresses can be explained by thermo-mechanical coupling effects.

Short Crack Propagation Model Applied to Shot Peened Aluminium Alloys

2009 ◽  
Vol 65 ◽  
pp. 53-61 ◽  
Author(s):  
J. Solis ◽  
J. Oseguera-Peña ◽  
I. Betancourt
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Aluminium Alloys ◽  
Micromechanical Model ◽  
High Strength ◽  
Crack Arrest ◽  
Propagation Model ◽  
Safe Load ◽  
Compressive Residual Stresses

The Navarro-Rios micromechanical model was used to assess the bounds of two different damage zones: crack arrest region and crack propagation region of controlled shot peening (CSP) of high strength aluminium alloys. Performance of CSP in terms of fatigue resistance was investigated. This comparison indicated that CSP in terms of fatigue depends on the competition between its beneficial and detrimental products, i.e. surface roughness and compressive residual stresses respectively. The gathered information can be used for safe load determinations in design.

High Toughness Ceramic Laminates by Design of Residual Stresses

2001 ◽  
Vol 702 ◽  
Author(s):  
Nina A. Orlovskaya ◽  
Jakob Kuebler ◽  
Vladimir I. Subotin ◽  
Mykola Lugovy
Keyword(s):  
Fracture Toughness ◽  
Residual Stresses ◽  
Damage Tolerance ◽  
High Strength ◽  
Ceramic Composites ◽  
Tensile Stresses ◽  
High Toughness ◽  
Apparent Fracture Toughness ◽  
Layered Ceramics ◽  
Compressive Residual Stresses

ABSTRACTMultilayered ceramic composites are very promising materials for different engineering applications. Laminates with strong interfaces can provide high apparent fracture toughness and damage tolerance along with the high strength and reliability. The control over the mechanical behavior of laminates can be obtained through design of residual stresses in separate layers. Here we report a development of tough silicon nitride based layered ceramics with controlled compressive and tensile stresses in separate layers. We design laminates in a way to achieve high compressive residual stresses in thin (100-150 micron) Si3N4 layers and low tensile residual stresses in thick (600-700 micron) Si3N4-TiN layers. The residual stresses are controlled by the amount of TiN in layers with residual tensile stresses and the layers thickness. The fracture toughness of pure Si3N4(5wt%Y2O3+2wt%Al2O3) ceramics was measured to be of 5 MPa m1/2, while the apparent fracture toughness of Si3N4/Si3N4-TiN laminates was in the range of 7-8 MPa m1/2 depending on the composition and thickness of the layers.

Residual Stresses in Multilayer Welds with Different Martensitic Transformation Temperatures Analyzed by High-Energy Synchrotron Diffraction

2011 ◽  
Vol 681 ◽  
pp. 37-42 ◽  
Author(s):  
Arne Kromm ◽  
Thomas Kannengiesser ◽  
Jens Altenkirch ◽  
Jens Gibmeier
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Residual Stresses ◽  
Weld Metal ◽  
High Energy ◽  
X Ray Diffraction ◽  
Surface Areas ◽  
Transformation Mechanisms ◽  
Positive Effect ◽  
Compressive Residual Stresses

Low Transformation Temperature (LTT) alloys were developed in order to control the residual stress development by the martensitic phase transformation already during cooling of the weld metal. The positive effect of such LTT alloys on the mitigation of detrimental tensile residual stresses during welding has already been confirmed on the basis of individual laboratory tests. Within the current project it was experimentally investigated whether the phase transformation mechanisms are effective under increased restraint due to multi-pass welding of thicker specimens. The local residual stress depth distribution was analyzed non-destructively for V-type welds processed by arc welding using energy dispersive synchrotron X-ray diffraction (EDXRD). The use of high energy (20 keV to 150 keV) EDXRD allowed for the evaluation of diffraction spectra containing information of all contributing phases. As the investigated LTT alloy contains retained austenite after welding, this phase was also considered for stress analysis. The results show in particular how the constraining effect of increased thickness of the welded plates and additional deposited weld metal influences the level of the residual stresses in near weld surface areas. While the longitudinal residual stresses were reduced in general, in the transition zone from the weld to the heat-affected zone (HAZ) compressive residual stresses were found.

scholarly journals Numerical Analysis and Experimental Studies on the Residual Stress of W/2024Al Composites

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2746 ◽  
Author(s):  
Guosong Zhang ◽  
Changhui Mao ◽  
Jian Wang ◽  
Ning Fan ◽  
Tiantian Guo
Keyword(s):  
Residual Stress ◽  
Numerical Analysis ◽  
Residual Stresses ◽  
Experimental Studies ◽  
High Strength ◽  
Radiation Shielding ◽  
X Ray Diffraction ◽  
Transfer Coefficients ◽  
Medium Temperature ◽  
Heat Transfer Coefficients

W/2024Al composites can be used for radiation shielding with desirable mechanical properties such as high strength, excellent corrosion resistance, and low density. The quench-induced residual stresses in W/2024Al composites were studied by experimental measurements and numerical analysis using ABAQUS software. Due to the accurate calculation of heat transfer coefficients and the established constitutive equation for description of the variation of yield stress at elevated temperature with different strain rates, the prediction of residual stresses in as-quenched composite blocks achieved by finite element method (FEM) is reliable. Moreover, X-ray diffraction and crack-compliance method were carried out to measure the stresses that developed at the surface and interior of the composites to validate the simulation results. Quenching residual stresses of composite blocks were investigated by taking the influence of quenching medium temperature into consideration. In addition, a comparative study on residual stress magnitudes of as-quenched 2024Al and W/2024Al composites was conducted, and the results show that stress magnitudes of W/2024Al composites are lower than that of 2024Al due to lower thermal gradients during the quenching process.

scholarly journals A Mechanism for Inducing Compressive Residual Stresses on a Surface by Laser Peening without Coating

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 816 ◽  
Author(s):  
Yuji Sano ◽  
Koichi Akita ◽  
Tomokazu Sano
Keyword(s):  
Single Pulse ◽  
Laser Pulses ◽  
Mechanical Effect ◽  
Intense Laser ◽  
Laser Peening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intense Laser Pulses ◽  
Laser Peening Without Coating ◽  
Compressive Residual Stresses

Laser peening without coating (LPwC) involves irradiating materials covered with water with intense laser pulses to induce compressive residual stress (RS) on a surface. This results in favorable effects, such as fatigue enhancement; however, the mechanism underlying formation of the compressive RS is not fully understood. In general, tensile RS is imparted on the surface of the material due to shrinkage after heating by laser irradiation. In this study, we assessed the thermo-mechanical effect of single laser pulse irradiation and introduce a phenomenological model to predict the outcome of LPwC. To validate this model, RS distribution across the laser-irradiated spot was analyzed using X-ray diffraction with synchrotron radiation. In addition, the RS was evaluated across a line and over an area, following irradiation by multiple laser pulses with partial overlapping. Large tensile RSs were found in the spot irradiated by the single pulse; however, compressive RSs appeared around the spot. In addition, the surface RS state shifted to the compressive side due to an increase in overlap between neighboring laser pulses on the line and over the area of irradiation. The compressive RSs around a subsequent laser spot effectively compensated the tensile component on the previous spot by controlling the overlap, which may result in compressive RSs on the surface after LPwC.

Effect of Nozzle-Traveling Velocity on Oil Cavitation Jet Peening of Aluminum Alloy, AA 6063-T6

2007 ◽  
Vol 129 (4) ◽  
pp. 609-613 ◽  
Author(s):  
A. Sahaya Grinspan ◽  
R. Gnanamoorthy
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Cavitation Number ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compressive Stresses ◽  
Modification Process ◽  
Oil Jet ◽  
The Impact ◽  
Compressive Residual Stresses

A new surface modification process was developed to introduce compressive residual stresses at the surface of components. In this process, instead of oil droplets a high-velocity cavitation jet (cloud of oil bubbles) impinges on the surface of the component to be peened. The impact pressure generated during implosion of cavitation bubbles causes severe plastic deformation at the surface. Consequently, beneficial compressive stresses are developed at the surface. In order to find the potential of this process, aluminum alloy AA6063-T6 specimens were peened at a constant cavitation number with various nozzle-traveling velocities. Residual stress induced by oil jet cavitation peening was measured using X-ray diffraction. Oil cavitation jet peening results in a smooth and hard surface. The developed compressive residual stresses at the peened surface are about 52%, 42%, and 35% of yield strength in samples for peened at nozzle traveling velocities of 0.05mm∕s, 0.10mm∕s, and 0.15mm∕s, respectively.

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