The Effect of Shot Peening on the Surface Topography and Fatigue Strength of Selected Sheets

2015 ◽  
Vol 818 ◽  
pp. 19-22
Author(s):  
Łukasz Bąk ◽  
Magdalena Bucior ◽  
Felix Stachowicz ◽  
Władysław Zielecki
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Shot Peening ◽  
Experimental Tests ◽  
Special Treatment ◽  
Surface Layers ◽  
Impact Bending ◽  
Improve Fatigue Strength ◽  
Compressive Residual Stresses ◽  
Improve Fatigue

Numerous investigations have been performed in an attempt to improve fatigue strength of materials by creating compressive residual stresses in the surface layers as a result of the shot peening process. For example, during exploitation of the separating screener, some parts of screen sieve plate situated near the fixed edge undergo the largest deformation caused by impact bending and need special treatment. In this paper, the results of experimental tests are presented to analyse the effect of micro shot peening on surface layer characteristics and fatigue strength of steel sheet specimens. The effect of shot peening is more visible when fatigue life is taking into account. Thus, the use of shot peening of sheet surface made it possible to increase fatigue life of screener sieve.

scholarly journals Effect of Oil – Corrosion on Tensile and Fatigue S-N Curve Properties of AA6061-T6

2021 ◽  
Vol 39 (3A) ◽  
pp. 407-414
Author(s):  
Hussain J.M. Al-Alkawi ◽  
Ghgada A. Aziz ◽  
Shmoos R. Mazel
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Corrosion Fatigue ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Surface Layers ◽  
Compressive Residual Stresses ◽  
Behavior Strength

The present study described the effect of shot peening on mechanical properties and rotating corrosion –fatigue behavior (strength and life) of AA6061-T6. Ultimate tensile strength (UTS) and yield stress (YS) were reduced by 4.6% and 1.24% when immersing the tensile samples in crude oil for 60 days. The values of (UTS) and (YS) were raised from 307 to 316 MPa and from 248 to 254 MPa respectively when treated for 10 min. shot peening (SP). Hardness of oil corrosion samples dropped due to pitting corrosion and slightly raised for SP prior to corrosion samples. Oil corrosion reduced the fatigue strength by (-1.25%). This percentage was enhanced due to SP to 2.377%. SP significantly increased the rotating fatigue life by a factor of 1.19 and 1.3 at (UTS) and (Ys) loads respectively. (SP) technique improved corrosion-fatigue resistance due to producing compressive residual stresses at surface layers.

Exploring Autofrettage Process to Improve the Fatigue Life on High-Pressure Cylinder

2013 ◽  
Vol 457-458 ◽  
pp. 518-521
Author(s):  
Feng Ling Yang ◽  
Shi Jin Zhang
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Analysis ◽  
High Pressure Cylinder ◽  
Pressure Cylinder ◽  
Surface Variation ◽  
Life Improvement ◽  
Improve Fatigue Strength ◽  
Improve Fatigue

Autofrettage process is now widely used to improve fatigue strength of high pressure components. This paper focuses on the fatigue life improvement of the high-pressure cylinder treated by autofrettage process. In this process, a high pressure cylinder treated by autofrettage process has been simulated by using FEA software, and surface variation of the cylinder has been analyzed. To further understand this process, theoretical fatigue analysis has also been carried out.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

The Structure and Mechanical Properties of VT23 Welded Joints with Surface Layer Modified by Ultrasonic Mechanical Forging

2017 ◽  
Vol 743 ◽  
pp. 264-268 ◽  
Author(s):  
Anastasia Smirnova ◽  
Yury Pochivalov ◽  
Victor Panin ◽  
Anatoly Orishich ◽  
Aleksandr Malikov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Welded Joints ◽  
Experimental Tests ◽  
Relaxation Property ◽  
Surface Layers ◽  
Β Phase ◽  
Fatigue Life Test ◽  
Vt23 Titanium Alloy

The structure and mechanical properties of welded joints of VT23 titanium alloy received by method of laser welding after modifying the surface layers by ultrasonic mechanical forging (Treatment 1 and Treatment 2) were investigated. The experimental tests have revealed that the Treatment 2 provides a multiple increase in the relaxation property in fatigue life test. The formation of nonuniform distribution of vanadium, chromium and molybdenum in the welded joint increases the strength and, at the same time, the brittleness of β-phase. Mechanical treatment of the surface layers in the second mode provides a multiple increase in ductility up to 13%, in the as-received condition up to 9.9%. In consequence of plastic deformation, the β-phase intensity reduces twice with Treatment 2 which is related to its clustering. As follows from a presented data, the fatigue life of the VT23 titanium alloy has increased more than threefold.

scholarly journals Experimental Investigation on the Effect of Shot Peening and Deep Rolling on the Fatigue Response of High Strength Fasteners

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1093 ◽  
Author(s):  
Reggiani
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Published Data ◽  
Deep Rolling ◽  
Beneficial Impact ◽  
The Impact ◽  
Fatigue Life Enhancement

Shot-peening and deep rolling are mechanical surface treatments that are commonly applied to enhance the fatigue performances of components, owing to their capacity to generate compressive residual stresses and induce work hardening. However, literature is still poor of published data concerning the application of these treatments to high strength steels fasteners, although these represent a class of components among the most widespread. In the present work, the impact of deep rolling and shot-peening performed in the underhead radius of two set of fasteners made of 36NiCrMo and 42CrMoV for fatigue life enhancement has been investigated. The experimental tests consisted of six combinations of shot-peening and deep rolling, including the non-treated state. Two test campaigns have been sequentially carried out with different process parameters and treatment sequences. The results always showed a beneficial impact of the deep rolling on fatigue, especially for the 42CrMoV steel. Conversely, the effect of the shot-peening strongly depended on the selected set of parameters, alternatively leading to an improvement or a worsening of the fatigue life in relation to the level of induced surface roughness.

An Integrated DEM-FEM Model for Shot Peening Applications

2019 ◽  
Author(s):  
Dhanooj Bobba ◽  
Praveen Ramaprabhu ◽  
Harish P. Cherukuri
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Spherical Particles ◽  
Surface Layers ◽  
High Speeds ◽  
Compressive Stresses ◽  
Almen Intensity ◽  
Parametric Studies ◽  
Coupled Technique ◽  
Element Method

Abstract Shot peening is a commonly used technique for improving the fatigue life of machine components by inducing compressive residual stresses in the surface layers. This process involves plastically deforming the surface layers by impacting with spherical particles at high speeds. The induced residual compressive stresses resist crack propagation and thus increase the fatigue life. The intensity of shot peening, measured using the Almen test, is an essential quantity for ensuring shot peening effectiveness and repeatability. It depends on various process parameters such as the shot speed, shot size, shot material, impact direction, and flow rate. In this study, a novel computational model is developed to simulate the Almen intensity tests on a Type-C strip accurately. The model uses a coupled technique based on the discrete element method (DEM) and the conventional finite element method (FEM). The predicted Almen intensity values agree with analytically calculated values. Results from the parametric studies conducted to analyze the influence of various parameters on the Almen intensity indicate that many different combinations of these parameters can obtain a given Almen intensity although the residual stress fields may vary.

scholarly journals Fatigue improvement of welded elements by ultrasonic impact treatment

2020 ◽  
Vol 65 (4) ◽  
pp. 179-190
Author(s):  
Yuir Kudryavtsev
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Large Scale ◽  
Fatigue Testing ◽  
Fatigue Improvement ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of tensile residual stresses and introducing of compressive residual stresses into surface layers of a material. The secondary factors in fatigue improvement by UIT/UP are decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. Fatigue testing of welded specimens showed that UIT/UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UIT/UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The results of fatigue testing of large-scale welded specimens in as-welded condition and after application of UIT/UP are considered in this paper. It is shown that UIT/UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

Mechanical Behavior and Fatigue Performance of Carburized Steel Specimens

2016 ◽  
Vol 853 ◽  
pp. 72-76
Author(s):  
Ke Ji Pang ◽  
Huang Yuan
Keyword(s):  
Mechanical Property ◽  
Fatigue Life ◽  
Fracture Strain ◽  
Base Material ◽  
Fatigue Performance ◽  
Mechanical Parts ◽  
Carburized Steel ◽  
Carburized Layer ◽  
Compressive Residual Stresses ◽  
Improve Fatigue

Carburization is popular in design and fabrication of mechanical parts, such as gears, to improve fatigue performance. However, it is still open how to characterize the mechanical property of carburized steel and to quantify effects of the carburization to fatigue life of carburized parts. In the present paper four types of specimens differently treated and carburized are experimentally investigated. The experiments confirm significant increments in hardness and yield stress due to carburization. The fracture strain of the carburized steel is significantly smaller than that of the base material. Although the fatigue performance of the carburized steel is slightly worse than the base material, the solid carburized specimen shows significantly longer fatigue life. The fatigue limit increases from ca. 300 MPa for the base material to 550 MPa for the tensile carburized specimens. Detailed measurements display that the carburized layer in a carburized specimen possesses high compressive residual stresses, which arises the fatigue performance of the carburized steel.

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