Fatigue Improvement of Welded Elements and Structures by Ultrasonic Peening

2013 ◽  
Author(s):  
Yuri Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Fatigue Improvement ◽  
Surface Layers ◽  
Ultrasonic Peening ◽  
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 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 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 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.

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.

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.

Benefits of Ultrasonic Peening Treatment in Fatigue Improvement of Welded Elements

2012 ◽  
Author(s):  
Jacob Kleiman ◽  
Yuri Kudryavtsev ◽  
Alexander Lugovskoy
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Loading ◽  
Surface Layers ◽  
Ultrasonic Peening ◽  
Weld Toe

The Ultrasonic Peening (UP) is one of new and promising processes for fatigue life improvement of welded elements and structures. During the different stages of its development the UP process was also known as ultrasonic treatment (UT), ultrasonic impact treatment (UIT), ultrasonic impact peening (UIP). The beneficial effect of UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The results of fatigue testing of welded elements made of regular and high strength steels in as-welded condition and after application of UP will be presented. The yield strength of considered materials varied from 250–350 MPa to 700–1000 MPa. 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 increased fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used. It allows using to a greater degree the advantages of the HSS in welded elements, subjected to fatigue loading.

Underwater Stress Relief and Fatigue Improvement by Ultrasonic Peening

2012 ◽  
Author(s):  
Jacob Kleiman ◽  
Yuri Kudryavtsev ◽  
Alexander Lugovskoy
Keyword(s):  
Residual Stresses ◽  
Stress Relief ◽  
Fatigue Improvement ◽  
Water Cooling ◽  
Surface Layers ◽  
Welded Structures ◽  
Ultrasonic Peening ◽  
Weld Toe ◽  
Life Improvement ◽  
Compressive Residual Stresses

A new ultrasonic peening instrument was developed for underwater treatment of welds and welded structures. The Ultrasonic Peening (UP) established itself as a promising process for fatigue life improvement of welded elements and structures. The beneficial effect of UP is obtained through relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of materials, and through decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the materials. In the design of the underwater UP instrument specially selected anti-corrosion materials are used. The underwater UP instrument can be used for treatment of welds at depths up to 30 meters or, if required, with certain modifications, even deeper. Acoustic pump principle is used in the originally developed system for water cooling of the transducer. The developed UP system allows for improvement treatments at four different power levels and is using replaceable working heads that come in various configurations with variable numbers of pins, depending on the application.

State-of-the-Art: Fatigue Life Extension of Offshore Installations

2012 ◽  
Author(s):  
Luis Lopez Martinez ◽  
Zuheir Barsoum ◽  
Anna Paradowska
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Test ◽  
Welded Joints ◽  
Life Extension ◽  
Stress Concentrations ◽  
Weld Geometry ◽  
Compressive Stresses ◽  
Ultrasonic Peening

The use of fatigue life improvement techniques and specifically ultrasonic peening treatment to extend the service life of offshore structures has become an accepted practice during the last five years. The understanding of the process as well as equipment’s upgrading for treatment in-situ including quality control and assurance have been developed up to a level that it has become a current practice in many parts of the world. However, the efficiency of the ultrasonic peening is strictly dependent on the deep understanding of significant fatigue parameters as weld defects, stress concentrations and residual stresses and their interaction. In this paper we attempt to present the current knowledge and the physical reasons why the ultrasonic peening treatment is able to improve the fatigue life of welded joints. The local weld geometry or stress concentration, weld imperfections as well as welding residual stresses are all modified and improved by the application of ultrasonic peening. Local weld geometry and weld process inherent weld imperfections are the factors primarily influencing the fatigue strength in welded joints. Comprehensive studies have been carried out during the last 20 years in order to detect and document the weld defects as well as to understand their origin and effect on the fatigue strength of welds. Analogous efforts have been dedicated to understand and document the influence of local weld geometries on the stress concentrations and its influence on endurance and structural integrity. Similarly, efforts have been done to understand the influence of the relaxation by external loads of the by the ultrasonic peening treatment induced compressive stresses. Fatigue test results of ultrasonic peening treated relevant weld details have been used to assess the potential life extension. The results showed four to six times fatigue life extension. The spectrum fatigue test was designed to confirm that relaxation by service loads of the induced compressive stresses during ultrasonic peening treatment would not diminish the benefit.

Fatigue Life Improvement Using Mechanical Post Treatment for Weldment

2008 ◽  
Vol 580-582 ◽  
pp. 97-100
Author(s):  
Seung Ho Han ◽  
Jeong Woo Han ◽  
Yong Yun Nam
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Quantitative Measure ◽  
Fatigue Strength Improvement ◽  
Weld Profile ◽  
Weld Toe ◽  
Life Improvement ◽  
Hammer Peening ◽  
Compressive Residual Stresses

Mechanical post treatments for welded structures have been applied in various industrial fields and, in most cases, have been found to cause substantial increase in their fatigue strength. These methods, generally, consist of the modification of weld toe geometry and the introduction of compressive residual stresses. In hammer peening, the weld profile is modified due to removal or reduction of minute crack-like flaws; compressive residual stresses are also induced by repeated hammering of the weld toe region with blunt-nosed chisel. In this study, a hammer peening procedure, using commercial pneumatic chipping hammer, was developed; a quantitative measure of fatigue strength improvement was performed. The fatigue life of hammer-peened specimen was prolonged by approximately 10 times in S=240MPa, and was doubled for the as-welded specimen.

Effects of Residual Stresses on the Fatigue Performance of Welded Steels with Longitudinal Stiffeners

2013 ◽  
Vol 768-769 ◽  
pp. 636-643 ◽  
Author(s):  
Jonas Hensel ◽  
Thomas Nitschke-Pagel ◽  
Klaus Dilger ◽  
Steffen Schönborn
Keyword(s):  
Fatigue Strength ◽  
Residual Stresses ◽  
Stress Ratio ◽  
Fatigue Testing ◽  
High Strength ◽  
Fatigue Loading ◽  
X Ray ◽  
Initial Residual Stress ◽  
Stress Relieving ◽  
Longitudinal Stiffeners

Residual stresses may affect the behavior of welded steels under fatigue loading. However, for design of welded structures the height and distribution of residual stresses from welding are often not known so that tensile residual stresses in the order of the yield strength are conservatively assumed. Here presented results focus on the influence of residual stresses on the fatigue strength of longitudinal stiffeners made from a mild steel S355NL and a high strength steel S960QL. The initial residual stress conditions were measured using X-ray and neutron diffraction. In order to characterize the influence of residual stresses on the fatigue strength, specimens were tested in the as-welded condition and after a stress relieving heat treatment. The fatigue testing was conducted under alternating constant amplitude loading with a stress ratio of R=-1.

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.

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.

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.

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