The Paton Welding Journal, 2014, №05



2014 №05 (03)

DOI of Article 10.15407/tpwj2014.05.04

2014 №05 (05)

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The Paton Welding Journal, 2014, #5, 21-27 pages  

INCREASE OF FATIGUE RESISTANCE OF SHEET WELDED JOINTS OF ALUMINUM ALLOYS USING HIGH-FREQUENCY PEENING

V.V. KNYSH, I.N. KLOCHKOV, M.P. PASHULYA and S.I. MOTRUNICH

E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
A work is dedicated to experimental investigation of dependencies of fatigue resistance of sheet (d = 2-3mm) welded joints of average and high strength aluminum alloys, which were produced using consumable-electrode pulsed-arc welding in inert gases (PMIG) as well as determination of efficiency of rise of their fatigue life through application of high-frequency mechanical peening (HFMP) by set parameters of strengthening. Efficient parameters of HFMP strengthening of sheet welded joints with the help of portable manual equipment USP-300 were determined based on measurement of microhardness, local geometry parameters of weld and angular residual lipping distortion. Influence of HFMP of zone of weld to base metal transition on measurement of stress concentration factor, welding residual stresses and structure of surface layer of butt joints of small thickness aluminum alloys was investigated. It is shown that increase of radius of weld to base metal transition and elimination of angular residual lipping distortion after HFMP treatment provides for 1.35-1.49 reduction of stress concentration factor in the joints. It is determined that life on the basis of testing 2р106cycles of stress alternation for strengthened butt joints from D16T alloy shows 5 times rise, that for AMg6 alloy makes 4 times and 7 times for 6061-T6 alloy in comparison with initial as-welded condition. The recommendations are given on efficient HFMP strengthening of sheet welded joints for increase of their fatigue life and elimination of residual welding deformations. 15 Ref., 2 Tables, 11 Figures.
 
 
Keywords: welded joint, high-cycle fatigue, aluminum alloys, fatigue life, high-frequency mechanical peening, consumable-electrode pulsed-arc welding, increase of fatigue resistance
 
 
Received:                21.01.14
Published:               28.05.14
 
 
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