The Paton Welding Journal, 2014, №05



2014 №05 (08)

DOI of Article 10.15407/tpwj2014.05.01

2014 №05 (02)

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The Paton Welding Journal, 2014, #5, 2-9 pages  

EFFECT OF CYCLIC LOAD ON MICROSTRUCTURE AND COLD RESISTANCE OF THE 10G2FB STEEL HAZ METAL

V.D. POZNYAKOV, L.I. MARKASHOVA, A.A. MAKSIMENKO, E.N. BERDNIKOVA, T.A. ALEKSEENKO and S.B. KASATKIN

E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
Fatigue of structural materials is one of the main reasons of breakdown and failure of machines, mechanisms and engineering structures. Fatigue cracks in the welded joints are mainly nucleated in a HAZ, and process of their accumulation has long-term and phasic nature. Aim of the present work lies in investigation of effect of cyclic bending load on change of structure and properties of metal of HAZ in the welded joints of C490 strength class structural steel. Dynamics of accumulation of fatigue damages in the metal was investigated, and effect of cyclic load on cold resistance of the metal of HAZ in 10G2FB steel was estimated using model specimens, treated by welding thermal cycle. It is determined that formation of the fatigue cracks in welded joints as well as model specimens is proceeded by the processes of accumulation of fatigue damages in form of stable slip bands of different configuration as well as formation of extrusions and intrusions. The damages, accumulated in HAZ metal of low-alloy structural steels due to fatigue, promote embrittlement of the metal that results in reduction of its cold resistance. The results of investigations can be used as a basis for methods of testing of welded joints in metal structures of long-term operation as well as for taking the decisions on their strengthening or repair. 15 Ref., 9 Figures.
 
 
Keywords: arc welding, 10G2FB steel, welding thermal cycles, model specimens, heat-affected zone, cyclic bending load, structural changes, fatigue cracks, impact toughness
 
 
Received:                21.12.13
Published:               28.05.14
 
 
References
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