Automatic Welding, 2017, №10



2017 №10 (08)

DOI of Article 10.15407/as2017.10.01

2017 №10 (02)

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Avtomaticheskaya Svarka (Automatic Welding), #10, 2017, pp. 9-16
 

Peculiarities of formation of structure in welded joints of microalloyed structural steel S460M

G.M. Grigorenko, V.D. Poznyakov, T.A. Zuber and V.A. Kostin

E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazimir Malevich Str., 03150, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
Abstract
Structural steels of C440 strength class and higher have found a wide application in high-rise construction, bridge construction and freight rail transport. Application of steel roll stock with yield limit of 440 MPa allows reducing specific amount of metal per structure by 39 % in comparison with steel of St3sp (killed) (C275) grade and by 26 % in comparison with 09G2S (C345) steel grade. Present work examines the peculiarities of formation of structure in the welded joints of structural steel S460M. A CCT diagram of austenite decay in steel S460M was plotted. Effect of cooling rate of HAZ metal sample simulator on structure and strength properties was determined. It is shown that heat treatment of welded joints of steel S460M (thermal cycling, i.e. heating to 1200 °C with 25 °C/s rate plus annealing at 950 °C during 1 h plus air cooling) provides formation in HAZ metal of a favorable complex of ferrite-bainite structures due to decrease of banded structures, reduction of portion of Widmanstatten ferrite and pearlite. 8 Ref. 2 Tables, 7 Figures.
Keywords: high-strength steel, welding thermal cycle, microstructure, acicular ferrite, cooling rate, CCT diagram of austenite decay
 
Received:                16.06.17
Published:               13.11.17
 
 
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