The Effect of Microalloying on HAZ Toughness
Abstract:
The factors affecting HAZ toughness of modem structural and linepipe steels, microalloyed with Nb, V and Ti have been examined. Critical features include solubility, particle coarsening and dissolution rates, austenite grain size, transformation characteristics, microstructure development and precipitation hardening. Data are presented which demonstrate the effects of Nb, V and Ti on the toughness of the coarse grained region of the HAZ. This indicates that at low heat inputs the weldability of Nb and V microalloyed steels is similar to that of C-Mn steels but that vanadium microalloyed steels appear to be more tolerant to increases in heat input. Improvements in HAZ toughness can be obtained by the addition of titanium, which may be as a result of formation of TiN and/or an oxide of titanium.
Keywords:
vanadium, steel, HAZ.
Author:
P. S. Mitchell (1), P. H. M. Hart (2) and Dr. W. B. Morrison (3)
Affiiation
(1) VANITEC
(2) The Welding Institute
(3) British Steel Pie, Swinden Technology Centre
PDF:
Source:
Microalloying 95”, Pittsburgh, PA, USA, 11-14 June 1995, pp.149-162 (Vanitec Publication - V0295)
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