2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 3: Takano Intl. Symp. / Metals & Alloys Processing
| Editors: | Kongoli F, Noldin JH, Mourao MB, Tschiptschin AP, D'Abreu JC |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 550 pages |
| ISBN: | 978-1-987820-26-3 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Vanadium and Niobium Content Distribution across the Welded Joint during Submerged Arc Welding of Spiral Line Pipes
Rrahim Maksuti1;1UNIVERSITY OF MITROVICA, Mitrovica, Kosovo;
Type of Paper: Regular
Id Paper: 170
Topic: 3
Abstract:
Vanadium (V) and Niobium (Nb) are added in small quantities (0.01-0.1wt%) in High Strength Low-Alloy (HSLA) steels, or micro-alloyed steels, to obtain the desired mechanical properties through ferrite grain refinement and precipitation strengthening mechanisms by forming of the V(C,N) and Nb(C,N) particles.
During Submerged Arc Welding (SAW) of HSLA steels, or micro-alloyed steels, a considerable content of these micro-alloyed elements from the base metal (BM) passes through (dissolved) into the weld metal (WM) and during cooling of the weld pool, it occurs the formation of new precipitates (reprecipitation) of these micro-alloyed elements with different content of vanadium and niobium, whose acting effect in the microstructure and mechanical properties of the weld metal (WM) and heat affected zone (HAZ) is very complex and yet unclear.
The objective of this study was to determine the content distribution of vanadium (V) and niobium (Nb) across the welded joint during Submerged Arc Welding (SAW) of spiral line pipes. Three types of micro-alloyed steel were used, single micro-alloying with vanadium (V), single micro-alloying with niobium (Nb) and double micro-alloying with vanadium and niobium (V+Nb). The chemical compositions of the samples were determined using an Electron Probe Micro-analyzer (EPMA), JXA8900RL, Fa.JEOL.
The results of this research indicated that the content distribution of vanadium (V) and niobium (Nb) across the welded joint during Submerged Arc Welding (SAW) is inhomogeneous and with the decreasing tendency toward the weld metal (WM).